Brake pressure regulator question, OK to bypass?

My brakes stopped working properly not long ago. It took an excessive amount of effort and time to stop the car (the green one ). I brought to a local mechanic that does brakes, tires, suspension work, who I'm usually quite happy with for those things. The master cylinder was leaking, so he replaced that, but that didn't fix the problem, which we learned a couple of hours later, so we brought it back. They troubleshot some more and determined it was the brake proportioning valve (called brake pressure regulator in the Bentley I believe). They had said they couldn't get the part, and so they bypassed it and the brakes seem to be working properly right now. I have read in the forum a few posts regarding this part, so I'm thinking we probably should replace the part. I know I can get it from worldimpex. (I didn't know that at the time I spoke with the mechanic). My question is, is it OK to drive for a while with it bypassed? This mechanic doesn't have a lot of VW experience, but plenty of brake system experience with other cars. But maybe he doesn't ubderstand this part, if it is kind of VW unique. If I get the part, how hard would it be to replace it myself? (I read what to do in the Bentley, but not sure I understand how to do what it says.)

Get the right part and replace it asap. With an improper brake bias, it is likely (if your rear brakes are functioning properly) that under hard braking your rear tires will lock up first, possibly resulting in a fishtailing skid. Which could be fun if that's what you're after. But if you drive on snowy roads it can be especially dangerous.

In theory replacement shouldn't be difficult. Unhook the brake lines, remove the allen head screws holding it in, and install the new one. In practice it seems these can be a royal pain. The allen screws are aluminum and form a chemical bond with the different metals that come in contact with them. It seems that typically the heads of the allen screws will strip out before coming loose. The only solution is then to cut, drill, heat and mangle the old piece out. I have never personally replaced one, but that seems to be the typical way it goes. Proceed with caution.

Another thing to note is to never buy or use the craftsman or craftsman professional flare nut wrenches. I just had the unfortunate pleasure of running some new brake lines on my car from mangled tubing nuts. Make sure your flare nut wrenches fit well before applying ANY pressure to the brake line fittings. The $12 set I got from Napa worked much better than my craftsman pieces of junk.

Its not VW specific. My toyota truck runs a similar system. Wheelers often bypass it. I keep mine in place.

You decide. its your car. I would (and do) keep the valve in place.

A new valve isn't that expensive, and makes the car a lot safer to drive.

-Jason

A new valve will cost about $200

Here's a good post on replacement and part number.

Tony

TonyJetta said:

A new valve will cost about $200
Tony

Click to expand...

not quite that bad:

http://catalog.eautopartscatalog.com/archsoftware/europartsetc-us/wizard.jsp?partner=europartsetc&year=1996&make=VW&model=PAS-TD-001&category=N&part=Brake+Proportioning+Valv&partnerSession=c5025bb322d3015e4d9d5c23c88d068b

Around $100

Don,
Thanks for posting that link!

Tony

$81.10 http://www.europartsdirect.com/cart.asp

Thanks for all the responses. Worldimpex has them too, for 78.55 http://www.worldimpex.com/parts/german-brake-pressure-regulator_271994.html so I will be ordering one soon.