Page last updated 7 Aug 96. Added part numbers for 404.1 w/ 180.928 engine.
Warning:This document has not been independently checked for errors.
Maintenance schedule for a 404.1, and service parts for a 404.1 with the M180.928 engine.

Maintenance Schedule: Unimog-S (404.1)

The schedule is based on service intervals of 4,000 kms (2,500 miles). In addition, checks on engine oil level, coolant level (a corrosion inhibitor or anti-freeze should be used all year round), tire pressures (normal: 35 psi - front and rear), tightness of wheel nuts (30 miles after wheel change) and air brake equipment (if fitted) should be carried out more frequently. If the vehicle is only used occasionally, oil changes in engine, transmission and axles should be carried out annually.
1.   Drain and replace engine oil every 2,500 miles.  Replace  
     oil filter and seals every 2nd oil change.  Before
     starting engine after an oil change, turn engine without  
     ignition until oil pressure is indicated on gauge.  Then  
     start engine.  This procedure should also always be 
     followed if the vehicle has been left to stand for more
     than 3 weeks.

     If the vehicle is used predominantly off-road, oil
     change intervals should be based on the amount of fuel
     used since the last oil change (265 US gallons).

2.   Check and adjust engine valve clearances between camshaft
     and rocker arms with feeler gauges every 5,000 miles:

     Engine cold:   Inlet:    0,10mm    Exhaust:  0,20mm
                              0.004"              0.008"

     Engine warm:   Inlet:    0,15mm    Exhaust:  0,25mm
                              0.006"              0.010"

     If the clearance is not correct, it must be adjusted by
     turning the ball pin head adjuster either in or out as
     required.  This procedure is facilitated by use of
     adjustment tool (111 589 00 01 00).  Should the adjuster
     be loose on its base (<14.5 - either the ball pin
     head or its base or both should be replaced to prevent
     rotation and changes to the valve clearances whilst the
     engine is running.

     If the adjuster screw bottoms out in the base before the
     minimum clearance is achieved, the plate in the top of
     the valve spring keeper can be replaced with a thinner

3.   Clean out fuel filter every 2,500 miles.

4.   Clean mesh filter in fuel pump every 5,000 miles.

5.   Drain and replace oil in air compressor (if fitted) every
     2,500 miles.

6.   Check and tighten all manifold and exhaust fittings every
     5,000 miles.

7.   Replace oil and clean air filter every 2,500 miles.
     Weekly if operating in very dusty conditions.

8.   Remove and check spark plugs every 2,500 miles.  If to be
     reused, clean and reset gap to 0,50mm (0.020").  Replace
     plugs every 10,000 miles.

9.   Check mobility of butterfly valve in exhaust manifold
     every 2,500 miles. (DO NOT LUBRICATE!).  If necessary
     replace bimetallic spring.

10.  Check and adjust tightness of all V-belts every 2,500

11.  Check oil levels (EP90) in water pump and fan hub every
     5,000 miles.  Top-up if necessary.  If water is present
     in the water pump oil, the seal in the housing will need
     to be replaced.  Do not block the drain hole of a leaking
     pump as this will cause water to accumulate and damage
     the bearings in the pump.

12.  Check distributor components and breaker gap every 5,000
     miles.  Inspect distributor cap for cracks and wear. 
     Check points are not burnt and that gap is 0,40mm
     (0.016").  Engine can be rotated by jacking up one rear
     wheel with 6th gear engaged and turning wheel forwards to
     allow adjustment of gap.  The setting should be checked
     using electronic equipment to achieve a dwell angle of
     36-38.  If the vehicle is fitted with braided ignition
     wires, it will be necessary to improvise connections to
     allow hooking up to electronic test equipment.

     Moisten felt in distributor shaft with a few drops of oil
     and lightly grease rubbing block and cam.  Ensure no oil
     or grease on points.

     Pack connections of ignition leads to distributor with
     silicone grease.

13.  Check tightness of screws on fuel lift pump every 10,000

14.  Lubricate choke cable every 10,000 miles with a few drops
     of oil.

15.  Remove and clean out carburetor every 10,000 miles. 
     Before loosening from manifold, remove the fragile
     mixture control screws from the base.  A gasket set will
     be required to rebuild the carburetor.

16.  Check brake fluid level and brake drum adjustments (cold)
     every 2,500 miles.  Check hoses and brake lines for
     damage and corrosion.  Avoid contaminating hoses with
     solvents.  Check brake pedal has 10mm (0.4") free-play. 
     Adjust handbrake settings (through hole in rear brake
     plate and not the cable) only after brake shoes have been
     correctly adjusted.

17.  Check tightness of all chassis frame nuts and bolts
     including engine/gearbox mountings, suspension components
     and axles every 2,500 miles.

18.  Check clutch pedal free-play with engine running every
     2,500 miles.  The clutch pedal must have at least 35mm
     (1.4") travel before the release bearing makes contact
     with the clutch pressure plate.  To adjust, stop engine
     and adjust the length of the threaded push-rod as
     required.  Recheck free-play with engine running until
     required travel is achieved.

