Multiple problems with bleeding brakes

-

ESP47

Well-Known Member
Joined
Jul 3, 2009
Messages
2,519
Reaction score
1,475
Location
Sacramento, CA
Just did a drum to KH disc conversion. Went to bleed the brakes and had multiple problems.

The proportioning valve I bought from Summit leaked from the top nut so I tightened it down and it improved things but still couldn't get it to stop leaking all the way. It also leaked where the line going to the rear end screws into it. I took it out and reseated it multiple times and it leaked every time. I'm returning the part and I'll buy one from inline tube. I'm not so concerned with the top nut leaking because I assume that'll be fixed with the new prop valve but the line going to the back leaking has me worried because I'm not sure if that's a problem with the Summit prop valve or with my line itself.

I'm using a small vacuum pump bleeder for the first time ever. I've always done it with 2 people in the past. So I'm just trying to see if it works on the front calipers. I pumped it up to create vacuum, broke the bleeder screw loose, it spit a little bit of brake fluid into the line and then I closed the bleeder screw. At this point, there was still a little bit of brake fluid sitting in the tube right at the bleeder screw but I could see it continue to bubble until I released the pressure on the vacuum pump. I went to the other caliper and it did the exact same thing. I'm guessing I have bad bleeder screws that aren't quite closing all the way when tightened? Anyone ever have this happen? Seems odd to me.
 
How much vacuum are you pulling? It may be air in solution in the fluid bubbling out. If it's air getting in, the most probable place is the bleeder screw threads. I loosen mine about a third of the way out and rub a very small amount of Teflon paste around the threads next to the caliper/wheel cylinder, and then run it in and leave it "cracked" just enough to bleed. I have used vacuum bleeding before. Now, I almost always push fill brakes from the bleeders back to the master cylinder with a thumb pump type oil can with a piece of tubing attached to the bleeder. This eliminates need to bench bleed the master cylinder and pushes the air from the lowest points in the system to the highest. You do have to Teflon paste the bleeders to keep the system sealed while pumping it in, though.
 
Bleeder screws were my biggest problem too. I just put a little bearing grease around the base to keep air out.
 
How much vacuum are you pulling? It may be air in solution in the fluid bubbling out. If it's air getting in, the most probable place is the bleeder screw threads. I loosen mine about a third of the way out and rub a very small amount of Teflon paste around the threads next to the caliper/wheel cylinder, and then run it in and leave it "cracked" just enough to bleed. I have used vacuum bleeding before. Now, I almost always push fill brakes from the bleeders back to the master cylinder with a thumb pump type oil can with a piece of tubing attached to the bleeder. This eliminates need to bench bleed the master cylinder and pushes the air from the lowest points in the system to the highest. You do have to Teflon paste the bleeders to keep the system sealed while pumping it in, though.
autozone sells one of these setups for like 8-10 bucks, I used it on my jeep last spring and WOW does it make that job easy
 
FIRST THING you MUST do is get the system air/ liquid tight

Personally I DO NOT LIKE vacuum bleeders, and the reason might be related to your problem. If you pressure bleed, and that is WHAT the system normally sees, any leaks will tend to show up. Plus you will not be sucking air into the system. Wheel cups can ingress air under vacuum.

Many people have good luck with gravity bleeding.

For any vehicle I've ever bleed, I've been able to lash up a cap for the master and create a pressure port. For a recent Dodge Dakota, I bought a new cap and epoxied a tube into the cap Some guys use an old weed sprayer bottle for pressure
 
FIRST THING you MUST do is get the system air/ liquid tight

Personally I DO NOT LIKE vacuum bleeders, and the reason might be related to your problem. If you pressure bleed, and that is WHAT the system normally sees, any leaks will tend to show up. Plus you will not be sucking air into the system. Wheel cups can ingress air under vacuum.

Many people have good luck with gravity bleeding.

For any vehicle I've ever bleed, I've been able to lash up a cap for the master and create a pressure port. For a recent Dodge Dakota, I bought a new cap and epoxied a tube into the cap Some guys use an old weed sprayer bottle for pressure

I use a squeeze bottle with a tube on it and pressure fill from the wheels up if I have to do it by myself, but usually the Wife is around somewhere and knows the drill already.:D
 
yup, " Some guys use an old weed sprayer bottle for pressure "
 
i use speed bleeders in EVERY car i own. And every car i work on the brakes i ask people to install them. Ive had pressure bleeders, vac bleeders, motive, handheld, ect...the speed bleeders are just plain easier than all of them.

install, crack one open, pump away, leisurely close it whenever you want and move to the next one. a true one man job with zero pressure on the person doing it


no hokey, homemade contraptions needed either
 
I returned the prop valve to Summit and bought another one from Inline Tube.

