Hi,

Has anyone had ongoing issues with these PV2 proportioning valves leaking? From online searching it seems there is no shortage of people having the exact same issues. At first, right after the install it was leaking from the end with that rubber cap. Turns out you can buy a replacement piece and seal for that end. It worked and was leak free for the season, but now it appears I have a new leak from the top plastic piece that connects to the brake light. Apparently there should not be fluid in this area so likley one of the internal o-rings has failed.

I can't seem to find new internals which seemed like replacing those would be easier than replacing the whole part. Does anyone know if these are just standard size o-rings that would be easy to replace, nothing odd shaped or sized in there? If not I will just have to try a new one, I just read a lot of people went down this road and are on thier third or worse. On that note, is there any alternative or brand that is better than another?

 

I haven't purchased from them but I've heard good feedback about their products & their service.

Master Power Brakes

Can't answer your question(s) regarding O-Rings.

 

Thanks! A bit pricey but as long as it is a quality part that doesn't require replacing every year it would be well worth it.

 

Update:

I have the new proportioning valve installed and put that piece in the top to keep it centered. After snugging up a few lines at the valve to fix some leaks i moved on to attemp bleeding. Just like last time, i am getting nothing at the rear. Last time i assumed it was because i didnt have that centering tool installed and it moved. Now i dont know what the problem is. Any ideas?

 

I suspect you have 50+ yrs of crud in your lines - &/or your bleeder valves are clogged/gunked. Did you flush the brake lines? Remove the bleeder valves, perform a complete brake flush.

 

Hi,

All lines are new except the line running from the valve to the rear. I would have thought blockage too, but with the last valve and a lot of messing around I finally had good flow to both back wheels so I think the line is OK. I'm just worried that we may have pushed the brake pedal too hard causing the valves internal seals to fail. I'm trying not to do that again. It just seems to me with a 95% new system and a new valve with the centering tool installed there should be easy flow to all four wheels. Instead the pedal seems to easily move about 2" then get really hard. I actually just went and tried a front wheel - no fluid there either. I had leaks at the valve, so I assume there is fluid from the master cylinder to the valve, just not understanding how it stops there.

One thing I heard about was brake booster rods sometimes needing to change length when a front disc conversion is done. Could that cause this issue? They seemed to operate fine once they were finally bled. Just kept getting leaks.

 

You have several seems & assumptions. Assume nothing. Begin at the MC, open each line from MC> Input of Combination Valve>Output of Combination Valve>Each Bleeder Valve ensuring you have fluid flow.

 

I went and started loosening lines at the proportioning valve. Confirmed fluid at outlets to front wheels and outlet to rear wheels. Out of curiosity I found a vacuum pump and tried pulling fluid from a rear wheel and it came through. So it looks like what I thought was the valve not allowing fluid through or trapped air or clogged lines isn't the issue. With that progress made it looks like whatever is causing that strange feeling pedal is to blame. I don't think a brake booster would cause this, so I suspect something is wrong with the new disc/drum master cylinder that cane with the kit.

 

I went through this last year on an el Camino. 3 MCs (1 bad new one) and 3 PVs (1 bad new one) before getting volume and pressure at all 4 wheels and properly distributed Frt & Rear. Exasperating!

…

 

Did you bench bleed the MC prior to installation?

 

I did bench bleed the new MC. Somehow after using the vacuum pump to pull some fluid through we went back a few hours later and were able to get the brakes bled without any extreme pressure on the pedal. Maybe it was air trapped somewhere. I made sure everything was tightened up so tomorrow I will check for leaks and hopefully get it fired up for a test drive. Thanks for the help, hopefully with the new valve my brake problems are over.

 

Likely you hadn't expelled all the air from the brake system. I generally bleed brakes twice.

 

Looks like I still might not have all the air out, lol. Started it for the first time this year and the brake light was on. So I took it for a very slow drive up the street and back. After the drive the light went out, but if I held the brakes down I could get it to flicker or come back on. At least I know there is fluid at all the wheels and there are no leaks. I will get under it again, give it a thorough leak check and bleed again.

 

Having fluid at all four wheels with functioning brakes which correctly stop the vehicle is of course the primary concern. I suspect you used the original brake light electric switch mounted above the pressure differential valve at the center position where you would have installed the valve bleeder tool during brake bleeding. Any issues w/ re-inserting the brake light switch back into the combination valve? You should be able to remove that switch, examine it and reinsert w/ no loss of any fluid (obviously making sure you don't step on the brake pedal w/ the electric brake switch removed).

 

Correct, using the original electrical connector, and did use the centering tool. No issues, went in by hand pretty much all the way, then snugged up with a wrench. I was planing to re-install that tool when bleeding them again so I will take a look and make sure everything looks fine there. Looking at the valve with a flashlight after the drive it looked like there may be a small leak at the valve outlet for the drivers front wheel so I will tighten that a bit before bleeding.

 

Don't go gorilla crazy when tightening things up on outlets. Sometimes they might need a little tweak - very slight loosening then another cinch.
Pressure differential brake light switch is working (that's good) although intermittently, maybe? I wouldn't sweat that switch for the moment as long as brakes are functioning as designed. That brake light switch may be a little finicky after having been removed then reinserted after how many years of having never been removed? Just removing it and reinserting it may help, but I'd drive that car several days>a week or so & see how it behaves. Obviously, that lamp switch is independent of the actual brake system. If the lamp illuminates when IGN SW is in ON position, then it's working/illuminating. See if it behaves better after a week of driving then revisit.

 

Good points, maybe I will just recheck for leaks, check the plastic connector on top and reinstall, then just jack up each wheel and make sure I do have brakes at each wheel and give it a careful drive or two and see how it goes.

 

I guess it slipped my mind to ask you have the stock configuration disc/drum configuration or were the brakes upgraded to disc/disc? You obviously purchased the correct combination valve I'm sure.
You appear pretty confident the brakes are working. If that is the case & you suspect that is the case, I would not baby the brakes with a slow careful drive. I'd be more inclined to be aggressive making sure they're designed to uphold in a panic stop. Additionally, I'd take a couple solid runs in reverse & lock them up. No time like the present to ensure those drum self-adjusters are working as designed.

 

It was drum/drum and I installed the front disc conversion kit with the PV2 disc/drum valve. Once I have confirmed brakes at all wheels I will do some "emergency stops" like you say to make sure it's all good. I just went and tightened up that one leaky fitting so hopefully it's leak free now. I always expect leaks because I'm worried about damaging the flared end by over tightening. I typically just snug them up and expect leaks, then go gradually tighten things up until the leaks are gone. Pain in the butt and messy, but easier that having to redo some flared ends.

 

Smart man.