Keep it regular, every time I have the front wheel off I give the brakes a clean .It is a time consuming, mucky, fiddly old job but will keeps your brakes performing and will save you the agro of having to strip the calipers down to replace stuck pistons and leaking seals..
I’ve just upgraded the calipers on the Trumpet so have included a few picks from the change over as a guide to basic maintenance..in fact I’ve had the old 4 pots off put new Tokico 6 pots on and then changed them for some Alcon 6 pots all with out the thing turning a wheel !!!
You will need:
Plus Red Rubber grease and either copper slip or better still Aluminum grease
Working on one caliper at a time, loosen the pad pins, then unbolt the caliper from the fork leg (assuming it’s the front brakes your working on of course !) .Fully remove the pad pin and the pads and attach a support bungy or some such to the caliper, this is to stop over stressing the brake line. You can at this stage give the caliper a general clean up, a bucket of soapy water and a brush will do all depends how bad they are ?
Once the caliper is dried off the aim is to be able to pump out one piston at a time in order to clean it before pressing it back home and moving onto the next. Use plastic or wood to press the pistons back into the caliper in order not to damage them, when the pistons you are not working on are pressed home zip tie them in place so that when you use the brake lever to pump out the piston to be cleaned the can’t move too far. I sometimes zip tie a brake pad in, or just the piston, or even hold some back with a block of wood, anything to keep all but the piston you want to work on coming out..
You get the picture…
Don’t pump the piston out too far, it needs to be out far enough so that all the dirt is accessible but not so far that you may be in danger of pumping the piston out altogether !!!
Take the Brake cleaner spray the dirty piston and scrub it with your small brush all round it, you may want to spray some cleaner onto a rag and rub at stubborn deposits too. Sometimes it can be difficult to get at the top of a piston because there is very little room between it and the end of the caliper, I have found spraying some cleaner onto a cloth feeding the cloth through the caliper and then running the cloth over the piston and pulling to and fro in a sort of flossing action works quite well…still fiddley though…
When you have cleaned the piston you are working on press it back into the caliper body zip tie it in and move onto the next, occasionally I will lube the piston with a little Renolit Red rubber grease push the piston home and wipe off any excess..
Carry on until you have done them all, then clean the backs of the pads apply a smear of copper slip grease or better still hi temp aluminum grease to them and pop them in, clean and grease the pad pins in the same manner and refit, put the caliper back onto the bike and do the other side.
Couple of words of caution..Brake dust is unhealthy stuff so by using the brake cleaner it suppresses it, and also watch out with the brake cleaner it is a strong solvent and I had it stain the front fender extender before.
Spongy front brake
I had been bleeding the front brakes about every 3 months, I find sooner or later the travel on the front lever can get a bit too much, this seems to happen on both the Sprint & the Speed Triple. Some people use temp quick fix, they zip tie the lever back over night allowing any trapped air in the system to rise into the master cylinder, well that’s the theory anyway but after some years and speaking to many I think this method is either hiding another problem like a necessary master cylinder rebuild or stripping the caliper itself. After rebuilding many 2,4 and 6 pot calipers if the complete system is in top form it cuts down on the need to keep bleeding the brakes quite so often which also keeps lever travel to a minimum.
I use a Mitivac to bleed the brakes, this is a vacuum pump that sucks the fluid through as opposed to the manual method of cracking the bleed nipple and pumping the lever. I find it gets me good results even if the system is dry from replacing calipers or hoses. It’s quick and effective.
It does require a little getting used to as the vacuum can suck air from around the hose at the bleed nipple so don’t think this is necessary air from the brake system the you are seeing in the tube, instead bleed the brakes on feel. I normally find a few alternate sides of bleeding and a little manipulation of the brake lever while the vacuum is sucking fluid gets a nice firm lever feel in short order.
Be handy with regular top ups of fluid though as the vacuum can empty a master cylinder surprisingly quickly !!