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  #1041  
Old 07-08-2019, 04:31 PM
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I also took this opportunity to install some retracting seatbelts from Morris Classic Concepts. I already have a set of their rear belts and decided to do the front ones now as well. I actually really liked the original, non-retracting shoulder belts that tucked up along the headliner when not in use. They were good for autocross because you could cinch them down and stay very secured in the seat, but they were also a little troublesome on a daily-basis because to reach anything or turn to look out of the window, you basically had to unbuckle. In they went...





When I reinstalled the seats, I found the retractor and metal strap would hit the seatback release mechanism. All I had to do to correct this was move the retractor and metal strap to the OUTSIDE of the lower mounting bracket rather than the inside (as shown) and turn the mounting bracket slightly to angle things out away from the seat. That worked perfectly and everything clears fine now.



Here is the finished product. This shot has just the right lighting to show how the rear area of the headliner is slightly distorted from installing the shoulder belts. Normally I can't see this at all but it's shadowed enough here to make it look more pronounced. I would love it if TMI would either prelocate these holes or provide cut outs in the fiberglass in this area so the seat belt mounting locations don't distort things.



Overall I'm really happy with the quality and ease of installation for the headliner. I like that I can take it back out later and reuse it and it could even be recovered if I wanted to change interior colors or if the vinyl eventually gets damaged by age. Now I finally have a presentable interior!
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  #1042  
Old 07-08-2019, 04:32 PM
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Somewhere in the middle of all this, I did some data logging on my OBD2 reader and found my fuel trims were in the negative teens, indicating a rich condition. I also had some DTCs that didn't make sense, like a rear O2 sensor heater issue which should have been disabled in the original tune. Plus I have had a long cranking start issue from the very beginning, so I decided it would be a good time to schedule time with the tuner to see if we could clean things up. Back I went to Alex at New Era Performance in Agoura Hills after 2-1/2 years since the original tune.



Alex went right to work. Here's what she sounds like screaming on the rollers. It's so satisfying to hear and feel this thing at WOT, especially reverberating in a shop!



The car made a baseline run of 401rwhp/386ft-lb. That's down within the margin of error from 408rwhp when it was tuned a few years ago, except this time the car was able to stay in 3rd gear instead of tuning in 2nd like we did last time due to shifting problems. Alex made a few changes and ran a few more WOT pulls before this happened:



We noticed the power jumped a whopping 15hp from the previous pull and as we started the next, coolant began spouting from the overflow tank. I shouted to stop and we shut it down. The belt had come off and the engine briefly overheated. We put the belt back on and continued tuning without further issues. Here is what we ended up with:




That's a healthy 417rwhp/400ft-lb peak, but more importantly a nice wide operating range.

Alex cleared up all the DTC codes and spent a long time trying to fix the long crank startup issue, but without success. He showed me how bumping idle airflow didn't improve the situation and he thinks the issue is priming fuel pressure being bled off. I have checked fuel pressure but I'm wondering if the gauge I used had some kind of check valve in it. His suggestion was to try hot wiring the fuel pump temporarily to see if that makes a difference and if it does, maybe install a check valve inline to keep pressure at the rails between priming. I'll try that later for sure.

After leaving the shop, i took a look at the belt to see what was going on an sure enough the idler pulley wasn't lining up right. The belt was riding off the side by about 1/4" and that was also causing it to rub the lip of the crank pulley.



So I picked up some shims and a longer flange bolt from the local hardware store and got it to align nicely. I also installed a new belt and kept the old one as a spare.



With all this power, fancy retracting seatbelts, and a tight headliner, I was nearly ready to go driving but I have been missing something for a while that has been driving me crazy - a place to put my dang cup! So I picked up a cheap cup holder at the autoparts store and damn has that been nice to have!



I also needed to replace my old window shade that disintegrated after 20 years. None of these things are short enough for the upright windshield on a Nova, so I just bought a cheapy and cut it down to fit. This keeps my car cool when parked on the tarmac between runs at autocross or while I'm in the grocery store on a hot day.





I also mounted a 5lb extinguisher on my transmission tunnel where it would be secure and easy to see / grab from either side of the car in case of the worst.





