A mechanical tire pressure gauge is a very simple device. Press one end down on the valve stem of the tire and at the other end a stem pops out to show the pressure of air in the tire. Usually, there’s very little that can go wrong with a tire pressure gauge. Very occasionally, however, the stem can stick, meaning that it won’t pop out or back in. You need to fix this.
Step 1 - Manual Repair
If the mechanical tire pressure gauge is stuck with the stem out, it could be that the stem has become jammed against the side. Try wiggling it gently to see if it will move. In some instances this can offer a solution to the problem. You can also try gently pulling on the stem and releasing it. This might also offer a solution and the stem will slide back in.
Step 2 - WD-40
If the stem is stuck and your fingers won’t release it, try a squirt of WD-40 down the stem tube of the mechanical tire pressure gauge. If there’s a scrap of rust, for instance, that’s making the stem stick, this can free it up. Follow up by wiggling and pulling lightly on the stem.
Step 3 - Spring
If the stem is stuck in the tire pressure gauge and won’t come out when needed, the chances are that the spring has broken. You’re now faced with a choice. You can either replace the tire pressure gauge or you can replace the spring. For the latter you’ll need to have the correct spring, which won’t be easy to find. You’ll probably need to take it from another tire pressure gauge; gauges are so cheap that most people simply replace them if there’s a problem.
Step 4 - Removing the Old Spring
Lay the tire pressure gauge on a table. You’ll be able to see that the stem tube attaches to the base of the pressure gauge. You need to disconnect it. To do this, put a pair of pliers on each part. If you don’t want to mar the surface, wrap each jaw of the pliers in masking tape. Twist the pliers away from each other and the two parts will begin to unscrew. Don’t unscrew completely with the pliers.
Finish unscrewing very gently with your fingers. This will expose the spring. At one end it will be connected to the air pressure valve and at the other to the stem. Gently remove it from both. You might need to use tweezers for this operation.
Step 5 - Replacing the Spring
Take the new spring, making sure it’s facing in the proper direction, and fit it in the stem and the air pressure valve. Gently hold the two parts of the casing and push the together-this might take some pressure. Begin to screw the stem on to the base. Finish off by tightening completely using the pliers. To check the tire pressure gauge repair, test it on a tire. The stem should move out and back very easily.