Seized brake piston

[MudPuppy]

Tearing into the front wheel assembly on the SX/4 to do what we thought would be a wheel bearing replacement, noticed that the front brake was seized (not to mention they need replaced anyways). Removed the caliper and then the old brake pads. The piston is seized up and will not retract. It retracts if you push on it but only 1 side or the other (not the whole thing at once). And when you do push on it, it sprays out brake fluid.
We are going to take it off, clean it and see if it needs new seals or needs to be replaced.





But worse case scenario, I have a few questions...

- Anyone have parts numbers? Or in case my local parts stores say "No" to having these parts for Eagles is there another vehicle that interchanges?

Also, for some reason I thought I had a socket big enough for the axle nut... boy was I wrong lol.
- What size socket fits the axle nut?


Will keep posting here during our brake detour if problems or questions arise.
Any kind of help is appreciated.

[mudkicker715]

Axle nut is technically a mm of some size i forget what,butt 1 3/8 works. buy a new caliper and save the grief it is available at any parts store.

[MudPuppy]

  Doh!
Didn't think they would have the whole caliper but went ahead and called a few places. They all did sorta, has to be ordered and shipped in.
But got new ones on the way and since they were cheap enough went ahead and got both driver and passenger side. Now just have to wait.
I believe this might be the culprit instead of a bad bearing. But we'll see.
Thanks MK for knocking some sense into me. I tend to over-think and complicate things beyond reason.

[mudkicker715]

My favorite saying is i know nothing.

your welcome

[68AMXGOPAC]

yes I would second that - just get new calipers , rotors aren't that expensive either.
I have rebuilt the ones on my 68 AMX, they are 4 piston style and pretty much unobtanium !! You can buy rebuilts , but with a core charge etc., I think they were close to $300 each. I got the rebuild kit From Kennedy American for I think under $75 for both sides.
I bought a small wheel cylinder hone and used that on the piston recess in the caliper.Still wokring after 8 years.
Good luck MudPuppy. 

[maddog]

the socket for the axle is 36mm deep well. but get one that is intended for an impact wrench as they are much stronger than normal sockets.

[standup650]

also your rubber brake lines can break down and plug up and sometime act like a oneway valve. if original maybe worth unhooking and see what blows out.

[carnuck]

Looks for signs of cracking in the brake hoses by flexing them. The life you save....

[MudPuppy]

Brake lines look good.
Got the calipers in today. Got the driver side (the one with the problem) hooked up but the piston would only extend but it will not retract    still.
We unhooked the brake line and put that end in a cup of brake fluid and pumped the pedal to see if it would suck any fluid up into it- it did suck slightly, not nearly as much as was coming out.  

Is it the brake line?
Or does this sound like a Master Cylinder issue?
Or?

[standup650]

I cant say for sure but i have had lines that looked good on the outside but on the inside the rubber was breaking down and they did what is happening to you. How old are they? if you dont know change them.

[68AMXGOPAC]

I don't think they retract all the way back at all.If you look at one that is on the car normally, the pads sit right against the rotor when the brake is off anyways.All it does is release pressure to the pads when your foot is off the brake.That is why when you put new pads on you have to remove the master cylinder cover and use a special tool or a c clamp and an old pad to compress the piston back in to allow for the greater thickness of new pads compared to the old worn ones.......just my thought and how it has worked when I have replaced them on any car that has had disc brakes........

[thereverendbill]

I would replace the rubber lines just to be on the safe side cause i have seen where the lines look fine on the outside but have really gone to heck on the inside and swelled near shut

[MudPuppy]

I guess I will go ahead and order the brake lines, like y'all are saying it can't hurt.  I just hate that no store here has the parts in stock, so they have to be ordered. And I have to wait days for them to arrive.
I hope the steel part of the brake line, the 3 way piece and the brake booster are good.

68AMXGOPAC- I looked into what you said and that is correct. It makes sense, yet another "duh" moment for me.

[thereverendbill]

while your there ordering the front rubber lines might not hurt any to get the rear line as well so that you have it on hand when it is time to tackle those rear brakes

[MudPuppy]

Yea, might as well.

Oh, almost forgot... when we hooked up the old brake line to the new caliper and applied the brakes it would squirt out fluid near the connection of the 2. We have the washers installed but it still squirts fluid when brakes are being applied. We have the connection pretty tight too.
What would be causing this?