The accuracy of the machine's rotation sensor is directly related to the integrity of the machine's hose tray and guide rods.

There are several different types of hose trays by machine manufacturer. However, the importance of having a straight hose tray and guide rods remains the same.

Properly fitted guide rod and hanger
As seen in the image, the guide rod should be secured within the hanger bracket and have just enough play for free movement.

Worn guide rod and hanger
If you find that the guide rods have been worn excessively or have broken free of the hanger brackets, you will need to rectify this issue.
It is up to the Topcon dealer if they choose to address and rectify the problem, or they may ask the equipment's owner to do so.
The Topcon system will not be accurate until the worn guide rod and hangers are properly shimmed.

It is also recommended to check the hose tray pin which attaches the hose tray to the underside of the hydraulic swivel.
This is another source for slop in the machine's rotation reading and will directly affect machine accuracy and performance.
The image is of a properly fitted hose tray on a John Deere 772GP grader.

To shim up the guide rod:
- Ensure the rods are straight.
- Using a washer large enough to allow the guide rod to have free movement, weld the washer to the existing hanger bracket.
Topcon has several bushing kits available, depending on the machine's manufacturer. These shims, if available, are included in the machine installation kits.
