How to fit the recoil spring / track adjuster assembly

1. Park and lift machine

• Park on level ground.
• Raise the side you are working on.
• Support machine securely.
• Release track tension first.

2. Release track tension

Locate the grease adjuster valve near the idler.

Slowly loosen the bleed valve or grease nipple:

• grease will come out
• idler retracts backward
• track becomes loose

Do this slowly and stand clear. Sometimes dirt pressure keeps tension on the system.

3. Remove the track

Usually easiest by:

• walking the track off the front idler
• or removing master pin if fitted

4. Remove old recoil/adjuster assembly

The CX31B recoil assembly normally slides out from the track frame after:

• removing retaining bolts/stops
• disconnecting idler yoke
• sliding assembly rearward

Inspect:

• idler rails
• adjuster rod
• grease leaks
• cracked spring housing

Broken springs and leaking seals are common failures.

5. Install new assembly

If using a complete assembly:

• grease the sliding surfaces
• align adjuster rod with idler yoke
• slide unit into frame carefully
• install retaining hardware
• reconnect idler

Do NOT try to compress the recoil spring manually.

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How to adjust track tension

After reinstalling the track:

1. Pump grease into adjuster

Use a grease gun on the adjuster fitting.

Grease pressure pushes the idler forward:

• tightening the track
• compressing the recoil spring slightly

2. Check track sag

For a mini excavator like the CX31B:

• lift track off ground
• rotate track
• measure sag midway between rollers

Typical sag is around:

• 10–20 mm for normal conditions

Too tight:

• accelerates wear
• damages bearings/final drive

Too loose:

• throws tracks
• damages recoil housing

3. Recheck after operation

Run machine for 10–15 minutes and check tension again.

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Common problems

 

Lucas Parts stocks a range of track adjuster and recoil spring assemblies for many excavator models.

Properly maintaining  track tension is rictical for receiving satifactory track life, 

and track adjusters are designed to absorb shock to protect idlers and track systems.

Common issues in a loss of tension:

• broken springs lead to too soft tension
• damaged seals cause by bent cylinder rod