I have a PM with stock front discs and a ford 9" with explorer discs in the rear.What needs to be done to make it correct for a 4 wheel disc ?I saw that master power brakes sells a vac 4 wheel disc master cylinder is this the way to go or is there an easier solution. Thanks Steve B
4 wheel disc ?
- Thread starter StagedGN
- Start date
brakes
A master from a 87 GTA is 4WD the ports come out on the opposite side. The front is 12mm X 1. I do not remember the rear. I went to my local aeroquip store and made braided lines from the master to the proportioning valve for around $100. They work well and look cool too!! You will also need to remove the spring and plunger from the rear section of the proportioning valve this releases the 20 lbs preload from the rear line neccessary for drum, but causing discs to drag.
A master from a 87 GTA is 4WD the ports come out on the opposite side. The front is 12mm X 1. I do not remember the rear. I went to my local aeroquip store and made braided lines from the master to the proportioning valve for around $100. They work well and look cool too!! You will also need to remove the spring and plunger from the rear section of the proportioning valve this releases the 20 lbs preload from the rear line neccessary for drum, but causing discs to drag.
I have stock fronts with Aerospace rears with a powermaster. I tried to gut the stock cast prop valve , but half way there i found that the big front nut with the pin wouldnt seal without the inside crap out. I then removed it completely and used brass blocks to tie the fronts and backs sepatately from each other. I use a adjustable prop valveon the rears . Brakes have never worked better.
Same for me. Wilwoods all the way around with the stock powermaster. I had the proportioning valve jumped already back in the pre-tranbrake days so I just added an inline adjustable one for the rear brakes. Brakes stop just fine from 150mph trap speeds in 3500 pound car.
Greg Kring
Greg Kring
Got an El-Camino with vac brakes and a new rear disc conversion (cheapie kit 11.25" with metric calipers), stock master cyl is different than the GN, installed a spare Wilwood prop valve with all the ports, stock valve removed.
I like the Wilwood MC, but am looking for more of a stock option for this ride (think auto parts store) Need to be careful of the angularity, anybody got options ?
Prefer Alum.
I like the Wilwood MC, but am looking for more of a stock option for this ride (think auto parts store) Need to be careful of the angularity, anybody got options ?
Prefer Alum.
turbobitt
Well-Known Member
- Joined
- Feb 14, 2002
I'm going to take a guess here but I would start by looking at the TTA master cylinder and vacuum booster since it had factory disk brakes.
AG.
These were my first pass at usable units.
http://www.autozone.com/brakes-and-traction-control/master-cylinder-brake-system/buick/riviera/1978/8-cylinders-r-5-7l-4bl-ohv?filters=4294956069
http://www.summitracing.com/parts/sum-760177/overview/make/chevrolet
http://www.summitracing.com/parts/ssb-0477/overview/make/chevrolet
http://www.summitracing.com/parts/dhb-m390259/overview/make/chevrolet
http://www.summitracing.com/parts/dhb-m39576/overview/make/Chevrolet
Here is the turbo TA unit, looks like what is on the car but imagine it has one bore diameter.
http://www.autozone.com/brakes-and-...urbo?filterByKeyWord=brakes&fromString=search
Last edited:
turbobitt
Well-Known Member
- Joined
- Feb 14, 2002
Again, just shooting from the hip but the 1.417 (36mm) sounds about right for a 4 wheel power disk set-up. If it was manual I would say 1.032" or 1.125" bore, based on my experience.
EDIT - The one I see for a TTA is a 1.25 bore.
http://www.autozone.com/brakes-and-...ake-system-/486249_429915_2558/?checkfit=true
AG.
Customer went and bought one from the list I gave him, had to remove the rear caliper and tip it up to properly bleed it (cheap kit, badly engineered brackets) Then I added 2lb residual valves prior to the Wilwood Prop valve, hard as a rock now !
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