And then... it was time to put the numbers back on after a 1 year hiatus...



More on that to come.
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  #1043  
Old 07-08-2019, 04:33 PM
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Thanks to keeping an eye on motorsportsreg.com, I finally found an autocross event on an open weekend and signed up in June. The event was put on by Vapor Trails Vettes at the Santa Maria Airport, about 100miles from home. I packed up the Nova and hit the road at 5am to make the drive. This would be the furthest from home I've driven the Nova since the swap and of course it would be to beat the hell out of it at autocross. I was nervous as hell!

On the way out, I pulled off the freeway and into a parking lot to pick up a special passenger - my MOM! She joined me for the road trip up and to ride along.



We hit heavy fog driving the 154 over the hills outside of Santa Barbara. I felt better knowing my LED taillights would be visible, but it was still a little scary when visibility dropped to maybe 15ft in front of the car.



After cresting the mountains, we pulled off at a vista point to see the sun rising over the clouds near Lake Cachuma.



We gassed back up in Santa Maria and made it to the airport by 7:30. My car was the only classic out there.





Vapor Trails Vettes did a good job of running the grid and timing equipment. It's always a thrill pulling up to the starting line for the first run. You'll see alternating numbers (70 and 69) in these photos because I double registered the car so my brother could drive. We each got 8 runs for a total of 16. He gave me a few of his runs, so I probably drove the car 10 or more times around the track.



I may have to Photoshop this next photo to fix the dead passenger tail light. My passenger side bulb socket was having issues due to corrosion. The Easy Performance LEDs come with a bulb-like pigtail that fits into the original socket, but after having a few problems with the socket, I think I will cut it off and add a connector to hardwire everything.



Of course on the first run I had to catch a cone. I drove aggressively throughout the day - too much so. I often blew my lines and was up against major limitations with my still-mismatched brakes.



That didn't keep me from having a great time and running faster than a lot of the modern ABS & traction control cars out there.













Here is a video from one of my better runs:



A common scenario was braking too late, locking the fronts momentarily due to the inherently bad bias (way to the front due to the original large piston calipers vs. rear small piston "LS1" calipers), and then pushing out of the corner. Even without braking, push was a major theme of the day. In hindsight I wish I had tried different rear bar settings to overcome that. Stiffening up the rear bar may have helped.

But then again, there was one run where I managed to oversteer and spin. This likely happened due to too much throttle input. I found I could compensate for understeer sometimes by getting back into the throttle and "steering" with the throttle, but I was a little too aggressive here and spun the tires. My brother caught this photo as the rear was kicking out.



One thing about autocross is every event organizer, venue, and track layout is different. The main reason I do autocross instead of track days is the relatively low speeds and low likelihood of crashing the car. This track had one big sweeping corner in the back with a scary barrier and some parked vehicles/storage. I drove a lot more conservatively entering and driving through this corner as a result.







The car did really well and I had an awesome time. I will say afterwards I looked through some of the video I took and really wish I had done that between runs - I could see a lot of obvious areas I needed to slow down and change my line or brake later or sooner. In generally when I slow down I tend to go faster.

The only issue I had was near the end of the day my passenger exhaust V-band came apart. You can see it dangling in the last photo above. The t-bolt went missing, but one of the guys happened to be a diesel mechanic and had a clamp on hand I was able to steel hardware from and put it back together. I am pretty sure the V-band was pulled off by a large lip entering the airport because on the way out, having just repaired it, the same lip pulled it back off and I had to repair it a second time before heading home. That poor v-band is just way too low on the car.

I also lost one of my center caps in one of my last runs. Luckily it came off at the same corner my brother was working and rolled right over to him. When I got back to the grid someone told me it was missing and I took the remaining ones off for the last runs. I was surprised it managed to come off because the caps are very tight, but I guess that's what 1.1g lateral does to things. Maybe the wheel heated up and/or flexed under load and sent the cap flying.

The car drove great on the 100mile trip back, but it very badly needs an overdrive transmission. With the TH400, 3.73s and 25" tall tires, it's turning about 3,500rpm at 70mph. When I get a T56 (which has a double overdrive 0.64 ratio in 6th) that will go down to a much more friendly 2,200rpm. Gas mileage is suffering tremendously.

