Binding rear brake?

[matt7chunk]

Hey guys,


I just rebuilt my rear caliper (new pistons,  seals and fluid)  the whole job went fine but now it's back on the bike I drags,  not massively bit enough to generate a decent amount of heat on the disc after riding,  any ideas?  The disc is straight I clamped a straight edge to the swing arm right up to the disc and can't see any sign of a wobble, 


I'm stuck with what to do next

[slappy]

When you put the new pistons  and seals in did you give them a light coating of rubber grease or brake fluid? If they are "dry" this might be why they are not retracting enough  after you use the back brake.

[His Dudeness]

did you use oem seals?

[celticdog]

Sounds like you need to do a bit more work on the rebuild. Get a torch in there, see if it's dragging from one side or both.

[matt7chunk]

Yer I used powerhouse seals and pistons plus red rubber grease,  also soaked the seals over night,  think I'm gonna strip it down again and check everything over again,  I done the fronts not long ago and had no problem with powerhouse seals at all,  I'm stumped

[darrsi]

How badly is it binding though?
When you took the pads out did you put them back in the same way?
The pads may just need bedding in again if they've been swapped around as the grain on the pads will be slightly different to the disc.
Unless it's literally fixed on to the point where you can hear it rubbing i would give it a chance for a few days to sort itself out.
Try not touching the rear brake at all for a few miles then put the bike on the centre stand and see if the rear wheel spins freely enough, if it does then the piston are moving okay so the disc needs a bit of time to cut a new grain on the pads.

[robby boy]

Did you clean out the groove the seal sits in, sometimes the aluminium corrodes under the seal and tightens it against the piston which in turn gives a bit of brake drag.

[triker]

When I rebuild my rear caliper I split it, then cleaned out the groves with a dremmel fitted with a  3mm brass circular brush. Very corroded from road salt. Replaced Pistons as they were pitted. New OEM seals and rubber grease. Brakes like new. Oh if you split caliper don't loose the small o ring!

Hope that helps

[matt7chunk]

yer i split the caliper put new seal in there too , also used dremmel to clean the grooves got rid of all the white crap that had built up , its not binding so much i cant spin it freely but can hear it rubbing the disc, i'll carry on riding untill friday when im off work and if its still rubbing i'll split it again and completly re trace my steps


thanks for your support guys


love the community here, so helpfull

[bandit]

If you can spin the wheel with one hand easily with no binding a slight rubbing of pads on disc is quite normal.