Hey peeps. I have recently removed both my front callipers to free off, relubricate. Clean up etc. I now have them back on to bleed when I get a moment the question is do I HAVE to bleed the rear nipples even though they werent removed or just the fronts? I didnt bother clamping as im replacing all the brake fluid in system anyway but can I get away with just bleeding the fronts if I cant free off the rear nipples?
brake bleed question.
- Thread starter SparkyMarc
- Start date
SirChris
Educated Bodger
I don't know why I hadn't done that sooner.suck it and see
Its cool. Got 3 nipples loosened. I snapped off the 4th rear bleed nipple. So....going to have to wait an age for ebay to post out a new wheel cylinder...then when that arrives wrestle with the rusty nuts holding it on and the brake line nut...all good fun and long walks to work
On the rear? What do you mean by that... pop it out at one end while pumping or?...
Seeing as ALL the brake fluid has drained from the master cylinder/reservoir and individual nipples....do I have to bleed the master cylinder as well as the other 4 cylinders? Or is the master optional but obviously prefferable? How would I bleed the master?
Pretty sure master cylinder seal has popped. All air is bled out lines and pedal still hits floor. Just a slight pressure on the pedal but hits the floor.
So now ill have to wait till I can afford a replacement used one and then feck about fitting it argh
Nah had 3 of us out today doing it and my main helper is a truck mechanic
Yep...still a dead pedal
Been doing some thinking and something seems odd to me. I thought if the master cylinder was bad wouldnt pressure drop gradually I.e the pedal would be firm at first then go down in stages as the seal opened more and more through pressure. Whereas in my case when engine is on pedal drops to floor as if it isnt even connected to anything. When engine is off and obviously servo, I get slight pressure but still hits floor. I noticed today that one of the washers off one of the caliper hoses was lying on my dashboard :O. I will put this back on tomorrow but will this make a big difference or do you still think it could be the master cylinder? The pedal sort of clicks/clunks at a certain point of upward and downward travel. Dont know if this is normal or not when pressure is affected. Going to have another look tomorrow and scrutinise the whole system. I haven't bled the master cylinder via the brake lines and wondering if this could be a cause or if the mc seal is a culprit as I originally thought. I did pump the brake pedal a few times with no fluid in system before learning that is a no no I guess that might have broke something possibly. Checked all the pistons for leaks. All are dry and good. No leaks from hoses. So all I can think of are that removed washer or something mc related. Im lost at the moment
frank
Club Member
its not gonna be the m/c or copper washer, you can only flip a seal when using caliper winders, and a missing sealing washer will just cause a minor fluid leak.
the k11 has a diagonally split system and can be a mission to bleed if only 1 side of the system has air locks.
the rear bias valve causes bleeding problems too
the k11 has a diagonally split system and can be a mission to bleed if only 1 side of the system has air locks.
the rear bias valve causes bleeding problems too
Ah right frank. I was doing it rear left. Resr right. Front left. Front right. Ill try it diagonally mate . How does the rear bias valve interfere?
frank
Club Member
nah, the problem is if the 1 diagonal has less air in it stops you getting a full stroke of the pedal (so the bad side is,nt being bled properly) i would try bleeding both systems together (open both fronts, then open both rears)
and the bias valve does,nt open till the pressure gets to a certain psi, and that complicates the bleeding
and the bias valve does,nt open till the pressure gets to a certain psi, and that complicates the bleeding
Aah I see.
Yesterday me and my mech friend tried pressure bleeding the system albeit corner by corner with his pressure bleeder yet no difference ia this of any significance frank?
Been back out at it. Replaced that washer. Feels little bit firmer at pedal while engined off but still while engines on pedal feels like its not connected to anything could it be the plunger behind pedal?
Going to rebleed as soon as I can get a helper (hard to grab em sometimes) its just strange how after getting nothing but clear bubble free fluid through the tube on each corner its still dead.
Pulled back the rubber bush behind brake pedal and stuck my fingernail in the master cyl seal on that side lightly and could hear air escaping through it
Ok. Ive confirmed its the master cylinder at fault. Seems easy to fit in mechanical terms but looks like it'll be a pig to get out and in. Anyone got experience of whether or not this will be a pig of a job?
Ok a wee update. Got the old master cylinder out. Unbelievably easy (seems to be a theme when working on this car). Took me 10 mins with res pre drained, wasnt happy with the idea of replacing with another used cylinder which may have seals just as knackered, but wasnt happy at paying 90 quid for one. Found one tonight online for 50 quid incl P&P brand new even comes with new reservoir...part numbers match up. Should arrive in 3 days. My mate has a workshop shed with bench and vice so I can bench bleed it for free . Also fitted new brake pads today and all new rear shoes and springs. Brakes should feel amazing . I was a bit worried at the thought of what if the new mc needs a rod adjustment, but im guessing thats highly unlikely?
. Also fitted new brake pads today and all new rear shoes and springs. Brakes should feel amazing . I was a bit worried at the thought of what if the new mc needs a rod adjustment, but im guessing thats highly unlikely?
