The Stovebolt.com Forums Home | Tech Tips | Gallery | FAQ | Events | Features | Search
Help is a click away!

VEHICLE
INFORMATION
KITS


at the

GM Heritage Center
All the details are here.

Searching the Site - a click away
click here to search
New here ??? Where to start?
Click on image for the lowdown. Where do I go around here?
====
Who's Online Now
4 members (Phak1, IHPWR, 66flea, 1 invisible), 119 guests, and 3 robots.
Key: Admin, Global Mod, Mod
Forum Statistics
Forums66
Topics128,091
Posts1,056,445
Members48,443
Most Online14,466
Apr 26th, 2026
Step-by-step instructions for pictures in the forums
Brad Allen's photos

AD Chevy Trucks

Pictures galore
Over 6,000 pictures

Brad Allen has an awesome collection of Chevrolet factory pictures that he has set up from film strips.

Check them out!

Lots of work on Brad's part ... pure enjoyment (and references) for you!

Big Thanks!

THANKS!

For helping keep this great
old truck web site
on the Internet for

over 30 years!

and not clogged down
with Ads!


Again, thanks!

Previous Thread
Next Thread
Print Thread
Joined: Jul 2018
Posts: 163
M
Jolly Roger
Jolly Roger
M Offline
Joined: Jul 2018
Posts: 163
In the 51 owners manual i found a section that says if you pull the light switch out and turn it clockwise you can "adjust the instrument lights". does anyone have any background on a possible history behind this? was this a "premium" feature? im just wondering because my repro OEM gauges dont have lights.. at least i dont think. ill figure this out once i do the wiring.


Owner of the most temperamental 1951 3100 in existence
Joined: Sep 2001
Posts: 29,269
Bubba - Curmudgeon
Bubba - Curmudgeon
Joined: Sep 2001
Posts: 29,269
The dimmable lighting switch is described here, in the 1951 Truck Operators Manual.

That rheostat-style light-dimming switch was very common in most vehicles, and was standard on 47-55st GM trucks (among other years).

(read "Description & Operation" in the Shop Manual and also here in the Shop Manual)

1951 OEM gauges had at least one dimmable bulb in each gauge/speedometer assembly/unit.


Joined: Jul 2018
Posts: 163
M
Jolly Roger
Jolly Roger
M Offline
Joined: Jul 2018
Posts: 163
thanks for the information, ill have to see. the mercury tube for my temperature gauge blew up so ill have to disassemble it. ill look then. thanks for the history too!


Owner of the most temperamental 1951 3100 in existence
Joined: May 2005
Posts: 1,624
B
Shop Shark
Shop Shark
B Offline
Joined: May 2005
Posts: 1,624
Mercury tube? That might not be quite correct. Bulb type temperature gauges are hard to repair. If one has to replace, I would think about variable resistance or electric type, my 2 cents.


Six volt guy living in a twelve volt world
Joined: Jul 2018
Posts: 163
M
Jolly Roger
Jolly Roger
M Offline
Joined: Jul 2018
Posts: 163
i bought a OEM instrument cluster. it was most likely mercury because of how it just kinda dripped everywhere. ill find out when i open it up . either way i ordered another one from classic parts and ill install it soon.


Owner of the most temperamental 1951 3100 in existence
Joined: Jul 2018
Posts: 163
M
Jolly Roger
Jolly Roger
M Offline
Joined: Jul 2018
Posts: 163
if it is mercury then ill have something to mess with hah


Owner of the most temperamental 1951 3100 in existence
Joined: Dec 2001
Posts: 14,522
Moderator: Welcome Centre, Southern Bolters, Legion Hall
Moderator: Welcome Centre, Southern Bolters, Legion Hall
Joined: Dec 2001
Posts: 14,522
I always thought there was ether in those original tubes??????
Back when I did mine, the 37 and 52, it cost as much to have it repaired as it did to buy one. Not sure about to day and most likely there is shipping either way. Keep us posted Mr. Dane