19.  Check operation of differential lock linkage every 2,500

20.  Check gearbox oil level every 2,500 miles.  Drain and
     replace oil every 10,000 miles (EP80/90).  Note that
     there are 2 drain plugs.

21.  Check axle and hub reduction oil levels in both axles
     every 2,500 miles.  Drain and replace oil every 10,000
     miles (EP80/90).  Note that there are 3 drain plugs per

22.  Apply grease gun every 2,500 miles to:

     Transmission output ball housings (2) 
     Swivel (king) pins on front axle (4)
     Universal joints of front axle drive shafts (4)
     Steering ball joints (6)
     Handbrake and control lever shafts
     Clutch release shaft on bell housing (1)
     PTO shaft joints (if fitted)

23.  Rotate wheel and tire assemblies every 2,500 miles. 
     Check toe-in: +3-1 mm.  Try for 0 with vehicle unladen.

24.  Lightly spray underside of vehicle with oil to protect
     against corrosion every 2,500 miles, shielding all rubber

25.  Check oil level in steering box every 5,000 miles.

26.  Check oil level in PTO relay housing (if fitted) every
     5,000 miles.

27.  Check air brake equipment (if fitted) for correct
     function and leaks every 5,000 miles.

28.  Check drop arm for tightness on steering box every 5,000

29.  Check suspension and steering dampers for leaks and
     damage every 5,000 miles.

30.  Remove and clean brake drums (use 2 M10 bolts to pull off
     drums after shoes have been slackened), check and clean
     brake linings (do not use solvents) every 5,000 miles. 
     Replace linings if worn down to the rivets.

31.  Check battery acid level and density every 2,500 miles. 
     Clean and grease terminals.

32.  Check all electrical equipment for correct operation and
     headlamp adjustment every 5,000 miles.

33.  Check all electrical cables and connections for damage,
     tightness and corrosion every 10,000 miles.  Check
     alternator mountings.

34.  Lubricate all hinges on body and towing hitch every 5,000

35.  Check all cab and body mountings for tightness every
     10,000 miles.

Service Parts

This is a list of service parts for a Unimog 404.1 with an M180.928 engine. These part numbers may change as newer parts supersede old ones, so check with the latest microfiche.

If you find that a part number has been changed, please send me mail so I can update this list.

Head gasket set          180 586 44 90
Head gasket              180 016 35 20
Piston ring set STD      002 586 22 03
Carburetor O/H kit       180 586 01 90
Fuel lift pump kit       180 586 02 90
DC Generator brush       000 154 26 14  600W/24V 
Starter drive gear       000 151 16 13

Ignition components for short-distance radio shielded,
splashproof ignition system:

Distributor service kit  180 586 03 90
Cap                      000 158 25 02  Bosch 1.235.522.267
Rotor                    000 158 20 31  Bosch 1.234.332.088
Points                   000 158 08 90  Bosch
Spark plug               000 159 84 03  

Oil filter               000 180 00 09

Fan belt 9.5 x 875mm     007753 009505
Fan belt 9.5 x 925mm     007753 009507
Fan belt 9.5 x 900mm     007753 009506  Hot climate (2x)

Hub oil seal             404 337 02 60
Wheel stud               404 401 00 71
Wheel nut                074361 018105
Brake lining axle set    404 421 05 10  oversize 6.4mm
Brake drum screw         404 990 02 30
Suspension damper STD    404 323 01 00  (4x)
Suspension damper HD     002 323 69 00  (4x)
HD front spring          404 321 00 04  SA 35254/1
HD rear spring           404 324 01 04  SA 35254/1

Brake master cyl. kit    000 586 01 88

Clutch pressure plate    000 250 20 04
Clutch paddle plate      003 250 38 03  Sintermetall
Clutch release bearing   000 250 32 15

Gearbox gasket set       404 586 00 85

Fuel pre-filter          000 477 91 01

Sealing ringng exhaust   153 492 01 08  Pipe to manifold
Silencer                 404 491 00 01  or 404 491 01 01

Rubber mounting G/B      404 241 00 13  

Water pump               127 200 04 01
Thermostat               001 203 08 75
Coolant vent pipe        180 200 04 58
Radiator mtg             404 504 00 12
Radiator mtg             404 504 02 12

Wiper blade 270mm        000 824 21 26
Speedocable              075532 000000
Windscreen               404 671 04 10

Unimog hydraulic jack    000 583 88 15

Gaiter H/B cable         000 427 02 96
Boot steering joint      000 330 02 85
Steering joint           000 338 18 10

Bush front engine mtg    180 223 04 12

Fuel gauge               001 542 18 03
Fuel level transmitter   001 544 29 32

Electric fuel pump 24V   000 470 07 94

Take me back to the Unimog-S 404 FAQ.
Patrick Tufts