Is my vaccum gauge going bad?

[Tim_K]

Do AutoMeter vaccum gauges need lubrication inside? I've had one that I've been using for about 4 years now, and it used to be really sensitive. Just by revving the engine in Park, you could get the gauge needle to swing all over the place. But it has been very slow responding for about a year now. Put the foot to the floor when racing off a stoplight, and a few seconds later it will get down to zero manifold vaccum.

I thought maybe the gauge was leaking, so I tested it. With the engine idling, I put some Vise-Grips on the rubber hose right near the intake manifold connection. Then I shut the engine off. The gauge read 13" of vaccum, and kept it there. After about 10 minutes, the reading had not leaked down, not even a little bit.

So do I need a new gauge, or can this one be oiled or something?

[PRO]

usually you can dissasemble the backside of the gauge and inspect the inner workings will its running,it should be obvious if its bad........PRO......

[Tim_K]

What should I look for inside it?

[jelsr]

Slow needle reaction is usually caused by restriction in the line or the guage itself. For instance, when working on single cylinder setups a ring with a pinch bolt threaded through the side of the ring is placed over the hose and the pinch bolt is tightened untill the needle reads steady instead of bouncing back and forth through a 20 to zero arc.