Allen screw on rear caliper stripped. What to do?

R

redbaron112358

Member
:
Protege5, 2003
Hi, guys, I am a newbie here and I am looking for some help on my 2003 P5. I appreciate your attention and help in advance.

I was replacing the brake pad on the right rear wheel and found out some problem:
1. the inner side pad was totally gone but the outer side is almost untouched;
2. rotor inner surface ruined and too thin, so I got a new one(solved);
3. piston stuck and can't be pushed back with a big C-clamp;
4. (most seriously, I think) the allen screw to adjust the position of the piston is stripped and won't come out even with the help of liquid wrench.

So my question is: what should I do to get this allen screw out? Is the piston stuck because of this? Is this problem bad enough for me to get a new caliper? and why only one side of the pad is gone?

I read the service manual and the how-to here, and it seems to push the piston back one need to rotate the allen backward first. But on the other hand, when the new pad was installed last time, the allen screw should be good for the new pad, which means there should be some space to push piston back without touch the allen screw. Any other possible reasons for the stuck piston? Thank you very much.
 
Replace the Caliper with a Rebuild..

They are Quire Affordable when you return the old one for Core Charge.
 
Its probably time for a new calipe. The calipers tend to seize up quite often and those Allen bolts are worthless after a while and tend to strip. Get a new caliper and be done with it. Where in Ohio are you? We have a pretty god group of people here in Ohio and we're always hanging out.
 
Either new caliper time, or weld the correct allen wrench to the screw. You will need a new screw, but it will get it out.
 
i had this happen to me. and was able to get it off using a pair of needle nose vice grips. then i replaced the guide pin with one the exact same size, but the new one had a 10mm head on it. which is alot smarter then the allen head design. the guide pin was for a 88-92 mx6 caliper for reference. ;)
 
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Thank you for all the replies. Probably it's time to get new caliper. The parking brake barely work now. I guess it's also related.

Btw, do I need a retract tool to get the piston back? Am I doing it right with a C-clamp?

I am in Kent, OH.
 
xxxmonoxidechil said:
i had this happen to me. and was able to get it off using a pair of needle nose vice grips. then i replaced the guide pic with one the exact same size, but the new one had a 10mm head on it. which is alot smarter then the allen head design. the guide pin was for a 88-92 mx6 caliper for reference. ;)
Click to expand...

totally agree that allen head is a bad idea in this case. Thanks for the info, man. Are these the thing I should replace if I take the old one out?

http://shop.advanceautoparts.com/we...ake_3552039-P_351_R|GRPBRHWAMS_1691154672____

http://shop.advanceautoparts.com/we...er_26950648-P_351_R|GRPBRHWAMS_1072192171____
 
redbaron112358 said:
Btw, do I need a retract tool to get the piston back? Am I doing it right with a C-clamp?

I am in Kent, OH.
Click to expand...

No, You release the piston with the adjust screw and releasing pressure through the bleeder.

Back it off. Install it, turn it until it is tight, then back it off 1/2 turn.

Apply the park brake and see if it is proper. If not adjust tighter or less.
 
btw, how much of the rare pads should be consumed after 20k mixed drive(local, highway)? the other side looks pretty thick still. I am thinking they may not be working at all because of some rust in the piston part...
 
Do NOT use a c-clamp on the rear caliper. Do your best to get the screw out. You can replace just that if you can get it out. Else you'll have to replace the whole caliper. When you get the new caliper, do NOT use a c-clamp on it.
 
yangsui said:
Do NOT use a c-clamp on the rear caliper. Do your best to get the screw out. You can replace just that if you can get it out. Else you'll have to replace the whole caliper. When you get the new caliper, do NOT use a c-clamp on it.
Click to expand...

you mean I can push back the piston by hand after removing the allen bolt? will a c-clamp cause something bad?
 
Only use the allen screw to back out the piston. I guess using the c-clamp could have jammed the set screw leading you to strip it.

Maybe try applying the brakes with the caliper off of the rotor and see if the piston at least moves out. But put enough things in front of it so that the whole piston doesn't pop out. If the piston still moves, the caliper may be salvageable....if you can somehow get the allen screw out.
 
yangsui said:
Only use the allen screw to back out the piston. I guess using the c-clamp could have jammed the set screw leading you to strip it.

Maybe try applying the brakes with the caliper off of the rotor and see if the piston at least moves out. But put enough things in front of it so that the whole piston doesn't pop out. If the piston still moves, the caliper may be salvageable....if you can somehow get the allen screw out.
Click to expand...

Thanks, man! I will definitely try that. A new caliper without the bracket cost a hundred bucks, so it worth a shot. I will try the glue thing or the gribit kit thing to get the allen bolt out. Then I will come back with some results, hopefully.

Will it be much help if I bleed the brake fluid? Worth a shot?
 
BRIAN_MP5T said:
Agreed, I never pushed the piston in manually.. That is probably why it's busted..
Click to expand...

I tied to screw out the allen bolt first, then it got easily stripped. With a flash light, I looked inside and saw wet and rusty. However the copper washer is still shiny without any green on it. Then with the thought that there might be some space to move the piston, I used the C-clamp, but it did not do anything-- no brake fluid flood over the reservior under the hood at least. Suppose the piston is rusted, can I apply some liquid wrench in between the piston and the holder to lube it? Will this thing go into the brake fluid and cause some bad?
 
redbaron112358 said:
Thanks, man! I will definitely try that. A new caliper without the bracket cost a hundred bucks, so it worth a shot. I will try the glue thing or the gribit kit thing to get the allen bolt out. Then I will come back with some results, hopefully.

Will it be much help if I bleed the brake fluid? Worth a shot?
Click to expand...

Umm ... Rockauto - Rear caliper with bracket for like 72 FYI
 
redbaron112358 said:
I tied to screw out the allen bolt first, then it got easily stripped. With a flash light, I looked inside and saw wet and rusty. However the copper washer is still shiny without any green on it. Then with the thought that there might be some space to move the piston, I used the C-clamp, but it did not do anything-- no brake fluid flood over the reservior under the hood at least. Suppose the piston is rusted, can I apply some liquid wrench in between the piston and the holder to lube it? Will this thing go into the brake fluid and cause some bad?
Click to expand...

What I am saying is... Replace the caliper... Dont Eff around with brakes... Even if you get it back on and it seems to work... if the adjuster does not move like it is supposed to, then you will eventually have no brakes on that side..

1. Will make the others wear out faster
2. Will have Park on one tire
3. Will probably Flip and die in the rain+corner+brake=Dead
 
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