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Old 28th March 2024, 09:36   #3
Kearton
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MG ZT-T CDTi

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Default Corrosion Caution

Quote:
Originally Posted by MissMoppet View Post
Yes, I know there are other maybe neater solutions to this age old problem of broken lugs etc. as the units are now unobtainable, but I offer this to others as a possible answer. I used alu sheet (2mm) which is always useful for making up brackets plus some stainless self-tappers. A quick and simple job. If I need to change a bulb, I'll remove the screws from the metal not the plastic lens. Close the tailgate and of course the brackets are not visible.



Thank you. This is very simple & neat solution.

A word of caution. One thing to be aware of is the possibility of corrosion between the dissimilar metals (aluminium, stainless steel, & alloy steel - possibly zinc plated) - galvanic corrosion. Rainwater running down the drainage channel and between the metals will accelerate this. The rate of corrosion depends on the composition of the metals (i.e their galvanic corrosion potential).
I had a look in an old corrosion engineering book for sample galvanic potential values, but there was a lot of variation for each metal depending on its exact composition & manufacturing process.

As a minimum I suggest:-
  • painting the holes in the body after they have been drilled,
  • putting an insulating medium between the bracket & the body (e.g. insulating tape and/or mastic sealant) to keep the water out, and
  • greasing the screws (not copper grease) on each ocassion before (re-)inserting them.
Anodising the bracket after it has been made would also help.

If it were practical to remove the screws from the plastic lens rather than the car body when changing bulbs, that too would be better, but it does risk damaging the lens futher.

IHTH

Last edited by Kearton; 28th March 2024 at 09:43..
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