1930 Model A - stuck temp gauge bolt

[KCW]

Hi everyone -

I’m trying to replace my Model A temperature gauge. The bolt where it enter is stuck. Attached is a photo. I can’t get it to budge at all. I’m an amateur and was wondering if there are any tricks to remove it. I do have a portable torch I could use to heat it but thought that could be dangerous. Can I use the torch? If not, how to I remove the bolt?

Thank you!

[Y-Blockhead]

Looks like the smaller fitting is pretty well rounded off. Are you going to be using the temperature gauge again?

If not, I think I would just cut off the lead and use a 6 pointed socked on the larger fitting to unscrew. JMO...

[Vern]

If you want to save the gauge, Don’t cut the lead going into the radiator neck. It’s a hollow tube that has a bulb on the end inside the neck. If you cut the tube you will have to get it repaired which is not cheap, but can be done.
If you run the car enough to heat it up, try to loosen it then.
If all fails, Williamson’s Instruments in Arkansas will possibly be able to do the repair to the gauge

[Y-Blockhead]

Originally Posted by Vern

If you want to save the gauge, Don’t cut the lead going into the radiator neck. It’s a hollow tube that has a bulb on the end inside the neck. If you cut the tube you will have to get it repaired which is not cheap, but can be done.

Exactly. That is why I asked him if he was going to use the gauge again.

[nkaminar]

Special wrenches are made for things like the nuts on the ends of the steel tubing for hydraulic brakes. These are heavy duty 6 point box end wrenches that have the end cut out so that it can be placed where there is a wire or tube coming out of the nut. Look for this special kind of wrench on McMaster Carr. Otherwise buy a new gauge and cut the wire and use a 6 point socket wrench.

[Bob C]

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Harbor Freight has line wrenches.

[J Franklin]

If it was put together with RED LockTite. you will need to heat the joint and use your muscles to remove it.

[nkaminar]

You may also want to use some penetrant.

[katy]

Have you drained the cooling system?

[KCW]

I tried the torch - didn’t budge! Not sure what my next move is. Maybe that wrench that was recommended?

[Phil Brown]

Drain the water to below the part that your heating then try, no go.....get it hotter

[nkaminar]

The problem with the heat is that you are expanding the internal part which will make the threads tighter. Try the special wrench.

[Y-Blockhead]

Originally Posted by nkaminar

The problem with the heat is that you are expanding the internal part which will make the threads tighter. Try the special wrench.

That small fitting is pretty well rounded off. That is why if he is not going to use the gauge again, I suggested cutting the lead and using a 6 sided socket on the larger fitting.

[Big hammer]

Yep heating metals makes them expand………. Then when it cools it shrinks a teeny tiny bit………. Just what body men do with sheet metal, heat shrinking :-)

[ModelA29]

Originally Posted by Big hammer

Yep heating metals makes them expand………. Then when it cools it shrinks a teeny tiny bit………. Just what body men do with sheet metal, heat shrinking :-)

The heat/cool process if about getting enough expansion/contraction to break the bond of the corrosion. It's not like putting together pressed assemblies where a part goes in the freezer and you heat the other part so they can be easily assembled.
The problem with this type assembly is you have a hollow soft brass tube with a hex cut on it. It's a tapered thread so it seals by being firmly jammed into the other threads. A open end wrench just deforms the tube and lets the wrench round off the hex. When it gets bad enough vise grips are all that works. He could pull the neck and unscrew the main fitting without destroying the temp gauge tube.
But since he's trying to "replace" the gauge cut it and take it off at the water neck. The new gauges come with an assortment of adapters. Put the new one in with teflon tape and tubing wrenches. The next owner will thank you.

[CWPASADENA]

A while back, I was confronted with this same problem. I carefully filed down the flats on the hex part of the gland nut to the next smaller wrench size and used a line wrench. I did soak in penetrant for a few days before I tried to turn it.

I would be careful using heat because you may damage the capillary tube.

That is what I did.

Chris W.

[katy]

Cut the tube, use a 6 point socket and remove the adapter from the water outlet. Get a new adapter to go w/the new temp gauge.