Stopping bolt corrosion

[thekauz]

I put new bolts on the rear brake drum dust shield. To stop the corrosion that made taking the old ones out a real chore, I'm trying to come up with a method for protecting those bolts. Anyone have any idea's? I was thinking about just coating them with high temp grease. Putting a dab on each bolt head.

Any ideas would be appreciated.

[Merlin93]

For lug nuts, I've been using a mixture of wheel bearing grease and as much graphite as I can _reasonably_ mix in. I mix it in a 35mm plastic film cannister. The first batch lasted me 25 years, and I'm still on my second batch after about 6 years. A _VERY_ small dab on the first thread or two of the lug and the inside of the lug nut is all I use. I sometimes have to remove lug nuts on the road or trail, and I don't carry power tools. The grease helps exclude water, and should the grease evaporate, there are still solids left behind to lube the threads. It's rather like poor mans anti-seize compound, which would be my second recommendation.

I distinguish between high- and low-temperature applications, and use the anti-seize for the oxygen sensor, exhaust manifold, and muffler bolts. I suspect anti-seize would also work on brake parts. I've used brass/bronze bore brushes to clean out interior threads in steel. I believe that starting with clean surfaces is important.

[thekauz]

What about the bolt heads on the drum shield that are exposed? They always corroded badly.

[Merlin93]

Originally Posted by thekauz

What about the bolt heads on the drum shield that are exposed? They always corroded badly.

If ultimate strength isn't a requirement, stainless steel is an option. Most stainless strength is a bit under US grade 5 (120,000 PSI), or it's metric equivalent, class 8.8, but above common steel, US grade 2 . Stainless tends to gall, so be sure to use anti-seize (or something) with stainless.

One metric hardware site that I found, mmsacc-stainless.com Metric Products, advertises its stainless at "85,000-90,000 P.S.I. Average Tensile Strength". Most common, low-strength metric stainless, A2-70 or A4-70, is around 100,000 psi.

ARP makes a good range of high-strength (metric class 10.9 = US grade 8) metric stainless (arp-bolts.com) and totallystainless.com carries most of them, plus some low strength SS (A2-70) as well. Be alert NOT to use common low-strength stainless where a medium or high-strength bolt is required.

[thekauz]

I'll look for SS and give that a shot