Completly rebuilding front brakes/calipers

[Rand soper]

When I bought my NT the front rotors were warped. The bike had only about 5500 miles on it at the time. The right front was much worse than the left and the cause was one of the anti-rattle clips in the caliper was installed wrong and it caused the inboard pad to sit cockeyed and constantly rub. The left front rotor was also warped but I didn't really notice it as the right was so bad. I replaced both rotors and the pads on both sides and though that would be then end of it. Unfortunately it wasn't.

Currently my left front rotor is starting to warp again (the right is fine). I believe it is the center piston on the left caliper that is sticking, causing the pads to rub most of the time. I do use the rear brakes a lot and often sit at a red light with the rear brakes, and the center left piston, holding the bike in place. When I replaced rotors and pads the last time all I wanted to do was get riding again and I did not clean the slide pins etc or bleed/replace the brake fluid. I am taking no chances this time and will be cleaning/rebuilding/replacing everything. Rotors, pads and replacing all of the piston seals in the calipers as well as cleaning and lubing slide pins etc.

My question is this - has anyone replaced the piston seals in the calipers and if so is there anything I should be watching out for. I have rebuilt many calipers in my day both on cars and on motorcycles and it looks pretty straightforward in the FSM but sometimes there are tricks to make the job go easier.

This is a fantastic forum and I look forward to any knowledge and wisdom you can provide

Rand

 

[Rand soper]

Finally got a Saturday to myself so I tore into the front brakes. Very straightforward but I will say that the caliper piston seals look to be way to big but they did fit. Bit of difficulty getting the old seals out, thank goodness for dental tools.
My theory as to why the rotor warped was that the center piston in the left caliper was sticking. That is the piston that is linked to the rear brakes. When I popped the piston out I noticed that the old seal was sort of crooked in its seat. After removing the seal I carefully checked the seat/groove that the seal fits in and was able to remove a small bit of what looked like metal. The new seal sat perfectly into the groove.
Bleed the brakes front and rear and man, what a difference! Butter smooth and it stops on a dime! Well, maybe a quarter, its not a superbike after all.
In all the job took about 1.5 hours. New rotors, pads and caliper piston seals.

 

[ARKNT]

Glad it went well. Let us know if you have any more issues.

Brad