Flat tire from TPMS with rubber valve stems

Dougherzog · 01-20-2020, 05:37 AM

My new tire pressure monitoring system, the TST 507, just saved our just completed trip to Florida. Thanks to you all I thought I had, and paid a lot, to Mercedes to replace my rubber valve stems and add metal valve extenders for my sensors. If you remember, I did see the front wheel valves Mercedes did NOT replace with steel. I did get BORG valve stems from ShinyRV.com, as suggested, for the front and my local repair shop installed them. I could not see into the rear dual's to check. Well, you were right, after about 2000 miles into our trip, I turned on the TMPS to check pressures. The warning came up right away on one of the rear tires, 7 PSI. Sure enough, after five hours just off of interstate 75 in Florida, Mecedes had road side assistance change to the spare (still have warranty). I added some air to the flat tire and soaped the rubber valve to verify that's what caused the leak. It didn't seem like a rub but I did see cracks (must be from vibration). We drove 160 miles to a tire repair shop in Georgia. They put in small rubber valve stems in the spare and all four rear tires because I couldn't trust the rubber valves. All TPMS was removed from the rear wheels. Lesson learned, TIRE PRESSURE MONITORING IS A MUST ALONG WITH STEEL VALVE STEMS. Rubber ones will crack and leak. I will order BORG steel valves for the rear wheels. Bad rap on MERCEDES.

Doug

Morich · 01-20-2020, 10:30 AM

Fully agree! I can easily see that the added weight of monitors placed on stems will add enough extra torque at highway speeds to really give the stems a workout and all that flexing will do them in quickly.
In my case, the stems come out very close to the fake wheel covers and to add a bit more "feel good", I added plastic ties to hold the stems and monitors tight to the covers. If/when I see the ties degraded, I will then also check the stems again.

Dougherzog · 01-21-2020, 06:04 PM

Quote:

Originally Posted by Morich

Fully agree! I can easily see that the added weight of monitors placed on stems will add enough extra torque at highway speeds to really give the stems a workout and all that flexing will do them in quickly.
In my case, the stems come out very close to the fake wheel covers and to add a bit more "feel good", I added plastic ties to hold the stems and monitors tight to the covers. If/when I see the ties degraded, I will then also check the stems again.

I will also add wire ties. Thanks a lot.

seaninnj · 01-27-2020, 05:24 AM

I just got a TPMS...the Tireminder Solar model. I haven't mounted them yet but now I'm wondering if I have to replace all the tire stems on our Micro Minnie as well?

Tireman9 · 01-27-2020, 08:33 AM

Yes it is STRONGLY recommended that any rubber stem, even the "High Pressure" rubber stems that have more brass than standard 65 psi stems should be replaced with bolt in metal stems. You might check the work order. IMO if you asked for metal stems and the dealer installed rubber, the dealer should pay for the new metal stems, the service call and replacement of any tire driven on with the air leak as there is the potential of tire damage if driven on with more than 20% air loss.

Doug you didn't say what your pressure readings were when driving. Was the 7 psi only after being parked for a few days? If you drove any distance at all with that 80% air loss I would consider that tire "scrap" and would not trust it.

Philip53 · 03-23-2020, 09:23 PM

I put the Borg Sprinter brass valve stems on my '17 Navion a few years and 15,000 miles ago. Love the TMPS system. But BEWARE, not to let the outer stainless steel wheel cover get to 'close' to the stem. The holes in those covers are extremely sharp and will cut into the brass stem with ease. Ask me how I know--well I'll tell you. On our recent trip to Big Bend (TX), inside rear alarm went off with tire losing pressure fairly fast. Stopped on the road and found the groove that had worn into the stem. Luckily I had an on-board air compressor and was able to limp into Pecos, where they fortunately had a stem that would work. I say 'fortunately', because the oem steel wheel is different (of course), from most all other wheels and it takes a special stem to fit it.

And yes, I had known about the potential interference and check it regularly, in fact just before this trip. But I guess that stem was on the bottom of the wheel and I could not readily see the past wear. So lesson learned the hard way, maybe I can help someone else avoid a similar problem.

BobC · 03-24-2020, 10:18 AM

Just to be clear, there are metal extended valve stems, like the Borg stems. This is what you want. There are also metal valve extensions, which don't solve the problem since they just screw on to your existing rubber stems.

GaryKowal1 · 03-24-2020, 11:35 AM

The TPMS only works when it is on. When the RV is moving, it should be on. Can be shut off when parked.

Cataska · 03-26-2020, 07:19 PM

I had a rubber valve stem break using TST 507 cap sensors ,I now have changed every valve stem to metal that i use the tpms on .

