Rear Brake Non-responsive

I have noticed today that my rear brake is really non-responsive, almost to the point of it doing nothing.

IWhen I got hom I looked at the brake fluid resevoir (I think it is the brake fluid anyway) and it isn't all that clear wheter or not there is much in there, but I suspect that it needs topping up.

My questions are these:

1. Would having little fluid cause this issue?
2. Am I looking at the right place (right hand side of the bike below the seat)?
3. How do I top it up, it seems quite inaccesible, unlike the front one?
4. I have just bought some Halfords universal DOT4 brake fluid, will this be o.k for the job?

Thanks,

Kev

[Biker Biggles]

Does the pedal feel spongy or have little resistance to pressure?If so it will need fluid,but you will need to bleed the system too.If the pedal feels hard but the brake does not work,then the caliper probably needs attention,cleaning at least,and possibly stripping down and overhauling.Best to get it looked at if you are not confident with brakes.

The pedal feel normal, but goes all the way down without doing much.

I was just going to try and see if topping it up would work, do I have to bleed the brakes even if I just top up?

Why? and then how?

[rictus01]

Not sure fluid is your problem, I'd suspect the brake needs a good clean/service and is binding.

If however it is the fluid ( and yes you're looking in the right place), you have a leak in the system, this is of more of an issue as brake fluid will eat through paint work and where has yours gone?

As the RES os only transucent(sp) and good fluid mostly clear, it can be hard to see it in there, does the pedel move freely? do the rear pads look clean, what about the piston ?

Cheers Mark.

The rear brake looks clean enough, as for the piston I'm not sure I would know where to look for that.......

I've seen no fluid on the drive or where I park at work, could it not just have been used?!? I might be showing my lack of knowledge up here.

[rictus01]

By it's very nature (compessable media) itwon't just "use up", it can change with heat builtup however, although this is normally seen by a colour change (goes darker), if as you suspect the fluid has gone, then it's leaking past a seal (or possibly the pipe is rubbing somewhere and developd a leak).

Check the banjo bolt sealing washers and also remove the rear caliper, take out the pads and you'll see the piston (round bit that pushes on to the pad).

although the quantity of brake fluid is fairly small, you shouldn't ever loose anywhere near enough to stop the brake working and only need to either replace it (because of age/condition or at most a little top-up.


Cheers Mark.

Could I just be being a bit over-dramatic?

Should I try a top up and see if that works?

[rictus01]

I'd have to ask when was it last checked, when did the brake last work ?

The level in the reservoir will fall as the brake pads wear, how many miles has you bike done ? It may be that the pads are worn, if you replace them, pushing the pistons back into the cylinders will cause the reservoir level to rise to its level when new, so be careful not to top up unnecessarily as it could overflow then. My bike is only 9 months old with 5000 miles but the rear brake lever had almost seized up and wasn't releasing properly, I think this was causing premature pad wear, I had to dismantle the pivot to free it and grease it.

I just checked the levels and they were a little low, but nothing too bad so I have toipped them up.

It has 10500 on the clock so is almost due its 11k service, I'm thinking that if after the top up things are still the same I might bring my 11k service forward......

Does anyone locally run a course on how to do bike maintanence I would really like to learn how to do all this stuff myself.