HELP ! ! What's going on relative to my brakes rebuilding ? ? - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.
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HELP ! ! What's going on relative to my brakes rebuilding ? ? by doonboggle on 02 Sep, 2010 15:47
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As indicated in other related threads, yesterday 'tested' the MC before putting it back on by putting in new brake fluid ... just enough to cover about 1/2 inch of both segments. Within a second or so, outlets for the wheels metal lines were dripping fluid slowly.
I took the cap off and blew into the reservoir to see if a bit more pressure would increase the dripping ... which it did noticably. I tested it one by one ... by covering the other 3 with fingers and observing the uncovered one. Each one had a decent flow of fluid.
So today I cleaned off the rusted MC as best I could with a wire brush wheel, and also smeared grease on the interior of the servo where the MC connects ... as others suggested. I then installed the 3 bolt plugs I got from True Value with the silicone tape sealer on their threads to prevent leakage of fluid ... worked A-OK.
After that, pumped the brake pedal up and down several times to make sure the servo push-rod was not hanging up, and also that the grease was getting side it's rubber 'shoulder' part.
Everything seemed to be A-OK, so proceeded to apply the silicone gasket stuff out of the tube ... no O-ring was there to prevent water intrusion, so this seemed to be sufficient ... and applied it as the stuff directed ... and then let it cure for an hour or so before tightening the nuts down tight.
Then, one by one ... while the lines were still loose from the cylinders and caliper cylinders ... had my assistant pump rapidly while I observed what came out of the lines ... trying to get the old fluid out of the lines. All but the r-rear one did not have anything of quanity, and blew bubbles ... but the r-rear one did show brown fluid 'trying' to make it over the hump in the metal line ... but just not enough pressure produced by the pedal pumping ... with no engine creating vacuum for the servo ... to make it.
So went ahead and finished final attaching of the lines to the cylinders ... and tried it ... with engine running ... to see if new fluid would migrate into the cylinders.
Nada ... no matter how much I pump ... the level of fluid in the reservoir is just not migrating. Even took one line loose from the MC and had wife pump ... and no fluid came out of the opening.
Any suggestions?
Diaphragm in vacuum pump was replaced last fall right after I got the pickup ... so it 'should' still be OK. I did no adjusting to the push-rod of the servo other than smearing grease on it ... and really don't understand it's significance anyway ... relative to protruding inside the end of the MC.
HELP !
OH .... have all 4 wheels off the floor ... why does the front ones roll when the motor is running? thought the moving power was all to the rear.
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#1 by theman53 on 02 Sep, 2010 16:48
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You can unhook the lines and blow compressed air through and get the brown gunk out. I bet there just isn't enough fluid to push the old out after all the unhooking and pumping going on. I don't know that you will ever get 100% of the brake fluid out with compressed air or pumping the pedal. I think you are to the stage of adding new fluid until it comes out clear and bubble free.
As for the tires I for get what car you have, but I think only some VW were rear wheel drive. Could just be inertia or vibrations moving them. -
#2 by doonboggle on 02 Sep, 2010 17:20
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I have the reservoir full to the top.
Don't have an air compressor ... just a 'dumpty-dumpty-dumpty-dumpty' tire inflater.
But my MAIN problem is why the fluid is not going into the lines and/or into the cylinders.
And on wheel ..... I screwed up royally. The rabbit is front wheel drive ... not rear. My FLUBBA FLUB ... big time ... another brain phart for today I accept.....You can unhook the lines and blow compressed air through and get the brown gunk out. I bet there just isn't enough fluid to push the old out after all the unhooking and pumping going on. I don't know that you will ever get 100% of the brake fluid out with compressed air or pumping the pedal. I think you are to the stage of adding new fluid until it comes out clear and bubble free.
