Front Brake problems on 1999 Dominator

[xrmanc]

You may have tried these two things but I would make sure the piston is moving freeley then reverse bleed the system. Pump fluid up from the bottom ( bleed nipple end ) Use an oil pump from halfords and some tubing. Air can get trapped and the piston is small and with so little movement will not move the bubble. Its a bit of a fiddle, because you will have to get fluid out of the resovoir to stop it overflowing - small syringe is good. Best of luck - These things can drive you mad !

[xrmanc]

Any luck James ?

[Manx James]

I took the caliper off and put a piece of steel in between the pads (about 5mm thick the disk is only about 3mm thick and I noticed on the side it says minimum working thickness 3.5mm). When the lever was pulled the pads gripped the steel, albeit in a half hearted way. I noticed one of the pistons was moving out, then slipping back a little and the lever had to be pumped quite a bit to get the caliper to grip. It wouldn't maintain pressure and the piston eventually moves away from the steel plate/disk.

So.... I've ordered a new disk and piston seals.

I'll let you know what happens when they are fitted.

[juscrooky]

I had similar problems on a 1995 kawasaki zzr600

in the end I put new pistons and seals in the calipers, still the same

I eventually found that the aluminium can corrode, leaving the white powder furr crap behind the seals this makes the seals grip the piston too tight and not letting it push the piston in, it will move a bit on applying brake pressure but this is just movement in the rubber seal, the piston is not actually moving past the seal (it needs a kind of one way ratchet effect for the brakes to work properly) however my pistons were retreating back into the caliper,

when you change the seals, use a right angled scribe, wire wool, small screwdriver and carefully clean the channels that the seals sit in

DO NOT use your new piston and seals until you have cleaned behind the old ones, you may not need to use the new ones and can get some cash back.

had a similar problem just recently with my 1999 dommie back brake,

bled and adjusted everything, still no brake

in the end pulled out the piston, removed the seals, cleaned the buildup behind them, old seals back in, works perfectly now.

see my website for more info

www.zzr600.co.uk

hope this helps

jus

[Manx James]

Hello All

I've fitted the new disk and piston seals, I gave the caliper a good clean out before I put the new seals in and the brake is finally working. It's spongier than I was hoping for, but it works. I went for a test ride earlier on today (I slipped down the road to watch some of the TT - mind bendingly fast) an hour or so later I tried the lever and it came right into the bar, but after a couple of pumps it was firm again. I'll tie the lever to the bar over night, which will hopefully let any trapped air out, then bleed it through again. This will hopefully fix things fully.

Thankyou to everyone that's helped me with this - Switch, Catteeclan, allanmac, pogo, mad4it028, StumpyFingers, xrmanc and juscrooky. Apart from learning a bit about hydraulic brakes, I've also learnt that I care more about my motorcycle than any garage ever will. This has given me the confidence and enthusiasm to tackle other jobs as and when they come up.

Thanks once again

James

[Manx James]

Brakes have been re-bled and everything is now working. Cheers everyone.