Monday, November 30, 2015

Power Booster Conversion Tri-Five Late Model Part 2

Power to the Front Move to a Dual Purpose MC and Disk Brakes Front Disc Brakes for a Tri-Five Classic Chevy

-Alan Arnell
I am still researching about my upgrade from a single master Cylinder (MC) non power Master Cylinder (MC) front drum brakes to a power boosted dual MC with front disc brakes.  After my last research, I had several questions about the research up to the point of the last blog.  In this series of blogs I will address further the installation of the dual MC and proportioning valve. And, steps to install front disc brakes.

Denny Williams had completed a better list of rotors and calipers which can be used:
  • 69-74 Chevy Nova
  • 70-72 Monte Carlo
  • 69-72 Chevelle
  • 69-72 Pontiac Grand Prix & GTO
  • 69-72 Pontiac Tempest
  • 69-72 Buick-Skylark, Grand Sport, Apollo, Sport Wagon

Of course this list is dated.  There is many modern aftermarket kits and parts that will make the 69-74 technology, like bring a knife to a gunfight.   In this blog, I will not dive into better more modern brake systems for two reasons:  At this point I am mainly using a tech article from Classic Chevy World penned by Denny Williams in 1982.  The guy I bought my disc brake system upgraded to the before mention modern system with huge calipers.  He also upgraded to 22 inch wheels.  I want to keep my vintage reverse 15”-chrome wheels and stay true to my car’s theme.  I want my car to look like the car I would have made and had in the early 70’s if I were able to do so.  Therefor, my 69-72 Chevelle system parts I purchased fits that goal very well.  My car is a driver.  I have neither the money or inclination to make it a 1000 point car, that I’m afraid to drive.  I’ll keep my car around 750 points and drive her everywhere.  From the stock ‘57 brakes to 69-72 Chevelle brakes will still be a major improvement.

This I am glad I found out about:
It is difficult or even impossible to bleed the system of a Tri-five with an installed dual master cylinder.  It seem the bleeder valves on the calipers are point down, this trends to trap air.  To solve this problem the calpers must be switched from one side to the other, side.  In this position the bleeder valve will be correctly facing up.  Unfortunately your original brake hoses cannot be used if this is done.  To fix this problem involve making a hose out of various fittings and steel braided lines which can be purchased. Denny put together a kit that contains two special brake hoses and two swivel bolts, sometimes called banjo bolts for banjo fittings.  Denny lists the kit as #20-30.  I will have to research this banjo thing and get back to you.  
I must digress.  This blog is only a simi-how to Tech article. In reality the blog is my research up to this time.  I am by far no expert in Automotive Technology.  I can research and if I have instructions I can make things go together and work.  But there is so much information out there to absorb and learn for such a complicated upgrade I fall back into old habits.   I find that I can only remember and understand half of a tech article before I dive into the rebuild project.  As you can imagine knowing half can be frustrating if not dangerous. My trick is to research, then think and write about what the research.  Many of the projects I will complete on my hobby car I will only do once.  I have car club friend who for all practical purposes has worked on Tri-Fives for 40 years.  He has done so many things to Tri-Fives, so many times he can skim or not even read instructions and make the project seem easy.  Kinda like watching golf on TV.  “It looks so easy,” I said, When I looked for my golf ball in weeds, over the fence in the farmer field next to the golf course.  I learned from my father, with 42 years of teaching experience, that the best way to learn something is to be forced to teach someone else about it!

I will now switch to a Super Chevy Brak Conversion at :

Classic Chevy World goes off on dual master cylinders at this point.  I on the other hand want to learn and write about putting on the front wheel discs.

The web posting on Super Chevy says, “It used to be that retrofitting discs onto to a older car meant scouring the junkyards for ‘70 disc brake cars to rob of spindles, calipers, MC, etc.  Well in 2014 we don’t have to do that anymore.  Thanks to companies like Classic Performance Products (CPP), installing disc brakes on a vintage Bow Tie is easier than ever…

I next went to web page The World of specifcially:

Posted on this page was:

If you have purchased one of the many aftermarket brackets for converting to disc brakes, you can use this information.  Besides your brackets you can get these parts at a parts store or an auto salvage.  The page list the same list as above, however here is some more than useful information about new wheel bearings.

It also uses the stock inner and outer wheel bearings associated with these rotors (Bower/BCA A2 and A6) Calipers:   
Buick           '76-'77 Apollo, '73-'76 Skylark, '77 Regal
Oldsmobile '73-'76 Cutlass, '75-'77 Omega
Cadillac       '75-'77 Seville
Chevy         '70-77 Camaro, '73-76 Chevelle, '73-'77 Monte Carlo, '77 Nova, '71-'77 El Camino
Pontiac       '70-'77 Firebird, '73-'77 Grand Prix, '75-'77 Ventura
GMC           '71-'77 Sprint      

As follows is  The World of Tech Instructions.  I will in blue only make minor comments.  When I have completed the upgrade on my car I will come back and add my two cents.  Alan

1.  Remove stock Chevy front brake drums, brakes and backing plates. (The drums come off after taking off the axle nut.) Clean and inspect spindle for cracks and or damage.  Be sure to thoroughly clean out the 5/8 " threaded hole at the top of the spindle-  this is extremely important.  Use a non-oil based cleaner such as trichlorethylene.  Clean the threads out with a bottoming tap is necessary  -  but clean it good.