I am ready to get back to the C6 Vette brake upgrade. Parts have been sitting for over a year now because I've been afraid of putting the car back on stands, but I pulled them all out and I'm back to work. Hopefully that 200mile plus racing trip will satisfy my thirst for driving until the brake swap is done. I'll post photos as I make progress.
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Last edited by TheBandit; 07-08-2019 at 04:39 PM.
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  #1044  
Old 07-08-2019, 09:44 PM
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Awesome report.
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  #1045  
Old 07-10-2019, 07:25 AM
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Solid update! I agree that the long form on forums is a lot nicer than IG...just takes a lot more effort on the part of the poster.

Looks like you have the "go" and "steer" parts pretty well sorted and you have a plan for "stop". 1.1 G is pretty solid for a muscle car, as is the 400+ HP at the wheels.

Any plan to include a bias adjustment as part of the brake upgrade? I think that could be really helpful for your autocross adventures.
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  #1046  
Old 07-10-2019, 12:33 PM
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Thank you! I'm really excited about where the car is at. I know there are folks with more tire and fancier suspension that will best my times, but I'm at the point where the car is capable and predictable enough that just working on my driving technique is a lot of fun. Also I think half the excitement of doing autocross is all the bench racing before and after. My brother and I are still recounting our adventures a few weeks out.

I currently have an adjustable proportioning valve in the rear line, but I have it cranked all the way open. The reason for this is I have a mismatched combination of small piston calipers out back from a '98-'02 Camaro with large piston original 1970 calipers up front. Taking caliper and rotor sizes into account, I calculated a bias (without proportioning) of 72% front / 28% rear. I've read a typical bias should closer to 67% front / 33% rear. Currently with the rear valve completely open, the car easily locks the front well before rear. From a safety perspective, that's better than the opposite, but I think it's asking way too much of my front tires going into a corner.

I plumbed it this way anticipating I would eventually install the smaller area front calipers and new master, which will be a much better match-up for what's in the rear. Based on the new rotor and caliper sizes, I should have a 64% front / 36% rear bias before proportioning. I can then reduce rear line pressure via the proportioning valve to get closer to where I need to be.

I'll also be swapping to a smaller 1" master instead of the 1-1/8" that's on it now, and a larger area dual 9" booster to replace the single 11" on it currently.
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  #1047  
Old 07-13-2019, 08:40 AM
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Ah, I think you've mentioned the prop valve before and I forgot about seeing it. Sounds like a good plan for your upgrade, you're definitely considering all the right things with the overall system bias.

Something I'm sure you're aware of, but I'll mention anyway is that a lot of prop valves seemingly work backwards. "Open" actually reduces line pressure so you have less rear brake, and "closed" increases line pressure because you're increasing preload on the spring in the relief valve.

Getting some more rear brake should definitely help your corner entry and get the car rotating better so you're not depending so much on the gas pedal to steer the car.

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  #1048  
Old 07-15-2019, 01:52 PM
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Great thing to point out regarding the proportioning valve. I remember when I put it on that threw me off a little. The knob has an arrow to turn counterclockwise for "less braking" which, as you pointed out, is a bit counter-intuitive. I turned it all the way clockwise to get maximum braking out of the rear and I'm still locking fronts well before rear.

Can you describe if and how the prop valve is used by racing teams to adjust the car for a given race? For street driving I assume adjust it so the fronts just lock before the rear when going in a straight line (most common braking scenario for street driving).
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  #1049  
Old 07-15-2019, 03:50 PM
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And so the front brake upgrade begins... inventory:



Parts list:
- Kore3 hubs w/*Timken bearings, seals, caliper brackets, and stainless lines with ARP 1/2" studs
- Stoptech Powerslot rotors 325mm / 12.8in (standard/base Corvette) 126.62085SR & SL
- Hawk HPS pads HB247F.575
- C6 standard*2 piston calipers and abutments (used)
- Tuff Stuff 2229NC dual 9" brake booster (original application is C3 'vette)
- Generic 3/8-24 clevis rod extender
- DSE 050302 reduced angle booster brackets
- S10 RHD master cylinder 1" bore 18M974

I started by installing the wheel studs with a bit of Loctite and 85ft-lb. I couldn't think of a better way to hold them while torquing than*threading in a couple studs in and holding onto lug nuts in my bench vise.







