What to look for when looking at U1750 Unimog. Common issues or signs?

Elbee

Adventurer
I'm going to look at at tray back 1750 Unimog.
Not sure what engine it has in it OM366 or OM352

What are some general things to look for? Common signs of wear and general weak spots?

Thnaks!!
 
Rust
shiftability of transmission in all gears plus presence or absence of working gears, condition of trans oil
presence of and condition of oil in portal gearboxes (look for metal shavings as evidence of bearing damage, look for water in portal oil)

Charlie
 

Elbee

Adventurer
Thanks Guys!
So this looks to be a 2001 1750L (even though it looks to be a short wheel base.
It has been sitting for a year, it was overhauled and rebuilt in 2012 and then shipped here and has sat since 2014. So it need the oils all changed probably and ran to see what and if there are any issues.
Here are some photos.

How hard is it to replace Portal Box seals??
IMG_6083 2.jpgIMG_6088 2.jpgIMG_6089 2.jpgIMG_6089 2.jpgIMG_6096 2.jpgIMG_6084 2.jpgIMG_6085 2.jpg
 

Elbee

Adventurer
Sweet, thanks!
It obviously needs some minor attention in some parts. Thanks for the advice and input!
yes there is a turbo, i didn't manage to get a photo of it, but its there.

i think the seals went due to it sitting for so long.
 

mogwildRW1

Adventurer
The "50" in 1750 does not mean longer wheelbase, it means longer frame overhang. That Unimog has the standard 3250mm wheelbase.

Here is the Data Card for the Unimog. Keep in mind this is the options it was sold and shipped with, lots can change in many years in a Unimogs life.

View attachment WDB4371131W176735_detailed.pdf

use google translate to translate any of the ones in German, and any unlisted descriptions you can cross reference here to get the detail of what the option order code is.

That Unimog has an OM366A and the more desirable (stronger) UG3/65 Transmission, along with, as Charlie mentions, the working group (additional 8 lower gears)

From the pictures it looks like at least one of the portal output seals is leaking, this is very common from sitting, it may seal up with a good few oil changes and a few miles put on but it's defiantly something to keep an eye on. They are not overly hard to replace, just a lot of heavy parts to remove to get at them. There is also a wear ring that you'll need to replace at the same time.

Things to look for? First thing I'd do is check the oil levels in the portals, if they are low and it's been sitting, rust can form on the gears and pitting can happen, this can get very expensive, very quick. I'd then drain the portals into a clear container, one at a time, and use a magnet to check for metal. A bit of metallic filings is normal (see if the drain plugs are magnetic, some are, some are not), a lot of magnetic sludge or chips is not normal, and can indicate a bearing or gear issue in the portals, again, that can get very expensive very quick. That Unimog however has the better 2pc heavier duty axles not prone to the "drivers side portal pump out" issue of the earlier, lighter 3pc axles.

Do the same for the Diff's and other fluids, the transmission does not have a dipstick, take a flash-light, you can take the rear plug (fill plug) out and look inside for fluid lever, it's fairly big.

Also remove the plug in the bellhousing. Not the engine oil plug or transmission plug, the bellhousing. See if a lot of oil comes out, it shouldn't. The 2pc rear main seals on Unimogs are known to seep, if this plug is left in place the fluid can fill up, and immerse the clutch, eventually the clutch will slip and need to be replaced. Also common on Unimogs that have sat for a long long time. I always take the plug out of any square cab Unimog I've owned, put it in the drivers side door pocket, and only put it in if I'm in really sandy conditions or crossing water.

Check the engine oil after running (within 5 minutes of shutting it off), the Unimogs have a big oil cooler inside the motor that will drain down into the pan making it look fuller than it is, you are supposed to run the engine for a few seconds, then shut off and immediately check the oil level, that is the proper level after the cooler has filled.

Look up under the dash for the clutch master, Unimogs that have sat a long time tend to leak here, it again may seal up with some use, and isn't very expensive of a part.

Run the Unimog to full air pressure, shut it down, look under the hood for the firewall brake valve (air valve, it will have 4 plastic airlines and one plastic vent), put your thumb over the vent for a second and then remove, if air has built up and whooshes out, the firewall brake valve is leaking, it's moderately common and pretty expensive for what it is. Rebuilt kits are available but I recommend a replacement OEM part from Atkinson Vos (1/2 the price of the Mercedes one, same OEM manufacturer), if it's leaking, it will only get worse.

That thing needs a serious bath. I would also check the pipe after the air filter and make sure it's not dusty or dirty, There was a TSB a while back on if the air tube after the filter wasn't sealed propery, dust can make it to the engine and cause pre-mature engine wear, since it's so dusty maybe something to check, but that dust looks like from sitting, not use, so maybe not a huge deal.
 
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It seems like a good Mog from the options but I would definitely add a Racor type fuel filter with water trap primary fuel filter (30 micron element), and an air dryer for the air system if it isn't present (can't tell from the option list).
Also, being 3250mm wheelbase it is less optimal for a camper conversion than a 3850mm, likewise the ag tires will be fantastic in Nilotic mud but not so long lasting on tarmac.

Charlie
 

Elbee

Adventurer
You guys are excellent! The dust and dirt is just from it sitting in a dusty storage area.
It not going to be built for overland or a camper installed. It will be used in muddy swamps and back roads. It is the only thing that can access areas during the rainy season, beyond atvs.
 

Craig Winters

New member
It seems like a good Mog from the options but I would definitely add a Racor type fuel filter with water trap primary fuel filter (30 micron element), and an air dryer for the air system if it isn't present (can't tell from the option list).
Also, being 3250mm wheelbase it is less optimal for a camper conversion than a 3850mm, likewise the ag tires will be fantastic in Nilotic mud but not so long lasting on tarmac.

Charlie
So a U1750L38 is the best camper option?
 

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