As for the tires I for get what car you have, but I think only some VW were rear wheel drive. Could just be inertia or vibrations moving them. -
#3 by Luckypabst on 02 Sep, 2010 18:29
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First you need to correctly bleed the master cylinder. The method that works for me is to plug each outlet port at the master cylinder, pump several times on the pedal (holding the pedal down on the final pump), cracking open each plugged port to allow air to escape, closing each port, then finally releasing the pedal. Repeat until you have no air coming from the master cylinder. This will push air out and draw fluid in to the cylinder.
After bleeding the M/C, you can begin bleeding each corner, one at a time, following a similar procedure.
Engine running, vacuum booster - that kinda stuff will have no effect on bleeding your brakes.
Chris -
#4 by doonboggle on 02 Sep, 2010 19:14
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Is that with or without fluid in the reservoir?
And while I am not sure of this, let me ask this also.
The last thing I did today was to remove the final plug (10mm x 1.0 fine threaded bolt) from the outlet I had plugged while awaiting a new brake line to replace one I buggered up on the first day.
I removed this plug ... after connecting the 3 brake lines to theie 'new' cylinders ... and pumped the pedal; reservoir has fluid.
Nada!
Should not have fluid come out of that port?
Essentially was not this action the same as you suggest ... except that the lines are connected to the cylinders instead of a plug in the opening.First you need to correctly bleed the master cylinder. The method that works for me is to plug each outlet port at the master cylinder, pump several times on the pedal (holding the pedal down on the final pump), cracking open each plugged port to allow air to escape, closing each port, then finally releasing the pedal. Repeat until you have no air coming from the master cylinder. This will push air out and draw fluid in to the cylinder.
After bleeding the M/C, you can begin bleeding each corner, one at a time, following a similar procedure.
Engine running, vacuum booster - that kinda stuff will have no effect on bleeding your brakes.
Chris -
#5 by Baron VonZeppelin on 02 Sep, 2010 19:35
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The master cylinder bore has air trapped now - no fluid wants to enter or go past there. So you have to bleed the MC 1st. Some (most) folks do a bench vise bleed while its off vehicle.
You need to do like Pabst suggested.
With reservoir full -
Bolt all 4 shut - pump pedal some at medium methodical pace - hold pedal down - release bolts a smidge - retighten bolts - let pedal up. Pump pedal - hold - release bolts a smidge - etc... "...." until you have good strait fluid pressure out of MC at all ports.
Then hook up 1 line to MC - have assistant push pedal down slow and hold it - you cap it with your finger on other end when she hits bottom - she lets pedal up - repeat ....
Do that until you get good clean fluid.
Then hook that line up to its respective partner. And bleed it as normal with the bleeder screw.
Then proceed to line #2 and repeat, until all 4 are done.
And x2 on engine off etc... not playing role in bleeding process. -
#6 by doonboggle on 02 Sep, 2010 20:14
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The master cylinder bore has air trapped now - no fluid wants to enter or go past there. So you have to bleed the MC 1st. Some (most) folks do a bench vise bleed while its off vehicle. You need to do like Pabst suggested.
So I don't screw up, would like to get some of this clarified a bit more for the old 'phart'. Realize some of these are rudimentary ... maybe even stupid ... but never had to do this process before.
With reservoir full - Bolt all 4 shut - pump pedal some at medium methodical pace - hold pedal down - release bolts a smidge - retighten bolts - let pedal up. Pump pedal - hold - release bolts a smidge - etc... "...." until you have good strait fluid pressure out of MC at all ports.
I'm using metric bolts from hardware store, with plumbers tape on the end ... and tightening it finger tight to it's bottom. When you say to loosen a 'smidge', does that mean that fluid will squirt out ... or just air?
With my bolt process, would I have to remove the bolt completely to replaced the expended tape ... or merely re-screw back in?
Then hook up 1 line to MC - have assistant push pedal down slow and hold it - you cap it with your finger on other end when she hits bottom - she lets pedal up - repeat .... Do that until you get good clean fluid.
Hooking up lines to MC ... and having to remove the bolt ... will something happen I should be prepared to try and prevent ... or control ... at MC end?
