TPMS sensors siezed to valve stems

porthole · Jun 8, 2011

So today I set out to adjust all the tire pressures. It's a pain on the new DRW Ford, have to remove the rear wheels to get to the inner tires.

Anyway ALL 6 sensors were seized onto the valve stems. I spent half a day trying to get the sensors off the wheels. I succeeded in getting all 4 off the rear wheels. I needed channel locks (small pair), vise grips, 12 mm wrench that I bent the open end to a 20 degree angle and I broke the TPMS special tool that is used to remove the sensors.

In 24+ years of automotive work I have never used the tire valve re-threader I have in my tool box - used it today.
The sensors went back on with a bit of "never-seize"

Not so lucky with the front wheels. I ended up breaking both valve stems!
2nd half of the day was spent running around with two wheels that needed new valve stems installed.

$36 and they are not even the full metal version.

JohnDar · Jun 8, 2011

Duane, just from the photos, it looks like you have brass valve stems that exhibit copper (green/blue) corrosion around the threads. I don't know what the TPMS sensor is made of, but it's possible you've got a problem of dissimilar metals in contact and the brass acting as sacrificial. The sensors look the same as the TST ones I've got on my trailer tires (steel stems). Can't put them on the gated rubber ones on my truck, though.

porthole · Jun 8, 2011

JohnDar said:
Duane, just from the photos, it looks like you have brass valve stems that exhibit copper (green/blue) corrosion around the threads. I don't know what the TPMS sensor is made of, but it's possible you've got a problem of dissimilar metals in contact and the brass acting as sacrificial. The sensors look the same as the TST ones I've got on my trailer tires (steel stems). Can't put them on the gated rubber ones on my truck, though.

John,

"TPMS" was generic for tire pressure monitoring system.
These are TST's, got them in Nashville.
On the new ford The rear wheels have plain brass on the inners (1st picture) and chrome plated brass on the outers. Same with the fronts.

These have only been on the truck since the end of December.

Are you sure your stems are steel? Even if they are steel that still leaves the "dis-similar" meal issue.

JohnDar · Jun 8, 2011

I'm pretty sure the stems on the aluminum trailer wheels are steel. Quite possibly stainless steel to avoid the dissimilar metals problem. Aluminum and plain steel are a no-no. I'm SWAG'ing (scientific wild arse guessing) on the corrosion cause. It's been a long time since I worked in corrosion testing and don't have the references I used to.

Maybe contacting TST would provide some information. Hopefully, they've tested their caps with different valve stem materials and have an answer.

GOTTOYS · Jun 8, 2011

Whoa, was going to install my TST sensors on the new metal valve stems on my trailer tomorrow. Looks like I'll pack my anti-seize along with me to the storage lot. Don

szewczyk_john · Jun 9, 2011

I'm getting new tires on the truck Friday and was going to install TST sensors on mine as well. Never even thought about never seize. Thanks for the post and pics. I need to find out what type of stems to get ASAP. I had not installed them yet due to having rubber stems.

Vtxkid · Jun 9, 2011

Sorry to hear about your bad luck Duane, I just removed my TST sensors yesterday to ensure the tire pressure on all four RV tires are identical and had no problems with them coming off or going back on. But their again, mine have only been on the trailer since first part of April. I have a on-board TPMS for my truck tires so I don't have the concern there...

mrcomer · Jun 9, 2011

Duane,
Could it not only be a dissimilr metal issue but maybe salt also? I have have my sensors mounted since the Nashville rally and have had no problem removing them but I do not have brass valve stems like it seems you do. Hope you get them all fixed up and back on the road.

See you in Goshen,
Mark

porthole · Jun 9, 2011

mrcomer said:
Duane,
Could it not only be a dissimilr metal issue but maybe salt also? I have have my sensors mounted since the Nashville rally and have had no problem removing them but I do not have brass valve stems like it seems you do. Hope you get them all fixed up and back on the road.

See you in Goshen

Could very well be, we do live in the "Salted Garden State".