The leak at the port to the real line is gone but the thing leaks badly from the top at the crush washer. What gives??? Getting tired of this.
 
Does anything in California work right?
I don't know anything about crush-washers on Mopar brakes, but if they ain't made of copper, then throw them away and get coppers. Coppers are reddish in color, not chrome and shiny. Aluminum will work in a pinch, certainly better than chrome-plated.

As for the vacuum bleeders, bubbling after the bleeder is tight, is sorta normal. Like said; the hose is just not tight enough on the bleeder, or it's pulling air from down the threads; I anti-seize the bleeder threads, and got used to seeing some of them.

As for brake lines; I learned to double-flare them and make my own. So if one leaks, I know who to blame,lol; Yeah not every flare is perfect........but mostly they are.
 
Last edited:
The fittings on Inline Tube proportioning valves are usually finger tight.

If the valve is already installed, you must hold the body with a Crescent wrench. Otherwise, you can't tighten the nut properly.
 
Yeah it has a copper crush ring. When I installed the lines from the MC to the prop valve, I put the prop valve nut fitting at the top in the vise to ensure it didn't turn at all when I tightened the line to it.

After installing it and attempting to bleed the brakes, it started dripping from the crush washer. After that I held the body with a pair of pliers and turned the nut fitting on top and tightened it a good bit. Still leaked after that. So I went back and tightened it as much as I could and it continued to leak.
 
I returned the prop valve to Summit and bought another one from Inline Tube.

The leak at the port to the real line is gone but the thing leaks badly from the top at the crush washer. What gives??? Getting tired of this.

I had the same problem. I stole the prop valve from my Scamp, rebuilt it using the guts from one of the new, leaky valves, and put it in my wagon. That cured the leak.

I e-mailed Inline Tube about it and they said they never had a problem like I experienced. I asked them what fitting they used in the top port if they never had any leaks, but they didn't respond to that question.

Find an old prop valve, that will fix your leak.
 
Thanks I'll look around for a used one. I'm also going to grab a crush washer kit and see if I can do a quick fix on it. Appreciate all the advice. What a pain and a waste of time this has been.
 
Yeah it has a copper crush ring. When I installed the lines from the MC to the prop valve, I put the prop valve nut fitting at the top in the vise to ensure it didn't turn at all when I tightened the line to it.

After installing it and attempting to bleed the brakes, it started dripping from the crush washer. After that I held the body with a pair of pliers and turned the nut fitting on top and tightened it a good bit. Still leaked after that. So I went back and tightened it as much as I could and it continued to leak.
I bet you it’s tapped with the wrong thread type...
 
I bet you it’s tapped with the wrong thread type...

That's what I thought. It's a 1/2-20 thread, which is very close to something metric 12-1.25 or 13-1 (I forget which exactly) I took the prop valve down to my local hardware store, which has an impressive collection of fasteners... The metric bolts didn't engage cleanly, the 1/2-20 bolt was the best fit. Inline Tube confirmed its 1/2-20 thread.

They're just made bad, like so many other parts these days.
 
The thread is not what seals it................Modern copper washers most seem to be hard tempered. You must anneal them, Google this. It's easy pair of pliers and a blowtorch................

 
I like using a pressure bleeding system as it will show you where your leaks are and what needs fixing. As mentioned before, first step is to get your system sealed!
 
Never heard of annealing copper but now I know. Thanks! Going to try that as well and see what happens.
 
Sounds like you need to get all the leaks fixed before you worry about bleeding. Bleeding standard non ABS hydraulic brakes is very simple.......as long as they don't leak. lol
 
Never heard of annealing copper but now I know. Thanks! Going to try that as well and see what happens.
at work we run 5000v through it for a minute or so, anneals the piss out of it
 
One person bleed the old fashioned way:
Hold the pedal to the floor with a heavy weight or a stick propped between the pedal and something.

Sealing at the combination or prop valves:
Like A/J mentioned I can't recall anything other than a SAE double flare. The flare seals to a matching cone. Thread in until the flare touches the seat, then tighten a fraction of a turn more so its snug. Sometimes there is an adapter fitting going from NPT tapered to SAE double flare.

Some illustrations:
Brake Line Flares: Metric & SAE, Inverted & Bubble - Race & Track Driving (formerly Win HPDE)
http://www.fedhillusa.com/webnuts/common flares6.pdf

This M/C has adapter fittings:
upload_2019-9-9_8-35-28.png


This proportioning valve does not, the seat is pressed in.
upload_2019-9-9_8-39-10.png


from: 1967 Imperial & Chrysler Disc Brake System - Session 233
 
-
Back
Top