The Stovebolt Site Forums The Shop Area Engine Shop Oil Pressure Gauge Trouble

I fixed the oil dripping from the fitting on my oil pressure gauge. It’s no longer dripping — now oil is pouring out from under the dashboard. At this point, I’m just not up to taking the dashboard apart again. I just want to drive it to where I store it for the winter and put it away for the season. I’ll deal with fixing it next year.

So I think that I need to plug this at the engine block. I did some searches but couldn’t find threads on this topic. Has anyone done this? Any suggestions on how to go about it? I’m guessing that I need some sort of pipe thread plug. Anyone know what size? Oh yeah, the truck is a ’53 3100, but the engine is from ’54 235.

Try a 1/8" NPT plug.

Will do. Thanks!

Well, I’ve found out some more about this since yesterday — stuff you old timers probably already knew, but I’m still learning. Turns out that it’s a 1/8” compression fitting which is quite different from pipe fittings both in size and threading — so my original idea is not going to work.

When I went to the hardware store, they told me that nobody makes a way to plug a 1/8” compression fitting opening. They had a couple of suggestions — a ball bearing to plug the tip of the compression fitting but I’d be afraid that it would still leak or that I couldn’t get the ball bearing back out when I try to fix it later.

They also suggested a compression to pipe coupler which I would connect to the engine block using a short piece of 1/8” tubing. But that weight shaking around at the end of the tubing just sounded to me like a problem waiting to happen — if that tubing ever fractured, I’d have a real mess on my hands.

So now I’m thinking of rigging up something on my own. Taking an inch and a half or two of 1/8” copper tubing, plugging about half of it with a piece of copper wire and solder (the kind they use for pipes) and then inserting that into the engine block with a compression fitting and ferrule.

Any thoughts on this idea?

Tcledermans idea should work if your plugging the block

1/8 pipe plug

The block is threaded 1/8" NPT. You can remove the entire fitting from the block and insert a plug.

You are correct that the fitting itself uses what can be hard-to-find parts to connect the oil tube, but the block to fitting threads are standard 1/8"NPT.

If you are using a remote oil filter, you can simply remove the pressure gauge fitting and run the filter directly to the block. The filter uses 1/8"NPT threads. You might need to screw a 1/8"NPT nipple into the block, then add a 1/8"NPT female coupler to screw the filter line into.

Matt

Any auto parts store, even an imitation one like Auto Zone, will have a replacement oil line kit with all the fittings you need to replace the line from the block to the gauge- - - -not do a patch job on a 65 year old system. New line, new compression fittings, and drive on!

Get the good-quality kit with a copper line, not the cheap plastic one.
Jerry

Thanks for all of the advice. Now I get it — the compression fitting threads into a pipe-thread hole. I hadn’t crawled under the truck to take a look yet. Waiting until Saturday for that.

I bought the 1/8” NPT plug while I was at the hardware store just-in-case (only a couple of bucks) so I should be ready to go.

One more question . . . is Teflon tape good enough to put on the threads or do I have to use pipe dope?

I just want to get the truck put away for now so I’ll do the full repair next spring (line, fittings, gauge, etc).

Just be very careful to never get shreds of tape in the fluid system, teflon ground up with a brush helps with that, looks just like pipe dope, small can lasts years, thin with acetone when gets too dry.

Ed

Most brass pipe fittings don't need sealer at all, especially if they're going into a cast iron or steel female thread. A small dab of brush-on Permatex sealer works better than any tape or pipe dope I've ever found if a thread seal is necessary.
Jerry

I think that I want to pull the instrument cluster before I put the truck away for the winter. That way I can work on repairing the cluster over the winter and have it ready to reinstall in the spring.

I guess that means that I’m going to have to plug the temperature sensor whole, too. Does anyone know what size that would be? 1/2" NPT seems to be a pretty common size for this opening, but I just want to be sure.

Also, I see that they sell just the oil pressure gauge. How hard is this to replace in the instrument cluster? Does it require any special tools or drilling out rivets? Any advice from your past experiences? I don’t want to make a bigger mess than I already have.

Pipe plugs: Take the sender to the store and match the threads...or measure and compare to web chart.

Gauges: They come off the cluster easily. No special tools or drill out. Buy a gauge, buy the tubing and plumb.

You can buy new "faces" for your gauges.

Gauge work is much easier from the front instead of crawling if you can remove ash trays, radios, speaker panels, delete plates, glove box, etc. on some trucks, Check that out.

DADS50 has a lot of advice on all this.