Mercedes Benz U 40
Built: 1966–1971 · Series: U 421
More machines from model year 1966
Not the right version? The data comes from vehicle registers holding many near-identical versions side by side. Photograph the data plate — we read make and type from it. Open the scanner e-mail address required
Mercedes-Benz U 421: the Unimog U 40 was a four-cylinder implement carrier built from 1966 to 1971 with a 1,988 cm³ engine, 40 hp (29.5 kW) at 3,000 rpm and a weight of 2,450 kg
From the 1950s the Unimog stood for Mercedes-Benz's off-road universal implement carrier, giving smaller farms and municipal services a single machine for towing, attachments and hydraulic work. The U 40 in the U 421 series was one of the lighter versions of this family from 1966 to 1971.
Read on 3 more paragraphs
The four-cylinder engine displaces 1,988 cm³ and produces 40 hp, or 29.5 kW, at 3,000 rpm, is water-cooled, and gives a top speed of 54 km/h. On a 2,250 mm wheelbase the U 40 weighs 2,450 kg, measuring 4,005 mm in length, 1,865 mm in width and 2,180 mm in height, more compact than the larger Unimog series of its time.
With its lower engine output and lighter build, the U 40 was aimed at smaller operations that still wanted to benefit from portal axles, power take-offs and mounting space front and rear, without carrying the purchase and running costs of a heavier series. On the U 40 too, the power take-off and hydraulics run to the standard values usual in farm machinery, so that commercially available attachments can be fitted.
When buying a used example, check the condition of the portal axle gearboxes, rust on the ladder frame, the tightness of the hydraulic couplings, and the condition of the clutch and gearbox in a machine that is now over 50 years old. Spare parts are found mainly through the Unimog enthusiast scene.
Sources: SpecCodex-Register: Kennwerte des Modells U 40, Mercedes-Benz
Technical data
Engine
| Fuel | dieselcorrect |
|---|---|
| Power | 40 hp (29.5 kW)correct |
| Rated speed | 3,000 rpmcorrect |
| Cylinders | 4correct |
| Displacement | 1,988 cm³correct |
| Cooling | water-cooledcorrect |
Dimensions and weights
| Length | 4,005 mmcorrect |
|---|---|
| Width | 1,865 mmcorrect |
| Height | 2,180 mmcorrect |
| Wheelbase | 2,250 mmcorrect |
| Ground clearance | 395 mmcorrect |
| Unladen weight | 2,450 kgcorrect |
Drivetrain and chassis
| Drive | four-wheel drivecorrect |
|---|---|
| Gearbox | 6/2 vollsynchronisiertcorrect |
| Reverse gears | 2correct |
| Front tyres | 10, 5-18correct |
| Rear tyres | 10, 5-18correct |
| Top speed | 54 km/hcorrect |
Working data
| Fuel tank capacity | 75 lcorrect |
|---|
Origin and approval
| Construction | (Unimog)correct |
|---|---|
| Units built | ca. 19.000correct |
Where this model stands
Power-to-weight ratio: 12 kW/t (30 kW / 2.5 t)
Power class: Compact (< 40 hp)
Stronger than 25% of the tractors in the register — out of 15,663 models with a stated power figure.
Calculated from the documented figures above — not a rating.
Frequently asked questions
How much power does the Mercedes Benz U 40 have?
The Mercedes Benz U 40 delivers 40 hp.
How much does the Mercedes Benz U 40 weigh?
The unladen weight is 2,450 kg.
What engine does the Mercedes Benz U 40 have?
4 cylinders, 1,988 cm³ displacement, Diesel.
How fast does the Mercedes Benz U 40 go?
Top speed is 54 km/h.
What are the dimensions of the Mercedes Benz U 40?
4,005 mm × 1,865 mm × 2,180 mm.
When was the Mercedes Benz U 40 built?
Production years: 1966–1971.
What to check before buying
- Check the hour meter against the service records — a replaced instrument is the most common gap.
- Compare the data plate and chassis number with the papers.
- Check the weights in the papers against the figures here — attachments change them.
- Check front and rear tyre sizes: mismatched pairs strain the drivetrain.
- Shift the gearbox cold and warm — jumps only show up at temperature.
- Load the hydraulics and watch for sag.
- Ask about parts availability for this build year — the running costs hang on it.
A general list for this type of machine — no substitute for an inspection or an appraiser.
We do not sell machines. We ask the dealers who carry this model and come back with price and lead time.
Request a quote →
We ask the suppliers and come back with price and lead time.
Request spare parts →
This page carries 23 individual figures for this model. They come from 1 recorded source; every figure can be traced there. What we cannot document is not here — we leave gaps open rather than estimate them.
Missing a figure you were looking for? Report it →
Know this machine better? Have a photo, a manual, or know that a figure is wrong? Add it to the register →
Sources: [1]
Tractor in 3D section
Turn the model, look inside and click an assembly — each one is explained.