But, these kits are sold to over the road truckers too, salt should not be an issue.
The bad part is it is such a pain to even get these on that it is not convenient to just put them on as needed. The DRW's need to come off to install the sensors.

I have new extensions added, so I will see if that helps. And the extensions were ordered from Always Shiny, same vendor we got the the kits from. That will eliminate the "my parts on your parts" answers.

jmgratz · Jun 10, 2011

Dont know what type of TPMS you have but our Doran TPMS sensors have never had that problem. We can even get them on and off without taking the outer wheels off. Not an easy task but doable. I would talk to the manufacturer or distributor of the system to see what they say. That should not be happening IMHO

szewczyk_john · Jun 10, 2011

I made a call to TST and the guy that has posted on this forum in the past (I think Dan) was not in but his coworker stated that he was not aware of any problems like this cause by the metal in the stems? I was hoping o get an answer as the wife is at the tire dealer getting new tires and stems installed. The TST system was highly touted and I even saw some OTR truckers posted about how good the system works.

porthole · Jun 12, 2011

Got a forwarded reply yesterday from TST. Apparently I am the 5th known case of this issue.

JohnDar · Jun 13, 2011

porthole said:
Got a forwarded reply yesterday from TST. Apparently I am the 5th known case of this issue.

Do they have a root cause or explanation? Curious (OK, nosey) minds want to know. Is it peculiar to brass stems, or is there something else to be concerned with?

SilverRhino · Jun 13, 2011

Just had new valve stems installed in the wheels of the BC last week. My tire shop used a chromed metal valve stem that they usually use on custom wheels. I have the TST 507 system.......Sure hope this won't be a problem!

Travel Safe!

ParkIt · Jun 14, 2011

SilverRhino said:
Just had new valve stems installed in the wheels of the BC last week. My tire shop used a chromed metal valve stem that they usually use on custom wheels. I have the TST 507 system.......Sure hope this won't be a problem!

Travel Safe!

Had chrome stems on the MH (dual in the back just like the BC) and never had any issues. I've replaced a lot of plastic to chrome over the decades on all sorts of regular vehicles, can't imagine you would need to worry about them.

porthole · Jun 25, 2011

TST replaced all my sensors.

I would recommend to those that have DRW's; get the 507 model. The anti theft caps are removable. With the caps on I have to remove the rear wheels to get the sensors on and off. Also had to modify a wrench to work on the fronts on the new Ford (wheels are really thick at the openings).

With the caps off they are fairly easy to get on and off, unless your hands are so big you can't get through the wheel opening.

BTW, the flats on the sensors are 12mm

SilverRhino · Jun 25, 2011

porthole said:
TST replaced all my sensors.

I would recommend to those that have DRW's; get the 507 model. The anti theft caps are removable. With the caps on I have to remove the rear wheels to get the sensors on and off. Also had to modify a wrench to work on the fronts on the new Ford (wheels are really thick at the openings).

With the caps off they are fairly easy to get on and off, unless your hands are so big you can't get through the wheel opening.

BTW, the flats on the sensors are 12mm

I just installed the TST 507 system to my trailer and inner wheels on the rear of the CTD, which required removing the outer dual. My sensors must be different than those mentioned by Duane......Don't see any "removable anti theft caps" on mine. The top of the sensor is removable.....thought that was only used to change the batteries. Either I am missing something or there is a different sensor available.

Maybe if Duane has a chance he will explain further about removing the anti-theft caps.

jnbhobe · Jun 25, 2011

TST has two models, one with 5yr batteries and one with replaceable batteries. I have the 5yr model and they have an anti-theft cover that just spins, you have to use a special wrench to remove them, or a 12 millimeter open end wrench.

porthole · Jun 25, 2011

I'll take pictures when I find the box of parts.

porthole · Jun 25, 2011

OK, here is a picture from the TST site (click on picture for a larger size)

This picture shows the sensor with the anti theft cap. Remove these 3 screws and the cover comes off in two pieces. You are left with an inner shell that can they be put on using only your fingers.

TPMS sensors siezed to valve stems

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