Assuming there are no leaks,it sounds like the master cylinder may be letting some fluid past the piston. That might explain the presence of froth right there,although there shouldn't be any. Don't know about teflon tape on the bleeders. I've always used one-man bleeders,and they work fantastic. You also didn't say if you still had the ABS. I got rid of mine years ago. So,that's never a factor for me.

 

Also think about hoses - when is the last time you changed them?

 

x2 on the MC. I had an old caddy with very similar symptoms you described. Replaced the MC and the problem was fixed.

 

Wow, go out with daughter to replace lip balm dog ate, and BAM BAM BAM ! right back at me. Thx fellas.

@slow
Yeah, I woulda thought B/F would leak out back of M/C onto booster when air gets in.
Teflon tape seals the nipple so air doesn't leak back in when getting off the brake.
Nipple -> hose -> glass jar with fresh fluid; is kind of a poor mans speed bleeder. As long as the hose and jar is full of fluid, it's all good.
Yes, I have abs. Very little likelihood it went dry.

@Doug. Hoses were done with Bill's HD12s and rear discs, just a handful of years ago. And no leaks, I woulda noticed that toute suite.

@4Door
OK, thx for sanity check. There's a cheap rebuild on rockauto for $26. Guess I'll be enjoying a nice DOT 4 mess again

 

Just wanted to make sure the hoses aren't being overlooked, not necessarily as the cause of the current problem, but as general maintenance especially with everything you're doing.

 

See ricpin066 on Youtube for a good segment on how to make a one man bleeder out of a bottle, metal tube, and stopper and then shows how to use it. Most of his work is on Saturns, but he is good and well worth watching for his technique.

I wish RicPin would be so kind as to do a segment on how to replace the B body fifth brake line, the one over the differential, and how to replace the upper mounts on the rear shocks. That's without removing the body from the chassis.

 

yep, that's a 1 person bleeder.

Richpin06a

'Cept you dont need to get that fancy, hose stuck in the jar with fluid is plenty.

 

Yea,that is a lousy way to bleed brakes. The master cylinder doesn't have to be leaking for the piston to "push-through" instead of "push-against" the fluid contained in the bore. You could easily have air trapped inside the ABS unit if the brakes are not bleed properly.

 

I dunno man, it's the same as a gravity bleed which a lot of folks have had success with. And everything ever written here and in the FSM says the ABS passages are clear to bleed without any special tools.

As far as pushing ~through~ the air trapped in the m/c, that's a possibility but I very successfully bench bled that blasted thing. And I pressure bled from caliper to m/c with a phoenix injector bleed tool. It's a big syringe that injects fresh fluid. No bubbles whatsoever.

I would have expected to dislodge at least a bubble or two. But with the m/c tilted back in it's installed position, I dunno.

Something is fishy with frothy foamy bubbles when it's running and pumped though. That's why I'm thinking m/c.

 

Some people get away with doing a lot of things that aren't right. That does not make them right. If you had one-man bleeder screws that would be a different story. The second I saw that guy smearing grease all over the bleeder,I thought "sure glad this idiot isn't working on my car" There is the right way,and there's every other way. Brakes are too important to just do any ole way. It really isn't that difficult to do them correctly.

 

Yeah, the grease was lame. Speed bleeders are definitely a good investment, but I'm abso****inglutely sure my problem isn't there.

I'm thinking more as you suggested, air trapped in the master. Even though I bench bled the thing, it's possible air went right back in when reinstalling it.

I'm gonna give the injection bleeder one more shot from the caliper. This time I'll unbolt the master and push it nose down. That should allow air to rise back toward the inlet port. Fluid should not have a chance to push around the air bubble in that case.

 

You're missing my point. While there might be air in the master cylinder. The issue I'm describing is as the piston is travelling forward, the seal to the bore is compromised allowing some fluid to get by the piston. Instead of being compressed as much as it should,some pressure bleeds off. It would very much seem like trapped air. Judging from the title of your post I suspect the brakes have been bleed plenty. Which is one reason I suspect the master cylinder itself. I almost hate to tell you after swapping out the master cylinder,you'll need to bleed them again. Get some real bleeders,they're only $10/pr. and worth every dime.

 

ok, thx. I've suspected the m/c for some time given the fact that I had to double tap the brakes every morning for the last year or so. And the old calipers bodies were dry as a bone, no sign of a leak. Even though their internals looked sketchy.

And hey, who can't handle an hour doing a bleed outside ? It was 40dgFahr here today. Pure joy, didn't even have to wear long johns

 

Grease on the bleeder

I don't think he mentioned why he used the grease in the bleeders but petty sure I know why. When I bled out my brakes I use a might vac pump to pressurize the bleeder and then pull air and fluid out. If I don't seal the base where the bleeder threads in to the caliper, then air gets pulled in thru the threads of the bleeder too. I've just used a dab af Vaseline for the same purpose.

Never used the speed bleeders but for the money, they are on my parts list when I redo my brakes.

