M1079 Timing Cover replacement

[Trackmagic]

Hey all. Long time lurker, first time poster. I have been looking out for a M1079 for awhile and have recently come across a couple for potential purchase. One of them has a slow leak from cracked front timing cover. I am well aware of this potential issue and have found a replacement kit (cover/gaskets) online, but haven't been able to find the proper manual or video on this replacement. I have worked on vehicles and very DIY friendly, but have never worked on anything quite this large.

Is anyone that has been through this able to shed some light or give some insight? Wondering if this is manageable with a manual and some more research... or if it requires pulling a significant amount of the truck apart to access and will eventually require more specialized tools/knowledge than your average weekend warrior is capable of.

Appreciate the knowledge and advice.

-From a good woodworker, but not so great mechanic.

 

[GeneralDisorder]

Which engine? (year, serial number, A0/A1/A1R, etc).

Have you considered which generation you want? There are significant differences between 1993 and 2008 (newest 1079 that I've seen on the civilian side).

 

[Trackmagic]

Which engine? (year, serial number, A0/A1/A1R, etc).

Have you considered which generation you want? There are significant differences between 1993 and 2008 (newest 1079 that I've seen on the civilian side).

 

[Trackmagic]

Which engine? (year, serial number, A0/A1/A1R, etc).

Have you considered which generation you want? There are significant differences between 1993 and 2008 (newest 1079 that I've seen on the civilian side).

Vehicle is a 1998

 

[GeneralDisorder]

So what parts exactly need to be changed? Just the *cover* to the timing case is easy according to the TM. Couple hoses and tubes and a bunch of bolts and it drops right off the front. But I suspect you mean the timing *case* which is what always breaks on the A0 trucks because the driveline balance and angle and the lack of Nord Locks on any of the accessories.

You do know the A0 trucks have a list of issues that can and do chip away at your wallet and often aren't actually cheaper than the (much better) later A1 and A1R trucks after you fix a bunch of stuff and potentially end up replacing the engine or the transmission or both right?

 

[Trackmagic]

So what parts exactly need to be changed? Just the *cover* to the timing case is easy according to the TM. Couple hoses and tubes and a bunch of bolts and it drops right off the front. But I suspect you mean the timing *case* which is what always breaks on the A0 trucks because the driveline balance and angle and the lack of Nord Locks on any of the accessories.

You do know the A0 trucks have a list of issues that can and do chip away at your wallet and often aren't actually cheaper than the (much better) later A1 and A1R trucks after you fix a bunch of stuff and potentially end up replacing the engine or the transmission or both right?

I wasnt aware I admit of the difference between A0, A1 etc. I appreciate the information and I will continue my research.

 

[Awesomeness]

I've pulled the front timing cover/case off. The big issue, that I recall, is that you can't remove it without pulling a big gear off of one of the cam shafts (or some other rotating shaft sticking out the front of the engine). The gear is like 6" in diameter, would not budge with a screw-driven puller, and required a large (10 ton?) hydraulic puller (and maybe heat too, I can't remember). The hydraulic gear puller was pretty large, and you might have to remove the radiator to do it (I had the engine out of the truck).

Once you get it off, I'm not clear how easy it would be to put the new gear on. It must be possible though, as shops clearly make the repairs. (I was just pulling the timing case, and scrapping the engine block, so I didn't put it back together.)

 

[Ronmar]

A complete set of the military A0 manuals can be found in the manuals section here on steel soldiers. These include the 3116 engine manuals…

As mentioned the driveshafts are steep and spin too fast. This in itself makes vibrations, any issues with the shafts make this worse…

most of these timing cases crack on the drivers side adjacent to the air compressor. Usually this is a result of the support bracket that ties the rear end of the air compressor over to the engine block in front of the starter, coming Loose, failing or completely missing, leaving the air compressor and PS pump hanging unsupported on the case.

there have been a few who have removed the compressor, ground out the crack and had them welded in place. I have not heard of anyone having a problem doing this, but I would suppose this would depend on the exact nature of the crack… Of course driveshafts must be perfect as does that support bracket, but this is true of all these trucks…

 

[DannyBtruckn]

Hey all. Long time lurker, first time poster. I have been looking out for a M1079 for awhile and have recently come across a couple for potential purchase. One of them has a slow leak from cracked front timing cover. I am well aware of this potential issue and have found a replacement kit (cover/gaskets) online, but haven't been able to find the proper manual or video on this replacement. I have worked on vehicles and very DIY friendly, but have never worked on anything quite this large.

Is anyone that has been through this able to shed some light or give some insight? Wondering if this is manageable with a manual and some more research... or if it requires pulling a significant amount of the truck apart to access and will eventually require more specialized tools/knowledge than your average weekend warrior is capable of.

Appreciate the knowledge and advice.

-From a good woodworker, but not so great mechanic.

I have an ‘94 1079 I should probably sell. Just haven’t gotten around to posting it yet. I think it only has 600 original miles on it. Its in NW Indiana right now but I drove it there from Baltimore where it was stored in a police warehouse. I had it fully mechanic serviced. It’s all stock still but has new batteries, newer tires, sandblasted and epoxy painted. I have about $40k in it.


Sent from my iPhone using Tapatalk

 

[coachgeo]

Cover leak is more likely a crack judging by history of these trucks. You may be better off to keep it on.. get an aluminum welder to put a stop hole on each end. of crack and weld it.. then search in here for all the loose bolts that tend to cause/be part of that scenario.

 

[DeMilitarized]

Hey all. Long time lurker, first time poster. I have been looking out for a M1079 for awhile and have recently come across a couple for potential purchase. One of them has a slow leak from cracked front timing cover. I am well aware of this potential issue and have found a replacement kit (cover/gaskets) online, but haven't been able to find the proper manual or video on this replacement. I have worked on vehicles and very DIY friendly, but have never worked on anything quite this large.

Is anyone that has been through this able to shed some light or give some insight? Wondering if this is manageable with a manual and some more research... or if it requires pulling a significant amount of the truck apart to access and will eventually require more specialized tools/knowledge than your average weekend warrior is capable of.

Appreciate the knowledge and advice.

-From a good woodworker, but not so great mechanic.

You have to take the radiator and intercooler out and pull all the timing gears out and the cam and all the accessories. Saw a buddy of mine do it in 16 hours strait.

 

[Ronmar]

You have to take the radiator and intercooler out and pull all the timing gears out and the cam and all the accessories. Saw a buddy of mine do it in 16 hours strait.

Which is probably why folks are opting to weld them in place