[Skier_Bob]

How do I know if I have one? Getting ready to install D52 Wilwood Calipers in 71 chevelle. I currently have discs up front and drums in rear. Wilwood recommends proportioning valve in the rear. shouldn't the car already have one? If so, where do I check? If not, where does it get installed? Hope this doesn't piss off the people who know how to do this..... !! sorry but thanks!

 

[davis95]

They are normally attached to the brake lines that come out of the master cylinder a few inches from the master cylinder.

 

[Skier_Bob]

roger. Thanks. So, when I put on new lines, I can just insert them there?

 

[Philip]

Bob just installed a set on my car. I used Wilwoods flex line kit and changed nothing else in the system.

 

[glide]

My '71 disc/drum had the prop valve bolted down on the inside of the left frame rail...

 

[sevendchevy]

What year do you have? Set ups differed in some years.IIRC 71-72 same 70 differant from them.

 

[LevonH]

BTW these are NOT proportioning valves. They are brake warning safety switches. If one side (F or R) loses pressure, a little pintle moves to block off that side and set the warning light. Proportioning is done in the master cylinder and residual pressure for the drums is often done by a little valve sometimes located near the rear distributio "T".

 

[Philip]

Okay Bob I guess I was not clear enough. The Wilwood D52 is a direct replacement caliper. Nothing needs to be changed if the stock disc brakes were working properly. Bolt them on, run the flex line, bleed and then break the pads in according to instructions. If you are reusing the current pads no break in needed.

 

[Philip]

From Bobs profile I saw he has a 71. 71 and newer is all in one unit and are combination valves.

 

[JWagner]

Just to clarify the valve stuff. Not all models got a combination valve, but for those that did:

From the shop manual, in the section on the combination valve. "This valve houses the failure warning switch, metering valve and proportioning valve in one assembly.."

 

[LevonH]

Interesting. Different things for different years.

 

[Skier_Bob]

Gentlemen - thank you all very much. ok..... so going to go with the direct replacement guidance and nothing else needs to be changed. just ordered wilwood flex line kit from summit

 

[Philip]

The brake line kit makes it easy, all the fittings needed are included. If your fluid is old the system should be flushed before installing your new calipers. The brake fluid should be almost clear, if it is brown looking it needs to go.