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After hours of searching on various forums, videos, manuals, etc. I could not find any information regarding how to rebuild Brembo flagship billet mono-block race calipers that include the 32/36 GP4-RR and 32/36 P4. All I read was mention of the meticulous cleaning, maintenance, and (very expensive) rebuild service that requires sending the calipers off to Brembo.
I am writing this post so that others may use it as a reference to safely service such a hefty investment.
Disclaimer: I do not race nor am I a fast rider. I'm a high school teacher who enjoys working on bikes in my spare time and sharing my knowledge with others.
Before we start, a note regarding surface finish! The newer Brembo billet mono-block calipers have a hard anodized finish that is extremely durable and corrosion resistant; however, the older calipers are nickel plated. These calipers will corrode with brake dust and moisture because of an electro-chemical reaction that occurs when metals are exposed to water.
![259228]()
For this reason, I would recommend the anodized calipers rather than nickel plated calipers.
In contrast to street calipers, race calipers do not have dust seals, and must be cleaned and serviced more frequently to prevent piston lock-up and permanent damage to the seal grooves. The exact interval will depend more on amount of brake use rather than miles of riding alone, but I recommend to remove the pistons to clean the seals and seal groove with at least every set of brake pads in addition to cleaning off brake dust as it deposits.
Step 1: Purchase replacement seals if desired. Brembo Racing seals are not the same as Brembo OEM seals; however, Brembo Racing seals are compatible across different race calipers. Several part numbers are listed. For example, if you have a 32/36 caliper, you would need four 32mm seals and four 36mm seals total. Included in each seal kit is a friendly reminder from Brembo that your warranty will be forever void. Expect to pay $10-15 per seal.
30mm 205595513
32mm 105570244
34mm 205595515
36mm 105570246
38mm 105570247
Step 2: Remove the caliper from the bike, clean off the brake dust with detergent such as Simple Green HD and a toothbrush, and retract all the pistons by hand.
![259229]()
Step 3: Use a ~1ft long Velcro strip to clamp two of the pistons in place on one side of the caliper.
![259230]()
Step 4: Cut a stack of rectangles out of either thick card stock or in my case I used gasket material. Add enough rectangles for a 1/4" gap between piston. This stack helps slow the pistons down.
![259231]()
Step 5: Using a rubber nozzle attachment on a blowgun set at 30psi, add pressure to the caliper where the banjo bolt screws.
![259232]()
Step 6: Remove a few sheets of material and blow again. Repeat until the piston just comes free. This gradual process ensures the pistons come out in a controlled manner.
![259233]()
Step 7: Insert a 0.5mm round nose guitar pick between the seal and edge of the seal groove. Then turn the pick down to take the seal out without damage.
![259235]()
Step 8: With the seals removed, put the two pistons back into the holes and use a Velcro strap to tie these same two pistons in place. Now we can blow out the other half of the caliper and remove those seals in the same way. Scrub the seal groove with a tooth brush and detergent. If desired, use brake cleaner on metal only, but not on the seals. Blow dry with compressed air.
![259236]()
Step 8: Install new seals and grease pistons with Brembo seal grease. Put a small dab on each piston and spread evenly. Do not apply excess grease.
![259237]()
Step 9: Slide greased pistons back into the holes. This should be very easy with hand pressure. Tilt the piston a little from side to side if it catches on an edge. Do not force the piston.
Wipe off any excess grease you may have on the exposed areas of the pistons and you are DONE (for now)!
![259238]()
If you service these regularly as intended, this process is very quick and painless. If you let dirt and brake dust get into the tight tolerances you will have a hard time getting the pistons out.
I am writing this post so that others may use it as a reference to safely service such a hefty investment.
Disclaimer: I do not race nor am I a fast rider. I'm a high school teacher who enjoys working on bikes in my spare time and sharing my knowledge with others.
Before we start, a note regarding surface finish! The newer Brembo billet mono-block calipers have a hard anodized finish that is extremely durable and corrosion resistant; however, the older calipers are nickel plated. These calipers will corrode with brake dust and moisture because of an electro-chemical reaction that occurs when metals are exposed to water.
For this reason, I would recommend the anodized calipers rather than nickel plated calipers.
In contrast to street calipers, race calipers do not have dust seals, and must be cleaned and serviced more frequently to prevent piston lock-up and permanent damage to the seal grooves. The exact interval will depend more on amount of brake use rather than miles of riding alone, but I recommend to remove the pistons to clean the seals and seal groove with at least every set of brake pads in addition to cleaning off brake dust as it deposits.
Step 1: Purchase replacement seals if desired. Brembo Racing seals are not the same as Brembo OEM seals; however, Brembo Racing seals are compatible across different race calipers. Several part numbers are listed. For example, if you have a 32/36 caliper, you would need four 32mm seals and four 36mm seals total. Included in each seal kit is a friendly reminder from Brembo that your warranty will be forever void. Expect to pay $10-15 per seal.
30mm 205595513
32mm 105570244
34mm 205595515
36mm 105570246
38mm 105570247
Step 2: Remove the caliper from the bike, clean off the brake dust with detergent such as Simple Green HD and a toothbrush, and retract all the pistons by hand.
Step 3: Use a ~1ft long Velcro strip to clamp two of the pistons in place on one side of the caliper.
Step 4: Cut a stack of rectangles out of either thick card stock or in my case I used gasket material. Add enough rectangles for a 1/4" gap between piston. This stack helps slow the pistons down.
Step 5: Using a rubber nozzle attachment on a blowgun set at 30psi, add pressure to the caliper where the banjo bolt screws.
Step 6: Remove a few sheets of material and blow again. Repeat until the piston just comes free. This gradual process ensures the pistons come out in a controlled manner.
Step 7: Insert a 0.5mm round nose guitar pick between the seal and edge of the seal groove. Then turn the pick down to take the seal out without damage.
Step 8: With the seals removed, put the two pistons back into the holes and use a Velcro strap to tie these same two pistons in place. Now we can blow out the other half of the caliper and remove those seals in the same way. Scrub the seal groove with a tooth brush and detergent. If desired, use brake cleaner on metal only, but not on the seals. Blow dry with compressed air.
Step 8: Install new seals and grease pistons with Brembo seal grease. Put a small dab on each piston and spread evenly. Do not apply excess grease.
Step 9: Slide greased pistons back into the holes. This should be very easy with hand pressure. Tilt the piston a little from side to side if it catches on an edge. Do not force the piston.
Wipe off any excess grease you may have on the exposed areas of the pistons and you are DONE (for now)!
If you service these regularly as intended, this process is very quick and painless. If you let dirt and brake dust get into the tight tolerances you will have a hard time getting the pistons out.
