After a front combined calliper rebuild I cant get any resistance in the pedal movement, either front or rear.
Neither can I get any fluid out of the front or rear calliper.
Pumping the front pedal does give some resistance, but this disappears once I stop pumping. The pads have come in to contact with the discs.
Any ideas would be appreciated before I start pulling it apart again.
Tony
If you aren’t getting any fluid out of the bleed nipples, I suspect the master cylinder has failed and needs a new seal set. Try slackening off the connector to the caliper and gently pressing the pedal, see if anything comes out. Is anything leaking? Try pumping the pedal and squeezing the lever for a few minutes, that usually sorts it out. Others swear by hanging weights of the pedal and elastic bands around the front lever overnight.If everything else is good, think it is a question of getting everything settled back in place after being disturbed.
are you just trying to pump the fluid through with the pedal? I’ve found that the best way is to pull the fluid through with a syringe or similar, at least initially to get some fluid through the system if its been empty…
Look in FAQ for the bleed method IF that does NOT work suspect the master cylinder …
Basically get a syringe and force fluid from the nipple to the master resevoir, 30 secs for fronts and under 1 min for rear.
The calipers fitted to older Guzzis, and other bikes that use thhese Brembo items suffer with trapping air behind the caliper piston (well that is what I was told many years ago) causing all sorts of problems bleeding brakes.
So to counteract that forcing fluid up through the system gets rid of any air whatsoever.
Be careful it des not take alot and it WILL squirt out when it gets to the resevoir so cover all paintwork and I use some clear plastic over the top of the resevoir.
Once there is some fluid through it is then merely fill up the res and pump the pedal IF ypu have nowt then …Master cyl seals…IF you still do NOT have pressure then suspect the new seals ain’t sealed OR look for leaks.
We have even had one club member almost tear his hair out over this when a NEW mast cyl did nowt… it was the new cyl faulty !!!
My 2 penn’orth … make sure master piston retracts fully when released, I.e. not ‘sticking’. If so it won’t draw more fluid from the reservoir and travel is seriously limited.
If you’re trying it that way round (pumping through) I usually pump up the pedal first, hold it down THEN open the bleed nipple. Any air will expand and escape in the direction of the nipple. Close nipple before releasing pedal, repeat procedure…
Alternate rear and front calipers while removing all the air.
Place bleeding jar higher than caliper, or even higher than master cylinder.
You may remember I had all sorts of problems bleeding my front brake (Convert) All new brake lines, secondhand master cylinder, new master cylinder, new seals, caliper seals, back bleeding, convenional bleeding, in fact every thing under the sun and no joy. Then Ray sent me a master cylinder to try and it bled in a couple of minutes. I still don’t know why!
jmee542014-04-01 21:28:39
'Cause summat up wiv it
Many thanks for all the replies. All I need now is the time to try them.
Thanks again.
Tony J
Patience is one of the key ingredients.
i just added it to FAQ again