Quick checks before you begin
- Document which drum and bar shows the problem before adjustment.
- Isolate the machine before access; movement tests require the complete manual procedure and qualified personnel.
- Record whether the bar is assembled, disassembled or still installed.
Which question are you trying to answer?
| Check | What it measures | What it does not prove |
|---|---|---|
| Bench straightness | Bar geometry in the specified fixture, with the locating pin or alignment gauge appropriate to its state | That all installed bars have the same spindle height. |
| Follower alignment | Follower position relative to the fixture gauge and tolerance ring | That the bore, sleeve and the checking fixture are all unworn. |
| Installed bar leveling | Relative spindle-plane height from bar to bar on a drum | That a distorted removed bar is straight or can be corrected by adding shims. |
When the checks become relevant
Ask for a bench assessment when distortion is suspected, a shaft binds during removal, or a bar is being rebuilt and the specified gauge does not fit as expected. The assembled-bar and disassembled-bar checks use different setups.
Investigate installed height when the work or observations point to differences between bars. TM2109 explains that a low bar can doff poorly and wrap cotton, while a high bar can increase doffer-pad wear after adjustment to the other bars. Those relationships are reasons to measure, not proof that every wrapping symptom is a leveling fault.
What a useful workshop record includes
TM2109 describes S201 straightener checks, GAD-9908 fixture checks and an installed planing-gauge procedure. A gauge that does not fit is a reason to investigate the setup, bore, journal or geometry under that procedure, not an instruction to force it or immediately condemn the bar.
- Unit and drum identity, the starting bar and each subsequent bar position.
- Whether the bar was assembled or disassembled for the straightness check.
- The specified fixture/gauge used and confirmation that the checking equipment itself was checked for alignment and wear.
- The actual readings, their units and the manual criteria used by the technician.
- The before/after result if a correction was performed, plus the reason for the correction.
Choose the next step from measurements, not appearance
If the bench check fails, keep the bar out of service until the workshop has assessed the condition and the correct repair route. If bench checks pass but installed heights differ, investigate the installed leveling setup separately.
If both are within the applicable criteria and the symptom remains, return to the relevant spindle, doffer, moistener or lubrication checks. Do not keep changing bar height to chase an unexplained symptom.
The full leveling procedure includes controlled machine movement and critical gauge positioning. This page deliberately does not provide tether-mode instructions, bending forces or shim-setting values. Never reach into moving units or use a measuring gauge as a press block.
Bar leveling is not cabinet alignment
A straight bar or a corrected spindle plane does not prove the cabinet and cam-track geometry is correct. After major overhaul or extensive cabinet damage, assess the separate Section 90 alignment requirements.
Do not add bar shims to conceal an unexplained track or cabinet problem. Keep the bar measurements and cabinet inspection record separate and complete the appropriate post-repair checks.
- 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
Will leveling fix a bent picker bar?
Leveling and straightness are different checks. Changing installed height does not establish or correct bench straightness.
Is wrapping proof that a bar is too low?
No. Unequal height is one documented relationship to investigate. Spindle condition, doffing, moistening and operating conditions can also require checks.