Brake Bleeding Issues

[dak440]

Looking for help on brake bleeding a completely new , dry system. New booster, master cylinder, lines, calipers, proportioning valve/metering block from In- Line Tube. First, I'm not a novice, and have done every conventional approach that have worked for years. Bench bled master cylinder, manually bled, mtyvac bled at wheel cal/calipers, replaced reman master cal twice, replaced proportioning valve / metering block with the original, checked all fittings etc. Getting fluid to back at wheel cylinders, but cannot stop getting air . Sealed bleeders with teflon tape , etc, etc. Bled a dozen times... still getting air, but no sign of fluid leak anywhere where air could be getting in. About ready to pull wheels and replace wheel cylinders...had put in remans. Anyone else solve this dilemma before?? Thanks.

 

[khryslerkid]

I'd get rid of the teflon tape. The line is sealed by the tension on the flared end, not by around the threads.

Bleed RR, LR, RF, LF in that order.

I've heard of some caliper kits that have the bleeder at or near the bottom of the piston and air is impossible to get out. The calipers are mounted upside down.

I like to bleed into a sealed bottle. Doing it by myself I have a hose from the bleeder into the bottle and the hose is submerged in fluid. When you let off the brake it won't draw air back in. I don't have much faith in the vacuum bleeders.

 

[Yatzee]

Looking for help on brake bleeding a completely new , dry system. New booster, master cylinder, lines, calipers, proportioning valve/metering block from In- Line Tube. First, I'm not a novice, and have done every conventional approach that have worked for years. Bench bled master cylinder, manually bled, mtyvac bled at wheel cal/calipers, replaced reman master cal twice, replaced proportioning valve / metering block with the original, checked all fittings etc. Getting fluid to back at wheel cylinders, but cannot stop getting air . Sealed bleeders with teflon tape , etc, etc. Bled a dozen times... still getting air, but no sign of fluid leak anywhere where air could be getting in. About ready to pull wheels and replace wheel cylinders...had put in remans. Anyone else solve this dilemma before?? Thanks.

I prefer to gravity bleed before doing bleeding via the brake pedal. I start with the rears first and it may take a couple or more hours to flow completely down the line bringing the air with it. I've also bled calipers by suspending them upside down tethered on a piece of wire and with the bleeder plug completely removed and at the bottom. Residual air bubbles usually come from the master and/or the prop valve. If you had a manual prop valve, bleeding is easier as you can shut off one circuit while you bleed the other. Remember, under pressure the air in the fluid breaks down into minute air particles and rejoins as larger bubbles as it sits. This doesn't happen when you gravity bleed. The absolute best way is to pressurize the master ( they make a kit for this) slightly and then start bleeding at the furthest point away. You can actually make your own cap with a schraeder fitting and pressurize to about 3 - 5 psi.

 

[Mike67]

Of all the jobs to do this is probably my least fav, just when you think you're done, you find out that your not.
I have a pressurized bleed system that is fine on modern MCs but not very good on the old cast iron ones. I also have a vacuum pump that does great to get the initial air out, but won't get the very small molecules out like Yatzee stated, sometimes they will be so small that the fluid will look milky, so I resort to the same method that KKid uses. A bottle filled with fluid, a hose that fits tight on the bleeder and is submerged in the fluid. Make sure the hose is as short as possible, the longer it is the more air you have to push out initially.
Something I'll add is to use a very thin wrench to open and close the bleeder as not to break the seal the hose has on it. I have an old set of distributor wrenches that are about 1/8" thick, they work great.

 

[71charger_fan]

Clamp off the rubber lines and see if you have a firm pedal. If so, you should have a good MC and no air in the lines between the MC and the rubber lines. Take off one clamp, check the pedal. If it's firm, you know that section is good. If not, there's a problem right there. Once you unclamp a rubber line and the problem returns, at least you've isolated the problem section. If it's in a caliper, you might have to take the caliper off the disc and turn it to get the bleeder pointed vertically to get the last bit of air out. On my '55 Plymouth, I had a stubborn air pocket in the rear brake lines. I finally bought and used a V-5 pressure bleeder after trying gravity bleeding, a mityvac, and the good old have someone push the pedal. The air bubble was in a rear wheel cylinder and stubbornly refused to come out. I clamped off the rubber line and tried pushing the fluid across the rear end and the air bubble was still in there. Finally, I took off the drum and with the rubber line clamped off, I used the V-5 to pressurize the rear lines and let the shoes expand and retract a few times. After about three times, an air bubble burped out and I finally had brakes. This was after bleeding 2 gallons of brake fluid through the lines and just about going nuts trying to figure it out. Mine was complicated by also having purchased a new, but defective, MC which I finally positively diagnosed by plugging the ports and pushing the pedal. After holding for about 2 seconds, it just sunk to the floor.

 

[Billccm]

You can read my brake bleeding night mare in this forum. I spent many weekends trying to get a good bleed after a disc conversion and replacement of all brake lines. I even had my MOPAR expert come by and we could never get a good bleed. Bought a MitiVac and still had issues.