Then hook that line up to its respective partner. And bleed it as normal with the bleeder screw.
Then proceed to line #2 and repeat, until all 4 are done.
And x2 on engine off etc... not playing role in bleeding process.
PS: Haven't forgot about the tail lites. Have to get truck back on it's 'feet' so can get to the box. -
#7 by Baron VonZeppelin on 02 Sep, 2010 20:26
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I'm using metric bolts from hardware store, with plumbers tape on the end ... and tightening it finger tight to it's bottom. When you say to loosen a 'smidge', does that mean that fluid will squirt out ... or just air?
With my bolt process, would I have to remove the bolt completely to replaced the expended tape ... or merely re-screw back in?
At first maybe just air - then some fluid and air - then just fluid when its bled completely. So long as she keeps pedal down - you could remove the bolts all the way - then reinstall. Backing it out 1/2 to a whole round will probly do the trick tho. Play by ear.
Idunno how the teflon tape will hold up - play by ear again.
Hooking up lines to MC ... and having to remove the bolt ... will something happen I should be prepared to try and prevent ... or control ... at MC end?
Nope, so long as the brake pedal doesn't move any.
Let it rest in the "up" position on that manuever. It might dribble just a dab from MC - but no consequence. -
#8 by Luckypabst on 02 Sep, 2010 20:39
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Just to add a couple thoughts...
The master cylinder will do funny things when it's not bled so don't panic if nothing comes out until it's properly bled.
Using regular hardware with teflon tape makes me cringe. Metric thread pitches may (and likely do) match up but in other applications, it's very easy to stuff the wrong "plug" into one of those ports. You should be able to find proper metric bubble flare plugs at a decent auto parts store (not autozone/kragen). Teflon tape may work to seal things while you're bleeding the M/C but to be clear - it's unnecessary and not a good idea to be used in your brake system. Brake lines seal with a taper between the lines and cylinders. Teflon tape is for tapered pipe fittings and not much else in life.
Chris -
#9 by doonboggle on 02 Sep, 2010 20:48
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Well, we don't have anything here but Napa, Kragen and CarQuest.
Looked on Napaonline, and only came up with a 10mm item that looks nowhere like the fitting to screw into the MC. Looks more like a union for joining 2 lines together.Just to add a couple thoughts...
The master cylinder will do funny things when it's not bled so don't panic if nothing comes out until it's properly bled.
Using regular hardware with teflon tape makes me cringe. Metric thread pitches may (and likely do) match up but in other applications, it's very easy to stuff the wrong "plug" into one of those ports. You should be able to find proper metric bubble flare plugs at a decent auto parts store (not autozone/kragen). Teflon tape may work to seal things while you're bleeding the M/C but to be clear - it's unnecessary and not a good idea to be used in your brake system. Brake lines seal with a taper between the lines and cylinders. Teflon tape is for tapered pipe fittings and not much else in life.
Chris -
#10 by Baron VonZeppelin on 02 Sep, 2010 21:25
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This is mostly unrelated ....
But at CarQuest - they can get WorldPac merchandise.
Same as what AutohausAZ and eGermanparts.com sells.
CQ bought out WorldPac.
The retail mark-up price is horendous. The "wholesale" price is still higher than online. Cut a deal with the manager for 30% over his cost and you get about same or better price as you would at AuothausAZ. And 9 out of 10 times the parts come in next day.
Just an option to keep in mind.
eGermanparts.com website uses the same part numbering system as WorldPac. So you can look up the parts and just give them the part number at CQuest.
I'm hooked up with my local CQuest store.
But on some things - they can't deal with AutohausAZ or RockAuto.
http://catalog.worldpac.com/ibusiness/JSP.v.1.01/part.jsp?header=http://egermanparts.com/header.txt&footer=http://egermanparts.com/footer.txt&partner=ipb&year=1981&make=VW&model=RAB-D-001&clientid=egermanparts.com&cookieid=2SB0PCE802SB0PCE7Z&baseurl=http://egermanparts.com/