# 69 disk brake holdoff valve



## Shadetree Racing (Apr 15, 2015)

i am trying to bleed the new front brakes system on my 69, from booster to caliper and i cant get fluid past the disk holdoff valve, i see it at the input side but cant get it past the valve.
the button on the back of valve doesn't seem to move at all, how much pressure should it take to engage this button on the valve? I have found very little informaion on this valve or its operation.
any tricks to evacuating all the air since all the lines and calipers are new up front? i have a small vacuum type bleeder kit,

thx


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## PontiacJim (Dec 29, 2012)

Take a look at this photo. The *Holdoff Valve* is at the upper left. The brass block on the left is the *Brake Proportioning Valve.* Click here: OE Style Distribution Blocks, Hold Off Valves & Brake Tees.

I think you are talking about the Brake Proportioning Valve? Personally, if either were original to my car, for the price of a new replacement I'd simply install a new one and go from there. Dirt, crud, corrosion, etc. could easily create a problem.

Let us know what valve you are referring to and additional info should follow as to a few things that you might try.


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## Shadetree Racing (Apr 15, 2015)

everything is new...The brass block on the right is the proportioning valve, the small brass item to the left is a Tee and the "ball like" valve on the left is the hold-off valve. i have installed a new hold off valve as well as the proportioning valve (installed on frame below booster).
i am referring to the roundish hold-off valve that mounts under the master cylinder on the 69.


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## PontiacJim (Dec 29, 2012)

OK, thanks for confirming the valve in question. I do not have any experience on this, but did a little web research. It may be that your hold off valve is defective. Check out this blog as it seems to be similar to your situation: Can't get fluid past rear hold off - Chevelle Tech

Hope that gives you some ideas to consider. :thumbsup:


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