maybe the sub-assy regulator on the control valve defective it's look like a check valve with a strainer inside on it try to replace it. i already encountered this problem....goodluck

the spring issue is remedied with a new style kit. have had problems with seats in the switch area (some), no hood hinge issues. as for the regulator you might try the Amine compatible replacement kit. much of the fuel in this area has some of this stuff in it and it is extremely volatile to the high pressure valve. if you are having complete washouts of the seal material this will help.

Once again this problem has resurfaced. Now it is a few different lifts, one in particular will go up, but will not come down even without load, safety check valves replaced just to be sure that isn't the issue. Springs are likely broken in these as well. I have no intention to fix this out of pocket anymore, there are far too many problems with this.

I have observed several problems with these lifts, from hood hinges and seats breaking to regulators that last between 400-600 hours like clockwork. Is anyone else having regular issues with the same components of these lifts?

your right it was a broken spring, on all 6 machines.

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alright, it is QSV (quad stage mast) with the class 2 carriage. All functions are normal with nominal loading. It is related to a higher pressure in the system, it feels like the selenoid just doesn't have what it takes to allow loaded freefall at the preset rate.

This is the opposite function, it will not come down with heavier loads, and almost ALWAYS does it at any height even 6 inches off the ground. The lift properly stages, mast is properly adjusted, including chains and roller shims, the carriage rollers are adjusted correctly and the tracks are clean and free of debris. I have also observed the rollers within the track at the maximum load stated on the dataplate, or three tugger batteries. We also inked the tracks to see if there was a scrub spot that for whatever reason we weren't catching. Nothing unusual. We did all this to eliminate it as a cause. I've also personally observed operating environment of these lifts, they should not be malfunctioning under these conditions at all.

I have to stay far ahead on PMs and weekly/daily checks here because these lifts never rest, they are operated 21.5 hours a day, and that is no joke. Having four of my fleet and that number continues to grow as we are forced to repurpose the lifts around the plant for people who don't use them for heavy pallets or stack. That is becoming an issue for management when they cannot reassign personnel to help out in a different department for this reason. It anyone has any ideas, I am all ears.

Also wanted to say Toyota has pretty much said it cannot be their electronics, sensors or valves. And that they wouldn't consider it a factory defect.

would you mind describing in more detail the nature of the malfuntion? Are the cyls or mast rails mis-staging at any point in their travel, or does everything work normaly until they are lowered from a certain hieght and then just lock up? Also, what type of mast is this? Toyota or some other brand like lift tech? 2 stage, TT, or Quad configuration?

I am not familiar with this toyota model, but I have seen similar problems in other machines. On Nissans with TT type masts I have seen the check valve inside the center cyl malfuntion and cause the center cyl's ram to lock up. Usualy what happens is the ram will only move through the first half of its travel & stop, then the outer cyls start lifting, but I have seen it happen the other way around too, the center cyl raises normaly, but then locks up while it is on the way back down.

I have also seen masts with rollers that were damaged, or shimmed to tightly lock up when lowering with low or no load. Including one location where three machines had been damaged the same way(damaged carriage rollers) by the same operator.