M1079 Right Front hub failure

M1079 Right Front hub failure update... and more

OK, I have a good update of the long saga of the troubled recovery of my M1079 van. I need more parts but the main battle is won.

Picked it up at Ft. Riley... and it was noisy as I drove. Seemed to be a lot of noise (of which more later) and lotsa noise from knobby tires. Nice and new. Little did I know that masked in the new tires and unfamiliar new truck, the hub was quickly eating itself up in protest for total lack of lube in the right front hub.

It took a while to learn about that. We drove to a gas station to top off and noted some oil leeking. Found 3 pan bolts missing, a bolt supposedly passing through a water pipe clamp and the front cover ahead of the fuel pump, fan loose, alternator loose, and belts turning on themselves. Fortunately the Son of the woman working the station is a Diesel mech and he fixed the fan and straightened the belts. They tightened up as the fan was tightened but the alternator wasn't in it's full outward position because its bracket was missing. It seemed tight enough to progress though. More of this later.

Two miles further down the road the van suffered massive grinding in right front hub and I ground to a halt. Removing the cap revealed a massive collection of steel shavings that had previously been parts of my planetary gears. They were toast. Bottom line is that those hubs need to be filled with lube... not being familiar with the lmtv I didn't check. Was advised the truck had just come out of the Ft Riley rebuild shop (good reputation from what I'm told) but I suspect it was coded out as not economically repairable due to the front axle.





Got the truck recovered to the mechanic's shop but then needed to get the hub repaired. NPT provided good info re axles and saved much trouble.

Ironplanet responded well to my call for a claim. They paid a bit over $1900 after the $750 deductible. That paid for the mechanic, towing, and an axle that provided all parts needed... plus others of course.

Turns out there was more.

The mechanic (Tony Moseby) switched out the planetary gears (and more) and we filled the hub.

I'd bought bolts to replace the missing ones and had a friend fabricate a new alternator bracket, but upon shifting the alternator Tony found the missing one hidden under the alternator. The homemade one was based on dimensions found on PartsTarget and would have worked fine, but it was good to have the original. We took the truck out for a short test drive.

And that's where we learned why the loose alternator, fan, and the missing bolts were as we found them... the water pump gasket failed. Seems that it had been replaced or was being worked on, and getting to it required loosening/removing some parts. Sooooo.... we cut and installed a new gasket.

Seems we used too much Right Stuff to get it to seal... as soon as I hit I-70 and got to full speed that gasket blew and the engine heated up and the red STOP light came on. I obeyed.

OK, we then went to the nearest Cat dealer and got a proper gasket. Cat doesn't glue that gasket in, and we didn't either.

Took the truck out for another test and the pump gasket held at full temp and speed... life was good. We headed out. The truck drove well, if not a bit bouncy at times. Nice vehicle.

Got to the western end of Kansas City rail yards and all **** broke loose. Buzzer alarmed and the STOP sign came on again. I noticed that engine oil pressure quickly reflected 0. John in the trail vehicle noted the oil blow and I had the truck stopped very fast. Oil all over the road and engine, rain falling, light fading, traffic whizzing by on the overpass. Not good. Couldn't see what happened.

A quick look at the Iphone found a towing outfit just across the tracks... Midwest Towing as I recall. They recovered at a reasonable price and let me store it for a week... bad weather was moving in so we retreated 400 miles home. Came back a week later with my M915A1 and hooked up to the van and towed it home. 420 miles. Slow. The hookup was actually quite good though, and the tow was safe if unfamiliar. Had plans A, B, and C for various elements of the tow and it was a good thing as plan C for tail lights... 12 volt trailer lights hooked to a battery in the van... was needed. Made it home in about 11 hrs.

When the oil was off the engine the cause of the oil leak was easily found... a "tube assembly", figure 29 item 35 connecting the fuel pump/governor or whatever all it is fractured and oil spewed out. $25 and a trip to Cat got it replaced in minutes, along with the seals under it.

So today the truck starts and runs... no leaks. Sorta knocks for a few seconds upon starting.

And as to the bouncy ride? Might have something to do with the two stabilizer bushings that hook the top of the stabilizer bar are missing. See figure 182 of TM9-2320-365-24P, item 13. I'm now on the look for two of them.

I'll post pics and contact info for Tony Moseby. He's about 30 miles East of Ft. Riley and I recommend him.

More later. Mark3395 BTW, if you have a source for those bushings please advise.

I'm not familiar with rebuilding them, but do know most I've come across myself or by others are dry in the front. 75-90 synthetic gear oil 11-13 ounces. Good luck.

Dave

I have all of those parts from axles I salvaged for high speed gears. If you want an entire axle, call Premier Metal Buyers in Brenham TX.

Each front hub should have around 13 ounces of gear lube in them as Shark Bait mentioned. Doesn't Gov Planet check everything out for their auctions? Good luck with your claim, keep us posted.

The truck will not pull with the gears/axles out ! Been there, done that !!

Looks like a standard planatary drive system. It shouldn't be awfully hard to rebuild. Parts are another thing.

