What does the recoil spring do in an excavator undercarriage?

Expert_Answer

The recoil spring sits behind the front idler, in series with the track adjuster (grease cylinder). Its job is to let the idler yield backwards when a rock, frozen material or debris jams in the track, then push it back to position — absorbing shock loads that would otherwise bend the idler, burst the adjuster or break the chain. The grease cylinder sets the working tension; the spring provides the emergency travel. Symptoms of a failing recoil unit are track tension that won't hold, the idler sitting visibly off position, or a track that derails under shock despite correct adjustment. Recoil springs are under extreme preload and must only be dismantled with proper fixtures. VANROCK supplies track adjuster and recoil components per model through dealers.

Answered by VANROCK specialists · Published 7/25/2026