A few weeks ago I started the task of rear brakes and axle hub.
Rear right was done, but do to other issues I had to move the car before finishing rear left.

Needless to say, I moved the car (and used brake) while the rear disc was off and caliper was wired up to axle. I now know this was a dumb idea.

Today I get back to the job and successfully replaced rear left axle hub.

I then went to start with brakes and saw that the piston was all the way out of the caliper with the rubber cover off of it. I finally wiggled the piston back into the boot but I can't get it to retract. I am using a cheapo harbor freight tool to try and perform this task.

The cover for brake fluid is off and I loosened the nut for the brake line as well.

Is this caliper hosed? I read various posts about twisting these back in place. Is that something to try? Should I get a loaner tool from AutoZone that is a bit more capable?

Thanks for your help.

I am going to bed as a frustrated Disco owner and aspiring mechanic and look forward to advice from the forum.

-Matt

 

Sound like you need a new caliper kit so you can rebuild you old caliper.
Unless there are other issues, you could rebuild it.

 

Loosen the bleed screw and try it.

 

a few more questions...

1)what does the rubber boot that goes over the piston do?
2)does it seal in fluid?

disco mike - not doubting you but just trying to understand.
3)why would rebuilding it allow the piston to go back in? i dont understand the mechanics of what is keeping it in place.

4)if i replace it, based on other posts here looks i need to do both side...right?

5)if i rebuilt, i assume i just rebuilt the one side. is the rebuild complex? looks like a few orings.

thanks guys!

 

probably easier to remove the caliper completely from the car, even tho you have loosened the pipe, you will still have some resistance to pushing the fluid back up the line and hence pushing the piston back in.......

put / support it on a vice and use firm even pressure to push the piston back in (squarely). Nothing mechanical holds them in, hence if you do what you did, it will just be pushed out by hydraulic pressure.

The rubber boot is just a dust seal thats all, the seals for the "fluid side" are at the back of the piston. If you remove it all (carefully) makes sure its perfectly clean when you re -assemble it, use clean brake fluid as a lube to re-install the piston back into the caliper

 

i cant really figure out the rebuild kit.
seems like it comes with a new boot and o-rings.
not sure how that could help getting piston back in anyway.

i will take your advice and remove this thing and see what kind of magic can happen

thanks
-matt

 

No, a rebuild kit won't help getting the piston back in. The reason to get a kit would be if you damaged the seals, either the wet seal, or dust seal/boot.

 

ok, thanks for the clarification.
i think i will pull the piston back out to inspect the oring inside. then proceed with trying to get it back in place.
no need to do all this work and then flood new pads w/ brake fluid.