fogging gauges

M151 General Discussion and Chat Board
Post Reply
old man
Sergeant Major of the Gee
Sergeant Major of the Gee
Posts: 490
Joined: Fri Mar 07, 2014 8:32 pm
Location: New Ulm, MN

fogging gauges

Post by old man » Mon Jun 05, 2017 2:09 pm

Finally had the A2 out for a test drive. I had a intermittent rattle mostly after I left of the gas also sounded like a loose or bad U joint, I will check into that when I can get it up on a lift.
My main question is after I run a short distance the fuel gauge and the oil pressure gauge fog up. After I parked it and left it sit for a few minutes the gauges cleared up. Not sure where to start with this problem.
Anyone have any ideas?
thanks in advance

User avatar
W. Winget
LTC, U.S. Army
LTC, U.S. Army
Posts: 1735
Joined: Mon Dec 16, 2002 12:37 pm
Location: USA, Virginia, Carrollton
Contact:

Re: fogging gauges

Post by W. Winget » Mon Jun 05, 2017 6:03 pm

They were waterproof, perhaps they are not now, drilling a small hole in the back side and allowing them to dry out on a hot (dry) day, or taking them inside and hitting them with a hair dryer for a few minutes, then applying a dab of silicone over the hole would likely 'clear up' the problem. Perhaps adding a layer of clear fingernail polish on the inside edge of the bezel may help seal them.
If they continue to fog up, replacement may be cheaper (they are M series, not rarer MB/GPW) than trying to disassemble the bezel and reseal the dried out seals.
V/R W Winget
Looking for 1918 Standard B 'Liberty' truck parts

Ben Dover
Gee Addict
Posts: 40883
Joined: Sun Mar 02, 2008 2:37 pm
Location: Proving Ground

Re: fogging gauges

Post by Ben Dover » Mon Jun 05, 2017 6:20 pm

Fogging is caused by age, even unused NOS 50s-70's dated Autolite, Stewart Warner, and AC with metal housings are dated 50's-70' have a tendency to fog with the engine running. The newer plastic housed ones by Faria do not seem to have this problem.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

Peterdodge6volt
G-Sergeant Major
G-Sergeant Major
Posts: 172
Joined: Tue Apr 19, 2016 10:19 pm
Location: Australia

Re: fogging gauges

Post by Peterdodge6volt » Thu Jun 08, 2017 4:43 am

Hi
I been restoring a lot of gauges and know all about gauges
You said it fogs when running and it goes back to clear when off.
Drive your vehicle again for a drive once the gauges start having fog. touch the glass with your finger for 5 to10 seconds you feel warm or hot on the glass. That means it's getting over power, ( running on high voltage )
If you put 6v gauges on 12v it will do the same thing fog on glass and hot and its taking high voltage.
when engine is running and charging during to high or a bit high on battery it will do the same thing.
I had that same proplem on my 38 military vehicles all get foggy when engine is running, I have put some resistor on my military vehicles gauges to keep low voltage and it worked no more foggy.

Hope this helps


Cheers Peter

User avatar
W. Winget
LTC, U.S. Army
LTC, U.S. Army
Posts: 1735
Joined: Mon Dec 16, 2002 12:37 pm
Location: USA, Virginia, Carrollton
Contact:

Re: fogging gauges

Post by W. Winget » Thu Jun 08, 2017 4:56 am

Peter: Not a bad suggestion
All the gauges for the M151 (Deuce, 5T, etc) are only 24 Volt so unless his generator is shot and overcharging past 28.4 Volts (or such), that would be hard to send a surge to the gauges.

