So I may or may not have to replace the prop valve. When redoing the front brakes I had to replace the pass side metal line. It took a while, but finally got the line off and installed and all set up. After bleeding there is a small bit of residue around the brake line inside the nut. No drips or anything. I'm afraid the new line in not seating properly and worried I may have to replace the whole valve.

My question is, I know its a Corvette and the parts are $$$ because of the name but after all, it's a Chevy. So after some google foo, can anyone tell me the difference and if its worth the extra cost?
The first link is a Chevy PV4 valve for $40
https://www.ebay.com/itm/GM-CHEVY-DI...9aTrbp&vxp=mtr

The second link is for an "78-82 Brake Proportioning Valve" for $80
https://www.zip-corvette.com/78-82-p...ing-valve.html

To my eyes they are the exact same and $40 saved is nice to put into other parts of the car.

 

Looks the same as the new combination valve that I purchased from a Corvette vender.

The part number on the box is PV4.

I'd save the coin and buy the one on fleabay.

Craig

 

The pain of it is, I didn't seem to have any problems with the valve inside being stuck, just a small leak where that line was replaced.

 

Even the smallest of leaks is enough to get air in the system.

 

If you have tried tightening the leaking fitting, you likely have a little piece of dirt/debris in the flare or the flare has a bit of damage on the line or the seat. Try snugging it up some. If not joy, take the fitting out and give it a VERY GOOD inspection for debris or surface damage. If the prop valve flare seat has damage, it will need to have the seat re-surfaced or just replace the valve. Either will require you to bleed the brakes again. But, it needs to be fixed and seal completely.

 

If it's still leaking, I'll have to pull the line off and check it out, it really needs a new driver front line too. The worst part is the front brakes worked fine, I pulled the calipers to rebuild them for preventative maintenance and it's causing all sorts of headaches.

 

I notice you say there are no drips, just a little residue. When you screwed the lines in, did you put any brake fluid on them first? When replacing all my lines I did this initially to smooth the entry and it would leave some residue, but like you said, no drips. Even if you didn't do this, could the line have picked up some fluid from the valve while the line nut fitting was not pressed against the line flange? My first question would be is it really leaking? I'd start by just getting the residue cleaned up and then pumping the brakes to see what happens from there.

When you put the line in was the prop valve still attached to the frame. My experience was that it was nearly impossible to get the lines to stay perfectly aligned in the fitting as they can never be perfectly bent with all the twists and turns they take en route. I opted to pull one of the prop valve mounting bolts and loosen the other one so it could move around to get better alignment when putting screwing in the fittings.

Also, once inserted I tightened then slightly loosened the fittings 3 or 4 times. This is old school from my grandfather who was born before the Model T and owned a garage from the 40's to the 70's (both decades and his age). The theory being that if the line is being pushed to one side of the fitting the repeated tightening cycles will bend the flange into alignment with the seat. True? I don't know for sure, but I didn't have any leaks after I was completely done (see next paragraph) and my prop valve is the original in my 80.

Lastly, if you're like me you might be hesitant to torque the fittings down for fear of stripping them or rounding the nuts. Also, it isn't exactly an easy place to work in, so what may seem like a lot of pressure with your hand in an awkward position may not really be that tight. I did have one or two fittings that did have very slight leaks a day or two after all the lines were in. So I then did turn the offending fitting or fittings a little more. That ended the problem.

As they say - advice worth price charged

 

preventative maintenance - Definition: Activity which prevents use of the device

 

Personally... I'd loosen the lines from the valve... and then torque them down again... it sounds like there may be a seating issue.

Proportioning valve replacement is very unusual... in most cases you can remove the valve, remove the switch, clean them and then re-install.... I can say that in the last thirty years, I've only replaced one and that was at the customers request. They are just a distribution block that can get plugged up at times but it's really rare to replace the valve. I'd also question the front to rear distribution of the aftermarket valve... I looked and it's not showing to be a direct replacement for the one on your car. The original valve was 1257208 for your car...

I'll leave this convo... with saying that the current reproduction valves also have an issue and are not made correctly. Lone Star imports them and they are junk.... And yes if Kenny @ LS is reading this... they are junk... import better parts and stand behind your products...

IMHO,

Willcox

 

Thanks for the response guys! I pulled the line off, cleaned off both surfaces, applied some anti-seize, and then cranked that sucker down. Shot it with brake clean and then compressed air. Bled those puppies and mashed the pedal so hard I thought the MC was going to fly off. So far no leaks. Just a little residue at the damn copper washer again. I tightened that up some more. Hopefully I'm done with the brakes. It seems to stop fine in the driveway.

Next is to get insurance so I can actually drive it. Being 24, I have been putting it off for as long as I can while I "tinker" on it. Its getting close to to where I want it. Plug wires next!

Oh and Willcox, you guys rock! I purchased a portion of my interior from you guys and it turned out great! I have been meaning to stop by the store in Jeff when I'm in town, but I'm usually there during the weekend so I don't get the chance.

 

Just a "word to the wise" for those in similar circumstances...

You may purchase a car that you are wanting to repair/rebuild and have no intention of putting it on the road until it is operational. BUT... the car could still catch fire..or the garage could catch fire and burn the car up, etc., etc.

As soon as you purchase the car, call your home insurance agent and put the car on the policy as "personal property". If it is unlicensed, it can't be insured as a car; but they will insure it for the "replacement" value (show them the bill of sale for helping to evaluate it).

Or, call a collector car insurer and get a policy on the car which will cover "comprehensive" claims ONLY, leaving the car in a state of 'storage' until you are ready to put it on the road.

Otherwise, if it gets stolen, destroyed, etc, the loss will get you absolutely nothing. And, thinking that your homeowner's insurance will cover it without contacting them and writing an addendum to your policy, is wishful thinking. If the car has value to you, get it insured as soon as it is in your possession.