Rust on front hubs

You've got salt air. Here around New England we've just
got ... salt. Wheel parts get a film of rust pretty quickly,
which quickly leads to that "grabby" feeling in the brakes after
the car sits over a wet night.
http://techno-fandom.org/~hobbit/cars/brakerust.jpg
that's after only like a day and a half of sitting.
.
_H*

 

After a serious wirebrushing to get rid of all traces of loose rust, I got a can of zinc "cold galvanize" and sprayed the brake calipers, and the non-machined portions (hub and edges) of the rotors.. On the rear, I sprayed the drums as well. This treatment has eliminated rusting of these components, even through the winter salt, and the braking system components also look 1000% better through the spokes of the alloy wheels vs. their old rusty appearance.. This doesn't help with the spots of rust that form on the machined surfaces of the rotors, but a good hard braking takes care of that..

While you're at it, get under the car, brush off all the exhaust system joints and the muffer and use up the rest of the can.. In my experience, I get at least 2-3 years more life out of cold galvanized exhaust system components than untreated..

 

The only part that will actually burn paint or coatings is the catalytic converter, so I don't spray it, but the pipes and the brake rotors/drums don't get hot enough to do anything to the cold galavanize, which in the good brands is 95-98% powdered zinc and just a bit of binder.. Most of these types of sprays are also "weld through" (despite the dangers of welding galvanized steel), which means that they can tolerate high temperatures.. In short, temperature is not an issue; this is doubly true on the Prius which runs cooler due to it's more efficient ICE and uses its friction brakes much less due to regeneration..


As for the threads, there's nothing to worry about here either in my experience.. If you're concerned, a tiny bit of anti-seize can be used, but a good nut and bolt should create a near-hermetic seal when torqued to the correct degree so no water or anything should be able to get in there.. If you swap out the OEM nuts with aftermarket parts that have some manufacturing slop, the story may be different, but just like any "rusty bolts" that I have removed in the past, the portion that is engaged by the threads of the nut are almost always clean and shiny once the parts are separated, it's the rust forming on the exposed portions that keep you from extracting the fastener, and this shouldn't be a problem on the Prius due to its capped nuts (ie, hole only one one side of the nut)

 

The lock nut crimp prevents backing off of the nut, so the nut and the thread normally have a thin coat of bearing grease smeared all over it which should prevent any problems of rust and seizing.. On my car, the nut and hub area was the one place on the rotor assembly (besides the machined braking surface) that was completely rust free due to the grease..

 

Since I have the winter wheels and tires on, it was easy for me to go down into the condo parking and check. Mine have very slight corrosion. During the first winter, I smeared Loctite Nickel Grade Anti Seize on the exposed threads and nut. It lasts a *long* time.

I would worry more about the caliper slide pins than surface corrosion on the stub shaft. The Prius calipers are fairly easy to remove, but if you just take out one slide pin at at time you won't disturb the caliper.

Loctite and other companies actually make a special synthetic caliper slide pin lubricant in a small plastic tube. Carefull clean off the slide pin, removing any corrosion that may be there, and smear a light film on. Don't overdo it or the excess may end up on the rotor.

I do this every fall and spring, but the slide pins appear to be good for longer. With my 1992 Honda Prelude, if I didn't do this procedure faithfully every fall/spring, the rear caliper slide pins would seize. Ditto with my 2000 GMC Sierra, the front calipers would be ok but the rear caliper slide pins would seize.

Just to get me angry, then I couldn't get the slide pin out, the bolt would spin the sleeve. A special wrench can be put on the sleeve to get the bolt out, so I just took an old wrench and ground it down with a grinder. I taught quite a few GM/Chevy truck owners that little trick.