Temp Gauge Revisited

[Joe Flanagan]

Today I dug out my temp gauge sending unit. It's not anywhere near as bad as I was remembering. In fact, it's pretty much intact. I've posted some pictures below.

This is the ether bulb:

Here is the end that attaches to the gauge:

Is the bulb re-usable? The threads are a bit mangled. I don't know whether re-use is advisable or not. There is a pinhole where the tube meets it, so does that mean the ether has leaked out?

I would like to reuse the tube and the coupling that attaches to the back of the gauge. The only problem I see is the very end of the tube looks like it might be plugged with grime. I was thinking of cutting off a quarter inch or so from the end. There is plenty of slack. How would you guys proceed with this?

[Don Coatney]

The bulb is toast. Trash it. You may be able to graft a replacement tube and bulb into your gauge fitting. But to do this the fitting needs to be connected to the gauge. I think you have seen the procedure for doing this. It is on the webpage of Tod Fitch.

[Joe Flanagan]

Since the capillary tube is intact, couldn't I just get a new bulb and attach it? Or did they come from the factory as a sealed unit, bulb and tube together?

The other end of the tube is still attached to the gauge.

[TodFitch]

It might be possible to dig out that old bulb from its position frozen in the fitting, clean it up, fill it with ether and solder the tube back on. But soldering directly on a bulb filled with ether will be very difficult at best. And maybe impossible. That is why I have done it by splicing the bulb and capillary tube from a donor gauge on the the dash unit.

If you don't want to follow the pictures at http://www.ply33.com/Repair/tempgauge then wait until next month and they should be in Skinned Knuckles magazine.

[Joe Flanagan]

So, Tod, do you recommend doing the same thing you did in the article? Cutting the old capillary at the gauge head and installing everything new from there?

Just curious about the ice and salt. What is the purpose of the salt? I notice you seem to have cellophane over the container of ice, too.

I'm going to give this a try tomorrow since it will be freezing cold outside and I won't be doing any outdoor work. I'll report on how it goes. Thanks. Oh, and I've never soldered before, so I'll have to learn that. HA! YouTube does have its uses.

[Rodney Bullock]

I find this very intersting. I always though that the tube had mercury in it. Why did I think that, I remember when I removed my gauge and bulb from my car I could smell this odor when I broke the tube.

I sent mine to John Wolf, he fixed the whole unit. He redid the gauge face and gave me a new line, bulb and it was all connected. The car over heated and it blew the gauge( needle got stuck in one position) I sent it back and fixed the over heating problem. I did not know you could do this at home. How do you calibrate the gauge?

[Joe Flanagan]

According to Tod's article, it might not need calibrating. If it does, apparently you can bend the needle a little but it sounds like a delicate operation.

[TodFitch]

So, Tod, do you recommend doing the same thing you did in the article? Cutting the old capillary at the gauge head and installing everything new from there?

Just curious about the ice and salt. What is the purpose of the salt? I notice you seem to have cellophane over the container of ice, too.

I'm going to give this a try tomorrow since it will be freezing cold outside and I won't be doing any outdoor work. I'll report on how it goes. Thanks. Oh, and I've never soldered before, so I'll have to learn that. HA! YouTube does have its uses.

Cellophane is just to keep the mess down. Basically all the salt does is make it colder so you have a bit more margin for error.

Salt depresses the freezing point of water, so adding salt to ice melts it, which is an endothermic operation. Causes the temperature to go down so instead of 32F you can get as low, with the correct salt/water ratio, as 0F. Which, if the lore I heard "way back when" is correct is where Mr. Fahrenheit decided to set the zero point on his temperature scale. Along with 100F for the temperature of a healthy human. He was wrong on the 100F, so the 0F is likely to be wrong too.

[martybose]

According to Tod's article, it might not need calibrating. If it does, apparently you can bend the needle a little but it sounds like a delicate operation.

It probably will need calibrating, and it is a pain. I took my gauge out of the car and tested it in a pan on the stove, and it was 20-30 degrees off compared to a couple of different thermometers. As I found out, you can't simply adjust it at one point and declare victory, as the response is definitely non-linear. Adjusting the needle involves a combination of length and angle of an internal link, and requires both time and patience. I eventually got mine to within a few degrees from 120 to 212, and declared victory at that point.

