Page 1 of 1

Brake line leak on hardline @ prop valve

Posted: Fri Mar 02, 2018 10:12 pm
by CloudStrife
Hey guys,

I'm not good with hydraulic lines but I have a weird leak symptom. It seems as though there is a very small but consistent leak on the upper connection for the hardline which goes into the (top of the) prop valve. It's odd though, that it's leaking (gradually pooling) where the nut and the line meet, so on the inner circumference?

Not sure if that makes sense but I'm just sort of confused how a leak progresses there.

Re: Brake line leak on hardline @ prop valve

Posted: Sat Mar 03, 2018 2:43 am
by totta crolla
Could be vibration if the brake line is long and not supported anywhere close to the connection.
If there is no evidence of corrosion near the connection you could try tightening the nut.

Re: Brake line leak on hardline @ prop valve

Posted: Sat Mar 03, 2018 10:04 am
by CloudStrife
I could see that.

I'm a little weary of over-tightening hard-line nuts. But if it's anything else it'll more than likely be replaced I guess.

When I installed the prop valve and new MC, almost all the lines were not kinked properly. I had references of factory routing and kinks so I know they were right, but I'm thinking one of them didn't go in right.. I'm pretty good about orientating threads to prevent cock-eyed thread movement though

Re: Brake line leak on hardline @ prop valve

Posted: Sat Mar 03, 2018 11:14 am
by CloudStrife
Ok, I guess I gave the shop too much credit when they did the brake bleed. Seems that nut was loose.

I'm gonna re-bleed and see how she goes, but pedal pumping doesn't seem to produce any kind of pooling so looks good!

Re: Brake line leak on hardline @ prop valve

Posted: Sun Mar 04, 2018 12:42 am
by CloudStrife
So I went for a drive after bleeding all the brakes from furthest to closest, and made sure there were no bubbles.

No leaks visible on any fitting, and all fittings nice and tight.

I bedded in the brakes, but it still feels like the pedal is too hard. if I apply good leg force, she stops good, pretty damn good actually. But the amount of force is too much.

Now I powdercoated my brake pedal brackets, and basically replaced all the fittings and switches etc. Could I be in need of adjusting the pedal freeplay or something?

Maybe booster isn't working properly?

Re: Brake line leak on hardline @ prop valve

Posted: Sun Mar 04, 2018 3:19 am
by davew7
Sounds like the power brake system is not holding a vacuum. Inspect the hose fitting on the canister which has an internal check valve, including the grommet, also the hose, and listen for any air leaks around the chamber. If you can borrow a hand vacuum pump and hook it up to the canister, it would verify if you have vacuum leak when trouble shooting. davew7

Re: Brake line leak on hardline @ prop valve

Posted: Sun Mar 04, 2018 10:28 am
by CloudStrife
Thanks Dave,

I actually found out that the check valve between the hoses was flipped the opposite way.

I flipped it back, and now the power brake system seems to be working. However, when I step on the brake @ idle (haven't driven), the pedal will go down, but become "sticky" when it hits bottom, and has a little trouble coming back up. Pretty terrible pedal feel, it is very soft and doesn't build up in pressure. So now it's working too well? :x

Would this be just a vaccum leak? It seems more like internal failure in the booster.. Could having the vacuum check valve with the wrong orientation killed my booster?

Re: Brake line leak on hardline @ prop valve

Posted: Sun Mar 04, 2018 10:51 am
by CloudStrife
I pulled the hose after the check valve (going to the booster) off, after running the car for a bit and turning off.. and a good amount of pressure released from the hose, hissing and what not. Wouldn't that mean normal operation?