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WD-40 and Rubber

I bought already mounted tire and when checking the air pressure i had a sticky valve stem.

Question: Would WD-40 hurt the seal in valve stem?

Probably not but I would just replace the valve stem to be on the safe side. A flat tire is never fun.

Probably a good idea

Plug kit wont fix a valve stem…


The schrader valve

can be easily screwed out and replaced.

I don’t trust a solvent and water displcement like WD40 “not” to harm a small rubber seal by drying it out over time. Wd40 does a lot of things but must be used with care around plastics and rubber. Agree, replace.


Petroleum products are absorbed by most kinds of rubber - and the compounds used in tires contains these types of rubber. This absorption causes the rubber to swell and weaken.

So do NOT use petroleum products around tires - and I think valves ought to be included in that statement as we just can’t be sure what kind of rubber is being used…

This is why i asked. I am aware of possible effects of petroleum products on rubber and was thinking about the little rubber seal in a valve stem


I’m pretty sure I damaged the CV boots on my VW Rabbit by spraying WD 40 on them. Happened years ago. I thought at the time it would displace water, keep the innards dry. But I think it weakened the rubber, and within 6 months they both shredded apart and I had to replace both boots on both axels.