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MG TD TF 1500 - Frozen TF Bonnet Latch

The spring shaft on a bonnet latch on TF681 is frozen to the guide. Rust and crud, I suppose. How can I free it?

I've use all of the basic penetrating liquids - ATF+Acetone, Liquid Wrench, PB Blaster. I heated the entire latch with a heat gun. I heated the hex head with a propane torch (not to red hot). I've banged, pounded, and twisted.

No luck.

>> Anyone have a left side TF bonnet latch for sale?

Thanks for your help and suggestions,

Lonnie
TF7211
TF681




LM Cook

One more photo.

Lonnie
TF7211
TF681

LM Cook

Put the torch on the barrel for about 5 to 8 minutes. After it cools down put the bolt end in a deep socket and give the bullet end a smack with hammer.
L E D LaVerne

Thanks LaVerne. I’ll try it.

Can a propane torch get the spring hot enough to damage it?

Lonnie
TF7211
TF681
LM Cook

Possibly but I doubt it. Even if it does and you are able to get it apart then it could be replaced. I have a small torch that I can get the flame pretty much where I want it. It would take longer to heat the thing up but you might look for one. Ideally a small Map gas flame would be ideal where you can get good heat in a small area. You need to get the metal pretty hot...like red hot for it to be effective in breaking the corrosion bond loose. I would use a socket on the bullet end as well for the hammer strike. I used both a standard propane torch and this small one to break all kinds of screws and nuts loose on this last project. It order to get good results the screw or bolt needs to get glowing red and almost always it will come apart after that. If it's really stubborn I may give it some oil after heating but while still hot. It will smoke like the dickens and you don't want to be breathing the fumes. And it may require heating more that once.





L E D LaVerne

What torch are you using in your photos. Might be time for a trip to the tool store.

Lonnie
TF7211
TF681
LM Cook

I don't know the brand name. Picked it up at one of the big box stores I believe. Refills with one of the small cams of propane.

Looking at your pictures I don't believe my method with the hammer will free it up. Looks like you need to back the bolt out part way...as in your photo and the smack the bolt head to free it up. I have one (right side) out in the shop I can have a look at later today if you want. Might give me some more insight into disassembly.
L E D LaVerne

Ok I just looked at how it was made. Appears that the bolt runs through the guide and is screwed into the bullet end. To free yours up I would again apply some serious heat to the guide. When it cools down I would set the bolt head in something like a socket. The use another socket that will allow the bullet to enter freely but not the washer ring around it. I would give that a good whack. Once free I would add the lubricants and use the bolt head to turn it around and round to free up the corrosion.

Good luck.
L E D LaVerne

This product or one similar may preserve the temper in the spring.

Regards, Tom

https://www.zoro.com/nu-calgon-heat-sink-compound-putty-12-oz-4371-38/i/G4321660/
tm peterson

Thanks everyone for your help and suggestions.

I took the easy way out. I purchased a partial latch from a club member and combined parts from it and parts from my frozen latch to make one good one.

After I got the second latch, I got more aggressive with the frozen one.
> I found that the pointed top above the spring can be unscrewed, and the spring removed.
> I heated the shaft of the frozen latch to a dull red. I was able to rotate the shaft a few degrees and move it up and down a mm or two. It's still locked in place pretty solidly. I won't work on it anymore.

Now that I know that the pointed top can be unscrewed, I'll periodically check the latches on my TFs to make sure that the tops aren't loose.

Lonnie
TF7211
TF681





LM Cook

Lonnie: Can you soak the last assembly in an acid rust remover for a week and then see if you can get the bolt out?
Christopher Couper

This thread was discussed between 23/06/2022 and 29/06/2022

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