thermostats

[Jerry Whitt]

One of the thermostats failed. Ordered a new one, but got to really looking at it. Put the thing in a small can of water, then squeezed it.
Saw bubbles coming out of a crack on the end where a shaft attaches. I tried to solder it with poor luck. Anybody else have any luck repairing one these things?

[terribleted]

As I recall they are filled with some inert gas not air. I would say repair is not possible. I would add that repros work but in my experience they do not last a long time. Good NOS or used would be my choice to use if I had some.

[acarlson]

I just replaced a thermostat on my Corsa. I thought, "what the hell I wonder if I can fix this".
Some research turned up this info: http://corvaircenter.com/phorum/read.ph ... 398,707104

Don't know if that'll help with your bellows...

In the end I decided it wasn't worth the aggravation so I ordered a new one from Clarks - part #C50RM

Alec

[Jerry Whitt]

Read over the info from Alec. Seemed like a doable job. Bought a new small butane torch today. Hope you don't hear an explosion in the Hemet area tonite!!

[Steve62]

I just saw a bright flash, and heard a loud boom southeast of here...you OK, Jerry?!?!

Just kidding...

[Jerry Whitt]

There were alot of sirens a little while ago, but they went on by to someone else, this time.

Used the torch and was able to take a disc with attached end off of the bellows. Looked inside and found lots of white dirt. Not sure what that was.
Experimented with wrapping solder wires around in circle in area the cap attaches. Placed the cap back on, and with bellows compressed, heated the cap thinking the solder would melt and stick. Looked good. Hmmmm, that was too easy. Then took the thermostat and placed it in a pan with water, placed it on the stove, with a thermometer. Eventually the water began to boil, and lots of bubbles came from the cap area, and the bellows did not expand.

Taking a break. Will sleep on it and see if another better idea comes up.

[Jerry Whitt]

Installed the new thermostat. Works good. Maybe try a repair later

[Allan Lacki]

When I had my engine rebuilt in 2007, we installed new repro thermostats. One of them failed. It failed-safe, in the open position, as it was designed to do, but it failed.

So, I bought a pair of used thermostats at the Detroit Homecoming and installed them. I believe they are original GM units. They certainly had enough dirt on them! (I cleaned them up before I installed them).

That was a couple of years ago. I've driven the car a couple thousand miles since then. They're working fine.

Maybe the originals are, in fact, more reliable than the repros.

Al Lacki

[1949chevy]

I just fixed two of them this past week out of the 3 I had that were bad. If you put it in water and squeeze it a little and bubbles come out of the end...usually the end that goes toward the flap, I can fix them. At least I fixed mine. I installed it on my car and for two days that I have driven the car , it works great. It actually opens about 10 degrees earlier than the best one I have that is original. They are fixable....not pretty when I am done but work for sure.

I check them in my toaster oven and set it to 250 or just a hair higher.

The one that I have opted not to fix is releasing bubbles in the center...might tackle it in the near future.

[notched]

I seem to recall others stating that they are filled with alcohol.

[toytron]

There is a YouTube video on repairing them. I don't have the link. These type of bellows are used in industrial gauges also. The video shows that there is actually a hole in the threaded screw end that had been soldered shut. So you have to make sure the bellows cap end is not leaking and that the screw hole is open and clean. Then I believe it was ISO alcohol used in it and you would have to experiment with how much or find that video. Once it is filed then with a soldering iron (not a torch) and the bellows compressed you would solder the hole closed and let it cool.

Ed Stevenson

[toms73novass]

I seem to recall others stating that they are filled with alcohol.

Yes they have a type of alcohol that vaporizes at the correct temp range and expands the bellows.