HELP,,,,,,,,Soft rear brakes on 2002 RSV

[maddog2498]

I have a 2002 RVS, with 135k and my rear brakes are soft and will not slide rear tire. I put new rotary on rear app 40k miles ago when I put on new tire, and they were a little soft but would slide wheel if I tried. About 16k miles ago I put on new rear tire and when I got it back together they, I bled the brakes, but they were a little softer than the last time, but I could still slide rear if I tried. I just put on another rear tire. This time I use a 1 man vacuum bleeder and still pump brake to bleed them the best I can. When  rode today I could not get the rear brakes to slide the tire. It has stopping power but very soft. Now the rotor that I put on was an after-market. I notice my old OEM rotor was app 7mm thick and was worn down to 4mm. The new after-market rotor was only 4mm thick brand new. Do you think this is my problem. Any help and advice will be appreciated. thank you

[Freebird]

I’m not sure.   Certainly sounds like the new rotor is too thin but could also be other things.  You said you bled the brakes but how long since a complete fluid change?  At those miles, I would hope that has been done.  Other than that, which is the first thing I would try, it could be your master cylinder 

[M61A1MECH]

Have you flushed out the brake fluid to ensure there is no old contaminated fluid in the system?

Have you inspected or rebuilt the rear master cylinder?

Try getting a speed bleeder for the rear bleeder port, those work great make bleeding a breeze.

I would also consider going back to OEM rotor, you can check the specs on the rotor thickness requirements in the service manual found in the tech section here on the forum.

 

Well I see Freebird beat me to it as I was typing.

[maddog2498]

1 hour ago, Freebird said:

I’m not sure.   Certainly sounds like the new rotor is too thin but could also be other things.  You said you bled the brakes but how long since a complete fluid change?  At those miles, I would hope that has been done.  Other than that, which is the first thing I would try, it could be your master cylinder 

I have not done a complete fluid change. Never have done one, but maybe that is the time. With my vacuum pump, I never could get a complete stream of fluid. Never had fluid go bad. Thank you.