#1  
Old 03-29-2023, 09:00 AM
rustyrelic rustyrelic is offline
Senior Chief
 
Join Date: Dec 2005
Posts: 449
Default Question about 69/70 disc conversion

I posted over in the 67 and up full-size group, but things are pretty slow over there and so thought I might get a response over here.

For folks who have converted to front disc brakes using the 69/70 spindles, brackets, calipers, rotors, etc., did you also use a proportioning and hold-off valve? If so, which ones? Supplier and part number if you have it please.

I am currently running just the disc/drum master without a proportioning valve and hold-off valve (residual valve) and the brakes work ok, but I think the rears are doing more work than they should.

Also wondered if anyone is running EBC red pads. It looks like they are available for the 70 full size but they are a bit pricey and would like to hear others experiences.

  #2  
Old 03-29-2023, 06:06 PM
rustyrelic rustyrelic is offline
Senior Chief
 
Join Date: Dec 2005
Posts: 449
Default

Bueller? Bueller?

Nobody has done the front disc brake conversion using 69/70 full size car factory hardware? Come on, somebody has done this, it used to be the only way to add disc to full size. Did you use the 69/70 proportioning valve near the master cylinder, and did you then also use a residual valve in the rear brake line?

I would like to hear your experiences.

  #3  
Old 03-29-2023, 09:14 PM
Stuart's Avatar
Stuart Stuart is offline
Moderator
 
Join Date: Apr 2003
Location: Minneapolis
Posts: 7,938
Default

Give it some time, it's been less than one day since your first post.

  #4  
Old 03-29-2023, 10:35 PM
Goatracer1 Goatracer1 is offline
Ultimate Warrior
 
Join Date: Oct 2003
Location: NH
Posts: 3,768
Default

If you are using the stock master there should be a residual valve in the master for the rear brakes. Just use the proportioning valve for the 1971 up big cars. I believe Ames has them.

The Following User Says Thank You to Goatracer1 For This Useful Post:
  #5  
Old 03-30-2023, 09:12 AM
rustyrelic rustyrelic is offline
Senior Chief
 
Join Date: Dec 2005
Posts: 449
Default

Goatracer, thank you for the reply.

After doing some more on-line research and attempting to winnow out the crap, it is beginning to look like maybe the best move would be to swap the 68 drum/drum block (with pressure switch) to a later combination valve (distribution block, pressure failure, and proportioning valve) from say a 70 or later, rather than try to add separate valves for different purposes. Does anyone know to tell if the drum/disc master cylinder I have now has a residual valve? Is it similar to Ford which has a sort of rubber diaphragm that you can check for with a paper clip in the port of the rear brake reservoir?

Will likely also add the EBC red pads. (They were big step up from parts store pads on the 66 Mustang, which I also swapped to a 68 dual drum/disc manual reservoir master, and then added an adjustable proportioning valve and an inline residual valve while retaining the stock 66 distribution block.)

  #6  
Old 03-30-2023, 05:04 PM
AROWHED's Avatar
AROWHED AROWHED is offline
Chief Ponti-yacker
 
Join Date: Feb 2004
Location: Central Illinois
Posts: 984
Send a message via Yahoo to AROWHED
Default

On my 65 GP I used to have a 72 Bonneville combo valve with 69 master and disc brake calipers and stock 65 drum rears. But now its 4 wheel manual disc with a 7/8" bore master, no valve at all, and had to change to 7:1 pedal ratio!

__________________
Red\black 65 Grand Prix 467 E-head stroker, Viper T-56 6-speed, 4.10 spool
Reply

Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -4. The time now is 07:17 AM.

 

About Us

The PY Online Forums is the largest online gathering of Pontiac enthusiasts anywhere in the world. Founded in 1991, it was also the first online forum for people to gather and talk about their Pontiacs. Since then, it has become the mecca of Pontiac technical data and knowledge that no other place can surpass.

 




Copyright © 2017