Brake piston

[powders]

Changed my front brake pads over weekend and I'm struggling to get one of the pistons back fully
I don't have the tool to push it back in
Anyone any tips ?
It's the non abs model if that helps
With the new pads in it sits perfectly on the disc but as soon as I drive the bike and apply the brakes it then rubs from then on ( like the piston doesn't return )

 

[alex]

If there is a noticeable difference in one piston then you probably need them serviced.


- Sent from Mobile

 

[fast_ryan]

Brake Pads

Depending on what type of brake pads you have fitted you may need to sufficiently bed them in during first use. That and it's always worth cleaning the caliper and pistons thoroughly before fitting new brake pads.

 

[powders]

Thanks lads
I did clean them with soapy water and a toothbrush .
I'm using ebc HH.
Think I'll have another go today with brake cleaner and see if I can free it up a bit

 

[mibridger]

Re: Brake Pads

I think you need to clean the pistons, I regularly service my brakes, take out the pads and pump the brake until the pistons extend, be careful not to push them out too far, sometimes one will be stuck and you will need to hold the others in place to get it to move, then when they are all visible, use brake cleaner to remove any debris that may be causing the pistons to stick.

Then push them all back into the caliper and refit the pads.

 

[alex]

Safest way is to have a piece of wood in the gap between the pistons which allows the pistons to extend out, grip the wood and not fall out.

 

[DrIoannis]

The pistons, as its been told, need to be cleaned. The first time I cleaned mine was at 5000km and cleaned them for more than 2h to make it perfect, Its a PITA but someone has to do it. Your mechanic will not do it the way you will...
Here is a video

 

[powders]

Sorted
Went at it again with brake cleaner and freed it up nicely
Thanks for all the advice lads will have to keep on top of it now so it doesn't happen again
Ps did like the tip about the piece of wood I'll be doing this in future

 

[DrIoannis]

If you clean them frequently you it will not take too much effort,10-20 min and you will be OK...

 

[Gaffa22]

I always spray with GT85 after cleaning, I find that helps keep them free and easier to clean next time.
it also helps prevent corrosion

 

[stuartb]

Is that stuff (GT85) ok on the seals..?

Stuart

 

[powders]

Not sure myself
I know you can't use wd 40 as it swells the seals
They say use brake fluid to lubricate

 

[bananaman]

Had that prob on my '10, even took pistons right out for a thorough clean. Only successful way was new piston and seal kit, perfect!

 

[Gaffa22]

Is that stuff (GT85) ok on the seals..?

Stuart

yes it's fine

Not sure myself
I know you can't use wd 40 as it swells the seals
They say use brake fluid to lubricate

brake cleaner is not very kind to rubber seals, anything petroleum, based will swell rubber but we use that on brake calipers

 

[DrIoannis]

As far as I know the seals are in contact with the brake fluid all the time since they seal the pistons. You can always use just liquid soap with neutral Ph:tennis:.

 

[Gaffa22]

As far as I know the seals are in contact with the brake fluid all the time since they seal the pistons. You can always use just liquid soap with neutral Ph:tennis:.

Only the bottom edge of the seal is in contact with the brake fluid.

Soap is fine and will clean the piston ok and provide some lubrication for when you push the piston in, but it does not have sufficient anti corrosion properties if you use your bike through the winter

Don't use washing up liquid though its very salty and corrosive.

 

[DL84]

Had that prob on my '10, even took pistons right out for a thorough clean. Only successful way was new piston and seal kit, perfect!

where did you source the piston and seal kit bananaman? was it pricey? considering refreshing mine over the (wisper) winter.......