Shrader Values - Extra Long Core

[turbopilot]

I am stumped. Just completed FreightLiner annual service. They just had to fill my tires up to 120psi (based on weight normally run 100/90 in the NA front/rear). So I had to go around and let some air off. On one tire the right inboard dual they bend the Shrader valve core so that as soon as you pull of the TPMS it starts to leak. Pulling the valve stem out with pliers closes it off. So stem is bend. That's problem #1.

Problem #2 is apparently they use a Shrader valve with a long core on it. So off to the truck tire store to get another Shrader valve with a long core and I hear crickets. They have no idea what I am talking about.

Searching around the web I was able to find an image showing different sized long core Shrader valves but I have no idea what part number I have. Even if I did I can't find anyone who sells these things. A few posts on the internet suggest this long core valve is used for those folks running beads in the tires so that the beads don't clog the valve core extension. Makes sense.

Does anyone know what this is all about? Can I just put in a normal small Shrader valve since I am not running beads?

[10 fan]

I have no experience with this but they all look the same on the threaded end

[Spk64]

Sounds like you have extensions. The long cores are used in those and there will be a second schrader valve in the actual stem. The long core depresses the original core in the stem. Better off to replace the extension, or better yet replace with one piece valve stems.

[LongRanger]

I just pulled the extension and bent it back. It’s been good for a couple years now.

[turbopilot]

Originally Posted by LongRanger

I just pulled the extension and bent it back. It’s been good for a couple years now.

Good idea. I considered this but was worried about screwing it up since I have no replacement.

[turbopilot]

Update

Today I pulled the sticky "mystery" Schrader valve out of the right inside dual tire and replaced it with a standard sized Schrader valve. So far everything is normal. TPM reads normal.

Took the "mystery" Schrader over to the truck tire store. Still crickets. They have never seen anything like this and have no idea how to order one. I can't find them anywhere on the internet.

Here are some close up images. The rod swaged on to the bottom of the Shrader is solid. No air passing through it. So what could it be doing?

Also the valve core pin does not seem to be bend and does not stick outside of the tire. Really odd.

[Spk64]

If you pull the valve on an extension. That is what they look like. The rod is to depress the valve that is in the short stem at the wheel.
I am surprised TPMS is still working unless the core at the wheel is damaged also.

[turbopilot]

Originally Posted by Spk64

If you pull the valve on an extension. That is what they look like. The rod is to depress the valve that is in the short stem at the wheel.
I am surprised TPMS is still working unless the core at the wheel is damaged also.

OK, that makes sense. Tire shop told me just to replace the stems with the continuous stem but it requires pulling the wheels and breaking the bead on the inner duals which I understand is a good idea.

[Spk64]

Yes it is alleviates these type issues. I did that a few years ago after fighting leaks and TPMS issues with extenders.

[TheBigBus]

Hey Turbo - I had the same experience with losing air - and - very confused looks at a tire shop. I replaced them with these:

https://www.amazon.com/Wheel-Masters...r=8-3-fkmrnull

No leaks and the TPMS works great.

[Ann n Gene]

A lot of tire and auto parts stores carry replacement valves and extensions. I am surprised a good tire shop was not familiar with them. I have used them for years. Putting one piece, longer stems is bar far the best but high quality steel extensions work great also. Just don’t get the flexible kind, they don’t last and tend to leak and cause trouble.

[turbopilot]

Originally Posted by Ann n Gene

A lot of tire and auto parts stores carry replacement valves and extensions. I am surprised a good tire shop was not familiar with them. I have used them for years. Putting one piece, longer stems is bar far the best but high quality steel extensions work great also. Just don’t get the flexible kind, they don’t last and tend to leak and cause trouble.

Yup, on the cause trouble part. Guess I will pull the wheels and put in the one piece stem. Good chance to do an 12,000 mile inspection.

[turbopilot]

Originally Posted by turbopilot

Yup, on the cause trouble part. Guess I will pull the wheels and put in the one piece stem. Good chance to do an 12,000 mile inspection.

Ok, now the rest of the story. What a mess it has caused because FreightLiner does not use a one piece valve core extension.

Below is the valve stem and valve stem extension removed from my inner dual. As you can see this configuration has two Schrader valves: one on the end and one at the junction between the valve core and valve core extender. When they took it apart they found the Schrader valve on the inner valve stem was partially screwed out and leaking. So what was happening is that the tube attached to the outer Schrader valve on compression was jamming against the side of the partially screwed out inner Schrader valve not allowing it to pop back out after being depressed. That also explains why my TPMS measured pressure when I replaced the Schrader valve with the core with a regular Schrader valve without the core.



Since we had the wheels off I had them replace the valve stem with a single piece valve stem. That resulted in a slight shorter extension that in turn allowed for the removal of the valve stem protective grommet that has been the subject of a safety recall.

[Stuart W]

The long rod depresses the valve stem valve. I had one the the rod was to short and won’t let my TPMS read that wheel