Need help re tire pressure sensors on my 1990 Coupe

**Bob M** · 05-12-06, 10:50 AM

My 1990 Coupe needs new tires re dry cracks from lack of use. My tire dealer is concerned that the tire pressure sensors may be damaged during the dismounting of the old tires and he doesn't want to be responsible if they don't function properly after the new tires are mounted.

My questions are:

Should the dismounting/mounting procedure effect the pressure bands within the tires? If the low tire pressure light is activated after tire mounting, is there any way to disconnect it so I don't have to see it illuminated on my dash?

How much do new sensors cost? I've been told they are in the $175 range and I really don't want to be buying four of those along with four tires.

My coupe is in good shape but I really don't drive it much more than a thousand or so miles a year. Currently it has 77K on the odometer. The tire pressure sensors are not that important to me that I want to spend the additional funds to make them function in the future if the original ones should fail.

Thanks in advance for your technical help regarding this matter.

Bob M
North Attleboro, MA

**LT4man** · 05-12-06, 11:02 AM

If your tire man is afraid of the sensors, GET a NEW tire man! I am not kidding about this.

The sensors might NOT be available anymore. Call Chris at Superior Chevy 1-800-728-8267. Don't do anything until you find out the info.

You can not disconnect the system because I believe it is tied into the cruise control fuse. Buy the plastic info insert available from MAM and put a piece of electrical tape behind it to cover up the lite. No one will even know it is on.

A tire guy has to know how to dismount the tire with the sensors in place. If they do the job correctly, they will not be broken.

SAVE THE WAVE!

**Tuna** · 05-12-06, 11:30 AM

Listen to lt4man - get a new tire guy.

On the C4 system, the tire pressure sensors are located 180 degrees from the valve stem - opposite side of the wheel. When the tires are broken down from the rim, the tool used should be placed 90 degrees to the valve stem and the bead should not be moved any more than needed to pop if away from the rim.

If the break down process is done in the wrong place, it is possible to break the plastic housing from the band or break the band itself.

The last time I checked, the sensor/band were in that price range.

**LT4man** · 05-12-06, 12:36 PM

I know of what I speak. When I had my last set of tires put on, the fella at Just Tires said he was familiar with the sensors. Even tho he was very careful (I was standing right next to him) he ended up breaking one. He did not hesitate. He ordered one from Chevy right then and when it arrived a couple of days later, he installed it for me. Took full responsibilty for it. No charge, nada, nothing!

SAVE THE WAVE!

**Bob M** · 05-13-06, 07:47 AM

Originally Posted by Tuna

Listen to lt4man - get a new tire guy.

On the C4 system, the tire pressure sensors are located 180 degrees from the valve stem - opposite side of the wheel. When the tires are broken down from the rim, the tool used should be placed 90 degrees to the valve stem and the bead should not be moved any more than needed to pop if away from the rim.

If the break down process is done in the wrong place, it is possible to break the plastic housing from the band or break the band itself.

The last time I checked, the sensor/band were in that price range.

Hey Tuna, ...when you refer to the opposite side of the wheel are you refering to the back side of the wheel? Are all pressure sensors at that exact spot with no variations? When you refer to the "bead not being moved anymore than needed", do you mean once the bead is broken the tire should not be rotated on the rim at all and removed from exactly its original mounting position?

I appreciate the above replies and hopefully, I can get the new rubber on without a problem. My tire guy is a friend and also a fellow Vette owner. He is letting have the tires at his cost so it would be hard for me to hold him responsible if something went wrong and a sensor was damaged.

He and another friend are currently assembling two "kit-cars" which are powered by 2006 ZO6 505 hp engines. The "kit-cars" only weigh in at 2300 lbs. The engines are being mounted in the rear of the vehicle. I can't imagine the acceleration capabilities of those two vehicles, but that's another story for another time.

You will probably see my name appear in a few more posts as I'm beginning to experience a few problems with my Vette as it ages. I purchased it from the original owner back in 2000 with 67K. I've driven it for approximately six years with no problems. I change the oil (Mobil 1) and filter once a year, I've put one set of plugs in her, a serpentine belt, and a battery. There is now 77K on the clock. She is a six-speed with the FX-3 suspension, factory CD player, sport seats, and I believe about every option that was available for that year. It even came with two tops and Lojack.

I will call Chris at Superior Chevrolet and see what he has to say. I'll feel more comfortable with new rubber on the car and no low tire pressure light staring me in the face. Thanks for your technical support on my inquiry!

Bob M.
North Attleboro, MA

**Tuna** · 05-14-06, 03:26 PM

Originally Posted by Bob M

Hey Tuna, ...when you refer to the opposite side of the wheel are you refering to the back side of the wheel? Are all pressure sensors at that exact spot with no variations? When you refer to the "bead not being moved anymore than needed", do you mean once the bead is broken the tire should not be rotated on the rim at all and removed from exactly its original mounting position?

