Caliper Rebuild Questions
Thread Starter
Instructor
Joined: Jan 2008
Posts: 149
Likes: 8
From: Scarborough Qld
Caliper Rebuild Questions
Hi Everyone.
I am converting my brake pistons to the o-ringed version. (when they get here).
I have a few questions if anyone can help.
1. I have managed to split the caliper into two halves. In doing so, I have rounded the head of one of the 5/8 bolts. I am told it is grade 8 high tensile. The shop only had grade 5. Will this be a suitable replacement or should I get a grade 8 from somewhere else?
2. What is the best way to clean the calipers before I rebuild them? Petrol?
3. When I re-assemble the calipers, what is the correct torque?
I am certainly learning a lot from you guys.
Thanks in advance for your help.
Andrew from Aus
I am converting my brake pistons to the o-ringed version. (when they get here).
I have a few questions if anyone can help.
1. I have managed to split the caliper into two halves. In doing so, I have rounded the head of one of the 5/8 bolts. I am told it is grade 8 high tensile. The shop only had grade 5. Will this be a suitable replacement or should I get a grade 8 from somewhere else?
2. What is the best way to clean the calipers before I rebuild them? Petrol?
3. When I re-assemble the calipers, what is the correct torque?
I am certainly learning a lot from you guys.
Thanks in advance for your help.
Andrew from Aus
Racer
Joined: Jan 2010
Posts: 367
Likes: 1
From: Christchurch Canterbury
Hi Everyone.
I am converting my brake pistons to the o-ringed version. (when they get here).
I have a few questions if anyone can help.
1. I have managed to split the caliper into two halves. In doing so, I have rounded the head of one of the 5/8 bolts. I am told it is grade 8 high tensile. The shop only had grade 5. Will this be a suitable replacement or should I get a grade 8 from somewhere else?
2. What is the best way to clean the calipers before I rebuild them? Petrol?
3. When I re-assemble the calipers, what is the correct torque?
I am certainly learning a lot from you guys.
Hi,
You should use grade 8 bolts, any fastner supplier will have stock.
Clean the caliper bores in hot soapy water and use pot scourer pads to clean any marks off, dry with compressed air and coat with brake assy lube before they rust.
Richie
Thanks in advance for your help.
Andrew from Aus
I am converting my brake pistons to the o-ringed version. (when they get here).
I have a few questions if anyone can help.
1. I have managed to split the caliper into two halves. In doing so, I have rounded the head of one of the 5/8 bolts. I am told it is grade 8 high tensile. The shop only had grade 5. Will this be a suitable replacement or should I get a grade 8 from somewhere else?
2. What is the best way to clean the calipers before I rebuild them? Petrol?
3. When I re-assemble the calipers, what is the correct torque?
I am certainly learning a lot from you guys.
Hi,
You should use grade 8 bolts, any fastner supplier will have stock.
Clean the caliper bores in hot soapy water and use pot scourer pads to clean any marks off, dry with compressed air and coat with brake assy lube before they rust.
Richie
Thanks in advance for your help.
Andrew from Aus
You should use grade 8 bolts, any fastner supplier will have stock.
Clean the caliper bores in hot soapy water and use pot scourer pads to clean any marks off, dry with compressed air and coat with brake assy lube before they rust.
Richie
Burning Brakes
Joined: Jan 2003
Posts: 755
Likes: 32
From: Roswell Georgia
According to my Haynes Manual, the torque for the bolts on the front calipers is 130 ft-lb while the rear caliper bolts are only 60 ft-lb. (I don't ever remember using that much torque on the front caliper bolts, but it definitely required gorilla torque to re-assemble.)
Biggest problem with cast iron calipers is rust so be sure to use compressed air to dry all portions of the disassembled calipers including the bleeder valve passages. (Make sure these are rust free to begin with. I had great luck wrapping the upper half of each bleeder screw with Teflon plumber's tape to keep them rust-free and easy to open-shut after the re-build.)
Last item, be sure that you install the transfer passage o-rings in the calipers before you torque them back together. (Nothing worse than completing the task only to find two o-rings sitting on the bench top! Been there, done that, and not worth a tee-shirt to re-do the assembly process a second time.)
Good Luck!
Biggest problem with cast iron calipers is rust so be sure to use compressed air to dry all portions of the disassembled calipers including the bleeder valve passages. (Make sure these are rust free to begin with. I had great luck wrapping the upper half of each bleeder screw with Teflon plumber's tape to keep them rust-free and easy to open-shut after the re-build.)
Last item, be sure that you install the transfer passage o-rings in the calipers before you torque them back together. (Nothing worse than completing the task only to find two o-rings sitting on the bench top! Been there, done that, and not worth a tee-shirt to re-do the assembly process a second time.)
Good Luck!
