i searched but couldnt find an answer

ok i swapped out my rearend to a pbr rear
i have a 1991 camaro rs

i upgraded the front brakes to c4 setup

now i upgread to rear disc and my car wont stop
and if i pump the brakes 3 times ill put myself threw the windshield

but with no pumping the pedel falls to the floor and my brake light comes on and it barely stops

i have bleed the hell out lines and all im doing is shooting out my brand new fluid

if i pump the brakes 3 times ill put myself threw the windshield
but with no pumping the pedel falls to the floor and my brake light comes on and it barely stops


im told my prop valve is the same for both drum and disc rears

thanks in advance for help

 

i believe the drum M/C is the same between drum and later disc cars but the prop valve is different for disc rears and drum rears drums require more prussure to work and discs dont.

 

If you've gotten air in your M/C no amount of bleeding with it on the car will clear it. This is caused by allowing the reservoir to empty of fluid and is easy to do when bleeding the system. I'd pull it and bench bleed it before doing anything else.

 

I did this very same rear swap on my 91RS. The master cylinder is the same for both drum and disc rears. However, you absolutely need to change the porportioning / combination valve for the rear brakes to work correctly. Otherwise, you'll have the same problems.... Sorry, but the valve will need to be changed. Here's the GM part number you'll need; 10164112.

GM List price, about $107. Wholesale price (if you can get it), $75 from GM.

I've read other posts from guy's that have used salvage yard cars to get the right part as they claim it doesnt wear out. Your call there...

Good luck

 

Naf hit the head right on the nail.

You can bleed 100 gallons of fluid through the system if you want; but if the MC has air in it, you're fornicated. Because of the angle that it's installed at in the vehicle, the fitting for the line IS NOT at the highest point; and therefore, there's a pocket of air that will stay right where it is, and will NEVER EVER make it to the fitting to get expelled.

The combo valve doesn't matter. In fact, in 91 & 92, the factory used the same one on drum and disc cars, because the hydraulic requirements f the PBR rears are similar enough to drums that it works fine. That's not your problem. Air in the MC is what's wrong with your system.

 

If you didn't tamper with the master cylinder then that shouldn't be the problem. The proportioning valve is different between disc and drum cars and will need to be changed.

 

GM lists the proporting combination valve for disc and drums as seperate components for their respective intended application useage. Why risk it on a "close enough" call? Up to you...

Bleed it over and over again. Took me three quarts to expell the air b/4 all was good.

Good luck

 

I also support the air in the system theory, I'd advise you to take it to the dealer and have the system either pressure or vacuum bled. It shouldn't cost you more than $35-40.

Final answer: GM used the same MASTER CYLINDER on all '90-92 cars but the combo valves were different for disc and drum cars. I also advise you to install the disc rear combo valve to be correct, then you'll see the full effect of bleeding of the system.

Good luck.

Ed

 

What does PBR mean????

 

www.pbr.com.au
they make all the proformance calipers for most car makers
they where the company that made the rear alloy caliper on the 89-97 fbodys they also made the corvette and 1le and ls1 even the new z06 6piston is pbr aswell
also made the calipers for grand am and make some iron ones aswell
they have also been used on the mustangs for the mach 1 package but also make the stock package for them
and baer brakes use them in all there packages


on a side not i bleed the master cylinder and re bleed the brakes tell i had new fluid in all lines the car stops much better but now i have a differant problem
car stops great from 30 and above but under 30 mph my car takes longer to stop then a stock front brake/rear drum car
im wondering if its from useing ceramic pads or is it something else
like if stop from above 30 and ill bu 15- 25 feet behind a stock brake car but under 30 i take 5-10 feet more then a stock braked car