Bendy toy
Registered user
Ive just done mine with new seals so here's the procedure. No pictures sadly. I did not use a GS-911 as the main system was not disturbed.
Get a 40mm long M10 bolt and long M10 nut as used to join threaded bars. Put some threadlock in one end of the long nut.
Wrap the caliper and final drive with rags to catch any brake fluid drips. And use rubber gloves or barrier cream to protect hands from brake fluid.
Undo the hydraulic hose banjo with a 12mm AF ring spanner . A sharp tap on the spanner with a rubber mallet avoids bashed knuckles. Quickly remove the copper washers and use them with the M10 bolt to plug the hose banjo. Fit the long nut with the threadlock at the far end. Threadlock stops fluid leaking down the M10 thread and the long nut avoids contaminating the banjo with threadlock. The nut will need a 17mm AF spanner.
Put the banjo bolt back into the caliper to keep it clean.
Pull the small R clip and knock out the brake pads retaining pin from the caliper. Its easier to do on the bike. Use a suitable pin punch to knock out the pads retainer pin.
Remove the caliper from the bike. Take care to avoid dripping brake fluid onto paint.
On the bench put the pads to one side.
Put the banjo bolt back into the caliper with a large nut to take the place of the hose banjo ring.
Properly clean the caliper before doing any strip down work. For now, leave the sliding mount in place to keep the slides clean.
Pull off the caliper mounting off the clean caliper. You may need a blunt screwdriver to release the rubber bellows.
Take out the bleed nipple and screw a beachball or airbed adaptor into the nipple thread. Connect a bicycle tyre pump to the adaptor using a flexible connector tube.
Pump air into the caliper. One piston will move. Use a small G clamp to stop that piston moving.
Wrap the clean caliper with rags and put into a plastic bag. Pump it up until the free piston pops out. The bag catches any flying brake fluid.
Clean the piston and drain out the remaining brake fluid. Grease the piston inner end and put it back in just enough to seal the hole. Use the G clamp to stop the piston moving and pump out the other piston. finally, pull out the first piston.
Hook out the four rubber seals. They "can" be resused if in good condition but a new set is under £20 from Motorworks and you get a sachet of Brembo brake lubricant.
Clean pistons and all seal grooves. I used kitchen paper and an old blunt flat screwdriver with the blade tip bent 90 degrees. Be VERY careful to not scratch the anodising. Get the everything spotlessly clean. Grease the seals and seal grooves with Brembo lubricant or you could use red brakes grease. Fit the seals and refit the pistons. The seals are fiddly - I found tweezers helped.
If the anodising is corrosion damaged make sure ALL oxide is scraped out and clean out all debris. Use lots of red brake grease to half fill the seal grooves. Be sure the grease runs all around. Fit the seals and wipe off excess grease. This grease will protect the bare metal reducing the effect of any continuing corrosion.
Clean the mounting bar and grease the slide rods with the Brembo lubricant (or red grease). Refit the mount to the caliper and make sure the bellows are secure.
The anti rattle spring may be losing its plating but can be reused if protected with ACF-50. Ideally fit a new one coated with ACF-50 for good measure. Use anti seize grease on the pad end slots and under the anti rattle spring to reduce corrosion where the anodised oxide layer gets rubbed away.
Put the pads back and replace the retaining pin and R pin. My pin was quite rusty so a new one will be fitted later. I cleaned it up and used brake grease to protect it.
Remove the banjo bolt and put the bleed nipple back into the bolt.
Back at the bike, refit the caliper and torque the bolts. They go tight suddenly so doing it by hand isnt a good idea. Remove the M10 bolt from the hose banjo. Notice how the thread lock has sealed the threads. Quickly swap the copper washers to the banjo bolt and refit to the caliper. Better still use new washers. Again protect any paint from fluid drips.
Fit a length of neoprene hose to a 100mm syringe and the other end to the bleed nipple.
Remove the rear brake fluid reservoir cap and top up the fluid level. Bleed the brake until the flow is clean and bubble free. Top up as necessary. The syringe keeps the job clean. Only the brake end of the system has been disturbed so there is no need to follow the full fluid change procedure.
The brake should have lost any wooden feel and the disc wont be overheating. If the brake feels soggy, tie the foot lever down overnight to allow any bubbles to escape.
If you have access to a GS-911 bleed the whole brake system to change the fluid. This avoids old moisture contaminated fluid from collecting in the caliper seal grooves where corrosion can set in. Eventually however the seals will get gummed up & its time to strip, clean and lube the caliper seals.
