Brake Bleed / Proportioning Valve Question

[Jc.av8r]

I ordered a new proportioning valve as my current one is leaking and I figured I would just replace the entire thing for good measure.

I'll obviously do a brake bleed with this job but I am wondering, if I disconnect the lines to the proportioning valve will the master cylinder fluid drain out all over the place, or just release a few drips?

In other words--should I fully drain the master cylinder before disconnecting the lines and removing the prop valve, or will everything stay put with just a rag under the disconnected brake lines?

 

[Timmy390]

Cap the lines once disconnected with these...I use them all the time for brake work.
https://shop.advanceautoparts.com/p...VbRXUAR2dggjiEAQYASABEgIHKPD_BwE&gclsrc=aw.ds

Tim

 

[Timmy390]

Also.....Give this a try and tell me how or if it works
https://www.musclecarresearch.com/brake-valve-tool

It keeps the pin for activating the brake warning light inside the P-valve centered when bleeding. I just haven't ordered one yet to test it.

Tim

 

[Jc.av8r]

Also.....Give this a try and tell me how or if it works
https://www.musclecarresearch.com/brake-valve-tool

It keeps the pin for activating the brake warning light inside the P-valve centered when bleeding. I just haven't ordered one yet to test it.

Tim

Thanks--and actually the new valve kit comes with a plastic valve blocker you put in place of the brake warning light while you're bleeding.

My warning light isn't even connected so that's another thing I need to re-connect in this process.

 

[Timmy390]

actually the new valve kit comes with a plastic valve blocker you put in place of the brake warning light while you're bleeding.

Sweet.....

Tim

 

[FordBronc]

Also if you leave the master cylinder cap/lid on with the flip bail on it. It sort of creates a vacuum and you might only loose a drop or two when you take the lines off to put in the plugs.

 

[Apogee]

Yes, the master cylinder will gravity drain if you leave the outlet ports open. There are holes that feed into the fluid reservoir that are open until you slide the seals on the pistons past them, so be aware of that and either work quickly or plug the lines or ports. FWIW, you can get SAE inverted flare plugs to match the master cylinder outlet port sizes, which aren't the worst thing to have in your glovebox on the trail IMO...if you ever need to block off either the front or rear brake system and still have the other end be functional, they'll do the trick whereas a vinyl cap will not.

Tobin

 

[Jc.av8r]

Want to say thanks again to this forum for their guidance.

I purchased a brand new proportioning valve, replace it myself and did a full brake flush.

Eliminated all signs of leaks, flushed out some nasty brake fluid from my system and she's running great again!