I brought in a coworker who is a mechanical engineer and former BMW/Porsche mechanic who also wrenches on old 944s for his 'customers' on weekends. He had to tighten every tube fitting from the proportioning block to each wheel, and I mean tighten until the tube nut was destroyed. Brakes now work well, although the lines are no longer serviceable. Future repairs will require cutting the lines off, so I hope that day does not come anytime soon.

The problem was sucking minuet air at almost every fitting.

I will add that I used InLine Tube lines and I suspect a quality issue.

Let us know how you make out.

 

[threewood]

Hey Bill, were your lines stainless? I have heard they are harder to get to seal without a brass insert.

My bleed issue turned out to be at the master cylinder piston. The tab that holds the piston in the master cylinder kept getting bent out allowing air in behind the seal. Use of the original retainer plate or fabricated one did the trick for mine.

 

[Billccm]

Hey Bill, were your lines stainless? I have heard they are harder to get to seal without a brass insert.

No stainless, just the basic low cost steel lines from InLine Tube. I should add one of the lines was defective in that the double flare was off center just slightly and not round. My mechanic/coworker had a really nice double flare, bending fabrication machine and made me a new line.

If I ever have to tackle this again, I will borrow his machine and make the lines myself. Lesson learned.

 

[threewood]

No stainless, just the basic low cost steel lines from InLine Tube. I should add one of the lines was defective in that the double flare was off center just slightly and not round. My mechanic/coworker had a really nice double flare, bending fabrication machine and made me a new line.

If I ever have to tackle this again, I will borrow his machine and make the lines myself. Lesson learned.

I used InLine Tube for all my hardlines and they all sealed up without issue. A bad batch must have got thru.

 

[PeteBell68]

I'd get rid of the teflon tape. The line is sealed by the tension on the flared end, not by around the threads.

Bleed RR, LR, RF, LF in that order.

I've heard of some caliper kits that have the bleeder at or near the bottom of the piston and air is impossible to get out. The calipers are mounted upside down.

I like to bleed into a sealed bottle. Doing it by myself I have a hose from the bleeder into the bottle and the hose is submerged in fluid. When you let off the brake it won't draw air back in. I don't have much faith in the vacuum bleeders.

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Also remember to bench bleed the master first - do it slow for longer than you think , Teflon tape has to go .bleed into bottle always has worked while the wife worked the pedal slow .
Bleed the rear right passenger wheel first - farthest from master .

 

[threewood]

My personal bleeding trick is to use a length of clear tubing with a one way valve spliced in. The other end of the tube tightly into a water bottle. Wrap a wire around the tubing to suspend it above the bleed screw. Air goes up, valve keeps it from going back down and fluid runs to the bottle. I use it by myself all the time.
I also put a drop of blue loctite on the bleeder threads if it is loose in the wheel cylinder. Keeps air from going around the threads

 

[Billccm]

I used InLine Tube for all my hardlines and they all sealed up without issue. A bad batch must have got thru.

Not only a bad batch, but about four weeks of back and forth with InLine Tube to get my order correct. Since I can only wrench on Saturdays, I would go along and discover either a missing line, or the incorrect line (firewall line was not correct).

Glad your experience with them was good. I'd rather sell the car at a loss than deal with InLine Tube again myself.

 

[khryslerkid]

I bought all Inline for my '62. The front to back line was a little long but tightened the bends a bit and it was fine. Only had one small leak at one of the rear wheel cylinders and it was my fault. When tightening the line, my wrench must have stopped against the bleeder and I thought it was tight. Always use a line wrench!

The trick to tightening new lines, especially stainless steel, is to tighten, break them loose and tighten again. That will help form the flare to the seat. I also used DOT 5 and that's some nice stuff! I blead each wheel one time and had a full peddle. Did it one more time just for good measure. Used about a pint total. Did I mention, always use a line wrench!

 

[joemish]

Looking for help on brake bleeding a completely new , dry system. New booster, master cylinder, lines, calipers, proportioning valve/metering block from In- Line Tube. First, I'm not a novice, and have done every conventional approach that have worked for years. Bench bled master cylinder, manually bled, mtyvac bled at wheel cal/calipers, replaced reman master cal twice, replaced proportioning valve / metering block with the original, checked all fittings etc. Getting fluid to back at wheel cylinders, but cannot stop getting air . Sealed bleeders with teflon tape , etc, etc. Bled a dozen times... still getting air, but no sign of fluid leak anywhere where air could be getting in. About ready to pull wheels and replace wheel cylinders...had put in remans. Anyone else solve this dilemma before?? Thanks.

The Teflon Tape is the Problem. None required.

 

[Ski 61701]

What I do with stainless steel lines is on the back side of the flare where the nut makes contact, I put a small dab of anti sieze on it, and spin the nut so it gets spread out. Wipe off any that weeps out towards sealing surface. Install as usual. What I find is the antisieze is a lubricant that allows a nice smooth surface for proper torquing, kinda like using arp lube on rod bolts etc. Since using antisieze, I dont have pesky leaks anymore

 

[gtxracer]

After reading all the posts regarding brake bleeding issues, and all the ways we all attack this problem, it makes me happy to know lots of us have dealt with the same problems. Thanks for all the different ideas.

 

[furyus]

In case you haven't fixed it yet, i had a wheel cylinder that was new. Pulled the dust boot back, and i could see seepage past the wheel cylinder piston. Put the old one back on. Fixed.