Front Brakes Crap

[Jimmygixxer]

Last year i up graded to braided brakes lines on the front, changed the fluid & put new good pads in. But the brakes are still not great.
At the lever is a bit spongy and there is quite alot of notchy stickyness ( lever is not totally smooth through travel ).
So how likely would it be that the master cylinder would need a new seal kit, or could it be front seals?
Also, can the master cylinder be upgraded to one of any other bike?

[Chris]

The front brakes when working correctly are amazing and were used for the r1's of the same age so really they should be more than enough if working properly...

This would point as you mentioned to something not being right.

Have you had the front calipers off and given them a good clean out to make sure the dust seals haven't failed and let muck in behind them? Are the pistons manky and therefore not moving properly. What kind of weather do you ride in? if you're using the bike with all the salt and rubbish on the roads then perhaps the calipers have got a bit cruddy with grit and salt etc. The grittynes at the lever could be the master cylinder or just muck in at the hinge of the lever.

When the new lines and fluid were put in then was it you that bled the brakes? Have they felt bad since then or got progressively worse?

Chris

[Jimmygixxer]

The front brakes when working correctly are amazing and were used for the r1's of the same age so really they should be more than enough if working properly...

This would point as you mentioned to something not being right.

Have you had the front calipers off and given them a good clean out to make sure the dust seals haven't failed and let muck in behind them? Are the pistons manky and therefore not moving properly. What kind of weather do you ride in? if you're using the bike with all the salt and rubbish on the roads then perhaps the calipers have got a bit cruddy with grit and salt etc. The grittynes at the lever could be the master cylinder or just muck in at the hinge of the lever.

When the new lines and fluid were put in then was it you that bled the brakes? Have they felt bad since then or got progressively worse?




I fitted the lines, never got any worse just not good enough. The bikes never used in the wet and i cleaned the calipers a few months back.
Thanks

[Chris]

ok, Were the pistons all moving freely and the seals looked ok?

Could easy be the master cylinder as you thought.

Chris

[darrsi]

Start with the easy stuff, take the lever off, clean it up everywhere, then re-grease it and see if that makes a difference.
The gold coloured bush where the bolt goes through wears over the years from constant leverage, so if it's really "crunchie" then i'd even consider buying a new lever too.
Whenever i've had the fluid changed it's taken at least 2 or 3 times of bleeding before i've been happy as well, but try the lever clean up first 'cos it can be over looked.

[packie]

In were the lever hits the piston....this can get rough and it feels crap and not smooth at all when pulling on the lever. Spray WD40 in around that area and see were that takes you. You be surprised how much it effects the brake performance.

[Gnasher]

Last year i up graded to braided brakes lines on the front, changed the fluid & put new good pads in. But the brakes are still not great.
At the lever is a bit spongy and there is quite alot of notchy stickyness ( lever is not totally smooth through travel ).
So how likely would it be that the master cylinder would need a new seal kit, or could it be front seals?
Also, can the master cylinder be upgraded to one of any other bike?

Did you clean the caliper bodies/pistons before fitting the new pads?

[Jimmygixxer]

In around the lever is greased and clean. I did clean all the calipers and pistons. I think there was one or two pistons which were a bit more sticky than the others but not too bad.
Im just wondering about the seals, dont know if they have ever been changed or not. When i fitted the new lines i never noticed an improvement from the old ones.

[Gnasher]

Sponginess is either air, the pads are being held off of sticking pistons!  Take the pads out just before you do check they are sitting squarely in both planes examine each pad looking for tapering even a small amount will indicate the pad/s not moving freely or pistons seizing.

[Jimmygixxer]

Sponginess is either air, the pads are being held off of sticking pistons!  Take the pads out just before you do check they are sitting squarely in both planes examine each pad looking for tapering even a small amount will indicate the pad/s not moving freely or pistons seizing.

I did bleed them a good bit so i wouldnt expect it to be air. I will have another look at the pistons. Can old seals bulge that much to make a difference to braking force?
Cheers

[Gnasher]

Yes mate they can totally seize!

[Chris]

Yep, and once they've stopped working properly then they let in dirt which gum up the movement of the piston causing them to sieze up faster as Gnasher said.

Chris