Marty

[Dodgeb4ya]

I used to repair my old temp guages. There is a tapered cone plug under the solder at the end of the bulb. I cut the copper tube off flush at the bulb right where it was soldered to the bulb-used a drill same size as the copper tube. Drill whats left of the copper tube out of the bulb. Carefully Filed the solder covering the tapered cone plug at the other end of the bulb just till I could just see the outline of the plug-1/16" dia. Then used the drill to pop the cone plug out of the bulb. Then resoldered the tube to the bulb. Got Dentist grade ether from my Dentist -a lead 2 lb can. Used a syringe to inject the bul 3/4 full of ether. Tapped the cone plug back in tightly and used a small torch to solderseal over the plug. Now days you could probably find something a little less risky to seal the plug. WARNING- I had one blow up- Ears rang for a day. Did about 20 of them and got a little careless on one- young and dumb I guess! I must warn that no one on this forum should try this! This is just what I did! It was fun and worked too

Bob.

[Don Coatney]

I find this very intersting. I always though that the tube had mercury in it. Why did I think that, I remember when I removed my gauge and bulb from my car I could smell this odor when I broke the tube.

Rodney;

What does mercury smell like? And dont tell me it smells like over cooked ford:rolleyes:

[Joe Flanagan]

Rodney;

What does mercury smell like? And dont tell me it smells like over cooked ford:rolleyes:

It smells like ether, most likely.

Rodney, did you change your socks that day?

[Joe Flanagan]

I used to repair my old temp guages. There is a tapered cone plug under the solder at the end of the bulb. I cut the copper tube off flush at the bulb right where it was soldered to the bulb-used a drill same size as the copper tube. Drill whats left of the copper tube out of the bulb. Carefully Filed the solder covering the tapered cone plug at the other end of the bulb just till I could just see the outline of the plug-1/16" dia. Then used the drill to pop the cone plug out of the bulb. Then resoldered the tube to the bulb. Got Dentist grade ether from my Dentist -a lead 2 lb can. Used a syringe to inject the bul 3/4 full of ether. Tapped the cone plug back in tightly and used a small torch to solderseal over the plug. Now days you could probably find something a little less risky to seal the plug. WARNING- I had one blow up- Ears rang for a day. Did about 20 of them and got a little careless on one- young and dumb I guess! I must warn that no one on this forum should try this! This is just what I did! It was fun and worked too

Bob.

That's very interesting, Bob. I don't imagine you could find a dentist today who would give you some ether to take home. Had to laugh out loud when I read the part about your ears ringing for a day. That is really funny.

[Dodgeb4ya]

That's very interesting, Bob. I don't imagine you could find a dentist today who would give you some ether to take home. Had to laugh out loud when I read the part about your ears ringing for a day. That is really funny.

Yea, I imagine ether in bulk is kinda hard to get today unless your registered. I re-did these back in the late 70's. The explosion was not funny at the time. All my friends sure thought it was funny too. No compassion at all !

[Joe Flanagan]

I went to Auto Zone today to see if they might have one of the old-style bulb and capillary temperature sensors. You should have seen how confused those kids were. One of them was wearing these gigantic glasses that, I kid you not, had no lenses in them. He was wearing just the frames. For effect. He reminded me of an old Tom Waits song where he says, "I think about you every time I pass that Sunoco station, on account of all the grease you used to put in your hair." Kid had more grease in his hair than the front end of my Plymouth.

I described the item as an old-style temperature sensor with a bulb and a copper line. They turned this into "an old school temperature something-or-other," which, of course, they couldn't find on the computer. By that time I had left them to their own devices and was roaming the aisles. Lots of steering wheel covers. Lots of air fresheners. Lots of cheesy tail pipe extensions. No real parts. Called it quits for the day and did something else. But at one point I said, more to myself than to them, "I don't know what they use for temp sensors today," and one of them says, "I think they just use a gun."

Will try NAPA tomorrow.

[james curl]

Just go to the aux. gauge section of almost any parts store and buy an add on mechinical temp. gauge, it will have the bulb and tube that you need. Even Wal Mart carries add on gauges.

[blueskies]

If you just want to spring for another factory gauge, give Neil Riddle a try. Seaplym@hotmail.com

I twisted the bulb off of my original gauge when I pulled the engine, and let all the ether out... Rather than try to fix it with Tod's method, I just got another one. The gauge that Neil had at the time was for a '51, and had a different face on it, but was otherwise the same. I just swapped the face plates and mounted it. Works like new.

Pete

[BobT-47P15]

Joe, James beat me to it about the aftermarket kind of cheapie gauges....I have one

purchased at a swap meet for 5 bucks. Used in the convert for several years -

worked just fine. So, such an item should be a good donor for the bulb, etc.

The temp gauge now in the 47 actually is for a 41 Plymouth - just replaced the face with

a P15 face. Only a couple small screws involved.

[Joe Flanagan]

Thanks for the tips. I'll give Neil Riddle a call just to see what he has. Since my last post I located a store that is ordering one for me. Now I'm just trying to find the tubing that Tod used as a sleeve to join the old and new (1/16 inside diameter).