Jumpy fuel gauge

[Bonnewagon]

"Everyone always condemns the Monte gauges but the only problem I've ever seen with them is the dampening fluid will leak out and cause jumpy gauges." Yeah, that's what I think too, I just can't find where it leaked, or how to refill it, or what. This is why I don't want to ruin it, and a new one is pretty expensive. It took me a LONG time to find this one, and mine has the tach. For those who don't know, this is a '68 Firebird rally gauge pac.

 

[pontiacgp]

now that I up to speed on which end of the fuel gauge your working on... 😳

is there a way to change the face plate to your silver plate?...I'm sure I have another set of gauges and I'd be happy to send you a fuel gauge..

 

[Ringers]

Interesting post. I have had a few of those and never knew the cause. I'll be damned...

 

[jmt455]

I have an old GM fuel gauge that jumps around and flits back and forth as if it's reacting to every ripple in the gas tank. I know there is a dampening mechanism in the gauge to slow it down and stop that behavior. What I can't find out is what exactly that mechanism is so I can repair it. I have another crummy one to dissect if need be, but I am hoping someone knows the answer before I perform exploratory surgery.

What vehicle is the gauge for?

JoeT

 

[Bonnewagon]

Actually I need 2. My '68 Firebird project has the rally gauges and it's super jumpy. THAT"S the bitchy one to find at a reasonable price. The silver GA gauge I just got is starting to do the same thing. There is an NOS one on Epay for $145. So aside from just getting new ones, I'd love to be able to fix them. According to my internet search, it is a very common problem.

 

[Bonnewagon]

Well, I lucked out and got an NOS '78 fuel gauge on Epay for $40 so that made it easy. For the '68 all I'm finding is a worse looking than mine fugly gauge for $75. But I'm still baffled by the jumpy needle. The old bad gauge looks exactly as clean like the NOS gauge, no leakage, no nothing. There is a ceramic plate that looks like a resistor that goes across the back, might that be the culprit?

 

[Bonnewagon]

OK, here we go. I opened it up, and no sign of fluid except for discoloration on the plastic core that is wound with fine wire. All 4 posts on the back half are discolored the exact same amount, without regard to gravity, so I can't draw any conclusion about this. If damping fluid leaked it did a nice disappearing act. I read on another forum where a guy drilled a 1/16th hole into the core and injected silicone fluid he got from a hobby store that is used for RC car transmissions and is available in various viscosities. What I'll do for now is swap the normal gauge's internals for the defective gauge's and replace the black face with a silver one. The rivet hole measures .065" but the sites that sell packs of gauge rivets don't state the sizes at all, just by year. I may buy a pack just for the hell of it and see. Deanlemans81 the spoon thing worked great, thank's!

 

[Bonnewagon]

Fixed it. Found 2 micro tiny sheet metal screws that fit the rivet holes. So the guts from the black gauge are behind the silver gauge. Now I feel stupid buying the NOS gauge. Oh well.

 

[pontiacgp]

good news...did you find out what happened to the silicone or whatever they use to control the needle?

 

[Bonnewagon]

Not yet. I pulled a muscle in my shoulder and was down for a day or so. I am planning to remove the copper wire that is wound all around it, then drill a tiny hole and see what if anything comes out. If nothing, then I will dismantle it completely.Is it possible it was made defective, no fluid at all?