mazda3 rear brake caliper surprise

[windeye]

2007 Mazda3 i, sedan, > 110K miles. Heard a creaking noise from rear right lately when easing pressure on brake. Checked rear suspension components, rusted, but seemed OK. Found a piece of loose heat shield, thought that was it. No, still noise. So went checking yesterday on the rear brake. This is what I found: the caliper pins were very difficult to remove from the rubber bushing AFTER unscrewing the pin (unscrewing was easy). There was still lube on the pin. Baffled, took the rubber bushing out, and man there was HEAVY corrosion in bushing bore, baked on, hard. The picture below shows how much there was during 1st attempt of wire-wheeling. Old bushing was discarded. Guess have to make the bore checking part of the brake service routine. With clean bore and new bushings on both sides, used silicone grease to coat the bore the bushing, noise is gone. But I still can't believe how much corrosion there was. The caliper is aluminum. Anyone know a better way to prevent aluminum corrosion?

 

[Trav]

Give it to a machine shop and have SS sleeves put in, end of problem. Never seize will work as long as it does not come in contact the any rubber parts. Clean and a very thin coat.

 

[KrisZ]

I had the same problem but on the bottom pins, the top ones seem fine. I scraped the oxidation off with a small, flathead screwdriver and applied a thin coat of caliper pin lube. This was two or three winters ago, pins move freely to this day.

 

[Johnny2Bad]

Aluminum should be relatively corrosion-free, the aluminum oxide which forms on contact with oxygen is usually enough. Corrosive gases will do it, do you live in an area with lots of air pollution?

 

[windeye]

Originally Posted By: Johnny2Bad
Aluminum should be relatively corrosion-free, the aluminum oxide which forms on contact with oxygen is usually enough. Corrosive gases will do it, do you live in an area with lots of air pollution?


upstate NY. air quality is good. but there's road salt in winter.