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View Full Version : Unimogs..how strong are they?



Summiitt
10th February 2014, 08:48 PM
Can anyone with real experience tell me how strong the drive lines on the unimogs are and what if anything breaks in them..?
I've got a late model MA911 4x4 merc that I'm thinking of selling and going into a unimog.

djam1
10th February 2014, 09:53 PM
I spent years in the tourist industry in the NT with Unimogs and 911s
If I had my choice I would have a 911 they are pretty fool proof and durable.
The Mog was much more capable generally nothing broke unless really abused. (Yes I have seen them snap in halves):(
The issue with the Mog in the environment that we ran them in was the life expectancy of the components namely engines, gear boxes and bull gears.
I have never seen broken running gear apart from diff housings.
The 911 will go for years and is cheaper to fix but isn't as capable.

spudboy
10th February 2014, 10:41 PM
I started out looking at Unimogs for a large 4x4 project, and an issue that was raised from a number of specialists I talked to was the reduction hubs (?) that power the portal axles don't like long bursts of high speed running. They get hot and the oil goes off and then the gears fail.

I ended up going for an MAN 4x4 truck - 15 tonne/290Hp.

If you look up Daniel Mavin up in QLD and give him a call, you will get some good advice: UNIDAN | Universal solutions for off-road transport and expedition vehicles (http://unidan.com.au/) He was very generous talking to me when I was trying to decide what to buy.

The other person, who is a member here but not often online, is Nashy99. You can try PM'ing him. He also has a lot of experience with Unimogs.

What is your new project?

Cheers
David

Blknight.aus
11th February 2014, 02:06 AM
keep ahead of the maintenance and they are nearly indestructible. treated well it should outlast you without any problems

what goes in them..

clutchs if you abuse them
planetary synchronizers (does the shift from 4th-5th which is really sort of going from low range forth to high first) if you abuse them same as the reverse/forwards synchronizers
oil seals can be problematic.
They will eat tyres if you dont stay on the alignement, bush condition and tyre pressures.
door cards
wiper washer pump motors
exhaust brake linkages and the exhuast brake switch seals (keep that rubber boot in good shape and keep the drivers floor clean)
the cupola hatch rubber seal
The bolts that hold the rear drive output housing on have a tendancy to work loose over time, check them with every service.
the belts on the 1750 with AC can cause headaches. (in fact avoid the 1750 with AC maintenance is a pain in the ass if you want to keep the AC as is)
the canopy ridge pole clips are useless and rust themselves stuck and if the pole is bent they will spring loose.
the tailgate hinges get stretchy and the tailgate will jump off at you if you're not careful.

other than that.

I've NEVER had one fail to get me where I needed to get to except for the one time I had to try and bog one for a recovery demo and couldn't.

Summiitt
11th February 2014, 05:57 AM
My 911 is an ex country energy flat top with a genuine 120,000km on it. It has a hiab crane behind the cab and a 40,000lb garwood olding hydraulic winch that sits against the headboard, I use it mainly to lift and transport drilling equipment for my business, but have recovered tractors, fire pumpers and semi trailers with the winch. I have also had a 4500litre water tank made up for it with a lift on ex national parks fire fighting module that sits on the rear of the tray, complete with a yanmar diesel pump, hose reels and foam applicator. This is used to provide water on our earthmoving and civil jobs and a back up fire fighting unit.
I do bugger all km in the truck and it's in perfect mechanical condition, I've always wanted a mog, so will just see if I can sell the 911 to fund one..just need to measure up the tray to make sure everything will fit.. Are the army ones all the same wheelbase? And capacity? Thanks for your help.

dhula
11th February 2014, 11:10 AM
I've never seen a stuffed set of portal gears but that doesn't mean it hasn't happened. Keep the oil fresh at each service and all should be sweet.

To add to what Blknight.aus said up there ^^^^
Air compressors can often go west, usually the head gaskets or the reeds wear on their stakes and won't hold pressure.
The 24v alt is a pain. Lifting the cab to do work it needs to be taken off/moved and it often needs repair (the reg mostly).
I've seen a few steering boxes go bang
Accelerator linkages can be a PITA if not set up properly
The gear selector mechanism wears the brass bushes out quickly or the bushes fall out of the housing giving dicky changes.
The hi/low lever on the side of the box can shear away from the shaft.
Rocker cover gaskets (which is also the inlet manifold gasket) go quickly if the cover is overtightened.
Starters can be a pain.
I've seen more than a couple of gearboxes cracked down the centerline causing them to loose oil and seize
Gearbox output and diff input seals are common if the pressurization system is not set properly or the vent is blocked.
Can be hard on brake discs, especially rear ones if the park brake is set incorrectly.
Speaking on park brakes, they can be difficult to setup correctly and the actuator on the caliper can seize plus the quick release mechanism cause problems if hit in the wrong direction or they fill with crap.
Sway bar bushes are a PITA and can wear the sway bar badly
You can get weird air leaks from some Vv's that are caused by another Vv further down the line (one I recall is the park brake Vv leaking through the Exh port which can be caused by the breakaway Vv under the back end being faulty, but only happens when you hook up a trailer)
The seat height adjuster mech can go west
Seen a few broken rear axles (no diffs tho)
Front portal gear input shaft seal goes often, especially if the pressurization system is not set right or the vent is blocked.
The dash light for the blinkers can stop working if there are low wattage globes in the lights (hint, use 21w globes in the indicators).
The winches fitted to the army ones are Crap (with a captial C) IMO. Maintenance wise, pulling power wise. They jsut shouldn't be there I recon.

It's not all doom and gloom tho as I've never been stranded with a mog and they'll pretty much drive up the side of a cliff off road if that's what you need them to do

dhula
11th February 2014, 11:42 AM
Are the army ones all the same wheelbase? And capacity? Thanks for your help.

Pretty sure all army mogs are the same wheelbase except for the dualcabs which I'm fairly sure are slightly longer. The DC versions are a pretty rare beast tho and pretty sure only went to the school of trucks.
The trays are different sizes between the crane version (shorter tray) and the rest. Can't recall if the twist lock trays where the same size sorry.

Capacity was 4 tonne IIRC but pretty sure hey started out as 6 tonne in the beginning, could be wrong tho.
I know I copped a fair bollocking for strapping a Leo powerpack to a Mog when we couldn't find any other way of taking it in for rebuild.