After that I decided it was time to get the car up in the air and on stands. This part of a project always gives me anxiety not knowing how long the car will be out of commission. Also I actually did this twice; the first time*was Saturday after the Ridgecrest earthquakes and I realized just after getting it up on the stands that an aftershock could be dangerous, so I lowered the car and waited a few days before raising it again. Come to find out, someone actually lost their life under a vehicle during the quakes (article here).



Here is the stock front disc setup in all it's glory. It features an 11" rotor and a large single piston cast iron caliper.


*
After pulling the caliper and hub/disc assembly, you can see the spindle, dust shield, and caliper mounting bracket. The two lower bolts go through to the steering arm and the upper is threaded directly into the spindle.



I tend to make a mess. I like having all my tools in reach. This job was made a lot more comfortable with a stool.



Here is what it looks like down to just the spindle.



After a little cleaning, I attached the caliper brackets. The instructions provided by Kore3 show images with similar brackets mounted completely differently on a front-steer arrangement - I think the images were from a different application. The brackets mount with the milled-off pockets against the spindle and a large spacer at the top if you have disc spindles like mine. If you don't have disc spindles, you don't install the top spacer.





You might also notice I didn't replace the front steering arm bolt. I found the one provided by Kore3 was about 3/8" longer and could interfere with my swaybar standoff if turned to lock. So I reused the original bolt. I tightened the lower 1/2" bolts to 85ft-lb and the big 5/8" bolt up top to 135ft-lb.

Next I packed the wheel bearings with a high temp wheel bearing grease. I chose to do them by hand. Even though I have a tool to do this with a grease gun I just like doing them by hand. It's important to press grease all the way through and between the bearings so there are no air pockets and rotate things a few times to make sure everything is well coated.



Once the rear bearings were packed, I coated the rear seal with a little grease and pressed it in by hand using a seal/bearing driver.



Then I lightly coated the spindle seal and bearing surfaces with grease and installed the hub. Folllowing Kore3's recommendation, I tightened the spindle nut to a very light 12ft-lb and rotated/retightened a few times to make sure the bearings were seated, then I backed the nut off about 1/8 turn and installed a new cotter pin.



The hubs come with an o-ring sealed cap which is held by 4 very small socket cap screws. I'm pretty sure I'll strip these little guys out quickly so I may replace with something else if I can find anything more suitable.



Finally I was able to mock up the rotors and calipers.







I am pretty happy with where things are going. Here's the old vs the new:

Old stock discs, 11" rotor single piston


New C5/6 discs, 12.8" rotor 2-piston


Unfortunately I have a little work travel coming up so I probably will not make further progress for another week or so.*
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  #1050  
Old 07-16-2019, 06:49 AM
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Quote:
Originally Posted by TheBandit View Post
Can you describe if and how the prop valve is used by racing teams to adjust the car for a given race? For street driving I assume adjust it so the fronts just lock before the rear when going in a straight line (most common braking scenario for street driving).
It's mostly a tuning tool to help the balance on corner entry. Particularly on ovals where you're not necessarily braking at max effort, adding rear brake will reduce entry understeer. In a lot of cases this is a larger percentage of rear brake than you would use based on the max effort, rear impending slip calculation you would do for a street car. This works because panic braking isn't as much of a concern in a racing environment.
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  #1051  
Old 07-16-2019, 10:39 AM
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Thanks for the reply! I thought it might be something like that!
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  #1052  
Old 08-12-2019, 12:19 PM
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I've been working on the brakes off and on and making progress. It was finally time to take out the old master/booster combo.



I took a few measurements on the existing line locations to get a relative starting point for new lines down the road. I plan to reuse the original distribution block and warning switch, so knowing the relative location of the distribution block should be sufficient for planning out the new lines.



Here is the original single 11" diaphragm booster and the new dual 9" booster. The booster is a Tuff Stuff 2229NC originally for a C3 Corvette. I am using DSE low angle mounting brackets.