1937 Chevy Pickup
In the Gallery
1952 Chevy Panel
In the Gallery
More photos
1950 Chevy Coupe
Pictures!

I'd rather walk and carry a Chevy hub cap than ride in a Ferd.
I can explain it to you, but I can't understand it for you smile
Joined: Apr 2007
Posts: 1,038
L
'Bolter
'Bolter
L Offline
Joined: Apr 2007
Posts: 1,038
If you read Mr. Dane's original "post he states that he purchased a "repro OEM" cluster. So when he says "OEM" he is referring to reproduction parts, not original. So, one can only guess what material is in the temperature tube. Alvin is correct, the original mechanical temperature gauges used ether(with a small amount of glycerine). This would look like water and evaporate very rapidly, giving off a smell that would remind those of us over 60 of anesthesia in an operating room. Mercury, on the other hand, is a metal that is in a liquid state at room temperature. This will look very shiny, silver and the droplets will hit a hard surface and break into hundreds of small droplets scurrying about and have no odor. So, Mr. Dane what did the droplets look like when it dripped everywhere?

Kent

Last edited by Lightholder's Dad; 01/06/2019 4:14 PM.

1937 Chevy 1/2 ton
1942 Chevy 1/2 ton
1947 Diamond T Model 509
1951 Chevy 1/2 ton
1950 Chevy COE Model 5700 ~ "Barney" ~ And more pix
Joined: Jul 2018
Posts: 163
M
Jolly Roger
Jolly Roger
M Offline
Joined: Jul 2018
Posts: 163
update: its just a shop oil of some kind. smells like 90wt and synthetic mixed together, its nasty. either way the reason it leaked is one of the solder points broke causing a bad seal.


Owner of the most temperamental 1951 3100 in existence
Joined: Jul 2018
Posts: 163
M
Jolly Roger
Jolly Roger
M Offline
Joined: Jul 2018
Posts: 163
i found in my gauge cluster two plugged holes. i shined a old flashlight through one and sure enough it lit up one half of my gauge. ill just have to figure out how to install some lights in the holes.


Owner of the most temperamental 1951 3100 in existence
Joined: Jul 2008
Posts: 1,321
H
'Bolter
'Bolter
H Offline
Joined: Jul 2008
Posts: 1,321
Quote
just have to figure out how to install some lights in the holes.

Find an old harness and harvest the light sockets for your truck.
If you can't locate an old harness, try NAPA, Auto Zone, Advance, etc.
The photos below show what you need. The single wire uses the cluster housing as the ground the 2 wire has a separate ground wire.
Just run a wire from the sockets to the light switch.
Harold
Attachments
Bulb Socket.JPG (46.73 KB, 87 downloads)
Bulb Socket.jpg (19.96 KB, 86 downloads)

Last edited by Harold46; 01/07/2019 11:17 PM.

Harold
Is a restoration ever finished?
Joined: Nov 2018
Posts: 84
D
Awesome Grandpa
Awesome Grandpa
D Offline
Joined: Nov 2018
Posts: 84
Be careful with mercury ....

Liquid form of mercury is especially dangerous because it vaporizes at room temperature. And when it vaporizes, it fills the air with tiny, invisible mercury atoms that are both scentless and soluble in oils or fats.
If mercury vapor is inhaled, it is easily absorbed by the body, where it first gets into the lungs and from there into the blood and the brain. The nerve poison can cause sleep disorders, agitation, and paralysis.
Even a simple thing such as a broken thermometer can lead to mercury poisoning. It can be particularly dangerous in a children's playroom if liquid mercury seeps into cracks and corners and is left undisturbed to vaporize.
"It's not like with hot water - water vaporizes and is gone. But mercury vaporizes more slowly, it can take days or weeks, and could be inhaled over a longer period of time,"


Moderated by  Jon G, Rusty Rod 

Link Copied to Clipboard
Home | FAQ | Gallery | Tech Tips | Events | Features | Search | Hoo-Ya Shop
Powered by UBB.threads™ PHP Forum Software 8.0.0