I couple months ago I swaped the drum brake rear end out of my 1992 RS for a Borg Warner 9 Bolt with Discs. The discs look very similar to the stock ones on front.

I was told (before I did the swap) that I'd need a propotioning valve for the new discs in the rear. I can still drive my car and brake fine, but there seems to be no improvement from the drum brakes.

I bled the rear brakes when I did the swap, but the pedal feels pretty soft and it sounds like air pushes out (kinda a 'swoosh' sound) and the brake pedal sinks pretty far before it will really start braking.


I'm wondering if I need a proportioning valve, re-bleed my brakes, or something else? If it's the proportioning valve I need, where can I find one?

 

I have a 9bolt with discs swapped in my '82 so I kind of know what you are going through. First off, YES you need the correct PV for that style of rear discs. I'd try a junkyard since they don't really wear out. I'd also suggest doing a search for "rear disc brake recall" and get the kit to rebuild the calipers using the updated parts. The general feeling on these boards is that our early style rear discs suck. But after doing the swap, recall kit, earl's stainless steel brake hoses, "shimmed" PV mod, bendix pads, and a professional parking brake adjust, it stops like a champ. May not be the greatest, but it works pretty good considering the weight of these cars. Good luck with it.

 

buy an adjustable prop valve from wilwood or someone , their the way to go .

 

Where do I put the valve? I bought a wilwood one and I'm guessing I route the line off the master cylinder to the new valve and then to the rear lines., and plug the old valve (it looks like the wilwood one comes with plugs for the old one...

 

You install it on the line to the rear brakes.

https://www.thirdgen.org/newdesign/tech/propvalve.shtml

 

Wow, that seems like a great walk through. I read through it and I have a couple questions:

It sounds like the MC (that silver looking deal that the resevoir sits on) was replaced. Do I need to do this and if so, where do I get one?

Where do I get all the fittings required to do this job (and also the flaring kit)?

 

no, you dont HAVE to... his was probly bad or somthing.. if your MC is good, keep it. you can get a new one from any autoparts store. its a common item... there will most likely be a core charge.



almost any autoparts store. if theres a Bumper-to-Bumper local to you, go there.. otherwise goto NAPA... they usually have everything hydraulic you need.

any automotive tool place... or you can rent one for free from autozone.

 

Thanks a lot. I'm just waiting on the wilwood prop valve I ordered from a retailer on ebay to come.. sometime this week.

I guess I'll go to autozone and rent that kit and then napa for the hydrolic stuff.


Would it be better to just buy new tubing from the MC to the valve instead of using the stock stuff? It seemed pretty hard to work with. Of course I would just leave the chassis lines because those are much longer and harder to replace..