brake bleed

redeyedmonster5 · 19-10-2006, 01:59 PM

is there a trick to bleeding the brakes on my kc laser???? i have changed all pads, shoes and master cyl. got all new bits in without a hassle, but now i can only bleed the left front &right rear, why cant i bleed the other two as easy it is like there is a hidden valve or something stopping fluid from getting to them ????

dirty hands · 19-10-2006, 07:01 PM

wait for vippen or others

Should be a bleeder for every caliper
if no brake fluid comes out of the bleeder
then the bleeder is clogged or faulty - undo the bleeder right out if you cant clear it get new one
check that the brake calipers in line is not obstructed
check that the brake fluid is reaching the brake lines of the two calipers not bleeding

the other thing is some brake places- have in the past -forgot to drill the holes out in the master cylinder after a resleave

redeyedmonster5 · 20-10-2006, 02:40 PM

thankyou have done all that now im back to sq one, have master cyl. back out and my book says to prime before reinstalling once again only the same two ports seem to work is there a special way of priming the secondary piston so the other two ports work again? or any other suggestions which may help?

dirty hands · 20-10-2006, 10:55 PM

there is a fault in the master it may have been put togeather wrong take it back to where you got it from see if they can work it out

redeyedmonster5 · 20-10-2006, 11:43 PM

thankyou very much thought it might have been me,......i got it at littles in gympie n they guarintee or replace if at all faulty so i will ring them in morning thankyou again will look you up first if i have any future dramas.... cya from us in kingaroy

KA-put · 23-10-2006, 05:50 PM

There's usually a trick. The closest thing I've worked on is a late KB. This has a 4-port master cylinder (girlock p15, it has a round reservoir in case you have the same) that I'm told can really only be bled properly by pressure-bleeding. As far as I can tell the thing that causes problems is called a "fast fill valve" - check if you have one - I'm cursing mine as the cause of all problems in the world.

Word on the street is that a fast fill valve takes around 15 seconds after you pump the pedal to return to its natural state. So you wait 15 seconds between pumps... but what happens to small air bubbles in this time? They go back up the brake lines. So you pump the pedal, move the bubble a few inches, wait 15 seconds for this valve to reset in which time the bubbles slowly climb back up to where they were.

I have made a pressure bleeder out of some hose and an old m/cyl cap. You don't have to do too good a job because it only sees a few PSI - any more than that and you may damage the m/cyl. Haven't got results yet but I'll let you know.

The other thing is that some proportioning valves have a tilt switch or steering input swich to bias one side in turns. If you have one of those, you need the car to be dead level (or at least have it jacked up slightly on the correct side) and the steering wheel dead straight (or turned in the correct direction). Again, check your manual cos this could be causing your problems.

The secondary system on the KB i'm working on is harder to bleed than the primary system. The PBR website says that the engine should be running when you bleed certain cars (http://www.pbr.com.au/technical/repl...t_parts4.shtml - see the guidelines for bleeding FWD vehicles). FYI, PBR is the company that bought girlock.

Failing that, just take it to a good brake specialist.