Rear brake repairing. Caliper and disc.

ProXimaCore · Dougal Joined: 01 May 2003 Karma :

I've decided that since the rear of my bike is in bits just now I'd fix the rear brakes. The pads are badly worn, so I've taken them out and got a new set to go in. The only thing is that one of the pistons is seized and doesn't push the pad. I've stripped the caliper into as many parts as possible and tried spraying WD-40 inside it. Then I even tried leaving the caliper to soak in engine degreaser overnight. Don't know if that would actually do any good or not though. But it's no different as far as I can see.

The 2nd thing is I'm trying to get my rear brake disk on and the very last allen bolt has worn itself into a circle and I can't get it off now. Does anyone have a suggestion for this?

Also the spare brake disc, I may or may not have touched it with my greasy hands and was worried that it'll be a bit slippery now since I've been using WD-40 and copper grease. If there is any on it then it'd only be a tiny bit. But I want to be sure it's clean. Is there any method I should use to clean the disc?
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mr jamez · World Chat Champion Joined: 04 Aug 2003 Karma :

If the piston is seized then you need to replace the seals and possibly the piston, though that should come up with a clean. Put the brake back together and pump the pistons out, replace seals and give everything a good wash with brake fluid. WD40 is bad for rubber and is not a good idea to use it round the seals, brake fluid will clean it up fine. You haven't sprayed WD40/engine degreaser inside the caliper have you?

As for the brake disc, I got grease on mine, gave it a good scrub with petrol then hot soapy water and it has done the trick as far as I can tell Laughing

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

As above. With luck the pistons will be fine.

However these calipers are known for seizing up, especially the pins that locate the pads. I suspect that they are also common to most Suzukis, and probably the same caliper on a Bandit.

WD40 has a reputation for affecting the rubber used in seals.

Just get a can of brake cleaner to clean the disks up (it is just a good degreasant).

All the best

Keith
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Scotsman37 · World Chat Champion Joined: 17 Aug 2004 Karma :

In regards to the allan bolt you can get from your nearest hardware shop ie B&Q or maybe Halfords a drill bit designed to remove such things. You should be able to get replacement allan bolt or set of them from say a bike dealer or M&P for your brake disk.

Kickstart · The Oracle Joined: 04 Feb 2002 Karma :

Hi

Given the amount of stress that disk bolts have to take and the consequences of then shearing off I would use OE bolts or speak to a decent fastener shop to get something suitable rather than just just some cheap rubbish from B&Q.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

Scotsman37 · World Chat Champion Joined: 17 Aug 2004 Karma :

Duh!

I didn't mean buy replacement bolts from B&Q, but actually to get a special drill bit or something similar for removing damaged screws, bolts, etc. which can be bought via B&Q or Halfords.

Yes, the bolts for brake disks should be bought from; a bike dealer, M & P, The Fast One or maybe even Gear4Bikes.