Rear disc brake bleed
- Thread starter andre
- Start date
I once spent a whole weekend trying to bleed the rear brake on my Pantah after fitting new pads. I tried every trick I could think off. Calliper off and held in the best way. Using reverse bleeding, nothing worked so it went to a pro shop specialising in Ducatis and they fixed it at an eye-watering cost. They said the piston didn't move far enough to clear the tiny return hole. I was a happy boy till the rear brake stopped working heading home. The calliper had fallen off and was dangling below the bike bouncing off the road, luckily it didn't fall into the rear wheel and jamb it. They forgot to tighten the bolts holding it on. Happy it didn't kill me.
piranha-bro2
Hero member
- Location
- Melbourne
I trust 'the experts' explained exactly where all the money went to bleed a rear brake, Vince? The were obviously 'experts' because they put your life at risk through their 'expert' service.
Seriously, if you take on work as a PROFESSIONAL mechanic, bicycle, car, moto, whatever, it can mean people are putting their life in your hands, so you'd better be up to the fukkin' job!!
Seriously, if you take on work as a PROFESSIONAL mechanic, bicycle, car, moto, whatever, it can mean people are putting their life in your hands, so you'd better be up to the fukkin' job!!
Simonr501
Hero member
- Location
- Lympne, Kent. UK
Too true! There are very few people I trust to work on my bike, I have had some bad experiences. It is the lies some tell that are unforgivable!
I had the same issues with my rear brake when changing the fluid.
Raising the rear caliper did help a bit, but basically a few pumps now and then with rising bubbles in the reservoir did 90% of it.
A bit of patience did the trick eventually for me.
I had the same issues with my rear brake when changing the fluid.
Raising the rear caliper did help a bit, but basically a few pumps now and then with rising bubbles in the reservoir did 90% of it.
A bit of patience did the trick eventually for me.
Vince said:
A few years ago at the Bikers Classics in Spa Franchorchamps, our paddock neighbour was desperately trying to get some pressure into his rear brake on his Pantah. I asked if i could help, "Nah, I'll be alright..." so I went back to my beer. Next morning I asked if had had luck with his efforts, "Bloody shitheap, I'll be missing the first turns today." I took pity and suggested him to remove the entire braking system in one bit. "What for?" he asked. "I'll bleed it for you in a couple of minutes, when I've finished breakfast", I answered. He looked at me in disbelief, but did it none the less. Upon returning, I had him hold the caliper so the brake line exited at the highest point, and holding the M/C so air could escape, I massaged the lever. Sure enough, huge amounts of air bubbled out, and pressure was regained in a matter of minutes. Refitted the system and all was well. Guy was very happy, to say the least.
Despite arguing that all I did was using physics to cure the problem, I attained God status for the weekend! Didn't need to buy any more beer myself, either.
piet
Simonr501
Hero member
- Location
- Lympne, Kent. UK
Now you mention it Piet, you do have more than a passing resemblance to the classic images of the good lord.sfcpiet said:I attained God status for the weekend! Didn't need to buy any more beer myself, either.
Simonr501
Hero member
- Location
- Lympne, Kent. UK
Some others have got 'sexy fingers'! They f@ck everything they touch!Vince said:
SimonR501 said:Now you mention it Piet, you do have more than a passing resemblance to the classic images of the good lord.
. You know Simon, I followed the 'Gospel according to Piet' with the back brake of my Corsa before going to Breganze last year. And, 'Lo and Behold!' (So you see, Piet - I DO take in what you say :-*. Altho' I never did figure out just where the air had been trapped ...)
sfcpiet said:Yes, something like that, Mark. As I've broken a couple in my career, I need something a little sturdier, with more metal in it. Fuckin' gravity... :
piet
Piet,
this one is solid (also without metal), does its job and does not fall over all the time. You have only have to take care a little bit -> not to kink the hose at the connector to the reservoir after using it many many times. About 90 Euro:
Jens said:
Yes, Jens,
Something like that should do the trick. My favourite tool supplier has a similar set up, need to get some more stuff on the order list to make it worthwhile.
Guess I could always weight it down a bit with a litre or two of resin in the bottom of the tank.
piet
I think I've found the problem. Outer 'dust covers' (?) that goes over the little caliper pistons is blown out. Looks like it was leaking only very little fluid out but maybe sucking air inward. Anyway I'm confident a caliper rebuild (or replacement) should fix it.
Thanks for good advice.
Maintenance...
Thanks for good advice.
Maintenance...
Andre said:
Wouldn't rely on that, the dust cover is just that.
If you find moisture there, the seal behind it is leaking. But even that will not be the cause of your bleeding issue.
Leaks at the piston seals are often due to corrosion in the seal grooves, the seals themselves are rarely damaged. The corrosion allows fluid to seep through behind the seal and past the piston. If the corrosion is too severe, the caliper may be ripe for the scrap. The rubber seal can bridge only a certain amount of missing material. You might even find steel pistons in there, chances are they are corroded too. The corrosion usually only extends to the point where they have sat in the seals, push them inwards and they can damage the seals and may even jam tight. Junk them and replace with alloy items.
A slight leakage at the piston/s will not prevent the proper bleeding of the system.
Maintenance, or lack thereof...
piet