I was recently at a swap meet (Lawrence Kansas) and almost bought a gauge cluster for a 55-59 chevy truck. I passed because I did not know how to verify the gauges work. When I got home I did some research and all the information I found was based on the gauges being in the vehicle at the time of the trouble shooting.
My assumption is you take your chances with manual/mechanical gauges I.E. temp and oil pressure.
How do you verify electrical gauges work if they are out of the vehicle?
Im interested in how its done. I would like to be better prepared for the next oportunity.
Thank You.
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
A cigarette lighter will warm up a mechanical temp gauge and make the needle move. No claim to gauge accuracy, but as long as the system remains sealed it should be fairly accurate.
'57 GMC 102, Original 347 V8, HydraMatic, 3.08 rear gear, added A/C, disk front brakes, HEI, AFB carb, '98 Honda Black Currant paint. T-boned and totaled 10/12 '52 GMC 152 Stake Bed, Original 228, SM420, added A/C, HEI, disk front brakes, '67 Chev 3.55 rear gear. Gets used as a real truck.
A small thermos bottle of water- - - -boiling at the time it was filled- - - -should stay hot enough to make a temp gauge move for several hours. That might be more acceptable to a seller than going after his temp bulb with a lighter. A bicyclist's tire pump with the proper adapters can test an oil pressure gauge, or a small battery powered air pump would work as well. Some of them are small and light enough to fit into a backpack.
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
Gentlemen. thank you for the advice. i was thinking I should be able to check the electric gauges with a small rechargeable battery and a meter. I have a small 12v 3 amp rechargable battery. think I will do some experimentation.
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
Rock my experience is the two electrical gauges...fuel gauges and ammeters in these trucks generally work. The fuel gauge is only affected by resistance to ground and unless somebody wired it wrong and burned it up (which most usually will be visible if you can see the guts of the thing), it will be okay. Honestly that gauge if not damaged as I mentioned is very accurate and well-designed. We've discussed the fuel sender here to the point of cruelty. Some work very well and some don't. There is some real garbage being sold out there. The ammeter is even more simple than the fuel gauge. Not really known for accuracy (normally will be within 20% of an accurate test meter) but it is more of an indication than anything else. Good luck!
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
Dash ammeters use the principle of "Measure with a micrometer- - - -mark with chalk- - - -cut with an axe!" They're more or less a "charge/discharge" indicator. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
John G and Jerry. Thank you for the information on what level of accuracy to expect. As for the current state of parts being sold... With new parts i go with a buyer be ware attitude.
As I was writing this I asked myself, if I expect to have issues with new parts, why my concern with old parts at a swap meet? Hmmm.
A moment of clarity.
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
One other point I'll make. I have converted older style gauges to brand new state of the art gauges that look surprisingly similar to the OEM gauges. One example is the speedometer in AD type trucks. You can find pictures and maybe still a description of what I did in the "interiors" section. It is a GPS speedometer so I will always have accurate speed and odometer readings no matter that I have a T5 transmission and a rear end out of a 1969 Chevy pickup. I've also explained how to make slide decals using either a dot matrix printer or a color laser printer (like the ones FedEx/Kinko's use). Point being, there are options if you're happy with something that looks original but may not really be so. Clarity is always good. Please look up at the top of the Interiors section. I posted some decal templates and the GPS speedometer plus another oddball speedometer (combines a tach plus a vacuum gauge with a speedometer from one year of the S10 truck).
Last edited by Jon G; 05/23/20262:16 PM.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
John G thanks for the information on converting gauges. I have a newer modle T5 I want to instal. I will read your post to see what all is involved in converting to gps and retaining the classic look.
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
It can be done, Rock. The first step is to determine the degree sweep of your speedometer so we can start at 0 and go to 120mph following the same sweep. I have a feeling we'd need to use the 0 to 200 mph speedometer. Then we have to do some surgery/modification. Hopefully you can find what I did. Actually I did the same thing for a GPS speedometer and also for the T5 output pulse speedometer made at that time by SpeedHut. Both work fine...the GPS is easier and requires no calibration once you have it set correctly to 0 and 80 or 120 or whatever your top speed will be.
~ Jon 1952 1/2 ton with 1959 235 | T5 with 3.07 rear end
John G Thanks. The GPS speedometers I have seen so far look to sweep from the 7 oclock to 5 oclock position. The sweep on the 56 cluster I have looks to go from 9 oclock to 2 oclock.
So I think finding a GPS with the correct sweep could be an issue. I will keep looking.
If not I can always go with the option in the picture.
Rock49 aka C-Rodg work in progress 1956 Chevy 3100 261 engine
