1100 rear caliper seals

[MattW]

My back brake has been dragging slightly for a while so I've ordered a new piston seal set. I've previously overhauled the sliding pin arrangement and the caliper moves silky smooth.

On stripping the caliper, one piston was definitely harder to push in and out which confirms a possible problem with the pistons retracting.

Having removed the old seals to clean the grooves behind the piston and dust seals (a bit of gunk behind them), I'm looking at the piston seals on the bench and realise that they're actually slightly tapered in section. I didn't pay too much attention as I was removing them but I'm pretty sure that the large face of the seal faces outwards?

Could someone confirm this for me?

Yep, I know - schoolboy error....

 

[MattW]

Well, in case anyone else has this problem (unlikely I know...).

I've just refitted the original seals (rather than potentially damage the new ones if I have to remove them again). With them fitted 'large face outwards', they're fine and leak free (left the bike overnight with a 6lb weight hanging from the brake pedal).

The cleaning operation seems to have worked and brakes have also stopped dragging (might just fit the new pads and keep the new seals as spares)

 

[Hare About]

The cleaning operation seems to have worked and brakes have also stopped dragging (might just fit the new pads and keep the new seals as spares)[/QUOTE]

Just about to change the caliper seals myself.
With regard to the silver U shaped piece of metal that the back caliper is attached to. Should I use any lubriction on its sliders or are they assembled dry?

 

[MattW]

Just about to change the caliper seals myself.
With regard to the silver U shaped piece of metal that the back caliper is attached to. Should I use any lubriction on its sliders or are they assembled dry?

Yep, clean all the gunk off the sliders and out of their sockets. You can completely remove the rearmost rubber 'socket' and clean it with a solvent and cotton buds. Remove the little rubber gaiter from the forward socket and get into the alloy casting with buds and solvent. Lubricate with red rubber grease when everything is clean.

 

[Hare About]

Yep, clean all the gunk off the sliders and out of their sockets. You can completely remove the rearmost rubber 'socket' and clean it with a solvent and cotton buds. Remove the little rubber gaiter from the forward socket and get into the alloy casting with buds and solvent. Lubricate with red rubber grease when everything is clean.

Thats brilliant, thanks.
The liitle rubber gailters are £19 so when spending that sort of dosh I thought it was worth the ask.