Wyatt · 03-26-2020, 09:33 PM

Quote:

Originally Posted by Philip53

I put the Borg Sprinter brass valve stems on my '17 Navion a few years and 15,000 miles ago. Love the TMPS system. But BEWARE, not to let the outer stainless steel wheel cover get to 'close' to the stem. The holes in those covers are extremely sharp and will cut into the brass stem with ease. Ask me how I know--well I'll tell you. On our recent trip to Big Bend (TX), inside rear alarm went off with tire losing pressure fairly fast. Stopped on the road and found the groove that had worn into the stem. Luckily I had an on-board air compressor and was able to limp into Pecos, where they fortunately had a stem that would work. I say 'fortunately', because the oem steel wheel is different (of course), from most all other wheels and it takes a special stem to fit it.

And yes, I had known about the potential interference and check it regularly, in fact just before this trip. But I guess that stem was on the bottom of the wheel and I could not readily see the past wear. So lesson learned the hard way, maybe I can help someone else avoid a similar problem.

That’s a good “heads-up”, thank you. I added angle extensions to the metal tire stems we have to make it easier to check the pressure and add air. They moved in transit, despite tightening them down as best I could with needle nose players. No real surprise there, with the tire rotating at 60+ MPH.
My solution was to use white plumbing tape to create a better seal. Seems to have worked, as now thyme stay in place.

Cooperhawk · 03-27-2020, 09:18 AM

We've been running with TPMS from TST since they first came out. They've saved me from blow outs several times already. Just last week I got an alarm that my right hand inside dual, (has to always be the inside), was low. I inflated it with my on board air compressor and with in a few hours it was low again. Got into a Love's tires shop and they found a bad steel valve stem, replaced it and we were on our way again.

Don't leave home without them.

Tireman9 · 03-28-2020, 04:01 PM

Quote:

Originally Posted by Cooperhawk

We've been running with TPMS from TST since they first came out. They've saved me from blow outs several times already. Just last week I got an alarm that my right hand inside dual, (has to always be the inside), was low. I inflated it with my on board air compressor and with in a few hours it was low again. Got into a Love's tires shop and they found a bad steel valve stem, replaced it and we were on our way again.

Don't leave home without them.

Interesting.

Would really have been nice to know how the metal (brass not steel) stem was "bad".
I suspect the real problem was a leaking rubber gasket that seals the valve stem to the wheel. These rubber gaskets can "age out" just as tires can and old rubber can crack and the seal would leak. Also Improperly tightened metal valve stem nuts can also result in the stem working loose.

Anyway, your experience demonstrated the value of TPMS.

akeagle · 04-02-2020, 12:33 AM

For what is worth, I used some short steel braided extension hoses on the duallies of our Minnie Winnie. After they were installed I immediately saw the probability of chaffing at the edges of the wheel openings and wheel covers.

I went to a home improvement store and bought some wire loom sheathing from the electrical department. Its made of very flexible black plastic and split so it can be easily slipped on. My logic was that any wear caused by movement would be on the loom and not the hose itself.

After two trips up and down the Alaska Highway I'm happy to report it worked exactly as I had hoped. Just a little chaffing on the loom but none at all on the hoses.

Tireman9 · 04-04-2020, 10:57 AM

Quote:

Originally Posted by akeagle

For what is worth, I used some short steel braided extension hoses on the duallies of our Minnie Winnie. After they were installed I immediately saw the probability of chaffing at the edges of the wheel openings and wheel covers.

I went to a home improvement store and bought some wire loom sheathing from the electrical department. Its made of very flexible black plastic and split so it can be easily slipped on. My logic was that any wear caused by movement would be on the loom and not the hose itself.

After two trips up and down the Alaska Highway I'm happy to report it worked exactly as I had hoped. Just a little chaffing on the loom but none at all on the hoses.

Wondering if you have the outer end of the hose bolted down using the small "L" brackets that come in the kit. I have no movement of the hose and no chafing of the SS hose. BUT I think even some vinyl hose tubing might prevent some movement and stop or limit the rubbing of the hose.
It does help if the hole where the hose comes out is large enough so there is clearance around the hose.

akeagle · 04-04-2020, 05:19 PM

Quote:

Originally Posted by Tireman9

Wondering if you have the outer end of the hose bolted down using the small "L" brackets that come in the kit. I have no movement of the hose and no chafing of the SS hose. BUT I think even some vinyl hose tubing might prevent some movement and stop or limit the rubbing of the hose.
It does help if the hole where the hose comes out is large enough so there is clearance around the hose.

Yes. I should have mentioned those brackets were part of the air hose extension kit I bought from the same Winnebago dealer where we bought the rig. The only downside I can think of is that the brackets had to be fastened to the wheel covers. So whenever they must be removed the hoses must be disconnected from the brackets. Not really a big deal though.