Brake Caliper question... need help ASAP!

[DSG03COBRA]

Hey guys, so I'm in the middle of changing the brakes on my wife's '04 Expedition. I finally got past getting the rotors off and I already got one of the front's completely done. I'm now doing the driver's side front and I went to compress the caliper w/ a C-clamp. Well, there are 2 "pistons" that need to be compressed. As I compressed one of them, the other one started to push out (ie. like when stepping on the brakes). Well, it looks like it went out as far as it would go and now I can't seem to get it to compress back in! Did I just fuck up the piston by letting it push out to it's max?

I popped the cap on the brake fluid reservoir, which let out a little "hiss" like there was some pressure in there, but that didn't allow me to compress the piston any further.

Help!

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[FirstPlaceOils]

1. the cap should be removed before you start

2. when there is more than 1 piston ( I do this when there is only one also)
keep the old pad on the piston(s) and use the C-clamp on the old pad to push the pistons back in together,

if you are planning on doing the rears, some require a tool to "screw" in the rear pistons.

I work in Joliet if you are stuck email me tomorrow I could stop by and take a look.
[email protected]

 

[DSG03COBRA]

1. the cap should be removed before you start

2. when there is more than 1 piston ( I do this when there is only one also)
keep the old pad on the piston(s) and use the C-clamp on the old pad to push the pistons back in together,

if you are planning on doing the rears, some require a tool to "screw" in the rear pistons.

I work in Joliet if you are stuck email me tomorrow I could stop by and take a look.
[email protected]

If I compressed one piston and the other came out (probably as far as it's allowed) is that bad? I can't seem to get it to go back in at all now. :-(

 

[FirstPlaceOils]

it should go back in...
because you had the cap on the master cyl. that fluid didnt return to the ms it just pushed the other piston out, but It should go back in, make sure its not cocked or anything like that...

 

[CREJoe]

Both pistons need to be pressed in simultaneously. One other important thing I do on ANY ABS system is to crack the bleeder screws open on the caliper so the old, dirty fluid is released at the caliper as you press the pistons in. This way, if there is any debris (dirt, rust, etc.) in the system, it doesn't push it back up into the ABS module. ABS systems are a pain in the ass to trouble shoot and expensive to replace as well. It is very important to keep the fluid as clean as possible. Good luck.

Joe

 

[scca_stang]

Both pistons need to be pressed in simultaneously. One other important thing I do on ANY ABS system is to crack the bleeder screws open on the caliper so the old, dirty fluid is released at the caliper as you press the pistons in. This way, if there is any debris (dirt, rust, etc.) in the system, it doesn't push it back up into the ABS module. ABS systems are a pain in the ass to trouble shoot and expensive to replace as well. It is very important to keep the fluid as clean as possible. Good luck.

Joe

I was just about to say the exact same thing... when I worked at the dealer, the other techs thought I was crazy, they said it was more work than I "needed" to do... I totally disagree, it is "needed"... but I guess that is why I was (am) a ASE master tech, and they werent.

 

[DSG03COBRA]

ok, so what if I only pressed in one piston at a time? One of them is now "out" all the way, and the other is compressed all the way. The one that is "out" now won't budge... did I fuck it up????

Thx

 

[CREJoe]

ok, so what if I only pressed in one piston at a time? One of them is now "out" all the way, and the other is compressed all the way. The one that is "out" now won't budge... did I fuck it up????

Thx

If it won't go back in smoothly with an easy turn of the clamp screw, it popped out and needs to be re-installed carefully. DO NOT FORCE IT BACK IN. Any time the piston does not go back in smoothly and without a lot of force, the caliper should probably be replaced anyway since it will hang up in use and prematurely wear out the pads. Sometimes it is easier to just replace the caliper if you aren't experienced in rebuilding them and/or putting the piston back in it's place.

 

[FirstPlaceOils]

If it won't go back in smoothly with an easy turn of the clamp screw, it popped out and needs to be re-installed carefully. DO NOT FORCE IT BACK IN. Any time the piston does not go back in smoothly and without a lot of force, the caliper should probably be replaced anyway since it will hang up in use and prematurely wear out the pads. Sometimes it is easier to just replace the caliper if you aren't experienced in rebuilding them and/or putting the piston back in it's place.

very true
and rebuilt ones are not that pricey.
just make sure you take the old one 2 the parts store.

2 reasons


1 to make sure the new one is the same.
2 there is a core charge on them.

 

[DSG03COBRA]

If it won't go back in smoothly with an easy turn of the clamp screw, it popped out and needs to be re-installed carefully. DO NOT FORCE IT BACK IN. Any time the piston does not go back in smoothly and without a lot of force, the caliper should probably be replaced anyway since it will hang up in use and prematurely wear out the pads. Sometimes it is easier to just replace the caliper if you aren't experienced in rebuilding them and/or putting the piston back in it's place.

Is it a difficult process to put the piston back in place? I'd be willing to give that a shot before replacing the caliper, though I guess $80 ain't too bad for fucking up a brake job.... LOL!