Have gone over the 24p manual hoping that much in the line of parts can be salvaged from rear axles. I see wonderful crossover, but it seems that shim kits are needed to get parts to fit in various wheel assemblies. NDT has some parts available and I'm continuing to research. Next is a trip thru the maintenance manual to see what's involved with rebuilding these things. I suspect replacing the whole assembly (figure 132 of the 24&P manual) and then aligning the wheels is the way to go.


I look forward to hearing from some unfortunate soul who's gone through this.

Mark W

OK time for an update.

I submitted a claim to IronPlanet for repair parts, mechanic, and tow and they have reacted positively... reimbursing me for my claim minus the $750 deductible. I'm very pleased with their reaction. I'll post more later, with lessons learned (for both sides).


My plan is to go back to Kansas Tuesday to recover the truck (Plan A). I have a good mechanic holding it now, and will pull the parts needed from an MRAP axle. I'll be corresponding with the mech today to discuss the dreaded "what else bad could happen" scenario.

OK, the hub gears are toast. My concern today (which I should have explored earlier) is what damage could have happened to the differential or even the transmission as the hub was clunking and grinding. My plan is to have the mech pull the plug and inspect for metal parts. I'll take a borescope with me to peek into the differential from the fill hole.

If it's toast I'll consider having repairs made on site (Plan B)... and going to higher speed gears in the differentials at the same time (Plan B.1).

If impractical I'll look at recovering by flat-towing with my 915A1 or 936A1. I'll consider hiring a lowboy if I determine that makes sense.

Does anybody out there have any experience with hub damage affecting the differential? Any booby-traps to look for?

There is no way for filings from the hub to make their way into the center axle differential. My guess is that the shock loading from crunching up your wheel end would not damage upstream powertrain items.


Flat towing should be fine, follow the TM. I would replace the wheel bearings in your damaged hub first, as filings from the wheel end spider can easily find their way into the bearings.

Flat towing OVER 35 mph or 100 miles, REQUIRES that BOTH drive shafts BE DISCONNECTED FROM THE FRONT/REAR THIRD MEMBER.

Also, if you have to truck it, pull the box, this way you can use a step deck instead of a very expensive RGN .

NDT said:

There is no way for filings from the hub to make their way into the center axle differential. My guess is that the shock loading from crunching up your wheel end would not damage upstream powertrain items.


Flat towing should be fine, follow the TM. I would replace the wheel bearings in your damaged hub first, as filings from the wheel end spider can easily find their way into the bearings.

Click to expand...

Hi NDT I also think that the filings can't get through, but it is the shock loading I wonder a out... If it can go wrong it'll happen to me.

I'll check into getting new bearings or pulling them from another axle.

And thanks for the note re flat towing as well. I'm well set up to do that if need be but won't be bringing a tow vehicle down with me on this trip.

Mark3395

Good point. I'll work like **** to avoid flat towing it.

Perhaps it'd be practical to take along a towbar so a third party could tow it if need be. Might just be cheaper to find a bobtail heading back my way than to make another trip with my own.


Thanks much.

Mark3395

Wheel bearing nut size for LMTV

Am working to gather tools for the M1079 that suffered hub failure during recovery.

It's shown as appendix B item 70, but the size isn't noted. It's used to remove/install item 35 of figure 132... the wheel bearing nut.

Does anybody know what the size is of this nut, and thus the socket needed to work on it? It's goofy that nuts and bolts are listed without sizes.... which would be awfully convenient for the mechanic working on the thing.


Mark3395

What is the NSN of the nut?

Google that...
http://www.parttarget.com/5120-01-335-0784_5120013350784_TW321.html

Update:

Succeeded in replacing the planetary gears with take-offs from an MRAP axle. Good.

Turns out missing bolts and alternator bracket seem related to water pump problem. Gasket leaked. Cut a new one and it failed so we got a proper one from Cat and it holds.

Engine knocks a few seconds on startup then runs smoothly. Headed off towards KC and made it just to the edge. Then the truck failed.

Suffered massive oil leak... oil blown all over the engine compartment, pressure dropped from almost 80 to zero, lights came on, instrument cluster said stop, and I did so. Engine died, seemingly due to failsafe system.

Fortunately a good tow service was just a mile away and the tow wasn't too expensive and the storage modest. We'll head off with a 915A1 to flat tow back.

Am studying flat tow procedures now. Have proper towbars, chains, etc. Will pull rear axleshafts and pull the front driveshaft. Have air hoses to hook 915 to 1079 but the -10 manual seems to indicate that rear brakes need to be caged. Id prefer them working normally so am checking to see if I'm just confused.

Interestingly, the fellow who towed the truck is ex-GI and familiar with towing the FMV system and says that hooking the service or emergency gladhand (am confused which) tends to blow a seal in the truck, so he bypassed those hoses and fed air into the right air tank. Wanted to use the center one but the drain valve wouldn't come off easily. That fed air into the system and the brakes worked. Anybody heard of such a system?

I have fittings to replicate his trick but am more concerned about caging brakes.

Sure is great to have the manuals available here.

Mark3395

Wow that alot to happen. Any idea where the oil is coming from? ? Hopefully it isn't anything major !

Knocking on startup is not normal, likely your catastrophic engine failure is related to this. I have charged my air system with the emergency gladhand many times with no ill effects. Sounds like GP will owe you twice what you paid for it when this is all said and done.