Waterproof Plugs

I would like to ask what is probably a simple question. I want to change out the plugs on my M151. They are the water proof type. Am I correct that the plug screws out of the attached pipe end and if so are there any hints in getting the plug off with out cracking it. I have had no luck so far., I assume the plug must screw out of this pipe like fitting, Or am I way off and these fittings are permently attached to the plugs

The "pipe" does not come off. It's part of the plug. When you order new plugs you just screw them into the heads and attach wires.

To remove them you will need a deep socket. Deeper than most. A regular plug socket will not work.

The size of the plugs on my M715 is 13/16 inch.

Warthog

As M16 says...one piece. Just order a new set. I've gotten Mil plugs from NAPA and carquest...usually 9-12 bucks each...usually have to order and wait a couple of days.

Its a 2245 plug. If you have a friend at the parts store, you might get it a little cheaper, but not much.

A deep well socket will take them off. Unscrew the plug wires from the top of the plug. (Sometimes they don't want to budge and you may end up taking unscrewing the plug) Then unscrew the plug like you would any other spark plug. It's really simple actually.

Most deep wells, still won't get them out. 13/16" Snap-On deep wells are just long enough to do the job. I was lucky and the previous owner included one and a breaker bar in the tool kit.
Rainman

I have nos plug sockets @ $10 ea

While on the subject of spark plugs, I have a page on my website that discusses military plugs (including cross reference info for different manufacture's parts numbers for them) as well as some generic info such as what the condition of a plug tells you about your engine's performance.
See:
Spark Plug Info for M37 and Other Vehicles

One thing on the page is a note that the Autolite 2245 is a "medium" plug with cross numbers of:
Current Autolite 2245
Old Autolite AR7S
Milspec Number MS35909-2
New Champion 517
Old Champion XMJ17
AC WR46
Motorcraft AR7S
NGK BPR6HS

The table that has the above info also includes info on the 2243-2247 (cold to really hot) in case you need to make adjustments...

Good luck.

Did a bunch of searches for plugs equivalent to the Autolite AER72S. Best price was 6.89 for the Autolite 2245 at O'Rileys. Plus Autolite has another 50 cent rebate per plug right now.