Testing Rear Calipers Options

[Literati914]

Would you say that generally speaking, a rear caliper would definitely need a rebuild if the outside adjuster (for setting e-brake clearance) does not move? - but that if it can be adjusted, it would not necessarily need to be split for piston removal and complete rebuild?

I have completely rebuilt them before and could do so again, but not sure it’s always a necessity and I have several to choose from (some adjust, some don’t). Any specific tests?

[mepstein]

I believe Eric Shea has talked about spinning it with a drill to get it to engage. Maybe there is a thread or video on his site. If you can get the adjuster to engage and you mention a prior rebuild, I would think you would be good.
Granted, they are your brakes so please don’t rely on me to make important decisions.

[Ninja]

It's the age of the rubber that is the tipping point for me.

The square cut seals lose their pullback ability at 15-20 years. They get hard and no longer retract the piston a few ten thousands like when new.

Causes "dragging" brakes, faster wear, overheated parts...

Now, if I had rebuilt them 5 years ago and the adjuster didn't work, I'd try Eric's method first.

Anything with unknown seal age would be an automatic rebuild in my book.

[brant]

Completely agree
The need to rebuild is based on the age and heat amounts from use

Not based on adjusters

[davep]

They need to be rebuilt. The outer piston tends to seize more often since the fluid is hard to flush out and they get cruddy pretty fast. I was rebuilding them 45 years ago when no parts could be found. I have found over the years that it is always best to fully rebuild them and not take any chances.
Funny findings: one caliper had a brake pad worn right through with the piston rubbing on the rotor; another caliper had the brake lever just pull out of the bore since the circlip was not engaged behind the freeze plug.