Brake Caliper rebuild and cleaning solution?

Hey guys;
I have a set of calipers broken down and am completely rebuilding them; seals pistons. Came off a nicely neglected street bike and are quite filthy. When doing a complete tear down like this I would like to get them basically 100% clean inside and out. A lot of the black brake residue is stuck on real good, i don't want to get too aggressive scrubbing if i can avoid that.

Any insight on something I could soak them in? On person mentioned Vinegar may work?

 

Vinegar is highly acidic. No way I’d use that.

Grab a Harbor Freight ultrasonic cleaner. Start with a heavy dose of Dawn dish detergent and give that plenty of cycles. Beyond that, try 50/50 Simple Green. Beyond that, try Simple Green purple, but, creep up on the solution strength.

 

ahhh, good call. I never thought about one of those ultrasonic cleaners.
Vinegar had me on the fence. I know its acidic being why it can be used for cleaning; i think most consider it to be a mild cleaner, less harsh than any physical scrubbing i would be doing. I do have a jug of simple green i didn't think would be strong enough to touch the crud as it seems to be baked on from heat.

 

I recently cleaned a pair with some good auto wheel cleaner and a nylon brush that turned out like new. Letting the wheel cleaner soak for a bit loosened up the tough stuff. Took a few cycles to get it done

 

I use soap and water or can also use simple green.


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I use an ultrasonic for a lot of stuff. They’re amazing for carburetors and other items with passageways. I wouldn’t be without one.

Vinegar is mild to skin, glass, and certain other surfaces. However, the pH level will strip metals. A lot of uninformed will recommend it to clean a gas tank of rust. However, it completely strips the inside to bare metal, when most modern tanks are actually manufactured of rust-resistant materials. You don’t want to strip those coatings.

The heat of the ultrasonic, combined with a detergent, might surprise you. You’ll probably still need to consider using a stiff, nylon brush to further loosen crud in between cycles of the ultrasonic. But, you’ll get there.

 

Soap and water and an old toothbrush....start there and work your way up in aggressiveness

I've had good luck using scotchbrite pads to gently scrub caked on brake dust/dirt from around the outer edges of pistons.

 

Plus 1 for scotch Brite ...red pads are best for a fine finish, the green are a bit coarser.

 

How bad are the calipers? Has the brake fluid turned into that yellow dusty stuff? If you’re just cleaning as a CYA thing and there aren’t any visible issues I’d say brake clean should be enough. I installed Spears caliper pistons in my ninja 300 over the winter and just douched the caliper really good with 3m brake clean.
if you lube the pistons with brake fluid for assembly be sure spray them down brake clean afterwards. The little bit of left over fluid will dry out and stick the piston to the dust seal.

 

I use mineral spirits for cleaning off built on gunk of all types. Cuts through errythang.

Depending on what I'm cleaning I'll use brass or nylon bristle brushes. Kids toothbrush for tight spaces.

 

An electric toothbrush with an old head works great for scrubbing

The strongest cleaner that won't stain aluminum is probably citric acid. That's what's used in hot tanks for cleaning/degreasing AL engine parts.