Tech question (other bike)

[stutrump]

Hi folks. I've been trying to service the front brake caliper on a friends Beta trials bike.
Removed the pistons to clean them up and now they dont seem to go back in fully.
They'll go back about half way but that doesnt leave enough space for a set of new pads and the disk of course. I used a smear of grease on the pistons when putting them back in, maybe I should use brake fluid?
I hope that all makes sense.
Any ideas gratefully received. Thanks

 

[ballisticexchris]

Hmm, that is strange. Is it possible that you are trying to install them with the brake line attached, MC cap on, and bleeder closed? Grease will work fine. Brake fluid is ok as well.

 

[Nikolajsen]

I have once seen a caliper, where the piston had to be turned while pressed back.
And therefore had to be in correct position, when pressed back.

Only guessing....

 

[stutrump]

Thanks both. Going to the garage now to have another try. Tge caliper is off the bike and not connected to the hose. I'll update later if I get it sorted. Thanks

 

[stutrump]

Dear Nikolajsen. You are a star!! They're in!! I can't believe it though. I've done this job on other bikes before and the pistons will go back in any position.
These ones really seem to have one position that they will fit in. So strange...they are round after all. I'm baffled but also pleased that the job is done! Thank you

 

[Nikolajsen]

(in lack of the correct emoji )

"thumbs up"

 

[Don in Lodi]

Petroleum based grease would not be a good thing for the caliper seals. Brake fluid should have been your lube. Petroleum based products will cause the rubber to swell.

 

[stutrump]

Thanks Don. Used brake fluid in the dnd

 

[stutrump]

End!! Sorry..cant type on this bloomun phone