I started by measuring the clevis length on the original booster relative to the firewall mounting surface.



I bought a universal 3/8-24 clevis extension which of course needed to be cut down to achieve the right length. The bandsaw made quick work of that.







I had read about folks needing to clearance the firewall hole for this booster. Sure enough the bellows on the input rod measures about 2" diameter while the firewall hole measures only 1-3/4". This bellows is not intended to seal on the firewall - in the original C3 application, there is a seal right up against the booster and the bellows is just under the dash area. Using this in my Nova, I don't think there's a good way to make it seal without potentially interfering with the pushrod movement. I'd rather not chance the brakes hanging up, so I have decided I am willing to leave this area unsealed.





Here's the booster loosely in place to show there's no way the bellows would fit through the firewall hole unmodified.





I decided to open the hole to 2" diameter. I picked up a special mandrel that holes two holesaws at once so the smaller can be used to pilot the larger one. This worked extremely well! The mandrel is part of the Bosch HE1 hole enlarger kit.





Unfortunately even after enlarging to 2" there was still interference with the bellows at the bottom of the hole, which you can see below from the inside of the cabin.



So I marked the hole and used a carbide cutter to enlarge it at the bottom by about 1/4", which provided adequate clearance.







Here are the master and booster now installed in their new home. I'm happy to report good clearance all around using the low angle DSE mounting brackets.



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  #1053  
Old 08-12-2019, 12:20 PM
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Next up I needed to address brake lines. The process started with straitening out some 3/16" brake line tubing using my time-tested, vise-based door roller straightener.



I probably could have cut and reflared the lines going to the front wheels to mate up with the new location of the master/distribution block, but the flare nut out by the wheel was rounded off badly. I decided to fished out the lines and replace them completely. I laid the old line out on the concrete and transferred bend locations one at a time to replicate the original path.



While they are not absolutely required, I like the original spaghetti look and installation flexibility provided by spiral loops in the line.



Based on my measurements of the old and new setups, the lines needed to shift down about 2in and forward about 2".





Here is the completed line for crossing under the engine to the passenger side.



For flaring, I am using an Eastwood brake flaring tool. These use 45deg inverted flares which take two steps to form. Step 1 makes a sort of bubble flare.



Step 2 inverts that flare into a 45deg contact angle.



This is what it looks like when completed. This tool has always produced a really nice, concentric flare for me without the tube slipping. I highly recommend!



Here is the start of the driver's side line which is much shorter. I snapped this picture to show the hand bending pliers I got from Eastwood that I used for most of the bending on these lines. They allow you to place a bend very close to a completed end, which was needed in several locations and makes for tighter fitting lines.



I also made new lines to connect the new master to the distribution block and from the distribution block to the rear proportioning valve. They aren't perfect and it came out looking a bit jumbled, but that's partly a consequence of using the original distribution block. If you just use a basic tee for the front lines or a combination valve, you can reduce the number of connections and lines for a cleaner look.







It's probably worth noting that the rear port on his master feeds the front brakes. This required some cross-over on the lines.





I'm happy with the completed lines. The brake swap is just about done. I hope to wrap up and bleed the brakes in the next few days. Let's hope there aren't any unexpected snags!
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  #1054  
Old 08-12-2019, 05:39 PM
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Looking good! I bought a similar hole saw mandrel and haven't had a chance to use it yet. Definitely seems like a simple way to make a hole bigger.

Is keeping the distribution block mostly for the brake light switch? Or is there a residual pressure valve built into it also?
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  #1055  
Old 08-12-2019, 07:10 PM
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Yes the distribution block houses a differential pressure switch that triggers the warning light if front and rear pressures are significantly different. It has no valving functions. The original system had a residual pressure valve in the rear port of the master feeding the rear brakes and also had a metering valve installed for the front system. There are some good descriptions of the components at this link: http://www.camaros.org/brakevalve.shtml

I really didn't need to keep the block, but some years ago I had a rear wheel cylinder leak that went undetected until the light finally went off so I figured I'd include it. Plus I find the component technically interesting and original to the car so I wanted to keep it. I am weird like that.
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  #1056  
Old 08-16-2019, 05:26 PM
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Installed the passenger side brake pads and stainless hose. Confirmed the hose is okay at full lock.





