Pressure sensor nut size?
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Safety Car
Joined: Jan 2006
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From: Littleton CO
Pressure sensor nut size?
Ok so I have a slow leak in my driver rear tire. I am thinking about bringing it in to repair tomorrow but someone told me to check to make sure the little nut around the valve stem is tight. Anyone happen to know right off hand what size this is? I don't think I have any open end wrenches in that small of a size and think I am going to pick one up to check that it is tight before I leave my car with the tire shop for a few hours. Thanks for any help.
Drifting
Joined: Jun 2005
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You probably want a (deep) socket - not sure what size.
But be careful! The torque specification on that is pretty low, as its easy to break one of those things. The hollow stem won't take nearly as much strain as a bolt of the same size would. You really want it just tight enough to compress the O-ring.
P.S. soapy water around the valve stem will confirm if that's the source of the leak - or help find it if its somewhere else.
But be careful! The torque specification on that is pretty low, as its easy to break one of those things. The hollow stem won't take nearly as much strain as a bolt of the same size would. You really want it just tight enough to compress the O-ring.
P.S. soapy water around the valve stem will confirm if that's the source of the leak - or help find it if its somewhere else.
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Ok so I have a slow leak in my driver rear tire. I am thinking about bringing it in to repair tomorrow but someone told me to check to make sure the little nut around the valve stem is tight. Anyone happen to know right off hand what size this is? I don't think I have any open end wrenches in that small of a size and think I am going to pick one up to check that it is tight before I leave my car with the tire shop for a few hours. Thanks for any help.
Pro
Joined: Mar 2006
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From: Antelope CA
Please don't use an open end wrench. 7/16 or 11mm is right, dosen't need to be deep socket either. The torque is very, very light, like 15 inch pounds That's just over 1 foot lb. I think. Put it on a nut driver instead of a socket handle.
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From: Daytona Beach FL
It's 7/16" or 11mmThe torque, though, is 62 in-lbs. (about 5 ft-lbs.) which is very little torque.
I would pump up the tire to max pressure (44psi on the sidewall - the tire shop puts it in a cage and pumps it up to about 70psi to set the bead), then readjust tire pressure. Hopefully that will seat the grommet/O-ring into the valve stem hole on the inside of the tire. The very low torque on the nut doesn't do much to seal the O-ring - I think the internal tire pressure does most of that.
Bob
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Safety Car
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From: Littleton CO
Ok so when I sprayed it the end of the valve stem bubbled till there wasn't any more soap on it. Very slowly but a bubbly every couple seconds at first. Does it sound like it needs to be tightened?
Race Director
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From: Daytona Beach FL
The valve should be nickel plated, not brass:
The valve stem on the sensors is aluminum and the brass can have a dissimilar metal reaction and corrode the valve stem.
Bob
Pro
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From: Antelope CA
It's 7/16" or 11mmThe torque, though, is 62 in-lbs. (about 5 ft-lbs.) which is very little torque.
I would pump up the tire to max pressure (44psi on the sidewall - the tire shop puts it in a cage and pumps it up to about 70psi to set the bead), then readjust tire pressure. Hopefully that will seat the grommet/O-ring into the valve stem hole on the inside of the tire. The very low torque on the nut doesn't do much to seal the O-ring - I think the internal tire pressure does most of that.
Bob
When our tires got installed last week , I watched and ask how many pounds to set the bead, he said about 35lbs. and had no cage. 70 lbs. just sounds
but sounds like you deal with this more often than I
Race Director
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From: Daytona Beach FL
The tire shops use a lubricant to help get the tire on and off the wheel, and to get the bead to seat properly. If for some reason they have a problem getting the bead to seat, they can put the tire in a safety cage and use an extension on the air hose so they can stand well back and increase pressure, if necessary. But I don't think they normally have to go much over normal inflation pressure.
And, no - I don't deal with this much. So thanks for reinforcing the potential danger of overinflating a tire. There are serious safety consequences to pumping up a tire over normal inflation pressures.
Bob
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Knowing that you guys were wrong and I was right...
I went back to the car and re-checked the size. I couldn't find my 11 MM wrench. Looked over in the Non-metric wrenches and found my 11mm next to the 7/16. So, sue me! I can't read! The size is 11mm.
You guys were lucky that time
Elmer
I went back to the car and re-checked the size. I couldn't find my 11 MM wrench. Looked over in the Non-metric wrenches and found my 11mm next to the 7/16. So, sue me! I can't read! The size is 11mm.
You guys were lucky that time
Elmer
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Safety Car
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From: Littleton CO
If the bubbles were coming from the end of the valve stem (and not the area around the base, where it comes out of the hole in the wheel), you may just need to tighten the valve (the core inside the valve stem), or replace it.
The valve should be nickel plated, not brass:
The valve stem on the sensors is aluminum and the brass can have a dissimilar metal reaction and corrode the valve stem.
Bob
The valve should be nickel plated, not brass:
The valve stem on the sensors is aluminum and the brass can have a dissimilar metal reaction and corrode the valve stem.
Bob
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Safety Car
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From: Littleton CO
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Thread Starter
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From: Littleton CO
Thread Starter
Safety Car
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From: Littleton CO
how tight should the core screw in? I don't want to strip it out. But last night I was able to do about 5 full turns with 2 fingers. Seemed like it could go tighter but like I said I don't want to strip it out.