Brake piston cleaning-Servo assisted ABS

[MIKA]

Chaps

I have been advised after MOT that there is a slight pulse in the brakes, mechanic suggested cleaning the pistons and calipers before replacing discs.

I have done a search and a few people have said they have been told it is ok to push the pistons back in with finger pressure and it wont cause any damage to the ABS pump.

Has anyone here actually pushed the pistons back in without causing any damage? or is it too big a risk.

I don't mind stripping the brakes and doing it myself but for obvious reasons don't want to bugger anything up.

Bike is a 2005 ABS servo assisted, all discs were replaced under warranty three years ago for warping and the bike has only done 6,000 miles since.

TIA

 

[smartbear]

seems ok.

hi, i have the servo brakes on my 56 plate GS & it came to no harm when i pushed the brake pistons in by hand, i didnt even know the pump could be damaged by doing this?
my car ABS pump has one way by-pass valves to avoid damage by reverse fluid flow.
regards rob

 

[bmwrich58]

Chaps

I have been advised after MOT that there is a slight pulse in the brakes, mechanic suggested cleaning the pistons and calipers before replacing discs.

I have done a search and a few people have said they have been told it is ok to push the pistons back in with finger pressure and it wont cause any damage to the ABS pump.

Has anyone here actually pushed the pistons back in without causing any damage? or is it too big a risk.

I don't mind stripping the brakes and doing it myself but for obvious reasons don't want to bugger anything up.

Bike is a 2005 ABS servo assisted, all discs were replaced under warranty three years ago for warping and the bike has only done 6,000 miles since.

TIA

Brake fluid has to be able to flow back otherwise the brakes would be stuck "ON"..!!!

Try removing the pads and lightly sanding them with a fine grit sand paper.
Place sand paper on a flat surface like a table or smooth floor and hold it with one hand from sliding around. Take the pad in the other hand and put the contact side "pad" down on the sand paper and rub in figure 8's and circles using firm but light pressure,. This will remove any gunk or glazing (hard spots) that have formed on the pads.
Ya don't have to go crazy but you'll see the pads change a slight color as they get clean of junk. Don't forget to clean the rotor's too.
This has worked for me in the past when a light plusing could be felt in either auto or motorcycle applications.

 

[WindyChuffer]

Consider this: When the pads are changed, the pistons have to be pushed in to create enough space. Gentle use of fingers or a lever is fine.

 

[MIKA]

Thanks for the replies chaps.

I was wary as I had heard that damage can be done to the valves in the pump if pushed back in too far, but it makes sense to be able to push the pistons back in when changing pads without the need for special tools etc.

Always better to ask than be paying for something unnecessarily