Seized T-Stat screws and telltale plug

[sidenberg]

1987 Force 125 Screws for T-Stat cover and slotted screw plug above got telltale are frozen solid. Tried impact driver with no results except bent, broken, bits. I think all these parts are original. Any ideas besides drilling?

 

[foodfisher]

Re: T-Stat and telltale plug

Re: T-Stat and telltale plug

More and better bits, till the screws give one way or another. Loosened=congrats. Broken= PB blaster on the remains w/visegrip and wiggling. After that it's cobalt drill time. Good Luck PS, Be sure to take a twist in the direction of removal before whacking w/hammer.

 

[sidenberg]

Re: Seized T-Stat screws and telltale plug

Other posts in this forum suggest applying heat using MAP gas torch? I thought heat expanded metal and would make more sense to apply cold? Incidently, what engineer thought it was a good idea to use slotted screws here anyway!

 

[bman1bpm]

Re: Seized T-Stat screws and telltale plug

A Chrysler engineer haha. Heat causes the metals to expand and contract at differnt rates hopefully letting them loose. What kind of impact driver are you using? I tried a harbor frieight one once, the bits were trash and I brought it back to the store for a refund. I've got a Craftsman one now, you can whack that thing with a 3lb mini sledge and it loosens anything.

 

[foodfisher]

Re: Seized T-Stat screws and telltale plug

Those are my thoughts on heat also. Maybe the heat expansion compresses the corrosion enough to cause a seperation when it cools down. Engineers don't have to mechanic.

 

[my1stboat1]

Re: Seized T-Stat screws and telltale plug

the idea with the heat is to heat around the bolt you are tring to remove Thus expanding the metal around the bolt more then bolt, plug, etc itself making it easier to remove...

 

[sidenberg]

Re: Seized T-Stat screws and telltale plug

Okay, this is not fun anymore. Thanks for all the tips though. Apparently this is the original factory T-Stat from 1987. After more hours than I want to admit, I have 3 screws out but the fourth, the last one, the head broke off. So today I am drilling. The phrase,"It if ain't broke don't fix it" keeps doing through my brain. However I knew this T-stat was old and I do not want to have a problem as I often fish a number miles off shore. Anyway I am considering replacing the slotted screws with phillips head or some other type. Any recommendations? Also would it be best to use thread sealant or anti-seize?

 

[pnwboat]

Re: Seized T-Stat screws and telltale plug

I'm not 100% sure about the thread pitch, but I think it's a 1/4 20 thread. Take one with you to the store to get the correct pitch/length. You can use stainless steel allen head or hex head bolts. They're available at Home Depot, Lowes or Ace Hardware. Much easier to get a good bite on an allen head or hex head bolt than a slotted screw. Anti-seize compound is recommended.

 

[sidenberg]

Re: Seized T-Stat screws and telltale plug

Thanks, I picked up some hex head. The bad news is that last screw is not coming out. Extractors broke off twice. I ended up drilling with 1/8" bit all the way through so now I have a 1/8' off center hole. I guess the best approach now is to fill the hole and tap a new 1/4". Any other ideas?

 

[pnwboat]

Re: Seized T-Stat screws and telltale plug

You can drill slightly larger. Try a 3/16th bit. The more of the old bolt that you remove, the easier it is to remove. Just be careful to avoid drilling the aluminum. Heat and vibration is your friend. You can use a propane torch to heat it up, and tap lightly on the bolt to bust it loose from the corrosion. Sometimes you can also chill the bolt. Radio Shack has a product call Freeze-it. It's used to chill electronic components that are heat sensitive. Comes in a can with an extension wand.

 

[sidenberg]

Re: Seized T-Stat screws and telltale plug

The end of this story, sort of. This last screw is not coming out. Now I have a second extractor broken off inside. I said screw it. The other 3 screws where extremely difficult. I had to continue to use the impact driver until the screws were about 1/4" out and after that needed a power impact driver for the rest. So I put in the new t-stat, sealed the screw hole and installed the housing using only three screws and a bit of RTV sealant. Works fine. I will deal with this again later during the winter.