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MG MGA - Stuck temperature capalary bulb

I was removing the temperature sensor from a 1500 in my car. It was newly rebuilt a few years ago. The nut was easy to loosen since I put anti-seeze on it. The capalary bulb however will not come out. It is loose and wiggles around but it won't move out. The thermostat is out and while the bulb is loose I can't push it out. I am afraid to put too much pressure on for fear of damaging it.

It appears the nut has expanded the flange on the bulb so it is catching the threads. Any ideas??

Jim
Jim Ferguson

Jim, I have tackled this problem many times, usually breaking the bulb and requiring a $100 repair.
When you replace it, use a brass ferrule like the one in the photo below. I have done this on all my cars - it is easily removed and re-installed as the brass-on-brass joint comes away cleanly every time.
The part costs me about $30.
Good luck, Barry

BM Gannon

Jim,
If the capillary bulb is loose, you may be able to wiggle it out. This is a tedious process though. Also spray it with lubricating oil. It might help. Take a torch and heat up the housing, taking care to stay away from the bulb. It won't take a lot of heat before the housing expands enough. If you leave the heat on it too long, it will transfer to the cap. bulb, and won't work. Alternatively, you can try to freeze it.
good luck.
mike parker

Both Loctite and CRC make "Freeze" sprays designed to lubricate and chill stuck parts. The Loctite product is called "Freeze N Release", I don't recall what the CRC product is called but I get it at the NAPA store.

Be sure to check out Loctite's Freeze and Release web site, the banner states, "Rusty Nuts? Freeze 'em Off!"
MGA Larry

Hi Barry - that looks like a good mod - does it require the head to be adapted for it to fit? I have a Smiths dual gauge fitted by a PO and have now acquired a correct Jaeger one - so have to bite the bullet shortly to do the swap - hope mine comes out cleanly - but might try Barry's mod - good luck with yours Jim- cheers Cam
Cam Cunningham

Cam, It screws straight in - the same thread as the brass fitting which holds the bulb in place.
If you look at the photo you will see the larger hexagon ferrule permanently in the head and the original smaller brass hex fitting, screwed into it. They come away cleanly each time you have to remove the head.
They may be available in a plumbing shop - I can supply you if you get stuck.
Barry
BM Gannon

Thanks for the comments.

I got the Bulb out yesterday with force. I used a steel rod with a wooden stick with a dimple in it to fit the end of the bulb. I pried the bulb end from the thermostat hole while wiggling it thread by thread for two threads and then it poped out. It was scratched on the flange sides but otherwise ok. I will try to post a picture tomorrow.

I think I may have over tightened the nut when it was originally installed thereby slightly expanding the sealing flange on the bulb. The anti seize compound kept the nut free but did not prevent the overtightened.

I will remember the experience when installing it in the 1800.

Jim
Jim Ferguson

Well done Jim - saved you the cost of a new capilliary unit - will look out for the adaptor at the plumbers merchants Barry - cheers Cam
Cam Cunningham

This thread was discussed between 09/10/2008 and 12/10/2008

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