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MG TD TF 1500 - Removing Thermostat

To start with, I'm working on a '52 TD. I am trying to remove the thermostat from the cast metal housing to be able to bead blast the rust out of the housing and potentially put back in or replace the thermostat. There is a small bead of solder that seems to attach the end cap nut to the threaded shaft. Getting the solder off shouldn't be much of a problem. But how do you keep the thermostat from spinning to be able to get the nut off without damaging the thermostat?

The other problem that I created for myself is with the elbow that comes off the side of the thermostat housing. After bending 2 screewdrivers trying to get the 2 screws that attach it to the thermostat housing off, I tried applying heat and using pliers. Well, the heads of the screws twisted off very nicely leaving the screws very much intact. Will it eventually be a problem if I just leave the elbow attached with the headless screws?

I do not have a drill press nor something to hold the thremostat housing steady on a drill press to be able to drill out what is left of the screws. If I can get the thermostat out of the housing, I'm thinking that I still may be able to get everything clean enough to put back together and use.

This is one of those times that I ask myself: "What have I gotten myself into?" Yet, I still enjoy the little successes when something does go well.

Thank you and as always I appreciate your knowledge and patience with my rudmentary questions.

Patrick
Patrick Earles

Patrick - Look around for a retired machinist who has set up shop in his garage in your area. Start the search by contacting a local hot rod club and even ask at a auto parts house that does engine rebuilding. Once you find such a person, take the t'stat housing to them and ask if he or she can drill out the screws without damaging the threads, explaining to them that they are British Standard Fine threads and need to be preserved. If this person can get the broken screws out, keep their phone number handy - they will be one of the greatest assets in getting small machining jobs done that you can find. Cheers - Dave
David DuBois

Patric,
IMHO, the "end cap nut" is part of your thermostat, don't try to unscrew it,,, the whole thermostat assembly should come out as one piece,, it is not made to come apart,,,

The elbow will fall off if it is not attached by the screws,,,,(with heads),,
Go with Daves suggestion and have the screws drilled out,,,,,
SPW
STEVE WINCZE

The original thermostats usually aren't functioning well or consistently, in my experience. There were bronze housings available a while ago that were great, but I understand the current ones are porous castings, and ooze coolant. Not good.

The usual supplier sells iron housings with non-replaceable thermostats (reproduction), and aluminum housings with replaceable thermostats, the housings of which almost immediately start to corrode, and are made in China. A nasty white powder from the corroded and jagged aluminum is the result, often after less than a year!

For that reason I have commissioned (from Australia) a small test run of stainless steel thermostat housings, that are guaranteed not to corrode, can be polished, and can be easily modified for heater cars by drilling only one hole.

This new thermostat housing has the improvement of giving access to the thermostat (in the unlikely case you will need to) from the TOP of the housing, so all that needs to be removed is the top radiator hose. The aluminum housing offered elsewhere has a thermostat that is only accessed from the bottom, so the entire thermostat unit has to be removed from the engine.

These will be more expensive than others, but are lifetime products, as is everything I sell. More information, final price and photos soon.

Tom Lange
MGT Repair
t lange

TOM,
ANOTHER ITEM TO ADD TO THE REBUILD WISH LIST,,,,

SPW
STEVE WINCZE

Thanks, Steve and all; I'll post pictures and more information as soon as they arrive from the machinist.

Tom Lange
MGT Repair
t lange

A 10-32 tap will do nicely for a 2BA if you need to rethread the holes, and you will still be able to thread in the proper screws.

The original guts to the thermostat can be removed and replaced with a common thermostat; sometimes turning a shallow step is required in the large elbow to make the thermostat settle in. There will be no blanking sleeve but you can accomplish the same with a blanking plate between the small elbow and the housing with a 3/16 hole drilled in it, use an extra gasket. Or do like I did, drill a 3/16 hole in a stopper and place it midway down the hose.

Unless you are trying to recapture the entire experience and have the original type of thermostat these fixes are fully functional, and no one will be able to tell if you modify yours.

warmly,
dave

Dave Braun

Thanks to all,

I'm not sure the route that I will take. It will probably depend upon how much damage is inflicted while I try to clean/learn about the thermostat and its housing.

Finding a good machinist as Mr. DuBois suggests will be a must one way or the other.

Also, I would like to thank all that contribute to this BB. As has been stated many times, there is now way I could even think about taking on this project without it.

Patrick
Patrick Earles

Patrick,

Found this info on the Ttalk Site from Bud Krueger http://www.ttalk.info/Tech/TechIndex.html



http://www.ttalk.info/modern_thermostat.htm

If it helps.

Rod
R D Jones

I'll try left handed drill bits to drill out screws, and once in a great while, they may unscrew themselves out, or maybe give an EZ-out a try, but if the thread are siezed to where the heads snap off, more drastic measures are usually required.

I regularly use an Electric Discharge Machine with a copper wire to disintegrate broken screws and taps, from the center out to the threads, then pick the threads out.

On larger bolts, I weld a washer onto the broken bolt, then weld a nut onto the washer, and gently attempt to unscrew it, over and over again, sometimes.

If you pay shipping, I can spend an hour or two removing them with the EDM machine. If enough of a stump is sticking up, I may try the welding trick first.

One other alternative- Ebay.
JIM NORTHRUP SR

This thread was discussed between 03/09/2013 and 04/09/2013

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