Getting closer to a running chassis. Questions:

qualityhardware · Post by **qualityhardware** » Sun Jul 16, 2006 12:37 pm

Guys,

I am restoring a '53 M38. I am getting very close to be able to fire up the chassis and see how she runs.

Couple of things. I have a civilian block for an engine. Thus I am using a mechanical oil pressure gauge (repo) for an MB. I cannot for the life of me find any compression fittings to fit. Any ideas on who has them?

Second, I have something on the back of the dash that doesn't show up in the manual I have. any ideas on what it's for?

Finally, I salvaged the speedo and fuel gauge, but the glass on both are nasty. What's the best way to clean these up?

Thanks,
Scott

Post by **wesk** » Sun Jul 16, 2006 1:23 pm

Scott,
The M38 oil pressure sender goes right on the civvy block in the same location.

That oil pressure gage if it is an accurate repop of the MB gage uses 1/4" tubing with an inverted flare fitting just like a brake line and the other end had a short piece of hose with 1/4" inverted flare fittings which then screwed onto a 1/8" P to Inverted flare fitting in the block.

That is an instrument power circuit breaker on the instrument panel. It was used thru MC65042 (APR 52). Wire # 27 from the ignition switch connects to it then one wire from that spider fastens to it. The other three spdier wires fasten to the Oil press, water temp and gas gage. You need the TM 9-804 which was the first service manual for the M38 to have the correct wiring diagrams and instrument cluster views.. TM 9-8012 was a much later manual.

There are high dollar instrument rebuilders out there who can replace those deeply gouged lens. Otherwise you could try rolling the beaded lens bezels back and replacing them yourself with possibly regular glass.

PeteL · Post by **PeteL** » Sun Jul 16, 2006 8:13 pm

Places like "Hemmings Motor News" have sources for instrument rebuilders. But I have to wonder if finding replacement units might not be cheaper.

Be aware if you pry them open that military instruments and guages can have luminous paint on the dials. It is (very) radioactive!!!

I have verified this for myself with a geiger counter. Not sure about yours but my 1952 'A1 is hot.

Pete

Jeff_H · Post by **Jeff_H** » Sun Jul 16, 2006 9:22 pm

Have a look this page of my re-build site to see how I refurbished my gauges.

http://www.m38jeepproject.com/electrical%201.html

I found sand blasting the faces and then wet sanding through progressively finer grits finally ending up with buffing compound worked great.

Jeff

Post by **wesk** » Sun Jul 16, 2006 9:51 pm

Scott,
Don't let Pete scare you!

You would have to intimately handle hundreds of radium marked gages to develope any kind of reaction. Most later M series gages are radium free.
You are more at risk working under the jeep on a jack without jack stands.

Jeff the smaller gage might polish out. Those deep gouges in the speedo pretty well make her junk without a fresh lens to work with.

PeteL · Post by **PeteL** » Mon Jul 17, 2006 7:12 am

Handling gauges might be one thing. Ingesting or inhaling particles of radioactive elements might be quite another. People used to think nothing of working in the asbestos dust from brakes, as an example. We know better today.

I do have emergency response training and certification in radiological monitoring. The emissions from my 'A1 instrument cluster sent the counter off the scale. That gets my attention.

Not my intent to "scare" anyone - just wanted to share some safety information with my forum friends.

With all respect,

Pete

Post by **wesk** » Mon Jul 17, 2006 7:46 am

When we use a meter to offer people a quantitative description of something that description is only usefull when we also give them the calibration of the meter and the standard against which we compare the resultant readings. Obviously since the known energy radiance levels of the radium markings are extremely low your meter must be an extremely sensitive one or one that has been set to it's most sensitive scale. When offering warnings about hazardous materials it would be much better to list the actual scale reading, the maximum safe levels and/or quantities.

An example of what the lacking information causes is:
My daughter comes home and says her botfriend was driving crazy. He went so fast the speedo went right off the scale. Well this provokes a lot of worry since most speedos go to 100 or 120 MPH. So off you go to investigate and lo and behoild you find he has a 50 CJ3A and the speedo goes to 60 and has a worn drive cable and fluxtuates wildly.

PeteL · Post by **PeteL** » Mon Jul 17, 2006 10:28 am

Wes,

I take your point about assessing relative risk, and I apologize if I diverted this thread.

Just wanted to share a point of information about the Jeeps we all love to play with, regarding a possible hazard. Just as we know gasoline can explode or brake asbestos is bad to breath, I don't think it requires precise quantification for us to be aware and cautious.

My personal feeling is this. There is a growing body of medical opinion that there is no such thing as any "safe" level of radiation. These instruments are radioactive. There is some risk.

Exactly how much risk is impossible to quantify biologically; it is not a linear formula. Each exposure is more like buying a (negative) lottery ticket, one you don't want to win. So perhaps best to minimize the chances where possible.

To borrow your speedometer anology, you can't know exactly when, or even if, an accident will happen regardless of knowing precise speeds. You don't get just "so many" accidents "per MPH," but we can say that slower is generally safer. It's matter of odds.

I would therefore simply urge caution about opening up an instrument and releasing any radium contained by it. I understand others may disagree, and I hope all in good humor. Thanks.

Pete

Post by **wesk** » Mon Jul 17, 2006 12:30 pm

Pete,
We have already diverted the thread.

I take issue with your statement

"Exactly how much risk is impossible to quantify biologically; it is not a linear formula. Each exposure is more like buying a (negative) lottery ticket, one you don't want to win. So perhaps best to minimize the chances where possible. "

There are adequate establish safe levels of daily exposure and long term exposure. Though each version is not always universally accepted there are accepted levels posted by various organizations. I have been employed around radioactive material since the mid 1960's. I respect it, I excercise caution when handling it and I seek the appropriate medical authority if I have any questions on exposure issues. I feel no need to sensationalize or overstate it's presence in our everyday lives.

My original point is for one not to create an air of hysteria by announcing without qualification and quantification of the facts that sonething is dangerous or a serious risk factor.

If one must announce his personal analysis of the risk then just clearly state that.

Had the radium issue surfaced as a question then I would have posted something more along this line:

"Early gages do contain radium in their screenings and excessive exposure may have certain health risks. To properly decide wether to toy with this element in the early gages or not one should question their private health care system."

I am no more qualified to access this risk than you are. Therefore I feel neither of us should make any statement implying professional or technical expertise in the matter. This would be better handled by a nuclear medicine or nuclear physics student or degree holder or a professionally trained nuclear and biological waste counselor.

qualityhardware · Post by **qualityhardware** » Mon Jul 17, 2006 1:23 pm

Thanks guys.

WesK - great info. That diagram helps in spades.

Jeff - I will give your method a try and see what I can do. If I fail, I can always try the professional route.

Pete - thanks for the info. Would rather not pry everything apart. I breathe in enough nasty stuff as it is...

Scott