Trouble inflating tyres after exchanging rubber valves for metal ones

[Governa]

Ok so I was having trouble inflating the tyres of my W123 240D.

I have recently asked MB to replace the old ugly rubber/plastic valves for some metal ones (part number 1074000013).

But a couple of days ago when I went to my local BP petrol station I couldn't for the life of me properly fit the air pump nozzle to the valve so instead of inflating the tyres I was deflating them.

I actually had to go to MB where they had no trouble inflating them. They couldn't explain to me why it happened but their theory is that petrol station air pumps are a jack of all trades made to fit everything from bike to truck valves while the one they use is specifically made for regular cars.

When I came back home I tried my ForTwo's valve dust caps on the new W123 metal valves and found they fit perfectly so it does look they're the same size as any other tyre valve.

Scratching my head I asked around and got this explanation from a Portuguese cab driver, apparently these valves are too short so what's happening is that the pin inside the air pump nozzle hits the edge/rim of the valve before getting deep enough to perfectly seal around the valve and inflate the tyres without air escaping.

Mystery solved and so I have placed an order for a Ring RAC900 air compressor on Amazon.

I have also bought a flexible tyre valve extension. This last item cost me 10 quid and should be enough to solve the problem but since my 240D mostly "hibernates" during the winter months it's good to have an air compressor at hand to keep the tyres tip top without going out on the road.

 

[Kruger]

Hi there,

I have trouble locating these metal valve stems. Does anyone have a supplier for these, other than MB (£98 per one!

 

[optimusprime]

I had them and binned them ,,but mine were flush type ,,to inflate my tyres you had to screw in an extension and replace a flush screw cap after .

 

[zipdip]

Well filling station air leads are abused and battered,but have never had trouble with the old tyre valves,never had these metal ones

 

[Petrol Pete]

I wonder if the OP still has them ?

His first post is a just a week and a few days shy of 8 years old

 

[Flyinspanner]

Don’t put metal caps on your valve stem. They WILL corrode on, and you won’t get them off, always use the plastic caps.

 

[Kruger]

Thanks for the replies. For future reference, REMA TIP TOP AUTOMOTIVE UK LTD, Westland Square, Leeds, LS11 5XS supplies the correct part: 42MS AV. They're £2.62 each!

 

[NJSS]

Is that really the correct part number? It appears to be a "truck" not "car" valve.

 

[Kruger]

Apparently. It's the length of the stem (45mm) that you need on some Bundt wheels (part number starting with 108...) that just happens to be the length used ordinarily on trucks. Rema Tip Top supplies Alligator valves who apparently supplied the original MB ones. Car

 

[OneForTheRoad]

Any of you gents needing a bit extra length on your bits , try using one of these ,just till youve inserted your psi.The wife will love it.

 

[optimusprime]

Also rubber valves will fit in the contour of the alloy wheel those in posters picture dont, and i can see that paint will be coming off as tyres are inflated . You cant beat original tyre valves. And if need be, buy a set of covers [tubes ] to slip over the rubber tyre valves finish off with a nice chrome screw on valve cap .

 

[Deleted member 126251]

@op they look very similar to what my SL has (from teh factory). I’ve never had a problem in 5 years.

 

[Smiley]

The metal caps are a nightmare - they corrode and seize in place. You can end up ruining the whole valve tube assembly getting a seized cap off if you are not careful. My advice is stick to the plastic caps.

 

[Wolfie1]

Just put some copper grease on the threads then they will never seize on, i have done this on my other car, they have been on for 7-8 years without a problem

 

[Kruger]

Apparently. It's the length of the stem (45mm) that you need on some Bundt wheels (part number starting with 108...) that just happens to be the length used ordinarily on trucks. Rema Tip Top supplies Alligator valves who apparently supplied the original MB ones. Car

For whoever might stumble across this in the future: these valves don't work! You need a valve that is 42mm long but the thread needs to be the same from the top to the bottom of the stem. I'm reusing the MB collar on my old valves but it's M5 thread where these valves have a M8 thread.