Bleeding Disk Brakes ?

[KrazyIvan]

Long story short

I have an older MTB (about 4years old) that has sat in my garage pretty much unused since it was bought (another story for another time). Any way I decided at the weekend to try and get back to doing a bit of riding, road and local forests/riverside rides. But no matter how much I adjust the break piston I can’t get them to the point where they stop the bike or aren’t completely clamped on to the disk. I figure this is because there isn’t enough fluid in the tube to give enough pressure when pulling the leaver.

The brakes are the standard shimano ones that came with the bike, probably not the best but I am in no hurry just yet to start spending for the sake of it. They don’t have an external reservoir (like on a car) so I am guessing I need something like this

http://www.wiggle.co.uk/p/cycle/7/Shimano_Bleeding...

To resolve the issue.

Any advice before I start, IE what to do / not to do, cheaper place to buy the kit/fluids or DIY way of doing it ect ect.

Any advice/help from the PH lycra gang is much appreciated

[custardkid]

gee wizz that looks expensive,

wont a rubber band, yogurt pot and bit of tubeing do??

that works for my Hope's

Custard

[pdV6]

As a first attempt, use a cable tie or strong rubber band to hold the brake levers closed overnight and see if that makes any difference.

[KrazyIvan]

custardkid said:

gee wizz that looks expensive,

wont a rubber band, yogurt pot and bit of tubeing do??

that works for my Hope's

Custard

I was toying with just sticking my foot between the back tyre and the frame and see how long a skiddy I can pull

pdV6 said:

As a first attempt, use a cable tie or strong rubber band to hold the brake levers closed overnight and see if that makes any difference.

Thanks sounds like its at least worth a try

[snotrag]

KrazyIvan said:

They don’t have an external reservoir

Yes they do, under the top cap. They run an 'open' system, (self adjusting). You bleed shimano brakes exactly the same as you bleed car brakes.

NOTE. YOU MUST USE MINERAL OIL not dot. type brake fluid. Put this in and your brakes are going in the bin.

I'll write a proper how-to later if i've got the time - HTH for now!

[KrazyIvan]

snotrag said:

KrazyIvan said:

They don’t have an external reservoir

Yes they do, under the top cap. They run an 'open' system, (self adjusting). You bleed shimano brakes exactly the same as you bleed car brakes.

NOTE. YOU MUST USE MINERAL OIL not dot. type brake fluid. Put this in and your brakes are going in the bin.

I'll write a proper how-to later if i've got the time - HTH for now!

Thanks Snotrag, at how to would be great if you do have the time. Will have a closer look at the weekend, will also get some "proper" fluid from my local friendly bike shop

[Raven Flyer]

snotrag said:

NOTE. YOU MUST USE MINERAL OIL not dot. type brake fluid. Put this in and your brakes are going in the bin.

Interesting. SRAM are the opposite.

On this point, I have been thinking of trying some different fluids. Silkolene's Pro Race 2000 DOT 4 was far superior to any DOT 5.1 we used in the workshop and it had a higher boiling point. 5.1 is less hygroscopic than 4 but brakes felt like something was jammed under the pedal with the Silkolene fluid. I was told that this was because of what the fluid was made from to achieve 5.1 hygroscopicity ratings.

AP made some stuff that was just as good but I forget what it was called.

If your system uses mineral fluids, the same applies. Shop around for the best fluid as it does make a difference.