Bleeding brakes w/4 lines loose ? ? - Troubleshooting - VWDiesel.net The IDI, TDI, and mTDI source.

• Bleeding brakes w/4 lines loose ? ? by doonboggle on 01 Sep, 2010 17:36
• I'm now almost to the point of bleeding my brake system with the new wheel cylinder and caliper cylinders in place.  But ... having read a post advising to not infect new cylinders with old, and possible 'bad' fluid, by flushing all 4 lines.
  
  But does anyone have a process for this ... considering that if all 4 lines are open, and pumping takes place with the pedal, a lot of new fluid will be wasted ... more than IMO ... what is wasted when just one line is flushed.
  
  I realize that one can attach hoses and drain into a bottle ... but I'm asking how to temporarily 'plug' up the other 3 lines while the 4th line is being flushed.
  
  TIA
  
• #1 by Baron VonZeppelin on 01 Sep, 2010 18:59
• You won't get anywhere using the pedal with all 4 lines loose.
  Each time pedal comes back up - will suck air back in the lines.
  Will just keep going back and forth in the line - with little flushing.
  
  I don't know how to cap the lines in a way that would hold the other 3 sealed while you work 1 with a gloved finger. Maybe a hardware store with a Good brass section might have something.
  But it needs to be metric thread.
  
  Probably need a Mighty Vac tool or 1 man brake bleeder or similar, to suck fluid out each line one at a time. To get initial old stuff out. Then after that for a bit - hook em back up and do it all again with the pedal.
  
  Thats how i did mine. (Mighty Vac tool)
• #2 by burn_your_money on 01 Sep, 2010 19:29
• You can gravity bleed just by leaving the bleeders open for an extended period of time. Unless your fluid is really, really bad this whole idea is probably overkill.
• #3 by ORCoaster on 01 Sep, 2010 20:15
• I'd have to agree with fire yer dough.  Most likely you have dripped a good portion of the old fluid out of the lines just doing the work.  As careful as I try to be and not get fluid all over the place I get fluid all over the place.  So the lines are fairly open already.  I would connect them up and start pumping and watching the reservoir.  Do not let it suck air into the lines, or get low.  I think you pulled most of that old crap out of there anyway so your lines really only have a little section of old fluid in them.
  
  When you bleed each brake I bet you will be able to tell when you go from bad/old fluid to new/good stuff.  At least if you are watch a clear line or the side of the jar.  That dark stuff is old the clear is the good. 
  
  Overkill to drain all four, yep, just bleed em and call it good. 
  
  My nickel worth, inflation you know.
• #4 by Vincent Waldon on 01 Sep, 2010 20:24
• If you've got a source of compressed air you can apply gentle air pressure to the brake fluid reservoir (seal the top around the air hose with your hand or modify a cap from a junker) and speed the draining process.  Low pressure only... no more than 15 psi or evidently the MC seals will go.
  
  I've built a brake fluid reservoir cap with an air fitting attached specifically for this purpose... also works to pressure-bleed the brakes with new fluid.... which of course we all do religiously every two years, like the Bentley recommends.  
• #5 by ORCoaster on 01 Sep, 2010 21:02
• Ya sure Vince!  That is why we are the PROUD owners of 30 year old cars.
  
  Every two years  shheesseee
• #6 by Baron VonZeppelin on 01 Sep, 2010 22:31
• I forgot about the pressurized cap trick.
  There was a thread a while back talking about it - with a link to another thread somewhere. Guys were using pump up garden sprayers for the source of pressure - as one method.
  
  Its too easy to say this now - and hindsight 20/20 - but bleeding the piss out of them before tearing it down would have been the way to go.
  
  yeh i know .... why ya wanna tell me that now .... lol
• #7 by doonboggle on 01 Sep, 2010 23:10
• It occurred to me to go   to the local hardware outlet and get 3 of the shortest metric bolts, and some plumbing sealant 'tape' (forget it's name just now) I use on my sprinkler system. 
  
  Screw the bolts, with about 2-3 circles of the sealer tape around the threads, in 3 inlet connections of the M/C finger tite, and the 4th with it's steel line to the first cylinder ... and bleed. 
  
  Then leaving that connection there, do the same with the remaining 3 ... one by one ... by removal of the bolt.  Should help to prevent a big mess.
• #8 by rs899 on 02 Sep, 2010 04:22
• Yeah, I use one of those pressure bleeders that I made out of an old garden sprayer that had a bad nozzle.  I just found a way to adapt it to a spare cap.  Put some fluid in it , give it about 10 strokes and bleed away.  Greatest thing since sliced bread (actually, I hate sliced bread).  Takes about 10 minutes to bleed a car that way and no whining from SWMBO.
• #9 by Baron VonZeppelin on 02 Sep, 2010 10:52
• Sounds like a good try Doon.
  
  I'd put an old large towel or something under the MC - something that will act like a diaper. There probably will be leakages. Just in case.
• #10 by doonboggle on 02 Sep, 2010 13:00
• 
  So far ....
  1.  MC plugged outlets ... no leaks. 
  Yesterday, before beginning this, 'mouth' blew into the MC with some fluid in it ... and got a steady stream out of all 4 outlets ... one by one. 
  Also no leaks around the reservior '30 year old' plugs ... presumably ... either.
  
  2.  Have 3 lines plugged with my bolts, and #4 connected ... then pumped like heck and no real amount of old fluid came out ... but more importantly did get 'swoshing' sound, and drops ... indicating that at least that line is empty.
  
  3.  All of this is being done with no imput from the servo ... but apparently getting enough pressure thru the line from the pumping to force old fluid out, and air through.
  
  Now on to others.
  
  Have noticed though that with the rebuilt K-H calipers on the front, one of the wheels is dragging against the pads.  Wonder if that will improve once the servo is incorporated into the process with engine running???
  
  By the way, if anyone needs a rebuilt K-H caliper, have one.  While Rockauto had a swinging deal on them, close-out, they were not too sharp with shipping the initial order.  One had everything in it ... but the other one was without the mounting frame.
  
  Notified them ... and after a day of contemplating, they informed they'd send another one ... and to not return the first 'guts' of the item.
  
  So yesterday the replacement, with frame arrived ... but lo and behold, this time the bleeder plug was broken off.  [Looks like these 'buggered' units were returns from former customers, that the company merely put back on the shelf ... and now in their 'close out' sale, are shipping them out as good units.]  Thankfully, having kept the first 'buggered' one, I merely took the frame off this latest one and used the aforementioned 'guts' item ... and now have a complete caliper as advertised.
  
  So have a 'guts' part of the K-W ... and extra pair of new pads ... if anyone's interested.  Presume that if you have the ability to back out the broken off bleeder, you'll have a good unit.  Did see ... can't recall where though ... seeing new bleeders posted somewhere.
  
  
  
  
  

  Quote from: Baron VonZeppelin on 02 Sep, 2010 10:52

  Sounds like a good try Doon.
  
  I'd put an old large towel or something under the MC - something that will act like a diaper. There probably will be leakages. Just in case.
  
• #11 by Baron VonZeppelin on 02 Sep, 2010 21:30
• What a bummer on the KH caliper.
  Least they made it right.
  
  RockAuto is who got suckered on that.
  They bought those out, and musta been some "bad apples" in the batch. You get the good and the bad when you buy the lot.
  
  Hopefully they will start inspecting the rest of them before shipping. That isn't good for business.