[Maverick986]

Originally Posted by Black Tire

I change the differential and transmission fluid every year using Amsoil. This year, the fill and drain bolts were very rusted (outdoor parking and Minnesota winter road salt). I had trouble getting the hex wrench in the socket in the bolts, and used PB Blaster to make removal easier. I went to the dealer to look for new ones, and they wanted $13 each, so four bolts (2 for transmission, 2 for differential) would come to $52. Also, they did not have them in stock and would need to order them. Since it was Saturday, they would be ordered on Monday, and be in later in the week. My diff and transmission were already drained with the car on jack stands, so I came up with an alternative.

First I soaked the bolts in Evapo-Rust to get rid of the rust. The photo shows the bolts soaking in the Evapo-Rust solution, about an hour after putting them in. Note that only the exposed heads of the bolts are rusted, the threads are very clean. It took many hours before the bolt heads were nearly clean. I rinsed them and you can see the difference in the photo. I did re-soak them after that photo was taken to try to remove as much of the rust as I could. Some black spots appeared on the bolts at this point, but this is just carbon from the steel according to the Evapo-Rust website, and should not hurt anything.

I punched holes in cardboard with an old part of a lamp pole. The holes were just smaller than the bolts, and so I just screwed them into the cardboard. Then I painted one coat of Rust-Oleum etching primer, and one coat of yellow enamel. I didn't want to get the paint too thick where I couldn't easily fit in a wrench. Also, you are not supposed to use this paint for galvanized metal, but I figure most of it was worn off anyway and it's better than nothing. I used a halogen shop light that puts out a lot of heat about a foot away from the cardboard to "cook" the paint to speed drying, as it was quite humid at the time.

You can see the results. Hopefully when the time comes next year, the bolts will have little or no rust. The paint was slightly damaged by installing the bolts, but it should still protect them better than no paint at all.

How well did this hold up?

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