A Field Guide to Bomag Parts Diagrams (Without the $890 Mistake)

I'm a parts manager handling Bomag spare parts orders for about six years now. In my first year (2017), I made the classic mistake of ordering by memory instead of checking the diagram. Ended up with a $3,200 shipment of parts that fit a different model year. Straight to the return pile, with a restocking fee and a 1-week delay for the client. That error cost roughly $890 in total—not including the embarrassment.

After that, and a few smaller screw-ups (like the $450 color-coding error in 2019), I now maintain our team's checklist for reading Bomag parts diagrams. It's saved us a lot of money and headaches. Here's the exact process I use now.

Who This Checklist Is For

This is for anyone who needs to order Bomag spare parts using the official diagrams—service techs, parts counter staff, owners doing their own repairs. The list has 5 steps. If you follow them in order, you'll drastically reduce the chance of a costly mistake.

Step 1: Match the Machine Serial Number (Not Just the Model)

Sounds obvious, but this is where I messed up on that $3,200 order. I saw "BW 200" on the machine and grabbed the diagram for the current model. Turns out, Bomag updated the vibratory system in 2014 for that series. The machine was a 2013 build, and the diagram I used was for a 2015. Different final drive assembly, completely different part numbers.

Checkpoint: Find the machine's serial number plate (usually on the frame near the engine or operator platform). The number looks like 1016 12345. Use that exact number to pull the parts diagram, not just the model name. The model might tell you what family it is, but the serial number tells you the exact configuration.

I've caught 47 potential errors using this single step in the past 18 months.

Step 2: Decode the Diagram Section (The 'Exploded' View)

Once you have the correct diagram, don't just glance at it. Bomag diagrams are sectionalized (engine, drive, vibration system, roller frame, etc.). If you're after an engine part, stay in the engine section. I saw a guy order a hydraulic filter once because he was looking at the general layout view, not the hydraulic system specific diagram. Wrong part.

How I do it:

• Identify the assembly group from the table of contents (usually on the first page of the PDF).
• Find the exploded view for that specific group.
• Do not jump around. A part number in one section will not be valid in another.

Step 3: Verify the Part Number Index (The Often-Ignored Step)

This is the step most people skip. They find the part on the diagram, see its reference number (say, item 12), and then go straight to the parts list and grab the number next to it. Here's the problem: some diagrams have multiple sections on one page, and the parts list might not be right next to the graphic. I once ordered a complete hydraulic pump rebuild kit for $1,200 because I read the wrong line in the index. The line I was looking at was for the optional attachment, not the standard machine. Caught it in time, but it was a close call.

Checkpoint: After you find the reference number (like Pos. 12), go to the parts index table. Do not just look at the line next to your reference. Look at the header of the table. It will say something like "Section 03, Frame & Roller." Make sure that matches the diagram you are looking at. Also, verify that the part description matches what you expect. If it says "Seal Kit" but you're holding a metal gear, something is wrong.

Step 4: The 'Cross-Reference' Reality Check

Once I have the part number, I do a quick cross-reference using the Bomag spare parts system or my dealer's database. I'm looking for two things: 1) Is the part superseded? Bomag will sometimes change a part design and issue a new number. The diagram might show the old number, but the current inventory is the new one. 2) Is it listed as a 'mandatory part' for my machine's serial number range? I've seen cases where a diagram shows a general part, but the correct part for a specific serial number range is different.

Example from my logbook: In September 2022, I needed a bearing for a BW 120. The diagram showed part 123456. The system said "SERIAL NUMBER 1015 67890 - UP, USE 654321." If I had just ordered the diagram part, it would have been the wrong size.

Step 5: The 'Is This a Kit?' Check

This is one of those things that's changed over the years. What was best practice in 2020 may not apply in 2025. Bomag, like many manufacturers, has started packaging what used to be individual spare parts into pre-assembled kits. You might see a seal, a gasket, and a snap ring as three separate items in the diagram. But if you order them separately, you might end up paying $85 for three items, when the official "Seal Kit" (which includes all three + a special grease) is only $60. The diagram might not tell you this. You have to look for it.

My rule: If the part is a seal, filter, or gasket, I always check for a corresponding kit number before ordering individual items. The diagram is a great guide, but it's not always the most cost-effective way to order.

Common Mistakes & Gotchas

Here are a few things I've learned the hard way:

• Don't trust the thumbnail. The small diagram on your screen might look like a simple filter. The actual part might be a massive assembly. Always zoom in.
• Check the revision date. I've seen people using PDFs from 2018 for a 2025 order. Bomag updates these diagrams. An old diagram might have the wrong part number for a current production machine.
• Beware of 'DWG' vs 'P/N'. Sometimes the reference number on the drawing is a drawing number, not a part number. The actual part number is in the index. Don't mix them up.

This checklist isn't perfect—our situation is a mid-size service center with a dedicated stock room. If you're a field tech ordering from a mobile phone, the logic is the same, but the steps might need to be adapted. The fundamentals haven't changed: verify, cross-reference, and don't assume the diagram is perfect.