How To Prevent Brake Caliper Freeze?

[lespaul]

Mine are not frozen or sticking. Is there some maintenance task I can perform to keep them from freezing or sticking?

[Gene Wilkes]

Are you referring to the E brakes or the calipers? Brake cables in the winter can freeze up, but your calipers shouldn't!

[Grady Clay]

Brad,

YES.

When you bleed the brakes twice per year or more, this keeps fresh fluid in the system. Brake fluid is very hydroscopic (absorbs water). This water permits corrosion of the steel cylinder in the caliper (even alloy calipers have steel cylinders).

The pistons should be exercised a couple of times per year or more. A totally worn out set of pads are great for this job. With them installed, the pistons can’t come out of the cylinders. You push the pads and pistons all the way in and then pump the brake pedal to get them out and firm against the caliper. Do one pad/piston at a time so you don/t overflow the brake fluid reservoir when you push the piston in.

I use aerosol “silicon spray” on the road side of the pistons. With the extended nozzle you can lift the rubber dust seal and spray there. Do this with the piston all the way in and then exercise it.

Best,
Grady

[lespaul]

Thank you Grady. I will do it.

Brad

[David]

I use a caliper grease on the pistons. I've been using it on my kart brakes which are terrible about piston bore corrosion and it's helped significantly.

[Early_S_Man]

The best preventive medicine for avoiding sticking caliper pistons is periodic rebuilds for the calipers every 5 - 6 years with a heavy coating of Dow Corning 4, 111, or 112 Silicone Grease on the bores of the caliper and on the pistons, too! The brake fluid does not displace or mix with the silicone, so it stays in the caliper.

Brake fluid changes are neglected in most of these cars ... why else would the pistons get stuck and covered in rusty gunk?

Ate used to include a 1 cc tube of silicone grease in their rebuild kits for the '68 - '76 master cylinders. The appearance and consistency was identical to Dow Corning 4 or 4X. DC 4X was a specially-packaged tube of DC 4 for the automotive/motorcycle/off-road specialty industry back in the '70s. One of its' recommended uses was lubrication of hydraulic brake parts to prevent corrosion problems.

[mikeatfhc]

I am now a firm believer in replacing brake fluid...



And..

[DarrylD]

I use brake fluid test strips that tell you the condition of the fluid.



Cheating, I know but with 10 cars, it's like constant mechanical triage around my garage!