2.  In order to install the inner bearing you must remove .0004" from the spindle inner bearing seating diameter.  This can be accomplished with 240 grit emery paper (or equivalent) and a rotary sanding motion on the spindle.  This operation must be continued until the inner bearing can be slid onto the spindle without binding.  DO NOT TRY GRINDING OR FILING THE SPINDLE.  It only takes a few minutes with emery paper.  (I replaced my old roller ball some time ago and the sanding went real quick for me to make the new needle bearing to fit correctly.  I didn’t even need to sand them for a proper fit.)
Note:  This procedure must be accomplished on the inner bearing for the 55-57 spindle and on the outer bearing of the 55 spindle only.  (Not the 56-57 they are OK as is).

3.  Once the bearings have been fitted to the spindle, take the small support bracket (see figure) and install it on the outer surface of the spindle in the two lower holes.  Install one of the long (2-3/4") 7/16"-20 bolts through the support bracket, through the rear hole on the spindle and through the stock steering arm.  Install the shorter 7/16" -20 bolt (2-1/4") in a similar manner through the front hole.  Install the locknuts supplied in the kit and tighten.

4.  Take the appropriate caliper bracket (R/H or L/H as marked on the inside of the bracket) and install it as per the figure, and as follows.  Install the 1/2" X 2-1/2" bolt supplied in the kit through the caliper bracket, spacer and support bracket as shown.  Install the 1/2" locknut but do not tighten it yet, just snug it up.

5.  Take the 5/8" X 1" bolt and install it through the bracket into the spindle.  Do not tighten it yet, just snug it up.

6.  Take the GM rotor, clean and inspect it as necessary.  Install the inner bearing (don't forget grease) followed by a national #79345 seal.  This seal is used on 61-68 Chevy cars without disc brakes.  It is readily available at any auto parts store.

7.  Install the rotor on the spindle followed by the GM outer bearing.  Put the bearing retaining washer and nut on the spindle to hold everything in place temporarily.

8.  Turn the rotor on the spindle and check for any interference or minimal clearance between the inside surface of the rotor and the 5/8" upper mount bold.  (This is a judgement call - use your own).  If you feel additional clearance is required, remove the rotor and bolt, and grind the grade markings off the head of the bolt.  (Don't get carried away).  Check for adequate clearance on the 1/2" bolt also.  Reverse it if necessary.

9.  When you have adequate clearance remove the rotor and the 5/8" bolt from the spindle.  Coat the bolt with a few drops of the Loctite solution contained in the kit.  Make sure the threads in the spindle are clean.  Install the bolt and tighten it and the 1/2" bolt previously installed.
10.  Re-check all the bolts for tightness and re-install the rotor and outer bearing.  Install the stock 55-57 Chevy bearing retainer washer followed by the special wheel bearing retaining nut supplied in the kit.  Don't attempt to use the sock bearing nut - the cotter pin hole won't line up.  Adjust the wheel bearings and install the cotter pin.  Check for clearance and freedom of rotation once more.
11.  Install the brake pads and attaching parts in the caliper and install it on the bracket (remember there is a R/H and L/H caliper) using the standard GM caliper mounting bolts.  Tighten bolts to GM recommended torque.

12.  Repeat the procedure for the opposite side.

13.  Connect the brake calipers to the 55-57 Chevy brake lines using a suitable hose that will allow freedom of suspension and steering travel without interference.  Your local auto parts man can help you with this part.

14.  Procure a master cylinder of the dual reservoir disc/drum type.  (assuming you still have drum type rear brakes).  Plumb the master cylinder into the system using the appropriate metering/proportioning block from the vehicle from with you  obtained the brakes.  If you prefer a non-power get a master cylinder from a 70-77 Camaro or equivalent.  If you prefer a power set-up get the appropriate booster and plumbing.  Whatever method you use, DON'T attempt to use the 55-57 cylinder - it won't work.

15.  Fill the system with a suitable brake fluid, bleed it, and check for leaks.

Links to more Power Brake Posts:

Tri-Five Late Model Power Booster Conversion Part 1

Power Booster Conversion Tri-Five Late Model Part 3
Tri-Five Classic Chevy
Proportioning Valve, Dual Master Cylinder and Brake Lines

Brake Pedal Clevis Relocation After A Power Assisted Disc Brake Upgrade on a Tri Five Chevy.

Brake Troubleshooting for Tri Five Chevy/ Disc Retrofit

Front Wheel Alignment

55 Chevy
56 Chevy
57 Chevy

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