bake pistons

[Matsumike]

I am trying to install new rear brake pads on my 97 Tourer.   I have rear tire off for work, and brake hanging on side of bike from a bungee.   I've removed old pads, but cannot get new ones in due to no room.  The pistons will not push back into the claiper body.

Why not?  Aren't they supposed to move into the caliper body when you apply pressure to them?  Hints?

[Kymbo]

How muck pressure are you applying ? I use a 'c' clamp to force mine in

[Hef]

You may need to open the bleeder valve to releive the pressure and they should press in. Good luck.

[Baloo]

I use a 'c' clamp to force mine in

+1 on the C clamp. They're pretty hard to push back in.

[hubcapsc]

I bet the pistons are nasty... it is easy to take the caliper off, blow out the pistons with compressed air,
clean them up shiny like new, and put it all back together... we did Stanley Steamer's last
weekend...



Here's a picture of some pistons I cleaned as well as possible without removing them from
the caliper... then I blew them out a little, you can see that there's gunk down in there that
ain't coming off unless you remove the pistons...



Mashing that stuff back in there with clamps isn't all that much easier than taking it apart
and cleaning it, and can't be near as good... that's what I did when I got my bike, and
some number of months later my rear brakes started hanging and I missed
Britman's Memorial Day Ride that year... I think it was cause and effect...

-Mike

[Matsumike]

Thanks guys.  I think I will take them on out, clean 'em and bleed the brake system while I'm at it.  Was just tring to cut corners, but that is crazy when I already have the rear tire off. 
Never beld brakes before (can you beleive it and I'm 59 yrs old!)  I think I'll get a mity-vac and do it right.  Thanks for your patience with dumb questions.

These little things (like how hard the pistons are to move) are just things I don't know.  Funny - I can build a house from the ground up, and even though I've been riding 40+ years,  always avoided mech work till I started collecting old bikes.  Now or never I guess.

If it wasn't for the Valk club and the tech board I don't think I would be doing this.  Winters coming here in Alaska and I'll have lots of time in the garage.   Thanks again for the quick replies.  You guys are a lifesaver.    Mike.

[Ricky-D]

Depending on a number of factors I would suggest just shoving the pistons back in and installing the new pads.

Mileage on the old pads, whether this is the first brake pad change, the riding environment, how the old pads and brake are working, these and a lot of others should be factors in regard to rebuilding of the caliper.

If you remove the pistons it always is best to replace the piston seals and clean out the caliper body.

***

[hubcapsc]

Depending on a number of factors I would suggest just shoving the pistons back in and installing the new pads.

Our differences is what makes the world go around 

The only factor I'd consider is: are the pistons skank?  After rebuilding my caliper,
the next time I wore out a set of pads, the pistons were as grungy as all get-out again.
I just can't relate to mashing all that stuff back in there an calling it good.

I've had seals on hand and replaced ones that seemed fine, but I didn't reuse them after I
pulled them out, especially since I had new ones (cheap and not back-ordered)... Stanley Steamer's
seals were baked, I'm glad we had new ones there... you never know...

I've had pistons that were so gunked up I had to go down to the Napa store and get the
guy in the back to blow them out with his giant air compressor, mine wouldn't do it....

-Mike