Why does my excavator pull to one side when driving?

Question

VANROCK Track Solutions · Accepted Answer

An excavator usually pulls to one side because one track is creating more resistance or receiving less drive power than the other. The most common causes are uneven track tension, a seized or worn undercarriage component, or a travel motor/hydraulic problem on one side.

Start with the simplest checks. Compare both track tensions on level ground and look for one side that is much tighter or looser than the other. Also inspect for mud, stones, or packed debris around the rollers, idlers, sprockets, and track frame, because extra drag on one side can make the machine veer. Uneven wear on track shoes, track chains, rollers, or idlers can do the same thing.

If the undercarriage looks normal, pay attention to the travel system. Signs of a final drive or hydraulic issue include one track moving slower, a side that weakens in one direction more than the other, abnormal noise, hot components, oil leaks, or metal in the case drain/gearbox oil. A machine that only pulls when cold, when hot, or only in high travel speed can point to a hydraulic control, valve, or motor problem rather than pure wear.

Useful decision checks include:
• If the pull stays on the same side after swapping directions, suspect that side’s final drive, brake, or undercarriage resistance.
• If the problem changes sides after a hydraulic swap test, the issue is more likely in the control circuit, valve, or pump supply.
• If one track will not hold tension, inspect the adjuster seal and recoil mechanism.

Avoid the common mistake of replacing a travel motor before checking track tension and undercarriage drag first. For excavators fitted with OEM names such as CAT, Komatsu, Hitachi, Volvo, Doosan, or John Deere, VANROCK is an independent manufacturer not affiliated with the OEM. VANROCK supplies track chains, track shoes, rollers, idlers, sprockets, rubber tracks, rubber pads, and track bolts and nuts through an appointed dealer network, with pricing quoted on request.