Working on the M1078 LMTV

What destroys the old style is there is a rubber bushing that sandwiches that stuff all together in that rubber deteriorates and goes bye-bye and then nothing's holding the fan blade and it just sits there and Wobbles around and destroys itself

Coffey1 said:

Actually you can take that rubber out and Bolt the Hub to the fan

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Ken, I guess I’m not sure what rubber you’re talking about. It appeared that on my old unit the fan with the aluminum hub was sandwiched to the fan clutch with an aluminum spacer about 4” tall. I don’t know if that gave or the aluminum center to the fan gave but either way it didn’t appear to be an intelligent design. The steel hub of the new fan bolted directly to the studs on the newer style clutch seems to leave less room for catastrophic failure.

Edit - got it. Saw your other post after I finished this.

Pointman0853 said:

Mkcoen,

I did notice on my clutch (rebuild thread here: https://www.steelsoldiers.com/showthread.php?155684-Yet-another-M-1078-Fan-Clutch-thread&highlight=) that I have the newer housing with the holes and studs, instead of bolts. Is this type of failure due to the bolts holding the fan on becoming loose, or the fan having an aluminum mounting surface?

Pointman, getting ready to drive 600 miles to Overland Expo..

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Thats the style clutch I have on mine now. I’d still switch to the steel hub fan if you haven’t. If there’s any wobble going on at all the aluminum will succumb to metal fatigue much quicker than steel.

I don’t know if my bolts were loose causing the wobble (don’t think so as we just had it apart for the AC install) or if the clutch failed and then everything twisted. I am confident that if it had been the steel hub fan it would have stayed attached and not gone through my radiator though.

If you're worried about the aluminum that's made onto the fan you can always make you a couple steel shims exactly same matter fact I think there is a steel shim on there you can copy and put one on the front side and back side of the fan and support that aluminum better

The biggest thing is to do it now p.m. it before it destroys itself and wallows all them little holes out on the aluminum and then you shouldn't have any problem

I must be getting an expert at it because I've done two of them so far and I can have it apart the fan repaired and put back on within 45 minutes

Pointman0853 said:

Is this type of failure due to the bolts holding the fan on becoming loose, or the fan having an aluminum mounting surface?

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Coffey1 said:

What destroys the old style is there is a rubber bushing that sandwiches that stuff all together in that rubber deteriorates and goes bye-bye and then nothing's holding the fan blade and it just sits there and Wobbles around and destroys itself

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As Coffey said, the rubber part is supposed to be replaced each time you disassemble the fan, and not reused (per TM). Of course, nobody ever does that. So they languish for a decade or two until they get enough slop to vibrate themselves apart.

I also suspect the problem is exacerbated by worn drivelines that are introducing vibrations from the other end. Harmonic vibration from a driveshaft shakes the engine, and the rubber fan clutch bushing is already loose/weak and can't hold up.

It's worth noting for those that may read this thread in the future that the fans are not interchangable with the clutches. There is an original style clutch (which has threaded bolt holes on the front) that uses the multi-piece fan with replaceable rubber isolators. Then there is the newer style clutch with studs on the front, which the TM directs you to upgrade to when servicing anything that removes the fan (e.g. engine swap, etc.), and it uses the new one-piece fan with steel center hub. Though they look close, the new fan will not fit on the old hub, or vice versa.

Guess I'll pop the cab and head in there with a magnet tonight and check mine before our trip. Great call, thanks and sorry to the current victims of fan failure..

Pointman

Pointman you can tell if you got the old one it'll have Allen head screws or bolts in the front of it don't know if you'll be able to see the rubber because it's inside the hub center

If it has Allen head you need to take it apart as soon as possible and check it before it throws the fan

Thanks to all the folks chiming in on this. I certainly wish the information had been available before mine imploded. That’s why I put in back around page 75 for folks to check theirs. At that point there hadn’t been any other reports and I didn’t know there were different types of fan clutches available. Hopefully this will give folks some forewarning before theirs goes.

I’m looking for 4 of the CTIS/lug protector caps. Any info on where to find some. Thanks!

wildmansam said:

I’m looking for 4 of the CTIS/lug protector caps. Any info on where to find some. Thanks!

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You might want to start a thread under "Parts Wanted." Far more likely that someone sees it there rather than reading through 105 pages of this thread to get to see your post.

As the song says "and so it goes and so it goes, and so will you soon I suppose." After two years of fun with the M1078 it has moved on to life in the fun and sun of the Gulf Coast of TX. I wish it and it's new owner all the best and hope for a long and useful life of the fan clutch

did he take the camper box too? Sent a couple folk your way... hopefully one of them panned out.

I find it amusing that you sold the truck to my little sister's high school boyfriend - small world!

Cheers

Heh

Small world indeed...

M813rc said:

I find it amusing that you sold the truck to my little sister's high school boyfriend - small world!

Cheers

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Wow!

coachgeo said:

did he take the camper box too? Sent a couple folk your way... hopefully one of them panned out.

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I didn't see one (else I'd have asked) so I'd assume whatever it was must have sold.

I know he said he had sold his trailer (and he had a nice gen for sale, but far too big for my needs with no place to park it).

Third From Texas said:

I didn't see one (else I'd have asked) so I'd assume whatever it was must have sold.

I know he said he had sold his trailer (and he had a nice gen for sale, but far too big for my needs with no place to park it).

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I think he was posting to the wrong thread.

Love your avatar