Gauge gasket replacement

[ichthos]

I am trying to replace the gaskets between the outer rim and glass on my gauges. I think I have the correct square type "o-ring", but for the life of me I can't figure out how to get them to stay in place when I try to screw the outer rings back on. Has anyone done this before, and can you offer me any tips on how to do this successfully?
Thanks for your time,
Kevin

 

[RomanH]

Kevin,
The "O" ring does not go in between the outer rim and the glass. It actually fits between the glass and the gauge body itself.
For the glass to outer rim seal Smiths used some kind of a putty. I used plumbers putty but be careful not to use too much you may crack the glass upon reassembly.

 

[Tinster]

Ichthos-

When you took apart your old gauges, did you notice the crumbly black powder on the inside (underside)surface of the outer metal ring?

This was a bead of sealant put there during the original fabrication of the gauge.

Carefully and fully clean the underside of the metal ring.
Use acetone or xylene to remove all oils.

I then installed a thin bead of clear silicone sealant,
laid in the gasket and let it set up overnight.

If you have the locking tabs fairly well open, you should
not need to press down with much pressure to spin the
rim into position.

d

 

[ichthos]

Thanks for the input, but I am still confused. I have a 69 TR6. When I took apart the outer metal rings on the tach and speedometer some black crumbly material (what was left of it anyway) fell out. Now at least I know what that is - thanks. In addition to this material, on the other side of the glass was a thin paper gasket (at least for the tach and speedometer). The smaller gauges were similar, except that there was no paper gasket on the other side of the glass. Between each gauge and the wooden dash was a typical O-ring. Based on the two posts above, I am still confused. I am going to put the o-rings between the gauges and dash like before. I was going to put the square type o-ring on between the outer ring and the glass and glue it in place first with black silicon. On the two larger gauges I will put the paper gasket back between the glass and gauge body. Won't this arrangement seal off my gauges? Although I keep my car garaged, moisture is a big factor where I live. I get condensation inside the gauges. I am hoping putting in new seals will stop this. Any other suggestions?
Thanks, Kevin

 

[dklawson]

I'm confused by what you're trying to do.

The square o-rings go between the BACK side of the bezel and the wooden dash. They do not go between the glass and the bezel.

I do not use RTV as Dale does. RTV is a glue as well as a sealant. Once RTVed... you may never get the gauge open again.

Go to the home center (both Lowes and Home Depot) and find the window screen section. Look for a vinyl cord-stock called window screen spline. It's available in several different diameters. (Lowes and HD carry different diameters). Buy a small quantity of various sizes between 1/8" (.125) and 3/16" (.188). Cut a piece of the spline long enough to make a ring that nests in the cavity on the back side of the bezel and fit the reflector, glass, and bezel to the gauge case to check the fit. For some applications you'll need different sizes of spline.

BTW, before trying to fit the spline inside the back side of the bezel you MUST clean out all that old black goo. I soak the rings in parts cleaning solvent for an hour or so and repeat as necessary until it's all gone.

I make new paper rings for gauges from thin, black/grey gasket paper and a compass. You can replace the pencil in the compass with an eXacto blade to make nearly perfect circles.

EDIT: I don't think anything will keep moisture out of your gauges. Even if you seal up all the front, there will be some moisture that gets in along things like the illumination bulbs and the warning lights.

 

[John Loftus]

Just to throw another technique in the mix. I cleaned out all the hardened black goo from my Smith's gauge bezels and then repacked it with 3M Strip-Calk part no 08578 (black). This is butyl rubber compound that will keep the glass from rattling and doesn't harden over time. You can roll out smaller strips (much like a soft clay) to get the right amount. Some oozed out when replacing the bezel but that easily cleaned up with a razor blade and glass cleaner. You can find this stuff on-line or at any good auto paint/body supply store. It also comes in handy for setting badges (to keep them from rattling) and for all sorts of seam sealing on the body/frame.

For the square O ring that goes in between the instrument panel and gauge body, there are extra gaskets in the oil canister filter kits that will work on the larger gauges.

Cheers,
John

 

[Tinster]

Doug is totally correct, the gauge interiors will
always be at ambient humidity. Any "fogging" will
be natural condensation due to the laws of vapor
drive/dew point.

I kinda disagree about the silicone, Doug. While it does
have a mild adhesive quality to it;the gauges are
easily taken apart by sliding a single edge razor between
the glass and outside metal ring.

BTW: I totally had a brain infark about the paper
gasket placement. Mea culpa!

d

 

[ichthos]

Thanks for all the help guys. So, the square o-rings go inbetween the gauge and wood dash, a paper gasket goes inbetween the glass and gauge,and silicone or caulking compound between the outer lens and glass.
Thanks again,
Kevin

 

[dklawson]

I'm glad Dale has success with RTV but I prefer something that doesn't involve me cutting myself during disassemble.

The butyl caulk is tough stuff. If I remeber correctly, the dash coverlays are held on by strips of butyl rubber tape/caulk. It's really tenacious.

 

[Guest]

Another use for the Butyl Rubber Caulk Rope is a replacement for firewall rubber grommets that have gone south.
Often rubber grommets with get overstretched and allow water into the firewall resulting in another leak onto your carpet. I have simply trimmed away the old grommet and fashioned a nice donut of this material around the wiring bundle, putsey the stuff into place as needed (it adheres to itself to become a seamless donut). A little spit helps to mold it to look like the perfect grommet. Seals great!

 

[Crankshaft]

Google found this thread for me and I used the 3M product for a great result

 

[Popeye]

https://www.britishcarforum.com/bcf...and-Speed-inner-gaskets&p=1031263#post1031263
https://www.britishcarforum.com/bcf...s-on-chrome-gauge-rings&p=1031631#post1031631

Some recent conversations on instrument rebuilding, if that helps.