I also very quickly assembled the driver's side hub and caliper bracket. I though it would be a good idea to snap a photo of the brake pad install. With these calipers, you can remove the top bolt going into the slider pin and tilt the caliper down to install the pads into the abutments. This is WAY easier than the original 1970 setup where you have to load the pads into the calipers and handle all 3 at once as you put them on. I put high temp brake grease on all the sliding surfaces and where the pistons and caliper make contact with the pads. I also put the wear indicator on the inside pad at the bottom so I can easily check for wear without pulling off the wheel/tire. These are Hawk HPS pads which is the compound I ran on the old front brakes and the current rear.





I also think it's worth mentioning I use torque wrenches for all critical fastners (of which I feel steering and brakes are included!). I have a 3/8" drive in-lb torque wrench that I use for stuff under around 25ft-lb like the banjo bolts on the caliper hose and a larger 1/2" drive I use for all the big stuff. I like the clicker type wrenches. I also own a digital torque wrench but feel like it's a lot easier to overtorque with those even though they beep like crazy. For really light stuff like checking bearing preloads I use a tiny 1/4" beam type wrench, but I didn't need that for anything here.



Finally I was ready to bleed the brakes. My system used to have DOT5 silicon brake fluid in it and I decided to switch to DOT3 glycol based fluid. This was a good time to do it since I have new front calipers, lines and master and there will be less cross contamination. Before I pulled the old master off, I bled the old system with some DOT3 then I blew out the lines with compressed air. There is probably some trace DOT5 silicon left in the old rear lines and calipers, but I have done a lot of research and I think the concerns over switching back from DOT5 to DOT3 are overblown. Silicon fluid and glycol do not mix (they are immiscible just like water and oil), but I have not seen objective evidence that the two will cause problems when mixed. I have, however, seen very clear evidence that petroleum distillates (like brake cleaner or mineral spirits) will interact with rubbers and seals, so I avoided using anything like that to flush the lines. I figure blowing out the lines with compressed air and then flushing the lines with DOT3 is the safest way to clear old DOT5 out of the system. I plan to flush them again after some driving to clear out any residual moisture or DOT5 that's become entrapped in the new fluid.

With that explanation out of the way, let me introduce you to my new favorite method of brake bleeding:



I finally got to use my new Motive pressure-based brake bleeder and I am completely sold. The short process is as follows: top the master with fluid, screw on the cap, pump up (I used 10psi but you can supposedly go up to 15psi on this master), and then go to the wheel to open the bleeder. Keep an eye on fluid in the master and when it gets low, you can loosen the Motive gap/pump to bleed off pressure, refill the master and repeat. I found this thing worked great and saved me a ton of time. The only issue I had was the metal cap adapter I'm using, which is specified for late model GM masters, doesn't fit the "threads" (3 slots/tabs) in the reservoir very well. It still worked just not a great fit.

Here's a video



It's kinda cool to see fluid through the side of this master, unlike my old cast master where I had to pull off the cap to see what's going on. Here you can see how the master is divided for front and rear. In this case the rear part of the reservoir, which feeds the front brakes, is low on fluid due to where I was at in the bleeding process.



With the brakes bled, I had my 8yo help me torque on the wheels and went for a little test drive. It felt so good to be back in the car!





I managed to take the car out for two drives now: a quick putt around the block and then a few mile stint to bed the pads. Late in the second drive, I found a parking lot with good pavement and managed to get the proportioning valve adjusted so the fronts just lock before the rears - that took a little help from slow motion video on my phone which I'll upload when I have time.

