Rear brake trouble...

[Kieranrb]

A few months ago I bought a 99' M600 19k miles, from a guy who bought it to encourage him to do his test, but never bothered to, so the bike had basically sat for almost a year. i have been steadily replacing consumables and got to the brakes. the rear brake has always felt a bit vague, so i just assumed pads needed replacing. because of the crazy upside down placing of the calliper, i just took it off to make life easier. i got the pads out and they looked fine, and when i tried the rear brake i noticed only one piston was moving. i used a screw driver to hold the moving piston, and tried again, and the other piston moved. obv its not ceased so i was wondering if it only moves when the first piston comes under resistance. i replaced the pads and have taken it out, and there is still a lot of vagueness. i was wondering if anyone had any ideas before I pull it apart.
Thanks

[Mr Cake]

You'll find that. The fluid will pressurise one side of the caliper first, as soon as it meets resistance the pressure will even out. Try changing the fluid but don't bleed it upside-down. The rear brake on Monsters isn't great at the best of times; powerful enough but no feel.

C

[gary tompkins]

Slotted discs help keep pads from glazing and improve bite as well

[Nickj]

Vague but working...

Sounds like a good one then :mand:

[jerry]

fresh fluid is a good move it goes all watery after 2 years

[Paul_]

Just had the same vague problem with my rear brake, posted on here and was advised to change the brake fluid. However, whilst I was at it I went a bit further and the results are great! I now have a rear brake that works, whilst I was at it I also did my front calipers which are now working bloody brilliantly!

Take the caliper off and using the brake lever push both sides of pistons out enough so you could give them a good clean with a tootbrush and some aerosol brake cleaner, you wouldn't believe just how filthy the pistons can get! Be careful not to push them out too far or they will drop out and they are a bugger to get back in.

After cleaning them up put some high temp grease on them using a small paintbrush, you only need a very, very thin coat of it, then push the pistons back into the cailper each side with your fingers or brake spreader and out again using the brake lever. Cycle this a couple of times and you will feel that gets much easier to push them in and out. If they have come up well you will be able to push on side in with your fingers and the other slide out and vice versa.

Once cleaned up and lubed use a brake spreader to put between the two pistons and spread them both right back into the caliper body so they sit flush with the caliper. You could probably get away without using one of these but they make the job FAR easier, well worth the investment! Believe me you will see your money back several times over as you are supposed to do this job once a year to keep things running smoothly and is you can invest in one to share with your mates it make evenmore sence. Clean up the pads with brake cleaner and spread a very thin layer of copperslip over their rear face that rests against the piston before re-mounting them into the calipers.

Once done, replace the caliper on the bike, tighten up and pump the rear brake until the pads are against the disc as normal. When done bleed through the rear fluid with lovely new stuff until no air bubbles come through.

Did the whole job with a spanner, home made bleed kit (coffee jar with plastic tubing), brake spreader and a torque wrench. A mate to help with the bleeding can help as well but can be done on your own.

If this sounds like a bit past your spannering ability fear not, its not a complicated job. Just make sure your confident in doing it as brakes can come in quite handy on occassion.