Thread: Rust removal trick

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As I recall I came across this in Hot Rod magazine probably over 20 years ago.

Anyway this weekend I was working on the El Camino project and got to the drive shaft part. I needed a yolk for a TH400 tranny and after looking around I finally found my last one. Unfortunately at some point it had sat out in the weather and was a bit rusty. The outside cleaned up nice with a wire wheel and some 400 grit.

The inside where the splines are was probably worse, rusty and filled with crud. I wire brushed it and sprayed a bunch of oil and brushed it some more but even with a few light taps with a hammer it would not go further than about 3/4 of an inch.

I recalled the old trick I have used a few times in the past. I went in and got about 1/2 cup of vinegar. I set the yolk straight up and poured the vinegar to the top and let it sit overnight (about 18 hours).

I poured out the vinegar, sprayed it out with carb cleaner and this is the result. All but the deepest rust was gone and down to bare metal. I sprayed some light oil in it and it slipped right into the transmission.

Thought someone might find this useful in the future.

Kewl deal Mike---how to save a yoke that would otherwise have been a door stop!

Same thing works with windshield washer bottle on your cars when they get plugged up.
Got it to some Peterbuilts that the guys would use straite water in instead of washer fluid. They would get plugged up with hard water, then they would not work.
Throw some vinegar in there and watch it start foaming up, next thing you know the sprayers are spraying again. Good stuff, thanks for the rust tip. Kurt

I have done the same thing with spirings and such from drum brakes.....works like a charm.
Vinegar is the most produced and used acid in the world according to the discovery channel

this is a good trick for light rust, and gunk removal, but it actually damages the metal.
there is a electrolisys trick that uses rebar, and a car battery/battery charger, and replaces the rust metal with fresh iron... I'll try and find the link... it actually converts the rust pits to fresh metal. I've not tried it, but it looks like a good deal.

A lot of guys with old flatheads use vinegar to clean out the blocks. Especially good if the car is running - fill up the cooling system and run the car. All the crap, rust, etc loosens and comes out.

Great tip with the vinegar, will have to try that one out in the near future.

Originally Posted by vstech

this is a good trick for light rust, and gunk removal, but it actually damages the metal.
there is a electrolisys trick that uses rebar, and a car battery/battery charger, and replaces the rust metal with fresh iron... I'll try and find the link... it actually converts the rust pits to fresh metal. I've not tried it, but it looks like a good deal.

I have done the electrolysis before with great results. It is not recommended to use it on load bearing parts because hydrogen embrittlement can occur

Thomas

Cool idea; and it tastes good on salad, too.

HE! HE! HE! Good one falconvan.
Less filling, taste great.

Rust is iron oxide and all oxides are basic so an acid will react and dissolve the oxide, but strong acids will also dissolve the metal. In particular, common muriatic acid (30% HCl) will really dissolve iron easily! That is why vinegar works OK up to a point, it is only about 3% acetic acid and acetic acid is a weak acid and finally the results are acetate salts soluble in water so the vinegar produces iron acetate which can be flushed away with water. This is a good trick for large iron objects where you don't miss a little of the iron which is dissolved but could cause damage in a copper or especially aluminum radiator. That is why the folks who flush radiators use a basic solution rather than a weak acid. However the basic solution used to flush radiators will not have much effect on rust. After that long discussion, the case at hand for me was to flush out a (MG Midget) gas tank with rust in it. A thorough cooking in radiator flush process did little to remove the rust which presisted so I should have tried vinegar at the risk of creating pinholes in the tank. Instead I put scoops of gravel stones in the tank along with a short length of 1" chain and shook it up followed by rinsing but still I had rust that was so bad that I had to carry spare fuel line filters for on the road replacement. A better solution would have been to use vinegar followed by a tank sealer but I tell this to remind the vinegar users that it is a tradeoff of cleaning out rust versus creating pinholes. Conclusion: vinegar will dissolve rust but radiator cleaner basic solutions will not, but on the other hand thin metals in radiators could be damaged by vinegar so that is why basic solutions are used on radiators. Some metals like aluminum form oxides which will dissolve in either an acid or a base (amphoteric oxides) so the gentler basic cookout will clean radiators but have almost no effect on rust. Second conclusion: don't use vinegar on radiators.

Don Shillady
Retired Scientist/teen rodder

I just used vinegar to clean out a portable air tank, I just cut open for a gas tank. had rust on the bottom