240 General: bumper corrosion

[timetrip]

Hi guys, Just removed bumper off my 89 240 estate and where the main brackets are there's some corrosion so, looking for the best way to treat it ?. Have seen some inhibitors and other suggestions like white vinegar and water or lemon and salt etc,,,any suggestions ? regards Adrian.

[Moomoo]

If it’s just surface rust and they’re still solid, remove anything flakey , wire wheel, then any searching oily stuff followed by a wax product.
They are pretty substantial so let’s hope they’re still up to their job!

[Bob Meadows]

Done this one some years back on my '88 240.

Clean away as much rust as you can- wire brush, drill or angle grinder fitting.
Coat with Jenolite rust converter and allow to dry.
Paint with a zinc primer or etch primer (or both)
Top coat with something like chassis black but the preparation is the important bit.

Coat the brackets with waxoyl or similar: spray it diluted (engine oil) up the body chassis legs & associated areas, the hidden area of the car is very prone to rusting.
I also incorporate a waxoyled gasket between the bracket end fixing points that bolt onto the aluminium channel (dissimilar metals etc)

It will outlast you when done properly.
Good luck.
Bob.

[Moomoo]

Originally Posted by Bob Meadows

Done this one some years back on my '88 240.

Clean away as much rust as you can- wire brush, drill or angle grinder fitting.
Coat with Jenolite rust converter and allow to dry.
Paint with a zinc primer or etch primer (or both)
Top coat with something like chassis black but the preparation is the important bit.

Coat the brackets with waxoyl or similar: spray it diluted (engine oil) up the body chassis legs & associated areas, the hidden area of the car is very prone to rusting.
I also incorporate a waxoyled gasket between the bracket end fixing points that bolt onto the aluminium channel (dissimilar metals etc)

It will outlast you when done properly.
Good luck.
Bob.

This reply is the better one!🧐

[Bob 1967]

Originally Posted by Moomoo

This reply is the better one!🧐

I concur !!

[timetrip]

bumper 120230209_155524.jpg

bumper 220230209_155517.jpg a couple of photos of bumper corrosion..took sometime to work out how to down load but i got there ,lol. as you can see its just where the brackets are. !!

[Juular]

Originally Posted by Bob Meadows

Done this one some years back on my '88 240.

Clean away as much rust as you can- wire brush, drill or angle grinder fitting.
Coat with Jenolite rust converter and allow to dry.
Paint with a zinc primer or etch primer (or both)
Top coat with something like chassis black but the preparation is the important bit.

Coat the brackets with waxoyl or similar: spray it diluted (engine oil) up the body chassis legs & associated areas, the hidden area of the car is very prone to rusting.
I also incorporate a waxoyled gasket between the bracket end fixing points that bolt onto the aluminium channel (dissimilar metals etc)

It will outlast you when done properly.
Good luck.
Bob.

This is a good approach.

From personal experience I prefer neat phosphoric acid as a rust treatment / converter as it wets and sinks in better, etches the metal, and isn't diluted with the protective layer. You can also clean it off completely which allows the zinc primer to have contact with the steel. However in this case the jenolite will work well enough if that's what you have.

[Jungle_Jim]

A suggestion - make gasket/barriers cut in the shape of the bumper bracket ends (using flat plastic like an old oil container) to keep the aluminium and the steel separated (galvanic corrosion). Plus grease around the bolt so water can't get in. This is what I did when I replaced the previous rear Al bumper which was badly rotten in these areas.

[Bob 1967]

Originally Posted by timetrip

Hi guys, Just removed bumper off my 89 240 estate and where the main brackets are there's some corrosion so, looking for the best way to treat it ?. Have seen some inhibitors and other suggestions like white vinegar and water or lemon and salt etc,,,any suggestions ? regards Adrian.

Since it is the aluminium corrosion that is the issue.
Yes vinegar is the cheapest way, a bit of scotchbrite pad will help.
Then a coating of clear lacquer might help further corrosion.
The recommendation of a barrier/gasket between alloy and steel is also a good one.

I used a toothbrush and autosol to clean motorcycle engines followed by many a cloth. they blackened quickly, but the result was worth it.
Since the portion of the bumper in question is not visible, such extremes will not be required.
As someone else uses the tag; I'm not an expert, I will refrain from pinching it!
But I'm not.

[timetrip]

A big Thank you to all for the advise. I got some Jenolite and coated it as per instructions And then sprayed with 2 coats of etching primer and i have made a plastic barrier the same size as brackets which will be coated in waxoil when i refit the assembled bumper... Cheers Adrian.
p s, I use metalmorphosis on all the steal rust..!!!