6 Forklift Mast Problems: Which Ones Can Wait and Which Ones Can't

Your driver says the forks felt rough on the way up. You walk out and look at the forklift mast, and it looks the same as it looked last month. Now you've got a call to make with loads already scheduled. 

Most mast wear happens inside the pins, rollers, and cylinders, where a walkaround can't reach it. What you can see is the symptoms that wear throws off, and several of those tell you enough to act on without a single tool. 

Here are six to check on your Piggyback, and what each one means for the week ahead. Four of them can wait for a shop day you pick. Two can't. 

1. Slack on One Side, or Forks That Don't Sit Level 

Put the forks on the ground and look at the two chains. One hanging looser than the other means the chain has been wearing at the pins, which lengthens it a fraction at a time. 

Under 2 percent elongation is acceptable. At 3 percent, a leaf chain used for lifting has to come off, and the machine stays down until the new one is on. On a one-inch-pitch chain, the whole margin between those two numbers is about an eighth of an inch across a foot of chain. 

You can see the slack. You can't see the eighth of an inch, and that's what a chain wear gauge is for. Get it measured while you still pick the shop day. 

2. A Rough Patch at the Same Height Every Lift  

When a driver reports rough lifting, ask where in the travel it happens. A lift that runs smooth except for one spot, at the same height every time, usually means a roller has a flat spot or a pin starting to seize. Rough operation that doesn't repeat at a consistent height is worth checking against other problems on the machine.

One bad roller changes how the whole carriage travels. It grows into chatter, then binding, then grooving in the channel the roller rides in. Once the channel is grooved, you're buying more than a roller. 

Call this one in sooner rather than later. The longer you leave it, the worse the damage gets. 

3. A Carriage That Moves Side to Side 

With the forks empty and on the ground, take hold of the carriage and work it side to side. Some movement is normal, and how much depends on the mast. You can find the figure in that machine's service spec.

More movement than the spec allows means worn rollers, worn channels, or loose mounting hardware. On a Piggyback it can also point to the mounting system itself, because road vibration runs load through the mast and into the brackets every mile. 

Feel won't tell you how far past the spec you are. Get it measured before the machine goes back out. 

4. An Oil Film on the Cylinder Rod 

Wipe the chrome rods on the lift and tilt cylinders clean at the start of a shift. Run the machine like you normally would. At the end of the day, look at those rods again. A fresh film of oil on one, with dust stuck to it, means that cylinder is leaking past its seal.  

A leaking forklift mast cylinder still lifts and still holds a load, so nothing about this stops the machine today. The leak gets worse, though, and a cylinder that loses enough oil stops holding a raised load. Get it on the schedule. 

5. A Raised Load That Settles With the Control in Neutral 

Raise a typical load, put the control in neutral, and watch the carriage. If it comes down on its own, stop there. That's cylinder drift. 

An eighth of an inch of movement over five minutes is acceptable. A quarter inch or more is a failure. 

This is a safety problem, not just a performance one. A raised load that comes down on its own can come down on whoever is standing under it. Take the machine out of service the day you find it and get it into a shop. 

6. Cracked Link Plates or Damaged Chain 

Chains and rollers are already on the daily inspection list. When you get there, look for: 

• Cracks in the link plates 
  
  
• Pins that have turned or backed out 
  
  
• Rust in the joints 
  
  
• Stiff links that won't flex 
  
  

All of those are damage rather than wear. A worn chain gives you a measurement and some time to act on it. A cracked plate can let go at any load, with no warning first. 

29 CFR 1910.178 takes a forklift with a safety defect out of service until the repairs are done. Tag it out and get it into a shop. Nobody finishes the shift on it.  

Bring It In: Schedule a Mast Inspection with Beamer's Piggyback 

A mast that looks fine can still be worn, and your driver is usually the first one to notice. If anything on this list turned up on your machine, bring it in. 

Beamer's works on Piggyback masts every day, on trucks running highway miles and unloading on gravel instead of a level slab. We'll tell you what the mast needs and how soon it needs it, then handle the forklift mast repair work from there.

Schedule Your Mast Inspection.