View Full Version : Shimming stock brake proportioning valve

03-30-2002, 11:04 AM
Has anyone altered the stock brake proportioning valve? I believe this is done by shimming a spring inside the valve. I'd like to get alittle more rear brake bias this way until I have time to plumb an adjustable one in. I'm wondering what size shim to use for various levels of bias. If anyone has experience with this,I'd appreciate your comments!

03-30-2002, 02:51 PM
Brian, it is totaly none of my business but why play guessing games with shimming the stock valve. With the proportioning valve installed a 10 second adjustment is all it takes.

In my case I found the simplest thing to do with the differen threads was to get rid of the metric on the lines. Put on inch threaded fittings & redouble flare the lines.

Have Fun


C. Ludwig
04-01-2002, 01:01 AM
I'm with David. Plumbing a real prop valve is easy and doesn't take long. Try this guy. [email protected] He custom made my lines. No adapters needed. Bolt-on for a Wilwood valve. I'd hate to guess at bias adjustment.


04-02-2002, 10:36 PM
I agree with you guys,I'd prefer an adjustable valve. Don't have the time just now. Shimming the stosk valve can be an easy fix. I was hoping someone would reply with some specific shim sizes for a specific bias.I',curious as to what setting/settings you use most often? And how often you make an adjustment?

Allen Brown
04-03-2002, 10:45 AM
One way I have used to alter the brake bias that seems to work with my car (85 SE) is to check into the friction coefficients of the various brake pads out there, and apply one that you feel will fit the job.

I do hope to get the rear brake proportion valve added, but at this time I'm not there.

04-03-2002, 02:07 PM
When I had my 1st gen, I ran it with the stock proportioning valve and never had a problem with the balance. In fact, I was always very happy with my brakes. That is not to say that an adjustable valve might not have provided an opportunity for some improvement, but I never felt that I was fighting the brake balance.

If you haven't already, ou may want to try the stock setup until you have time to get an adjustable prop valve. You may find it works fine. I did.