Most likely in this case the seals are older and moisture from washing/rain/humidity in the air has intruded into the sealed unit and it needs somewhere to escape to, hence a small hole, dry it out, fill the hole technique I mentioned. Still might not seal it from more moisture if the bezel or rear electrical connections have dried up the seals.
V/R W. Winget
Looking for 1918 Standard B 'Liberty' truck parts


Ben Dover
Gee Addict
Posts: 40883
Joined: Sun Mar 02, 2008 2:37 pm
Location: Proving Ground

Re: fogging gauges

Post by Ben Dover » Thu Jun 08, 2017 5:33 am

This is why I hesitate to sell NOS Gauges, the fogging is a fact of life and many 50's-70's dated Temperature Gauges fail right out of the box.
2011 MVPA PIONEER AWARD - MVPA #1064
HONOR GRAD-WHEELED VEHICLE MECHANIC SCHOOL 1960 - US ARMY ORDNANCE SCHOOL(MACHINIST) ABERDEEN PG 1962 - O-1 BIRD DOG CREWCHIEF - 300,000+TROUBLE FREE M-38A1 MILES
LIFE MEMBER AM LEGION-40/8-DAV
7 MIL SPEC MAINTAINED MV'S
COL. BRUNO BROOKS (ARMY MOTORS) IS MY HERO

McQualter
G-Civilian
Posts: 1
Joined: Tue Jul 04, 2017 5:22 pm

Re: fogging gauges

Post by McQualter » Thu Jul 06, 2017 7:07 pm

Peterdodge6volt wrote:Hi
I been restoring a lot of gauges and know all about gauges
You said it fogs when running and it goes back to clear when off.
Drive your vehicle again for a drive once the gauges start having fog. touch the glass with your finger for 5 to10 seconds you feel warm or hot on the glass. That means it's getting over power, ( running on high voltage )
If you put 6v gauges on 12v it will do the same thing fog on glass and hot and its taking high voltage.
when engine is running and charging during to high or a bit high on battery it will do the same thing.
I had that same proplem on my 38 military vehicles all get foggy when engine is running, I have put some resistor on my military vehicles gauges to keep low voltage and it worked no more foggy.

Hope this helps


Cheers Peter
Peter
I have a muttm151a2 with identical symptoms and circumstances as yours(fogging, hot glass clearing after vehicle has been stoped for a while) and I would like to fit some resistors - I would be grateful if you could tell me the brand and where you actually fitted them!
I ave some difficulty getting parts for Mutts here in Australia and as a result I have to get all my bits and pieces shipped from the States
Thanks Bill

User avatar
W. Winget
LTC, U.S. Army
LTC, U.S. Army
Posts: 1735
Joined: Mon Dec 16, 2002 12:37 pm
Location: USA, Virginia, Carrollton
Contact:

Re: fogging gauges

Post by W. Winget » Fri Jul 07, 2017 5:33 am

Another possible solution might be to get one of those hot wax dips the ladies use for the their fingers or such, melt the paraffin wax, heat the gauge with a hair dryer set to low for a good while to dry out the inner air, dip the gauge and allow it to cool which may pull the wax into the cooling seals and help keep the air inside dry. peel off the wax, clean the contacts and face and reinstall it.
Be careful with the temperatures, wouldn't want to distort the face of the gauge, your hand being able to be dipped in the vat should be fine for most plastics I'd think.
Just a thought, other sealants applied after a hair drier may work.
W Winget
Last edited by W. Winget on Wed Jul 12, 2017 7:57 am, edited 1 time in total.
Looking for 1918 Standard B 'Liberty' truck parts

Peterdodge6volt
G-Sergeant Major
G-Sergeant Major
Posts: 172
Joined: Tue Apr 19, 2016 10:19 pm
Location: Australia

Re: fogging gauges

Post by Peterdodge6volt » Tue Jul 11, 2017 4:29 am

Hi Gens
I am still looking through my workshop desk trying to figure out where I bought it from I know I bought it on eBay.
24v to 12v resistor gauge.

I will keep searching on my desk and computer and let you know.


Cheers Peter

Post Reply

Return to “M151 General Discussion Board”

Who is online

Users browsing this forum: No registered users and 2 guests