Anyone else fitted the MX5OC tyre valve caps that were given out to members last year? Been trying to get them off my car to check tyre pressure but two have rusted on fast. They were all greased before fitting. Tried WD40 and Plus Gas but still not shifting. Can’t believe the club have distributed these to members if they rust on. Anyone got any ideas about getting them off?
How long is it since you checked the tyre pressures? To corrode to that extent it must be yonks,
I do mine at least once a month and they are still as new.
Had to use a mini grinder to cut all four off of a fellow members car. Its the only way!!
my caps were taken off less than 3 months ago. I’ve had cars were they haven’t been touched for over a year! Never had this happen. Why design caps that rust fast? Got a couple of options to try but mini grinder might be what’s needed. Other members beware!
No one “designs” valve caps that rust. I have never seen a rusty valve stem (they’re brass). Valve caps are either plastic or stainless steel, or a nickle plated alloy. Which don’t rust. More likely its stiction due to road salt/grime, rather than the fault of the Owners Club. The cap will also have a rubber insert that can bind.
Halfords used to sell a Shock n Awe freezing spray. For some reason they don’t do it anymore. This appears to be similar:
https://www.screwfix.com/p/arctic-products-crack-it-shock-release-spray-400ml/83415
I have an idea that brass might contract a bit more than stainless steel.
Can brass and stainless steel be used together?
Unless you know the specific types of stainless steel and brass, it should be avoided. This is because only certain types of stainless steel and brass can be used together. ... In the case of stainless steel (410) and brass, they are seven metals apart, which means they would be likely to corrode if connected directly.
Nerdy explanation:
Galvanic Corrosion can occur between the brass valve stem and the stainless steel cap.
This is accelerated by salt water spray from treated roads.
It also depends on the type of Stainless Steel used in production.
Agreed
And Regardless of the “grade of stainless steel” from the owners “nerdy explanation” it will be oxidization causing the owners issue not rust so i am guessing they are a alloy based cap, silicon spray or a silicone grease needs to be applied which is a common thing to happen because we love salt here for our answer to winter whingers, what ever “protection” on the threads/caps was applied as been washed off and attack a long time ago by the sounds of it from not being removed for a good while and i am sorry to say the protection not being applied correct and checked at the same time as tyre pressures???.
As said cut them down the length being careful of the threads and split them using a dremmel tool and cutting disc, common place for this to happen with the alloy caps that have not been protected correct, I have dealt with it many times and still do with others, info on these alloy caps is everywhere in a simple internet search.
To my knowledge with all the years of “cars” i have never seen metal caps on any cars let alone to of seen them “rusted solid” I honestly cannot see metal caps being made and if so anyone would be stupid to even think about buying them and fitting, they are either brass, S/S, plastic or alloy, i have always added protection in the cap and threads regardless of the make of caps any way, but i check the tyres pressures regularly with using mine on motorways , tyre pressures should be checked weekly regardless which as clearly not been in the case, sorry OP but it is a fact, time to learn from a mistake and put it back right, and lets not finger point the club for their free gift as a easy target to blame, maybe a simple warning on the inside cover could of helped from doing homework??but there are enough of us about that know to advise.
M-m
Interestingly Mazda warn of corrosion on their own valve caps here. https://www.mazda.co.uk/owners/accessories/?model=MAZDA MX-5&year=2008-10-01
They have TPMS and none TPMS items.
Metal caps corroding to the valve stem is very common. I have lost count of how many valves I have had to cut through and replace. Certain Alloys don’t like Copper and so with the right solution you are going to get issues. They are just valve caps though, the Club didn’t chose them as problems it is just what they are.
I’ve used a variety of alloy & steel caps over decades on a variety of vehicles from Vivas & Avengers till…well…last Sunday.
Never had an issue.
Over circa 1.3 million-odd miles spanning almost 50 years, had no more than a handful of bad luck punctures.
But then, I check my pressures & treads weekly and have done since around 1978.
5 minutes in the drive with a ciggy lighter plug in pump.
TBH, I don’t trust alloys to hold a perfect 26 PSI for 3 months…but maybe I’m a bit over cautious.
You can never G’tee when one decides to go a bit porous.
Sometimes 1 or 2 tyres need a pound or two for some odd reason on both our Fives
Sometimes not. But, add that 1 pound over a hypothetical 12 weeks…and bingo. One half deflated wheel…in theory.
For me, if I’m doing 70mph + in a lightweight vehicle with pretty much zero passive safety built in, 4 wee patches of rubber need a bit of TLC.