BSF Posted March 20, 2014 Share Posted March 20, 2014 I am really a Series man, but my 2B FC rebuild has Defender discs on the front. I have had huge problems bleeding the brakes and without going into the three week long saga it is definitely the callipers (established by working through the system blanking parts off). I have even taken the callipers off and bled from every conceivable angle, always the same spongy brakes with the pedal down to just above the floor. Anybody got any ideas before I buy a set of golf clubs? Quote Link to comment Share on other sites More sharing options...
Litch Posted March 20, 2014 Share Posted March 20, 2014 Has it ever worked correctly and is the master cylinder up to the job? I only ask as about 25-years ago I retrofitted my S111 SBW front drums with LWB items and could not get a pedal, it was only after a day of bleeding that I decided to replace the master cylinder. I thought there was already a LWB unit fitted but when removed and compared with the new one it dawned on me that the original item was a SWB unit and couldn't push sufficient fluid through. Needless to say that with the larger master cylinder fitted it all bled through perfectly first time, the old unit was perfectly ok but wasn't up to it. Quote Link to comment Share on other sites More sharing options...
BSF Posted March 20, 2014 Author Share Posted March 20, 2014 The master cylinder is a new one correct for a 2b. At the moment it is only connected to 1 calliper. Quote Link to comment Share on other sites More sharing options...
vulcan bomber Posted March 20, 2014 Share Posted March 20, 2014 Do you have the calipers on the correct sides? if not the bleed nipple will be lower than the inlet pipe, you'll never get the air out. Quote Link to comment Share on other sites More sharing options...
Disco-Ron Posted March 20, 2014 Share Posted March 20, 2014 As above, you'd be amazed how many people think the air comes out of the bottom......FAIL!! Quote Link to comment Share on other sites More sharing options...
BSF Posted March 20, 2014 Author Share Posted March 20, 2014 Callipers are on the correct side, bleed nipple at the top. Quote Link to comment Share on other sites More sharing options...
Litch Posted March 21, 2014 Share Posted March 21, 2014 The master cylinder is a new one correct for a 2b. At the moment it is only connected to 1 calliper. Ok, it is correct for a 2B but you are not using standard 2B cylinders. Has it ever worked on this set-up as I suspect you might need to push through more fluid than the master can supply? To prove the point one way or another can you rig up a 90/110 master cylinder on a temporary basis to see if that works, early ones were single line just like the 2B? Quote Link to comment Share on other sites More sharing options...
BSF Posted March 21, 2014 Author Share Posted March 21, 2014 I see your point, but disc brakes have virtually no flow when applied (no pad movement), just pressure. The drums do have a small flow to move the shoes from resting on the adjusters to contact with the drums, but the back drums have been blanked off. The M/cyl should be capable of applying 1 calliper, which is all that is connected right now. Thanks anyway Quote Link to comment Share on other sites More sharing options...
pat_pending Posted March 22, 2014 Share Posted March 22, 2014 So you have the m/cyl piped to one caliper and the pedal still feels spongy? Have you actually driven it with everything connected? If it's new pads, the pedal will be carp until they've had a chance to bed in. Quote Link to comment Share on other sites More sharing options...
BSF Posted March 25, 2014 Author Share Posted March 25, 2014 Partial success! After a suggestion from the guy who does my MOTs, I made 4 dummy "pads" out of some bits of steel about the same thickness as the backing plate on the pads and put them in the calliper. Then pumped the brakes to bring the pistons as far out of the calliper as was safe without them actually falling out. I then left them for 24 hours. The brake pedal was then held partially down with a piece of wood (to stop fluid moving in the system) and each calliper bled by levering the pistons back to fully retracted position. The pads were then replaced. The pedal is not completely solid, but it is much better and probably useable. Quote Link to comment Share on other sites More sharing options...
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