At once the right rear wheel blocks for a short time and we hear a terrible metal sound.
We stop the truck on the road side and I check the oil in both portal axle housings and the differential.
The oil in the rear portal axle housing looks terrible. It is black and is full with metal filings.
We lift the wheel and notice that it can not be turned. After removing it we see one of the little brake cilinders is jammed and pressing the brakepad against the brake disk.
We removed the lining from the brake pad so we can release the pressure and take out the brake pad. Now we can turn the wheel.
Our Unimog friend Unimog Donald advices us to block the brake by adding a bearing ball 5 mm in the oil hose, we did so we mounted the wheel again and tried driving but the loud noice was there right away again.
No internet
To find information about the Portal axle design and to ask for advice and talk to donald we need internet. Therefore we have to hitchhike to the main road, from Bishkek to Naryn. And after this we need to find a hike to Ottyk where there is cellular coverage.
When I arrived there the first time I found out there is a network, but not with my Beeline sim card. A Russian couple saw me standing at the roadside and asked if I needed help. They where so kind to buy me a Mega SIM card and di the whole registration process with their paspoort!!
The next couple of days we have to go through this driving and walking procedure at least once a day to get internet. One day I could not get a ride back so I walked and run this 26 km track over a 3.200 meter pass. Ppfff
Ruined Portal axle
A local mechanic where I bought this one bearing ball offered to drive me back to the Unimog. When he saw we could not drive he offered to help checking out the Portal axle. So we took it apart and where shocked by the damage.
The outer housing (partnumber 437 331 0105) is damaged. The bearing has worn out the housing.
Even the small portal gearwheel has broken gears. (total is 13 with part number 425 33607 / 10)
The large gear has 38 teeth and here is damage too.
Thru axle dismantling
When the thru axle is dismantled between the rear differential and the final delay, a lot of dirt comes out of the tube.
The little brake pistons are all scratched/oxidized, this probably caused the brake to jam.
Questions
The last 60.000 km we had some major damage in the drive train of our Unimog.
Some gears in the gearbox broke, the drive shaft between gearbox and differential broke and now the portal axle damage.
- Am I a bad driver?
- Can the oil be the cause?
- Is it because the unimog is 30 years old (1994)
- Is the Unimog not build for this kind of traveling?
- We especially bought the 2150L38 because it is build for heavy duty. Are we to heavy with our 11 tons weight? This Unimog is build for 14 tons + 30 tons trailer, so tje drive train should be strong enough to handle that.
- …
What we need
Unimog 2150L Unimog type 437 L38
VIN: WDB4371361W179982
The gears and the housing will be repaired in Bishkek.
The parts we need are:
On the axle (part 5) to the differential:
- Bearing (incl oilseal) 362336B inside small gear
- Bearing for outer side small gear in the housing inside 59 mm outside 88,9 mm
On the wheel “axle”
- Nummer 74 metal ring
- Number 72/71 oilseal 142,5 -175- 13/15
- Large bearing (completely damaged) number unreadable
- NUP312ECP/C3VE171 bearing + ring plates
- Some very thin spacers inner 60 mm to mount the bearing
For housing
(Number inside housing Portal 4373513415 ??)
(number outside housing portal 437 3310105)
- Seal for housing
Brakes
The little brake pistons are worn out. So we want to replace the complete pistons sets in and outside including the rubber seals.
Postal address:
Nomads Home
Vincent Kuiper
Drevesnaja Street 10
720045
Bishkek
Kyrgyzstan