Mechanics

GEO PRIZM PISTON PROBLEM

1996 Geo Prizm

Brakes problem
1996 Geo Prizm 4 cyl Front Wheel Drive Automatic 116000 miles

Car was braking poorly and pulling left slightly. I checked the front ones (couldn't get the back tires off yet) and the side I thought was bad has the pad is pretty much gone and the disc is kinda rusty and stuff, not clean and shiny like it should be. The wear on the pads was pretty equal the last time I checked, so the bad side must have gone a LOT faster. I had someone hit the brakes while I watched and it looks like both brakes are working, however the bad side is pretty sticky. Doesn't spin on idle or anything. Other side seems fine.

I was just going to replace the disc and pad on the bad side, but the sticking and stuff that suggests to me that the bad side isn't releasing correctly. So I would need to get it to stop sticking before I replace the disc/pad or it would be pointless. Sound right?

I don't know much about cars, so if I can get a plain english guess as to what's going on and what I need to do that would be great.
Avatar
Dlsso
September 18, 2010.



Hi dlsso,

Check the caliper piston dust cover for tears. If any found, the piston coudl be sticking due to contaminations and it would have to be serviced and the dust and piston seals replaced. Note if the piston is pitted due to rust and if yes, the piston would have to be replaced as well.

If dust cover is good and you can easily compress the piston with the aid of a G-clapm,

Check the slider bolts. After compressing the piston, remove the pads and reinstall the caliper. Tighten the slider bolts and move the caliper in and out on the axis of the slider bolts, it should move freely with no stiffness. If stiffness is present, remove the slider bolts and clean them and caliper mounts for slider bolts of rust and contaminations. Lubricate with molybdenum grease and retest. If slider bolt dust cover are bad, they have to be replaced to prevent contaminations.

If both above are good, check the flexible hose. It could be bad preventing fluid pressure from being released.

KHLow2008
Sep 19, 2010.
Thanks so much for your response. As I said, I'm not very familiar with cars, though I would like to learn.

I'm fine with figuring stuff out as I go, but if I could get pictures of what some of these parts look like it would be very helpful.

I'd specifically like to know how to identify the piston dust cover and slider bolts.

Tiny
Dlsso
Sep 19, 2010.
Here is a diagram of the front brake caliper assembly.


http://www.2carpros.com/forum/automotive_pictures/192750_CaliperFrtBrake96PrizmFig07_1.jpg


KHLow2008
Sep 20, 2010.
Thank you for your help. Repped.

Tiny
Dlsso
Oct 16, 2010.
Glad to know you have fixed the problem.

Have a nice day.

KHLow2008
Oct 16, 2010.