Get a 40mm long M10 bolt and long M10 nut as used to join threaded bars. Put some threadlock in one end of the long nut.
Wrap the caliper and final drive with rags to catch any brake fluid drips. And use rubber gloves or barrier cream to protect hands from brake fluid.
Undo the hydraulic hose banjo with a 12mm AF ring spanner . A sharp tap on the spanner with a rubber mallet avoids bashed knuckles. Quickly remove the copper washers and use them with the M10 bolt to plug the hose banjo. Fit the long nut with the threadlock at the far end. Threadlock stops fluid leaking down the M10 thread and the long nut avoids contaminating the banjo with threadlock. The nut will need a 17mm AF spanner.
Put the banjo bolt back into the caliper to keep it clean.
Pull the small R clip and knock out the brake pads retaining pin from the caliper. Its easier to do on the bike. Use a suitable pin punch to knock out the pads retainer pin.
Remove the caliper from the bike. Take care to avoid dripping brake fluid onto paint.
On the bench put the pads to one side.
Put the banjo bolt back into the caliper with a large nut to take the place of the hose banjo ring.
Properly clean the caliper before doing any strip down work. For now, leave the sliding mount in place to keep the slides clean.
Pull off the caliper mounting off the clean caliper. You may need a blunt screwdriver to release the rubber bellows.
Take out the bleed nipple and screw a beachball or airbed adaptor into the nipple thread. Connect a bicycle tyre pump to the adaptor using a flexible connector tube.
Pump air into the caliper. One piston will move. Use a small G clamp to stop that piston moving.
Wrap the clean caliper with rags and put into a plastic bag. Pump it up until the free piston pops out. The bag catches any flying brake fluid.
Clean the piston and drain out the remaining brake fluid. Grease the piston inner end and put it back in just enough to seal the hole. Use the G clamp to stop the piston moving and pump out the other piston. finally, pull out the first piston.
Hook out the four rubber seals. They "can" be resused if in good condition but a new set is under £20 from Motorworks and you get a sachet of Brembo brake lubricant.
Clean pistons and all seal grooves. I used kitchen paper and an old blunt flat screwdriver with the blade tip bent 90 degrees. Be VERY careful to not scratch the anodising. Get the everything spotlessly clean. Grease the seals and seal grooves with Brembo lubricant or you could use red brakes grease. Fit the seals and refit the pistons. The seals are fiddly - I found tweezers helped.
If the anodising is corrosion damaged make sure ALL oxide is scraped out and clean out all debris. Use lots of red brake grease to half fill the seal grooves. Be sure the grease runs all around. Fit the seals and wipe off excess grease. This grease will protect the bare metal reducing the effect of any continuing corrosion.
Clean the mounting bar and grease the slide rods with the Brembo lubricant (or red grease). Refit the mount to the caliper and make sure the bellows are secure.
The anti rattle spring may be losing its plating but can be reused if protected with ACF-50. Ideally fit a new one coated with ACF-50 for good measure. Use anti seize grease on the pad end slots and under the anti rattle spring to reduce corrosion where the anodised oxide layer gets rubbed away.
Put the pads back and replace the retaining pin and R pin. My pin was quite rusty so a new one will be fitted later. I cleaned it up and used brake grease to protect it.
Remove the banjo bolt and put the bleed nipple back into the bolt.
Back at the bike, refit the caliper and torque the bolts. They go tight suddenly so doing it by hand isnt a good idea. Remove the M10 bolt from the hose banjo. Notice how the thread lock has sealed the threads. Quickly swap the copper washers to the banjo bolt and refit to the caliper. Better still use new washers. Again protect any paint from fluid drips.
Fit a length of neoprene hose to a 100mm syringe and the other end to the bleed nipple.
Remove the rear brake fluid reservoir cap and top up the fluid level. Bleed the brake until the flow is clean and bubble free. Top up as necessary. The syringe keeps the job clean. Only the brake end of the system has been disturbed so there is no need to follow the full fluid change procedure.
The brake should have lost any wooden feel and the disc wont be overheating. If the brake feels soggy, tie the foot lever down overnight to allow any bubbles to escape.
If you have access to a GS-911 bleed the whole brake system to change the fluid. This avoids old moisture contaminated fluid from collecting in the caliper seal grooves where corrosion can set in. Eventually however the seals will get gummed up & its time to strip, clean and lube the caliper seals.