By opposite side of the wheel, I mean directly across the wheel from the valve stem - not on the back side. The sensor on C4's is mounted on a huge hose clam that mount inside the wheel mostly in the middle of the wheel. There is a counter weight that has a semi-circle cut out of it that aligns with the valve stem. The sensor and strap combination can be installed in any wheel - generally due to this arrangement.

As for the bead moving, I mean that when the machine squeezes the bead from contact with the rim, they shouldn't squeeze it any more. Some tire breakdown tools can squeeze the inner and outer sides of the bead all the way together if the tire guy isn't paying any attention and wants to breakdown the tire with one squeeze. If the tire guy tries this with a C4 wheel with pressure sensors inside, it's almost guarranteed that he/she will break the sensor of the strap. In my experience, the safest way to breakdown the tire/wheel is to do it in sections away from the sensor a little at a time to avoid pushing the sensor sideways inside the wheel.

**Rabbit** · 05-14-06, 03:52 PM

Originally Posted by Tuna

By opposite side of the wheel, I mean directly across the wheel from the valve stem - not on the back side. The sensor on C4's is mounted on a huge hose clam that mount inside the wheel mostly in the middle of the wheel. There is a counter weight that has a semi-circle cut out of it that aligns with the valve stem. The sensor and strap combination can be installed in any wheel - generally due to this arrangement.

As for the bead moving, I mean that when the machine squeezes the bead from contact with the rim, they shouldn't squeeze it any more. Some tire breakdown tools can squeeze the inner and outer sides of the bead all the way together if the tire guy isn't paying any attention and wants to breakdown the tire with one squeeze. If the tire guy tries this with a C4 wheel with pressure sensors inside, it's almost guarranteed that he/she will break the sensor of the strap. In my experience, the safest way to breakdown the tire/wheel is to do it in sections away from the sensor a little at a time to avoid pushing the sensor sideways inside the wheel.

That's good advice. Just had mine done by the dealer & that's the procedure He used.

**SPANISHVETTS** · 05-14-06, 04:02 PM

Originally Posted by Tuna

By opposite side of the wheel, I mean directly across the wheel from the valve stem - not on the back side. The sensor on C4's is mounted on a huge hose clam that mount inside the wheel mostly in the middle of the wheel. There is a counter weight that has a semi-circle cut out of it that aligns with the valve stem. The sensor and strap combination can be installed in any wheel - generally due to this arrangement.

As for the bead moving, I mean that when the machine squeezes the bead from contact with the rim, they shouldn't squeeze it any more. Some tire breakdown tools can squeeze the inner and outer sides of the bead all the way together if the tire guy isn't paying any attention and wants to breakdown the tire with one squeeze. If the tire guy tries this with a C4 wheel with pressure sensors inside, it's almost guarranteed that he/she will break the sensor of the strap. In my experience, the safest way to breakdown the tire/wheel is to do it in sections away from the sensor a little at a time to avoid pushing the sensor sideways inside the wheel.

All too true. I mount my own tires and it is damn easy to hit a C4 sensor. One side of the wheel has a long taper which makes it almost as easy to bust a sensor putting on the new tire as it is to do so while breaking the bead.

We use a Snap-On machine that has an adjustable stop on the breaker but the difference between just enough and too much is about 2 nat’s hairs. Having said that I change tires several times a year and have never broken a sensor yet; do we have a smiley for crossed fingers?

BTW I have a couple of extra sensors from some wheels that I bought. I am not sure which corners they come from one is yellow and the other orange. If you do get in trouble and need one it is yours for the junk-yard price.

**ßill** · 05-14-06, 11:01 PM

The sensos for the 90's are no longer available from Chevy. If anyone has some I need two front wheel sensors( 1 each)

**Tuna** · 05-15-06, 09:50 AM

One more tidbit of advice: my tire guy takes the sensor out of the tire/wheel assembly once they get the top bead off the wheel. The guy reaches inside and unscrews the hose clamp and pulls the clamp/sensor assembly out of the wheel. Then he can continue with the tire removal without worry about the sensor.

When the new tire goes on, he puts one side of the tire on, then puts the sensor back in place, then puts the last side of the tire on.

**Black Bart** · 05-20-06, 03:00 AM

Originally Posted by ßill

The sensos for the 90's are no longer available from Chevy. If anyone has some I need two front wheel sensors( 1 each)

I have a set that came off my 89. Don't know if all years are the same but would think they are. They are different colors and I forget what color goes on what wheel. I will need to check that but I have all four and when I took them off the car they were working.

tonylong · 05-20-06, 08:32 AM

The sensors aren't specific to a wheel. You do need to have four DIFFERENT sensors for the system to work. (different part nos / different colors).
If you have NO sensors installed then the system is OK with that. From 1 to three sensors wil give you a CHECK LTPWS alarn on the DIP, but any installed sensors WILL work and give a LOW TIRE PRESSURE warning alarm if true. Of course four sensors is the right number for everything to work OK.
I know this because when I bought my 89 it had a missing sensor and a duplicate sensor installed. (Had a lot of fun checking all that out, reading the FSM over and over againn with a lawyers eye.) System works great when everything is OK.