Hi I've had to sort out the front brakes for the MOT , they failed them because they were dragging or binding( not releasing completely).

Now I've replaced all the seals and the rubber boots , lubed the pistons up with brake grease , bled the brakes and replaced all the fluid . I didn't replace the pistons 'cos they seem OK and they're really expensive , Spent a lot of time on them , but they're still not perfect , the pads still drag on the discs slightly When I pump the brakes with the caliper off the disc the pistons can be pushed back into their bores with finger pressure , so I'm assuming that's not the problem

Is this normal?

Any help please , I'm starting to get pi55ed off with this now!

Thanks.

 

First off, I think it's stupid as hell that you can fail for that.

Are your discs slightly warped? Are they evenly dragging or just in one place?
Does it significantly slow the wheel?

 

+1

Another thing I was just thinking about is that your wheel may be SLIGHTLY misaligned. Maybe trying to more evenly torque the pinchbolts or discs could help?

However, there's a difference between dragging/binding and touching. If they were dragging bad before, but just barely touching now... you might be ok.

 

They'll brush the discs slightly always just never enough to drag the disc to a stop.

Thinking maybe push the pistons in and out a few times either side to free 'em up
a bit ......make everything move easily and as Trout says make sure it's "square"
and aligned

 

Ride the bike with the brake on for a mile or two.......................probably stop

 

Check if the caliper pin bolts are binding and doesn´t let the caliber move freely.

 

Thanks for the input guys , it seems to be the right calliper is the culprit , freed the pistons up already and I've been dicking around with the front wheel alignment for ages . The right calliper will stop the wheel from spinning freely , though it will spin , discs are not warped .

Got to go to work this evening , this is the last chance for me to get a re-test , so I'll have to take it down as it is and hope for the best

Thanks again for all the info/suggestions , I'll let you know how it goes

 

Woo Hoo! She passed

What a relief! I would have hated going away without her being sorted out.

Once again thank's for all the input guy's

 

For future reference - Caliper piston & seal kits arn't that expensive.

These are the ones I used for my 91 bike

http://www.bitzforbikes.co.uk/Two_Fr...9210-130-.html


and these are the ones for a CBS equipped bike

http://www.bitzforbikes.co.uk/Three_...225-130-0.html