Hello, I'm new to the motorcycle world and I just bought a 90 cbr 600 and the front brakes do not work. I have changed the master cylinder(which was needed) but it still did not fix the problem. When I squeeze the brake lever while the bike is moving nothing happens. If anyone has any ideas that would be great. thanks.

 

Have you bled the brakes? Do the pistons and slides move freely?

 

Yes, I have bled the brakes and no the pistons do not move freely.

 

It's possible that the pistons are seized in the calipers. Most likely if the bike has sat for long periods of time. I would look at the calipers and see if the pistons can be removed and rebuilt or replaced.

Rebuilding is much much cheaper. I used a shop rag and a little compressed air with the caliper off of the bike to remove both of mine, make sure your fingers are clear! Clean them up, installed new seals and dust covers, and reinstall with a c-clamp. Use a little clean brake fluid as a lubricant to help go back in.

My bike was driven several times last year before rebuild and when I looked over my calipers 1 piston on each side was sticking.

 

hi nickf1

If you don't have compressed air like me...(what I had to do)

1. took off one caliper (furthest away from master cylinder) and pumped out the pistons evenly using a c-clamp and pieces of wood that got thinner and thinner until both pistons were out the same amount and could be pulled out.

2. checked out the state of the caliper inside and the seal and the pistons.

3. cleaned everything up with new brake fluid (could've changed the seals and pistons at this point but didn't need to - just cleaned 'em up really well)

4. replaced pistons squarely using c-clamp (made reference marks on piston face and caliper to help do this before their removal)

5. bled it up and check operation of pistons, then put back on disc

6. repeated on other caliper

7. went back to first caliper and bled up again to get rid of bubbles then back to 2nd caliper

8. repeated stage 7 until the brakes where operating well and were nice and firm.

This was my poor-man's way cus I'm poor. If you can replace the seals and pistons it will achieve the best results.

Hope you're not as poor as me and you sort you brakes bud!

 

i cant seem to get my pin hangers out. they are not rounded theyre just stuck? any ideas?

 

Spray some penetrating oil in and let it sit for a bit. I had a hell of a time just getting the pin hanger covers off... Ended up using a special bit and a t handled screwdriver to get the little effer out.