On the first drive, I was really unhappy with how sensitive the brakes felt at initial pedal travel. It felt like the booster was taking the pedal from my foot and doing all the braking (not literally, but just a feeling like very little pedal input resulted in a lot of initial braking). This got better with bedding the pads and adjusting the prop valve to add more rear braking. It got better, but I'm not sure I like it yet. It feels like it just has a lot of boost and less modulation on initial pedal application, although I feel like it modulates okay after that. I also feel like the pedal is very slightly slow (milliseconds) to return when releasing, so I will double check that the compensating port is clear open and nothing is getting hung up. It may just be a feeling of having more booster than I had before. I will investigate.
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  #1057  
Old 09-11-2019, 05:24 PM
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TheBandit TheBandit is offline
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As promised, here is one of dozens of slow motion videos I took while adjusting the brake bias (w/ proportioning valve). I adjusted in 1 turn increments until the rear locked before the front, then I adjusted back in 1/2 turn increments until I found the sweet spot where the front would just lock before the rear. Definitely feels wild when the rear locks first - the rear wants to swing around so the car starts feeling very sketchy. When the fronts lock first, the car is stable and stops in a nice straight line as shown in the video.



I continue to drive the car. here are some photos I've snapped over the last month or so.



Small compared to modern cars...





Finally got a photo of me with the car at one of my favorite spots.







Also had a local artist Darren Hitchens (@hitchensartwork on Instagram) do a really cool sketch of my car aka the "Cone Killer"



The night I was out adjusting brake bias, I came home to find one of my center caps missing.



I remembered hearing a "clink" while I was driving, so I drove back to the spot and...

https://youtu.be/B1PwKQZhBHk

I was so happy I found it relatively unscathed.



After that I went around and added Loctite to all the center cap screws.
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Old 09-11-2019, 05:25 PM
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TheBandit TheBandit is offline
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As I mentioned earlier, I noticed a few times while driving that the brakes felt just a tad slow to release. One thing I decided to recheck was the clearance with the firewall hole and the brake booster bellows/boot. As it turns out the boot was catching on the firewall hole. Sometimes I found it on one side of the hole or the other after a drive, so it was definitely getting hung up.



I decided to stop rolling the dice and take my booster out to resolve the issue. Thankfully with all the brake line service loops I put in, the brake lines were flexible enough to move the master forward and get the booster out without opening up the lines. No need to rebleed the brakes!





While I was in there, I decided to get the proper tool for checking master/booster pushrod clearance. A long while back when I put this master and booster together for the first time, I noticed through the compensating port that the piston was moving as I tightened the master to the booster. To identify how much interference there was, I added shims between the the master and booster until I no longer observed movement when tightening them together. Then I took the shim thickness and ground off approximately that thickness from the pushrod. It was a considerable amount of interference - I want to say around .100in - and I wanted to make sure I had at least 0.020in clearance, so I had to take quite a bit off the pushrod. I was really curious to see if I'd taken off too little or too much. So I got the tool on Amazon (search "Power Brake Booster Pin Adjustment Tool").





Using feeler gauges I found I have about 0.040in clearance, which should be good. I've read anywhere from 0.20min to around 1/16th (0.063in) is ideal.

Next, I had to decide how to fix the clearance issue with the firewall hole. Doing a little research, I found Detroid Speed Engineering sells a booster/master combination that uses a custom boot and seal plate. I called them up and asked if I could buy just the boot and seal plate, since I already have their booster brackets. They sent me part numbers 99050028 and 99050030. Perfect! This boot just takes up the space between the booster and firewall while providing a watertight seal at both ends. It allows the booster pushrod to move freely inside.



Here is the "old" bellows that protruded through the firewall and moved with the pushrod



Here is the "new" DSE seal and seal plate that allow the pushrod to move freely inside.



When bolted up to the firewall, everything is watertight.



I took the car out last night and hallelujah, this resolved my braking woes! The pedal releases immediately now and no longer feels touchy/sensitive on initial application. I suspect the bellows interference must have been putting a strange input force on the booster, causing weird stuff to happen. Now it acts like it should and I can modulate the brakes properly. I do have some pull to the right under hard braking, so I will need to investigate. Perhaps the left caliper is bound up a bit. These were used calipers after. More to look into.
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  #1059  
Old 09-12-2019, 12:21 AM
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alwaysFlOoReD alwaysFlOoReD is offline
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Cool stuff. I'm learning too.
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Old 09-16-2019, 06:50 PM
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TheBandit TheBandit is offline
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Glad the info helps someone. I feel like I'm just stumbling through this stuff at times.
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