Brake problem

[True Blue]

I was out on my bike this afternoon and everything was working fine. I stopped on a hill and decided to use only my rear brake so I could give my arms a rest. When I pressed the rear brake pedal it was as if it wasn't there. It just went right to it's limit with hardly any pressure on it at all! I stopped to check it and the brake wasn't working whatsoever. As I was travelling home it did seem to get a bit better, but it is very spongy.

Any ideas what happened to it?
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[instigator]

Been using the bike much? Or has it been standing for a while?

How much mm of the pads are left?

Plenty of brake fluid in the reservoir?

I found after leaving my hornet for just 2 weeks stuffed the front brakes. Had to really use them quite hard to get any life back into them.

[stinkwheel]

Sometimes if you have been riding for a long distance on a bumpy road without using the back brake at all, the pistons rattle themselves back into the calliper.

Can take a good few pumps of the lever to push them back out into contact with the disc. Not usually a major problem as such as long as you are aware it happens you can just use the brake a bit more regularly with the front one.

Try pumping the lever repeatedly then tying it down in the fully on position overnight, then see what it is like.
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[Slinn84]

check the brake lever and all its housing, there's usually a pivot on the lever where the front goes down as you put your foot on it and the rear goes up into a pump, pushing the fluid into your calipers, check that this is working ok

check that your caliper bleed valves are tight, they could be leaking fluid or there could be a leak somewhere in the hose

take the wheel off and put a metal bar into the space between the pistons and pump the lever, see if the pistons come out or not to determine weather its the pedal or the hose thats the problem

[stu_m]

was you using it a lot

have you boiled the brake fluid ????

[True Blue]

[fazed]

Check for an Air leak on the hose or where it joins onto the caliper etc.
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gixxer thou K6 , Cbr400 gullarm x 2 , cb400 superhack.

[Kickstart]

Hi

Any signs of leaks? Any resistance when you pump the pedal? Does it get firmer when you keep pumping it. Does it then get softer if you leave it for a while? Check the pads, as it is not unknown for the friction material to fall off the backing material.

Stinkwheels suggestion is entirely possible, but I would suspect it would take a while. It can definatly happen on the front pads with fully floating disks (proper race style ones with a few mm of movement) when you have a tank slapper.

All the best

Keith
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[True Blue]

Had a check and I can't see any signs of a leak and the pads look ok too. The brake doesn't get any firmer if I pump it. It just feels very spongy now, though at least the thing works to an extent
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Past >>>> Honda NSR 125 >>>> Suzuki GSXR 600 K1 >>>> Suzuki GSXR 600 K4 >>>>Kawasaki Z1000 DAF >>>>Suzuki RMZ 250 >>>> Current >>>> KTM Superduke R 1290 >>>>

[kat250]

youre hoses could be bulging if they are the standard ones could possibly just be in need for a good serving clean the pistons pump up the system set of braided hoses if you are still using origanal pipes
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[stu_m]

sounds like you have boiled the fluid and it needs changing

[Robby]

Bleed it.

It was serviced, doesn't mean it was serviced well. Bleeding the brakes might not be part of the schedule.

I've had a few bikes where the previous owner never used the back brake and it was full of air.

[True Blue]

Yeah, I think I'll have to give them the once over myself. Might as well fit braided lines while I'm at it. I thought it was strange that they just stopped working like that instead of failing over time. I always use my rear brake, and I've not noticed it getting any worse.
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Past >>>> Honda NSR 125 >>>> Suzuki GSXR 600 K1 >>>> Suzuki GSXR 600 K4 >>>>Kawasaki Z1000 DAF >>>>Suzuki RMZ 250 >>>> Current >>>> KTM Superduke R 1290 >>>>

[stu_m]

if you boil the fluid you will not notice it getting worse it will just stop working no matter how hard you pump the lever

it will come back but it will be spongey and it will need new fluid

just bleed it through with new fluid it may work it may not

try one thing at a time dont throw money at it if you dont need to

[True Blue]

I'll give it a try first then. My brakes really do need cleaned up though. The front brakes are starting to bind a bit.
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Past >>>> Honda NSR 125 >>>> Suzuki GSXR 600 K1 >>>> Suzuki GSXR 600 K4 >>>>Kawasaki Z1000 DAF >>>>Suzuki RMZ 250 >>>> Current >>>> KTM Superduke R 1290 >>>>

[stu_m]

just pull the callipers off and give them a clean easy to do just dont push the pistons out the calipers otherwise you will need to bleed them

[Kickstart]

Hi

Worth bleeding the brakes through as a first check. Easy to do and reasonably likely. My guess, based on what you have said, is that the bike has managed to get air in the system somehow.

[True Blue]

Changed the brake fluid today and bled them through. They definitely work a lot better now, but I think I might take off the caliper and give the whole thing the once over while I'm on a roll.

Cheers.
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Past >>>> Honda NSR 125 >>>> Suzuki GSXR 600 K1 >>>> Suzuki GSXR 600 K4 >>>>Kawasaki Z1000 DAF >>>>Suzuki RMZ 250 >>>> Current >>>> KTM Superduke R 1290 >>>>