Does anyone know where I can get a proportioning valve rebuild kit for a 69 Z28? It is the original prop. valve.

Try here: http://www.mpbrakes.com/ I know they rebuild them.
BTW, Just to be clear we are talking about the same thing, - the valve up by the master cyl is a metering valve, the proportioning valve is down on the frame rail.
The metering valve just has a couple of O rings in it.
David

By all of the books that I am looking at they are calling the valve up by the master cyl. the proportioning valve. This is the valve on my car that is leaking. Can it be fixed by simply replacing a couple of o rings? I have not taken it appart yet.

Here is what GM calls a "Brake Pressure Valve" on the subframe. They also refer to a pressure valve on the master cyl but it does not limit rear pressure because is is in the front brake line not the rear line.
http://ourworld.compuserve.com/homepages/David_Pozzi/prop_location.jpg
The Metering valve which is in the front line has two O rings in it. One on the nut, one on the plunger end where it goes into the rubber boot.
Here is a shot of the valve inside:
http://ourworld.compuserve.com/homepages/David_Pozzi/meter_assy2.JPG

[ 12-05-2003, 08:09 PM: Message edited by: davidpozzi ]

The part I am refering to is the valve up by the master cyl., the one in the second photo. Mine is leaking out the end under the rubber boot, opposite end of the large nut. By replacing the o-ring in the plunger will this take care of this leak? Or is there another seal around the shaft that comes out where it is leaking? Would a viton material o-ring stand up to brake fluid? Is there another type of o-ring that would? Thanks Greg.

A quick search on the net shows EDPM O rings are the best for brake fluid use.
When apart check the stem of the leaky pin for pitting. If it is badly pitted you may need to replace it. Castrol sells a brake grease suitable for lubing the seals for assembly.

I changed the photo above to a better one. Thanks to whoever sent the photo to me. I forgot who sent it to me. graemlins/clonk.gif
David

[ 12-05-2003, 08:16 PM: Message edited by: davidpozzi ]

Thanks

After disassembling my valve I found that there is a small seal at the end where the shaft comes out of the valve. This is where mine is leaking. The seal appeared good, fit snugly with no damage to the lip. The shaft however had some deposits on it that were easily removed with a rag and brake parts cleaner. Thought I would add this for information sake.

David and others.......I am CURRENTLY expereincing the same leakage around the plunger shaft on my "VALVE" .......Can anybody direct me toward buying a CORRECT replacement....NEED this part TODAY !!!!!
Chuck Sharin

I checked with the above Power Brake Supply...On 10/11/04 I was told they now charge $65.00 to rebuild the 69 Metering Valve. They will NOT sell any parts. I also checked with WHITE POST who charges TWICE that. Called Master Power Brakes in N.C and they only sell aftermarket misc valves and NO parts to restore originals....
I'm just frustrated and dissapointed that I cant find a vendor to sell me the rubber "CUP" piece and plunger/shaft "O-ring" seal.
Thanks anyway, Chuck Sharin CamarosRus@aol.com

I don't see a rubber cup part in the photos. I haven't had one apart so maybe it's not shown.

Try an industrial Hydraulic supply/repair house for the O rings. Make sure they are compatable with brake fluid.

I would not worry much about the internal parts, this valve does not do much and can be removed from the system if need-be with no drawbacks.

The valve only helps when driving on snow and ice.
David

Right stuff detailing (800)405-2000 is about two weeks away (so they say) from coming out with a repop valve to replace the one that we are discussing here. I hope they come through as I have waited for other companies who said that this that or the other thing was about to be ready, but never was... graemlins/sad.gif


I have two leaky original valves....It would really be nice for someone to track down the required seals so they we could start rebuilding them instead of getting stuck leaking brake fluid, spending stupid money for a rebuild or waiting for a repop part to come out!!


We don't need the valve David? You know I have seen a couple of disc brake camaros without the valve and the owners said that the brakes worked fine. I suppose that the valve on the frame rail isn't needed either as many cars didn't even get them?

I had one of those leaking once. I was in a hurry and the only O ring I had that would fit was a square cut type valve stem seal. I don’t know what it was for though, either an old 6 cyl ford or big block chevy, maybe small block but it worked for at least 4 years until I sold the car..

Here are some pics of the rubber seal that causes the leak:


http://www.stratagaz.com/MeteringValve02.jpg

http://www.stratagaz.com/MeteringValve04.jpg

http://www.stratagaz.com/MeteringValve05.jpg

http://www.stratagaz.com/MeteringValve06.jpg


Any suggestions as to a replacement part? It does have "bendix 2225844" molded into the seal.

I have been checking this and other old posts out. Mine is rusted so the button does not have to be depressed to bleed the brakes. I also saw an old post by JohnZ that said that valve lets the rear drums actuate before the front disks hook. I do believe that this valve is needed. When I rebuilt my brakes a few months back the rear looked like they were not functioning very well. Maybe this was why. What was the resolution? Did anyone find the parts? :confused:

You only need to hold the plunger if pressure bleeding. This according to the service manual.
The rear brakes overcome their return springs and the delay valve should open directly afterwards. It is also open at low pressures which allow for gravity bleeding. About 15-30lb from your foot should open the valve when manual bleeding. It should open around 100psi.

Excess front brake wear can occur with a malfunctioning or missing valve for people who do light braking or 2 footed braking. The valve is open except in light braking. It can be important for this, and when stopped or stopping on slippery surfaces.

There are factory style replacements now for about $100+. I don't know where to get seals. I'll need to be rebuilding mine soon too.

Several places sell the valve, though most incorrectly call it a proportioning valve. There are also a couple non-factory style metering valves, and combination valves available, which are cheaper.

I have been told by 3 individuals in the "know" that the repo valves are not correct in operation. These 3 individuals are all dealers who sell these parts and have sent the repos out to be "built".

I use "LoneStar Caliper" out of Texas for my Corvette brakes and valves. I left an original 69 Prop valve with Ken on Saturday for rebuild. LoneStar is the largest rebuilder of stainless steel Corvette calipers in the country. They also do all sorts of different calipers for foriegn and domestic cars. They just completed a sleeve rebuild of a 69 original "309" master cylinder for one of my cars.

You should be able to find Lonestar with a google search. Their turnaround is VERY quick!

I am sending mine to Karp's Brake in Upland CA to be rebuilt for $65. graemlins/thumbsup.gif