Quick checks before you begin
- Isolate and secure the unit before access; do not turn the powered mechanism for a photo.
- Record the unit, bar and original cam track before parts are mixed.
- Photograph the outside rolling surface and the bore of the safely removed part.
Confirm you are checking the cam follower roller
The cam roller bushing runs in the cam track at the picker-bar follower. The pressed bushings inside a spindle nut support a different component. Their measurements, tools and replacement decisions are not interchangeable.
If you cannot identify the location, keep the removed part with a photo of where it came from. Use the part-number lookup or ask for identification before ordering a bushing by name alone.
Record these checks together
| Check | What to record | Next step |
|---|---|---|
| Rolling surface | Number and width of flat spots, with a clear photo | Compare against the exact manual criteria; do not judge only by shine or surface color. |
| Original cam track | Whether the removed roller fits and rotates during the specified isolated inspection | A roller that fails the manual's track-fit check needs a replacement decision; do not grind it to make it fit. |
| Bore and outside diameter | Actual ID and OD, units, measuring tool and part identity | Assess both dimensions and the combined wear calculation required by the manual, not one dimension in isolation. |
| Follower stud | Contact condition and measured size for technician review | Check the mating stud as well as the roller before choosing replacement parts. |
A good-looking roller can still need measurement
TM2109 Section 40-05 uses separate surface, track-fit and dimensional checks, including a combined wear assessment. Passing a visual check does not complete that assessment.
This article does not reproduce the dimensional acceptance table. Verify the limits and units against the applicable service documentation before deciding that a roller can return to service. If the unit or revision is uncertain, record the measurements but leave the pass/fail decision open.
What to do with the findings
- If damage or track-fit failure is confirmed under the manual criteria, identify the correct roller and inspect its mating components before ordering.
- If measurements meet the applicable limits, continue the picker-bar inspection rather than replacing the roller just because it is accessible.
- If binding remains unexplained, stop the adjustment attempt and have the follower, track and bar checked together by a qualified technician.
Send the exact reference if known, unit type, removed position, bore/OD measurements and photos of the roller and stud. A reference match identifies a catalog record; it does not diagnose the fault.
Check the track separately before calling the roller repair complete
A roller’s surface, dimensional and track-fit checks do not replace the full cam-track wear inspection. TM2109 Section 90 specifies a separate gauge check around the track; Section 40 addresses the roller and follower.
Keep roller wear, track wear and cabinet alignment results separate. Replacing one component is not evidence that the other relationships are acceptable.
- Check cam-track wear and cabinet alignment
Track wear, roller wear and cabinet alignment require different checks.
Technical basis for this article
The article paraphrases and organizes the sources below. It does not copy a service manual, and it does not replace the current documentation for the exact machine.
- TM2109 — PRO-12, PRO-12 VRS and PRO-16 Picking Unit Repair (20 July 2020), Section 40, Group 05John Deere Des Moines Works | repair manual
Bibliographic reference. Use the applicable manual for the installed unit. The purchased manual is not hosted on this website.
- TM2109 — PRO-12, PRO-12 VRS and PRO-16 Picking Unit Repair (20 July 2020), Sections 30 and 90, Group 05John Deere Des Moines Works | repair manual
Text, specification tables and illustrations reviewed: printed pages 30-05-1–6 and 90-05-1–5. Bibliographic reference only; the purchased manual is not hosted here. Verify the current procedure for the installed configuration.
Questions buyers and technicians ask
Is this the same as a spindle-nut bushing?
No. The cam roller is part of the bar's follower and track relationship. Spindle-nut bushings support the spindle and require a different inspection.
Can outside diameter alone prove the roller is usable?
No. The manual also checks the rolling surface, track fit, internal diameter and combined wear. Use the applicable criteria together.