Preventing Axle Corrosion - Good Factory Paint vs. SPI Epoxy?

B

beltv4th

New Member
Hi All,

I am tackling some corrosion issues on a car of mine this summer and am focusing on stuff underneath the car -- brake and fuel lines, fuel tank straps, suspension, etc. The car is in Iowa (USA) and is now 23 years old, so it was time to tackle some of this stuff. One other thing I'm working on is the rear axle which was very corroded. I have removed the rear axle from the car. My initial plan was to disassemble it and get it sand blasted and then coat it with epoxy primer, etc.

However, I came across an opportunity to purchase a used rear axle from a southern California car (same model year) with low miles that had never seen any salt, so I bought that axle. The factory paint seems to be in good shape on it.

My main goal is to prevent rust on this new axle. I don't really care what it "looks" like, as long as I prevent the corrosion from starting. My questions:

1. Should I leave the factory paint on there and simply start coating it with something like CRC Heavy Duty Corrosion Inhibitor once a year?

2. Should I leave the factory paint on there and spray/brush epoxy primer (and top coat) over the factory paint and then start coating it with something like CRC Heavy Duty Corrosion Inhibitor once a year?

3. Or should I remove the factory paint and then put on epoxy primer (and top coat) and then start coating it with something like CRC Heavy Duty Corrosion Inhibitor once a year?

I don't mind stripping it down and then re-coating it. However, I want to know that I'm actually improving things before I do the extra work. If I was using my old rusted rear axle, this would be an easy decision. But starting with a good rear axle with no corrosion and good factory paint makes me wonder.

Thanks!
Bryan
 
OE coating suck, I would strip and epoxy. I'm in Wisconsin and get at least 1 more month of salt per year then Iowa, and have found the epoxy to be holding up well so far. 3 coats with plenty of flash time between coats.
 
Thanks for the reply! Seems like a definite win for epoxy in the salt category. I neglected to mention that I live out in the country and sometimes I'm driving on gravel roads (not often but some). Will the epoxy hold up reasonably well in that environment against chipping? Or perhaps a better question, will it at least hold up better against gravel than the factory paint would?

Thanks!
 
Ill read up on your CRC inhibitor... I use Fluid film every year on my F150..Seems to work very well for me..If you have to work on your vehicle, thats when things get a bit messy
 
I experimented with how tough the SPI epoxy primer is on the frame and suspension of a horse trailer.

Two coats of unreduced epoxy and after a little over a month, I tried to scratch it with a screw driver. To my surprise it wasn't happening.

Since then I have used black epoxy on frames, axles, control arms, etc. for many years now.
 
Good to know! This might be a dumb question but for something like the axle and trailing arms where I don't really care about the look, but only care about the corrosion prevention, is it fine to brush on SPI epoxy primer? (I ask only because I don't currently have a spray gun or compressor.)
 
hapcj7 said:
Ill read up on your CRC inhibitor... I use Fluid film every year on my F150..Seems to work very well for me..If you have to work on your vehicle, thats when things get a bit messy
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The Crc is basically cosmoline so it sets up harder where the lanolin’s (ff, woolwax, blaster shield, etc) stay wet. But lanolin’s because of this also need to be reapplied more often. I’ve always been a fluid film guy myself but but some like the cosmoline type of products. I’ve heard blaster shield made by PB blaster is suppose to hold up a little better than fluid film. I bought a can to try out. I’m in the northeast so if you wanna keep something halfway decent you need some sort of oil/wax coating underneath.
 
beltv4th said:
Good to know! This might be a dumb question but for something like the axle and trailing arms where I don't really care about the look, but only care about the corrosion prevention, is it fine to brush on SPI epoxy primer? (I ask only because I don't currently have a spray gun or compressor.)
Click to expand...
It can, but spraying would be much better. Give it more time between coats as the unevenness of the brush will make it thicker in some areas, and extra time is needed for the solvents to get completely out before the next coat.
 
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