Ultrasonic Cleaner - Calipers

Can't think of any reason why not. If the are seriously grimy I suspect the ultrasound cleaner will struggle, but don't have any experience of trying this.

I found a toothbrush with full blooded alloy wheel cleaner would be reasonably quick.

Ps..if the ultrasound works please post before and after pics.

 

Should be fine, but make sure you choose the correct cleaning fluid. Carb solution for instance, removes all the finish from them.... don't ask how I know

 

Yes, ultrasonic is good for getting calipers (and master cylinders) “clinically clean”
I use a bio degreaser for most stuff in there now - harsh chems are not the thing doing the work - it is the implosion of the micro-(partial) vacuum “bubble” created by the ultrasonic, so long as the fluid will wet out the surface properly, and carry the dirt away then it’s normally enough for all external and internal surfaces.

 

Are your front brakes dragging then?

Mine are, driving me nuts.

 

I have done this regularly after stripping them. It doesn't take long but as said earlier don't use harsh cleaner in the tank

 

I don’t know if “modern” brakes are fundamentally different to the 20 year old ones I am used to, but I found that brakes dragging which were otherwise sound was normally either down to
1. the fluid seals, which had swollen over time and were not allowing the pads to pull back a fraction as they should.
2. Rotor bobbins seized so the tiny lateral movement that helps to ‘reset’ the pads was not happening.

 

Yeah, you can definitely clean calipers in an ultrasonic bath, as long as you’ve removed the pistons and o-rings like you mentioned. I’ve done it a few times, and it works really well for getting into those small, hard-to-reach areas.