Okay here is what went wrong and a warning about the adapter used to install 1/8" gauge or sending unit. I take responsibility for not installing the adapter as I should but was surprised what happened.
The adapter has an o'ring on it so it shouldn't be tightened much at all. You should install the gauge or sending unit in the adapter first as it is 1/8" pipe thread and has to be tightened tight so to seal the threads then screw the adapter with o'ring into block and tighten just enough to compress the o'ring. Well I screwed the adapter into block first and then not thinking about overtightening it I proceeded to tightened the sending unit and within a 1/4 turn the threads stripped out of the block. After removing it I think the adapter is undersized because threads are not stripped completely but just the very top of threads in block.
adapter will not tighten now thinking of using JB weld to permanently install in block and pray the o'ring compresses enough so it doesn't leak or the JB Weld seals. What do you guys think?

 

can you get a longer adapter to go into the filter housing and grab good threads?.if you have a hydraulic hose/ fittings inc type of place close to you you could probably fix it.i would try to get an adapter in the housing before i used jb weld on it.

 

I feel same as steelhead about trying to avoid J B Weld. All NPT is tapered. There are fittings available with more threads and faster taper to reach deeper into female threads. Check a plumbing supply house if the hydraulic hose shop doesn't have it.

 

Good idea guys will check it out tomorrow. The threads that are stripped are not tapered pipe but probally some metric size.

 

I would stay away from JB Weld for this application. I agree with the others that a longer threaded pipe is the way to go. Any good farm supply store should have a large variety of hydraulic fittings right on the shelf.

 

they are more than likely sae threads. usually o-ring type fittings are sae.

 

Everything I've read says M-12 x 1.5 thread size..If your using sae. this could be why your not getting full thread connection.