right ive finally sourced a cheap set of discs so i want to go about sorting the problem out thats caused me to need new pads and discs.
i have found 1 of the pistons on the caliper is sticking so i want to give them both an overhaul. can anyone put me in the right direction of anyhing i need to do the job.
sticking piston on caliper
XXX
If you find your calipers are knackered then give me a shout as I have a spare set that are no use to me, other than that try unbolting the caliper from the fork leg and pull in the brake lever slowly so that the pistons move out, then push them back home and repeat. be careful not to overflow the resevoir!!
then clean everything up with some GT?? brake cleaner job done.
If you find your calipers are knackered then give me a shout as I have a spare set that are no use to me, other than that try unbolting the caliper from the fork leg and pull in the brake lever slowly so that the pistons move out, then push them back home and repeat. be careful not to overflow the resevoir!!
then clean everything up with some GT?? brake cleaner job done.
"Always do sober what you said you'd do drunk. That will teach you to keep your mouth shut."
instructions
a firend of me gave me these instructions for stripping calipers:
Don't use copperslip on the seals, only use Red Rubber Grease, the seals can most likely be saved, but the dust seals may be shot.
with the calipers on the fork and the wheel still in place, Take out the pads & pump the pistons out to the rotor. You will see which ones are binding.
make sure the fluid doesnt run dry. The point of this is to advance all of the pisons in the bores as far as you can without letting air into the system. If you can do this, it makes the job a whole lot easier, as the seized ones are the most difficult to extract, and the best way to move them is with hydraulic pressure.
Take the line off the calipers and cable tie the lines out of the way. Unbolt the caliper from the leg, stick it in a vice to split it.
Dont lose the seal between the caliper halves where the pathways are machined.
As the pistons are out 95% of the way, you shoud be able to pull the them rest of the way with your fingers or wrap a bit of kitchen towel around the end to help grip, use care not to mark the pistons
Once pistons are out, lay all of them out on a clean area so you dont mix them up.
Take out the seals carefully and put them with their respective pistons
Use either some clean brake fluid or preferably a tin of brake cleaner and a jewellers screwdriver carefully scrape the seal grooves spotlessly clean in the caliper halves to get rid of all salt deposits.
Once they are clean, scrape the seals clean with a thumb nail and lube them with a bit of Red Rubber Grease. if the dust seals are shot, replace them, dont be tempted to run without them.
Stick the seals back in where they came from with a light smear of the red grease, not copperslip, this will make the seals swell and can bind the pistons as a result.
shine up the pistons with a bit of chrome cleaner, but make sure it is all off berfore reassembly. Everything must be spotlessly clean. stick the pistons back in and push them home with your thumb, no real force is req'd if its done properly.
stick the pathway seals back in and bolt it all together torquing up to the correct poundage (cant remember what it is ATM)
prefill the calipers with new fluid rocking them around to get rid of the bubbles, and bolt them back on the leg, bolt the lines back on with a new copper washer on the banjo bolt and stick the pads back in.
Bleed as you know best how to (I backfill from the bleed nipple on the caliper using a large syringe and a bit of rubber pipe)
and once your happy take it for a spin
Hope it helps!
Adam
Don't use copperslip on the seals, only use Red Rubber Grease, the seals can most likely be saved, but the dust seals may be shot.
with the calipers on the fork and the wheel still in place, Take out the pads & pump the pistons out to the rotor. You will see which ones are binding.
make sure the fluid doesnt run dry. The point of this is to advance all of the pisons in the bores as far as you can without letting air into the system. If you can do this, it makes the job a whole lot easier, as the seized ones are the most difficult to extract, and the best way to move them is with hydraulic pressure.
Take the line off the calipers and cable tie the lines out of the way. Unbolt the caliper from the leg, stick it in a vice to split it.
Dont lose the seal between the caliper halves where the pathways are machined.
As the pistons are out 95% of the way, you shoud be able to pull the them rest of the way with your fingers or wrap a bit of kitchen towel around the end to help grip, use care not to mark the pistons
Once pistons are out, lay all of them out on a clean area so you dont mix them up.
Take out the seals carefully and put them with their respective pistons
Use either some clean brake fluid or preferably a tin of brake cleaner and a jewellers screwdriver carefully scrape the seal grooves spotlessly clean in the caliper halves to get rid of all salt deposits.
Once they are clean, scrape the seals clean with a thumb nail and lube them with a bit of Red Rubber Grease. if the dust seals are shot, replace them, dont be tempted to run without them.
Stick the seals back in where they came from with a light smear of the red grease, not copperslip, this will make the seals swell and can bind the pistons as a result.
shine up the pistons with a bit of chrome cleaner, but make sure it is all off berfore reassembly. Everything must be spotlessly clean. stick the pistons back in and push them home with your thumb, no real force is req'd if its done properly.
stick the pathway seals back in and bolt it all together torquing up to the correct poundage (cant remember what it is ATM)
prefill the calipers with new fluid rocking them around to get rid of the bubbles, and bolt them back on the leg, bolt the lines back on with a new copper washer on the banjo bolt and stick the pads back in.
Bleed as you know best how to (I backfill from the bleed nipple on the caliper using a large syringe and a bit of rubber pipe)
and once your happy take it for a spin
Hope it helps!
Adam
G-clamps are also a good idea to use, if you are only wanting to do a quick clean and not a full strip down.
remove the caliper from the fork leg, take the pads out and use g-clamps to hold in the pistons that are free, this should unstick the sticky ones, as you pump up the pressure with the lever, doing one caliper at a time, if that doesn't work your into the full strip down as adstar describes.
holding them in with your fingers will work but you sometimes need about 10 hands to do it right.
remove the caliper from the fork leg, take the pads out and use g-clamps to hold in the pistons that are free, this should unstick the sticky ones, as you pump up the pressure with the lever, doing one caliper at a time, if that doesn't work your into the full strip down as adstar describes.
holding them in with your fingers will work but you sometimes need about 10 hands to do it right.
cheerz
kev
kev