Brake line leak on hardline @ prop valve

CloudStrife
Club4AG Pro
Posts: 630
Joined: Thu Oct 06, 2016 2:23 pm
Location: Middle of Hell, Florida

Brake line leak on hardline @ prop valve

Postby CloudStrife » Fri Mar 02, 2018 10:12 pm

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.
Success guardian... Successsssssss..

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


totta crolla
Club4AG Expert
Posts: 493
Joined: Tue Mar 26, 2013 5:21 am
Location: Oxford U.K

Re: Brake line leak on hardline @ prop valve

Postby totta crolla » Sat Mar 03, 2018 2:43 am

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.

CloudStrife
Club4AG Pro
Posts: 630
Joined: Thu Oct 06, 2016 2:23 pm
Location: Middle of Hell, Florida

Re: Brake line leak on hardline @ prop valve

Postby CloudStrife » Sat Mar 03, 2018 10:04 am

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
Success guardian... Successsssssss..

CloudStrife
Club4AG Pro
Posts: 630
Joined: Thu Oct 06, 2016 2:23 pm
Location: Middle of Hell, Florida

Re: Brake line leak on hardline @ prop valve

Postby CloudStrife » Sat Mar 03, 2018 11:14 am

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!
Success guardian... Successsssssss..

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.


CloudStrife
Club4AG Pro
Posts: 630
Joined: Thu Oct 06, 2016 2:23 pm
Location: Middle of Hell, Florida

Re: Brake line leak on hardline @ prop valve

Postby CloudStrife » Sun Mar 04, 2018 12:42 am

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?
Success guardian... Successsssssss..

davew7
Club4AG Enthusiast
Posts: 170
Joined: Fri Jun 06, 2014 4:34 am
Location: Michigan

Re: Brake line leak on hardline @ prop valve

Postby davew7 » Sun Mar 04, 2018 3:19 am

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

CloudStrife
Club4AG Pro
Posts: 630
Joined: Thu Oct 06, 2016 2:23 pm
Location: Middle of Hell, Florida

Re: Brake line leak on hardline @ prop valve

Postby CloudStrife » Sun Mar 04, 2018 10:28 am

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?
Last edited by CloudStrife on Sun Mar 04, 2018 10:55 am, edited 2 times in total.
Success guardian... Successsssssss..

CloudStrife
Club4AG Pro
Posts: 630
Joined: Thu Oct 06, 2016 2:23 pm
Location: Middle of Hell, Florida

Re: Brake line leak on hardline @ prop valve

Postby CloudStrife » Sun Mar 04, 2018 10:51 am

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?
Success guardian... Successsssssss..

Disable adblock

This site is supported by ads and donations.
If you see this text you are blocking our ads.
Please consider a Donation to support the site.



Return to “TECH: Corolla AE86”

Who is online

Users browsing this forum: No registered users and 1 guest