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-   -   Forklift mast not going up properly (https://www.shopfloortalk.com/forums/showthread.php?t=52451)

OldRedFord 09-19-2020 05:19 PM

Forklift mast not going up properly
 
1 Attachment(s)
When I go up with the forklift mast the first stage goes up about half way and then the second starts lifting.

This just started. What could cause this?

Walker 09-19-2020 06:58 PM

First guess is lack of lubrication. Lube the moving parts, put some weight on it and try again.

Whitetrash 09-19-2020 08:51 PM

I'm assuming this occurs with no load any kind of load should make a multi-stage cylinder behave correctly. Culprits bent cylinder rams, seals fucked up, forklift tower screwed up. Pay attention for noises signs of binding Etc.

mccutter 09-19-2020 09:32 PM

Quote:

Originally Posted by Walker (Post 761589)
First guess is lack of lubrication. Lube the moving parts, put some weight on it and try again.

Yup, looks kind of dry to me, too...

Ironman 09-20-2020 10:19 AM

Quote:

Originally Posted by mccutter (Post 761600)
Yup, looks kind of dry to me, too...

Yes, but...
I have the same size machine, and I faithfully greased the shit out of it. And one day I noticed how well that grease collected grit from my grinding wheels and metal shards from the angle grinder. I found out by wiping some grease from the mast off my hand and inbedding shards of metal shavings in my hand.

So I pressure washed it all off as best I could and used a bit of Fluid Film, coupled with twice yearly pressure washing.

mccutter 09-20-2020 01:12 PM

Quote:

Originally Posted by Ironman (Post 761616)
So I pressure washed it all off as best I could and used a bit of Fluid Film, coupled with twice yearly pressure washing.

I just said it looked a little dry. ;) As in NO lubrication. I'm not a fan of excessive grease either...

milomilo 09-20-2020 01:51 PM

The spray white lithium is a good lube and dries so crap will not stick.

OldRedFord 09-20-2020 09:34 PM

First i ran the lift all the way up and down a few times and it started working fine again.

Second I took some general purpose grease and coated the rollers for the mast sections.

bunkclimber 09-21-2020 05:11 AM

not going up properly
 
there's a shuttle valve that is usually located on the mast, follow the hydraulic hose from the truck to the mast,first stop should be a rectangular valve assembly that has a interstage valve..directs the flow to the lower first cylinder then at pressure it opens the flow to the second stage cylinders..sometimes this valve can give the same symptoms..if the first cylinder seals are 'fucked up' as said the pressure will rise and the second stage cyls will start to lift prematurely..this valve sometimes also has descent speed limiters or flow control fro reverse flow so the mast can't descend full speed from a high height.Some lifts have the descent limiting valves in the base of upper cylinders. I have a lift in the shop currently with the same issues but it has the larger lower cylinder seals that are 'fucked up'..the cyl was leaking, we discovered the cylinder was pitted inside,we honed the cylinder but it was too far gone..so we put the $17.00 seal kit into it anyway and reinstalled it just to see if it would work for awhile,pretty tight going back together,so we had our doubts..as we expected, two extensions under load and she seized up,won't go up or down..but at least the rod gland seals still are holding..but the cylinder is to be rebuilt..honed tubing ordered

USMCPOP 09-21-2020 03:00 PM

Quote:

Originally Posted by bunkclimber (Post 761636)
there's a shuttle valve that is usually located on the mast, follow the hydraulic hose from the truck to the mast,first stop should be a rectangular valve assembly that has a interstage valve..directs the flow to the lower first cylinder then at pressure it opens the flow to the second stage cylinders..sometimes this valve can give the same symptoms..if the first cylinder seals are 'fucked up' as said the pressure will rise and the second stage cyls will start to lift prematurely..this valve sometimes also has descent speed limiters or flow control fro reverse flow so the mast can't descend full speed from a high height.Some lifts have the descent limiting valves in the base of upper cylinders. I have a lift in the shop currently with the same issues but it has the larger lower cylinder seals that are 'fucked up'..the cyl was leaking, we discovered the cylinder was pitted inside,we honed the cylinder but it was too far gone..so we put the $17.00 seal kit into it anyway and reinstalled it just to see if it would work for awhile,pretty tight going back together,so we had our doubts..as we expected, two extensions under load and she seized up,won't go up or down..but at least the rod gland seals still are holding..but the cylinder is to be rebuilt..honed tubing ordered

I'm amazed at the accumulated knowledge and experience here. "Been there, doing that."


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