It ran fine after the wet session — a week later something has seized
Wet-run damage shows up days later, not on the night. How to recognize it, what is still saveable, and the two prevention steps that matter most.
It came home from the wet run working fine. A week later a bearing is rough, a screw is seized, or a connector has gone green.
This catches people out because nothing was wrong on the night. Water does most of its damage in the days afterwards, while the car sits in a bag.
How to tell that is what happened
- Roughness appeared without a crash. Nothing hit anything — it just went bad sitting still.
- It is worse at one end than the other, usually whichever went deepest.
- Screws feel tight starting to undo, then free up. That is surface rust in the threads.
- A connector looks green, dull, or brown where it used to be bright.
- Diff oil looks milky, like coffee with milk in it. That is water emulsified into the oil.
What to do about it now
[[Bearing spin test|Rough bearings]] can sometimes be cleaned and re-oiled, but notchy — catching at the same point every turn — means the races are pitted and it is replacement only. Rust pits do not come out.
Milky diff oil means that diff needs [[Rebuilding a differential|opening and rebuilding]]; it is not damping predictably any more.
Stopping it next time
The whole thing is preventable with about ten minutes on the night. Full procedure: after a wet, muddy or snowy run.
The two that matter most: rinse immediately if it was salt water, and never seal a wet car in a bag or box — trapped moisture with no airflow is the worst case there is.
> Ran somewhere dry and dusty instead? Different failure, opposite first move — see dusty and sandy runs.
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Add what you know. Ran a specific chassis through water and found out exactly what fails first on it? Found a receiver box that seals well, or one that does not? That is the sort of thing only someone who has done it can write — and this page is meant to grow.