Front brake - piston seized

[Lightrunner]

I think I've got a problem with the pistons on one side of one of the front callipers.

I changed pads a few weeks ago and noticed that one of the discs seemed to retain a lot more heat than the other one, same side every time.
I'm not in the habit of checking disc temperature normally so I wasn't sure what the problem would be, I wrongly assumed the cooler side maybe wasn't working properly.
Took some advice from Jason and had a look at both callipers just now to see if they were moving freely etc. I can't, using a reasonable amount of force, push the pistons back on one side in one calliper.

I'm assuming that they've seized or is there something else I should be looking at?
Is this a big job to try and fix - do I need to phone the bank manager or is it something that can be tackled at home? The bike's an '02 ABS model, if it wasn't ABS I'd be fairly happy to mess about with the brakes and bleed them through but I've been told that the ABS bikes are a nightmare to bleed, someone mentioned tank removal which I'm not keen to get into.
I use the bike Mon-Fri so need to get whatever I do done in a day, or find somewhere to take it to get it done.

thanks in advance

[bigblackfalco]

Andy, here is a temporary and cheap fix:
just take the calipers off the fork legs and take the pads out. Clean as much crap as you can from the caliper/ piston area. Then spray liberal amounts of GT85 lubricant onto the piston sides and clean more crap off.
Use a large mouthed size of pliers/pipe wrench to push the pistons back into the caliper body ( obviously if you are bothered about the jaws biting into metal work then cover the jaws with gaffer tape or whatever).
Then carefully apply small motions to the front brake lever to push the pistons back out. NOTE!! BE CAREFUL NOT TO PUSH THE PISTONS OUT OF THE CALPIER COMPLETELY!!!!
repeat the Gt85 and cleaning each time the piston is extended. Gradually the piston should move more freely each time you clean it.
This will help things for a while, but the only true fix is to buy a caliper/piston rebuild kit. The rubber seals tend to swell over time which stops the piston from returning normally.
HTH.
Bailey.

[Gromit]

Good advice from Bailey.

I did the very same thing recently on the rear caliper on the Blackbird - 2 of the 3 pistons had seized up; just got some brake cleaner spray from Cafco and, taking great care not to spray it on paintwork, gave the pistons a really good dousing with the stuff doing the 'pistons in and out' thing as Bailey describes.

Not had any brake problems for 2000 miles now.

[Lightrunner]

Cheers for that - one question, are there any tricks to making the 'stiff' pistons come out while you're carefully using small motions on the front brake lever?
When I did it there was one piston that would come out, the other three remained stationary. I ended up putting the pads in and out a few times repeating the cleaning each time. Was still fairly quick but was just curious.
After nearly 36k I'd quite like to give the brakes an overhaul, maybe even replace the hoses given the recent threads on the topic.
Just can't afford to loose the use of the bike

[bigblackfalco]

Cheers for that - one question, are there any tricks to making the 'stiff' pistons come out while you're carefully using small motions on the front brake lever?
When I did it there was one piston that would come out, the other three remained stationary. I ended up putting the pads in and out a few times repeating the cleaning each time. Was still fairly quick but was just curious.
After nearly 36k I'd quite like to give the brakes an overhaul, maybe even replace the hoses given the recent threads on the topic.
Just can't afford to loose the use of the bike

The only way to do it is if you've got a few extra pairs of visegrips/ molegrips or larger pliers, or if you can get an assistant to hold in the free-er pistons while you work on the sticky ones.
Bailey.

[mdouglas]

I'm around tomorrow (Sunday) afternoon if you want any help. I'm in Surbiton, with fully equipped garage. I've got a series of quickclamps, spring clamps and the like that I use to keep 3 pistons in place while you work on the 4th. I've got industrial quantities of brake cleaner aerosol as well. My Rockster was a dealer demonstrator and the Tokico calipers on that were a disgrace when I first got it. I've treated the K12R to an internal brushing of ACF50 and they're still like new, even after commuting right through the last winter.

Just PM me back if you're interested. it would only take half an hour to resolve. If things get bad, I have an airline for blowing the pistons right out.

[sproggy]

are there any tricks to making the 'stiff' pistons come out while you're carefully using small motions on the front brake lever?

Use a suitable thickness 'object' to stop the other pair moving by placing it in between the pistons (8mm ply, I think I used) and clamp the one opposite the stiff one.