Proportioning valve help

[akrapovic]

Hey guys,

I'm having issues with a leaking proportioning valve. I'm on my third one. Everyone is leaking on the out side to the rear brake lines. It is leaking at the adapter that goes into the valve line fitting is fine. Initially it was fine but after a 30 min drive it began to leak when the brake was applied. It is a slow drip but a problem none the less. I know it's not the preferred method but I even tried teflon tape. Should I tighten when the car is warmed up? That's when it seems to leak. Just looking for and tips or suggestions. I have attempted to tighten but doesn't seem to help. Oh yeah, it is a Baer proportioning valve. I'm using 1/4 aluminum factory type lines, c5 master and booster and c5 4 wheel disc brakes.

As always thanks in advance

[JRouche]

Humm, same valve fitting? For all three valves??? If so I would suspect that. Or do you get a new one with every valve. What kind of adapter is it? Flare to NPT? If its NPT then it should be self sealing, its a tapered thread. But... Sometimes a lil pipe dope works to help seal the threads and more importantly gives a lil lubrication to the threads so friction isnt causing you to bind up before the threads actually get to form a mechanical seal. I wouldnt use tape. If its a NPT that is leaking I would use a very small amount of good dope and use a flare wrench to put some solid torque to the fitting. Just a thought. JR

Hey guys,

I'm having issues with a leaking proportioning valve. I'm on my third one. Everyone is leaking on the out side to the rear brake lines. It is leaking at the adapter that goes into the valve line fitting is fine. Initially it was fine but after a 30 min drive it began to leak when the brake was applied. It is a slow drip but a problem none the less. I know it's not the preferred method but I even tried teflon tape. Should I tighten when the car is warmed up? That's when it seems to leak. Just looking for and tips or suggestions. I have attempted to tighten but doesn't seem to help. Oh yeah, it is a Baer proportioning valve. I'm using 1/4 aluminum factory type lines, c5 master and booster and c5 4 wheel disc brakes.

As always thanks in advance

[akrapovic]

I've been using a new brass fitting every time. In fact I tightened the first one to the point where it bottomed out and started leaking like a stuck pig. I have not tried pipe dope but I did use liquid teflon for the first one. I don't think that had enough time to set and was actually eaten away by the brake fluid. I'll try pipe dope next. I'm open to any suggestions so thank you.


here is the description from baer-

Acurately adjust front to rear brake bias with this adjustable proportioning valve from Baer Brakes.

The prop valve body uses 1/8 pipe thread (NPT) and the adaptors we supply with this are 3/8"-24 tube nut for 3/16" tubing and 7/16"-24 tube nut for 1/4" tubing.


Keep em coming.

[ItDoRun]

Before I started my current build, I installed a set of LS1 brakes on the front of my car. I didn't use a proportioning valve, but instead used a Wilwood residual valve between the front and rear of the car. After fabricating all new lines for the car, I learned that they make a 1/8-27 NPT and a 1/8-28 NPT thread.

What size is the connection that's leaking?

[JRouche]

Before I started my current build, I installed a set of LS1 brakes on the front of my car. I didn't use a proportioning valve, but instead used a Wilwood residual valve between the front and rear of the car. After fabricating all new lines for the car, I learned that they make a 1/8-27 NPT and a 1/8-28 NPT thread.

What size is the connection that's leaking?

Interesting. But I dont think there is a NPT in 1/8-28. The standard is a 27tpi. Not saying there isnt a 28tpi in some pipe threads, just that its not NPT. JR

[akrapovic]

What size is the connection that's leaking?

The 1/8 NPT fitting is leaking on the proportioning valve side.

[GregWeld]

So here's my .03 worth...

IF -- big IF -- you're running big ol fat tires in the rear - I'd leave the Prop valve OUT of the system. It's sole purpose is to reduce pressure to the rears just to the point of having the FRONTS lock up before the rears.... On most builds the fronts are narrow compared to the rears... so they're going to lock up (with brake dive added in etc) before the rears do. I'd only add the prop valve back if, after a test drive and the pads all bedded in etc it was needed.

Can't leak if it ain't there! LOL

I'm serious about leaving it out - if the above fits your build.

[akrapovic]

Well, is 295/35 considered big? I have plans on going to a 335 but not in the near future. I may have to consider eliminating it if my problems persist.

[Vegas69]

I have my proportioning valve dialed all the way out and have no problems with rear brake lock up. I'd leave it in the system just incase. Wilwood uses a special thread sealant on their proportioning valves. It looks almost like a dried red loctite.

[akrapovic]

Todd,

Baer had the same red stuff on theirs. This third one seems to be holding up. I snugged it up took it for a drive and it seems to be ok so far. Maybe I was just being over cautious and didn't properly tighten. Only time will tell I guess.

[Mick Mc]

1/8 pipe should not leak, as it is a tapered seal thru the threads.
Is the proportioning valve cracked from twisting the 1/8 fitting to far in? (yes this has happened to me before)

Pictures?

Is the valve leaking or is one of the adapters leaking?
The 1/8 pipe should not leak, by design. (again if it was over tightened it could crack the valve, the tapered design keeps adding more and more force as you screw inward. I see cracks in stuff from pipe threads all the time)
The adapter from the brake line into the 1/8 pipe is my guess, for the leak


Mick

[JRouche]

1/8 pipe should not leak, as it is a tapered seal thru the threads.
Is the proportioning valve cracked from twisting the 1/8 fitting to far in? (yes this has happened to me before)

Pictures?

Is the valve leaking or is one of the adapters leaking?
The 1/8 pipe should not leak, by design. (again if it was over tightened it could crack the valve, the tapered design keeps adding more and more force as you screw inward. I see cracks in stuff from pipe threads all the time)
The adapter from the brake line into the 1/8 pipe is my guess, for the leak


Mick

Ok, he already said he used a new fitting with each of the new valves.

You are right, a NPT shouldnt leak by design, but they can.

I dont think he is gonna crack the valve body. If its anything like my wilwood its a pretty solid block. Mine is aluminum. Only way you are gonna crack it is hitting it with a hammer. Even over tightening the fitting with a 24" wrench isnt gonna crack it. The fitting will compress and collapse first. Now bottoming out of the fitting is a possibility. Easy to check.

Its just leaking, simple. The fittings or the valve are cut a lil off from the standard for NPT.

I have wilwood brakes and their valve, I see the red sealant they use. I have searched their site and cant come up with what they use.

It looks like a solid setting sealant VS a pliable sealant. But I have used various pipe dopes on 10,000 PSI hydraulic systems and didnt have any leaks. You use just the slightest amount. Its not meant to fill any large gaps, say like a straight thread. But when used with a NPT that is self sealing it helps with getting a good seal in two ways. Helps with friction while tightening and helps to fill the microscopic gap you can get with a tapered thread. Most of the sealant is pushed out while tightening, thats why you only want to slightly fill some of the thread roots.

Really, try some pipe dope. And when I say pipe dope I mean any of the stuff available from permatex or lock tite. They both make some decent thread sealants. Thread sealant, not locker. JR

[Vegas69]

He said it was fixed...lol

[ItDoRun]

He said it was fixed...lol

:lol:

[JRouche]

He said it was fixed...lol

Hahaha.. I missed that line. Thanks. I need to pay closer attention to the words and not the problem :) Glad he worked it out. JR