Toyota Hilux: Rear leaf spring fatigue and U-bolt corrosion

The rear leaf spring packs on LN-series Hilux are subject to fatigue cracking and loss of arch, especially on vehicles used for load carrying. U-bolts, spring plates, and hangers corrode heavily on vehicles used in coastal NZ or exposed to wet conditions. Seized U-bolt nuts are common. Sagging or cracked leaves alter load-carrying capacity and handling geometry, and cracked leaves are a WoF failure.

• Rear sitting noticeably lower than front or lower than when new
• Clunking or squeaking from rear under load or over bumps
• Visible rust or cracking on leaf spring packs
• Uneven rear tyre wear from altered axle geometry
• Difficulty removing U-bolts due to corrosion seizure

1. 1

   Inspect all leaf spring leaves for cracking, fatigue, or separation.

2. 2

   Check U-bolts and spring plates for deep corrosion — probe with a screwdriver for pitting.

3. 3

   Look for mismatched spring packs indicating prior replacement of one side only.

Parts involved: Rear leaf spring, Body corrosion.

$500 to $1,400 at New Zealand independent workshop rates. That is for this job on its own, not for the car.

An estimate, in NZD, for the repair as normally carried out. What a specific car costs depends on which part has failed and what it damaged on the way — treat this as the floor for a negotiation, not a quote.

• “Has the vehicle regularly carried heavy loads in the tray?”
• “Have the U-bolts ever been replaced or re-torqued?”
• “Has it been used near the coast or in wet conditions?”

The failure described above is documented in published sources — owner forums, technical service bulletins, recall notices and workshop write-ups — held in our fault database. The inspection instructions and the cost estimate are KickTyres’ own interpretation of them, and it is a starting point for an inspection rather than a manufacturer statement.