 

yep, I used teflon tape as suggested in another thread. Takes the guess out of using the vacuum bleeder. Even the speed bleeders have thread sealant which is recommended to be reapplied in case you would like to change fluid every track session.

 

RichPin is the man!

4DoorSS, yes , Rich did mention why he smeared grease on the bleeder. Take another listen. This guy is a good mechanic. He does all this work in his back yard shop and does all his filming while he is working on the car. He is one of the best at the photography while working. You can tell from his heavy Boston accent and the constant Boston AM rock station in the background where he is from. That plus the heavy salt corrosion on every part of the suspension! I know he works a lot on front wheel drive cars, orphaned cars at that!? Because he is working and filming alone, he has come up with several devices to make his single mechanic jobs possible. He should have emphasized more about filling the M/C initially and keeping it full at all times during the bleeding.

 

I'm ready to off myself. Bought the centric FWB m/c from rockauto, cheap, and came with reservoir. Bench bled the basterd, but I'm still getting foam from the front circuit. What can it be ? ABS ?. This is a TX car, no rot, no questionable lines.

Damn pert near the end of my rope.

 

Well, damn!!

If the metal lines and hoses all look good....bad proportioning valve?? That's just a wild guess.

Edit - Maybe the seal on the Resevoir lid is bad?

 

thx 4door, I needed a 'virtual' friend and a pat on the back to get me through this bit of insanity

After switching back to the original m/c, bleeding the **** out of it on bench and off, I am starting to get a somewhat/kinda/not really firm pedal. However, pumping the brake doesn't produce the froth or foam as before. whew.

My problem may be perhaps from the equipment or lack thereof. Vacuum bleeder is old and doesn't pull much psi. Solo bleeding with the hose in the jar method seems to be progressively improving. Questioning the seal at the nipple threads, I gunked em with brake lube (teflon tape is a fail). If a set of speedie bleeders solve this no-brainer, I will most certainly curse the gods why I did not buy em before.


edit: prop valve replaced short few years ago when doing harper rear discs and result of having same nightmare bleeding. At a few intervals I did hear shuttle valve click/ploink due to air. However, it seems to have reset with inverse click/sproink under some pressure on brake..

 

... Solo bleeding with the hose in the jar method seems to be progressively improving...

Tried and true and...virtually free.

Questioning the seal at the nipple threads, I gunked em with brake lube (teflon tape is a fail)...

Please to and in no way band-aid the threads if not true. If fail in house, house gets wet. If fail in car, peolpe get injured. Only a retap of existing calipers w/ new bleeders or new calipers altogether will work. I simply wouldn't trust any type of "insert" to hold given the pressure, temperature extremes and caustic nature of brake fluid.

If a set of speedie bleeders solve this no-brainer, I will most certainly curse the gods why I did not buy em before...

What I use. The only issue w/ this one is that some have had the one way bleeder valve fail and leak. If you're concerned about this, pop on the speed bleeders when performing bleed operation and when done, remove them and switch back to standard nipples. Place SB's in your toolbox for nexc time.

gl

 

advice taken; Confucius say: Man who run in front of car get tyred. thx SEO.

I am not trusting that when I release brake and dash over to nipple, the threads have allowed enough air back in. Or I have not bled enough..... I'd best get speedy bleeders.

In retrospect, what I might have been imagining frothing up the front circuit reservoir might simply be the fluid flying up and bouncing off the lid seal. DOH ! <hangs head in shame> I topped the reservoir off good and full, capped it with seal and lid, and proceeded to pump pump pump. Hmmm, no froth really.

So now I imagine I have air left in there. My lame-assed attempt at solo bleeding has been a failure.

Edit: been searching. What are the thread size for front/rear speed bleeders ?
I think I got it:
keywords for future searches.: speedbleeder speed bleeder caliper bleeder thread size.

http://www.impalassforum.com/vBulletin/showthread.php?t=275347

OE Front hose connection on caliper is M10x1.5

OE Rear hose connection on caliper is M10x1.0

Bleed ports:

Front - M10x1.5 (iron caliper)

Rear - M10x1.0 (aluminum caliper)

Thx Bill.

SpeedBleeder Website: http://www.speedbleeder.zoovy.com/

Bought the Russel version from summit:
http://www.summitracing.com/parts/rus-639580
http://www.summitracing.com/parts/rus-639630

 

Got the russel bleeders, bled the piss out of all four corners and double-timed the rear. The bleeders work really well to move a lot of fluid through without assistance, and the thread sealant makes a very positive seal. Pedal is much firmer now. Thanks to all who helped maintain my sanity.

notes:
May have had an issue with one rear caliper hose. Noticed that it was looped upward instead of down.
I have heard that this can pose an issue with trapped air. That rotor had noticeable corrosion, so it is likely that it was not doing much braking duty.

Rear pads are also quite worn but not totally gone. I understand this may also be contributing to excessive pedal travel. Have some fresh pads coming monday.