I just acquired an ancient 3000 lb Clark forklift. The machine was used regularly in a retail establishment which was being auctioned off due to illness of the owner. It was well used but had been running without any problems. Unfortunately, now that I have it, it has a tendency for the clutch to lock up if it sits for a couple of days. It has a multiplate dry clutch that is reasonably accessible. I was able to break it loose by holding the clutch pedal down with a hunk of 2×4 and towing it a short distance in gear.
I remember hearing that this type of problem was typical with some types of tractors and that the owners parked them with the clutch pedal held down. Any better solutions? I won’t have suitable ground for popping it loose (tires will just skid) where I want to use it. Is anyone aware of any type of spray that will keep the plates from sticking together while still allowing enough friction for the clutch to work? Won’t have a place to pull the clutch out of the forklift until I finish my shop some time in the future.
Replies
I can only think of 2 things that would make a clutch stick in the engaged position.
First would be sticking linkage. Have you looked it over to see if something's binding? It could be that some lubrication is all that it needs.
The second possible problem I know of is grease on the pressure plates. We used to have a combine that had a grease zerk for the throw-out bearing. One time we shot too much in there and it got on the pressure plates.
The cutch would not disengage unless you hit the brakes hard so it started slipping. The only solution in that case was to disassemble it and clean it.
Farm equipment places will work on things like your machine. They're typically looking for work during the off season around here. (Which is now)
Actually, this is a fairly common problem with some machines. You see a lot of this with the early model Komatsu dozers that were imported from Japan. Any machine that was exposed to a salt water environment accelerates the problem.
Inside the clutch pack, is a series of metal and fiber discs. They slide on the inner and outer splines of the clutch drums. What happens is that the buildup of worn clutch fiber and rust locks these plates onto the spline and they can't release by sliding back and forth.
The only way to remedy this is to pull the clutches and sandblast the teeth on the drums and probably replace all of the discs. There are good aftermarket clutch parts available on EBay or from many suppliers in heavy equipment magazines such as Machinery Trader.
I coat the drums with Boeshield before assembly. Make sure you let it dry thoroughly before you assemble the clutch packs.
In extreme cases, you will find the rust buildup between the fiber face and the steel backing plate on the fiber discs will actually increase the thickness of the clutch pack so much that it won't release.
I agree with the BoJangles, the problem sounds like corrosion on the splines, which is making it so the clutch stack wont slide. It's also possible that what you have is an oil leak that has combined old oil with clutch disk dust to to make a sticky goo. The trouble is you can't get at it without dissassembly of the whole thing.
I haven't worked on any really old Clarks, so I don't know what access there is to the assembly without taking the thing apart. That said, if the problem is clutch dust, oil, and other stuff sticking it together, you might be able to free it up a little by spraying a can of brake cleaner into the assembly to wash out the built up residue. I give it low odds of working, but a can of brake cleaner is cheap (less than $10 around here), so I'd give it a shot.
One word of caution - brake cleaner is toxic stuff (as in causes cancer). Breathing the vapors is bad, but it also absorbs right through your skin, which is almost as bad. It will also remove paint, dissolve pavement, etc. Given the age of your machine, the clutch disks will contain asbestos - also bad. Clean the clutch outside, but be careful with the stuff that drips out.
Edited 6/8/2006 6:42 pm ET by FlashGordon
Edited 6/8/2006 6:43 pm ET by FlashGordon
Casey --
Look for a response from a guy named frenchy. He's breaktime's resident expert on forklifts, he's in the equipment business.
-- J.S.
in multi disk cluchpacks they usually ride in a spoked "cage" stacked disk,plate,disk,plate... the disks are free floating and the plates are male/female with the spokes of the cage... this is usually where the burrs would be that cause sticking problems... i'm not sure it'd be very good for your springs to keep it depressed when not in use... but i might try keep'n a little pressure on it... the other thing that can happen is rust... some plates and disks will rust together... almost welding to each other... it'd try a few things ... i wouldn't be scared to try to pressure wash the clutch assy you might get 30yrs of crud out... the brake cleaner might do a little but...as good as that suff is... 30yrs is alot of crud... high pressure water shouldn't hurt anything in there... i'd do it both with it running and not... but then i'm never scared of screw'n something up i know i can fix...
good luck
p
Thanks folks,
The clutch has an access plate that is about 8"x20" that gives a lot of access from the top of the folklift. I may undo the screws to the pressure plate and see wht it looks like. I think the idea of the fibers and junk is more likely than the sticking splines, but I will check that out. I may even try the break cleaner, assuming the EPA doesn't find out...
My tractor has the same prob on the hand clutch. I park on a hill & break it loose running on the way down.
I'm waiting for the Clutch Fairy to come in the night and fix it.
Waiting for the Hydraulic Leak Fairy to visit the backhoe too.
Good luck, Joe H
ROTFLMAO!
I kinda' like the name "clutch fairy"
seems nicer than some of the other euphemisms
I'm waiting for Lothar, the God of Exterior Paint Scraping, myself
Forrest
CaseyR
Call the Clark dealer.. You didn't mention where you live but every state has one central dealer and most have branches..
Talk to the service manager, while he may want to send out a mechanic ask him if he can help you diagnose the problem before you invest additional money in the machine.. Don't try to "figure it out" by yourself.. You can spend hours in nonproductive solution seeking.. If he's been there for a while he'll know what needs fixing and the short cuts.. Just for information I know one trick to replacing the clutch on equipment that will save about 9 hours of dirty greasy labor.. I'm not sure what model you have, you'll need both that and the serial number to get any real information.. Great service managers can be so helpfull you wouldn't believe it.. They are so helpfull it seems only fair to buy the parts from them, However.......
Once you've figured out what the problem is (with his help) don't feel that the dealer is the only source of parts for your forklift. He's not! There is a whole industry of aftermarket parts available for them.. Prices are often 50% or less!
Clark is a classic example of whats wrong with American industry.. At one time the so totally dominated the forklift market that Clark forklifts were sold world wide.. Management got greedy and made some stupid mistakes. for example the moved from Battlecreek Michigan to Tenn. to avoid the unions. That move cost them market domination and a terrible bleed in profits.. They then went to Korea and that move put them from a market leader to a middle of the pack at best, Now they stumble along with a tiny fraction of their market share (Single didgets) with no real identity or loyalty. The company has been sold so many times in the last few decades that dealers nor previous owners want to have anything to do with Clark anymore!
Edited 6/9/2006 10:16 am ET by frenchy
CaseyR
Are you speaking of the Clark AT30/40? If so I sold a lot of them & they are well thought of forklifts still very much valued. Continental 4 cylinder engine which is durable for about 8000 hours before an overhaul.. the bigger ones had either the chrysler slant six or the the waukasha six cylinder which were even more durable..
The transmission is an older designed ford 4 speed so transmission parts are never going to be an issue..
A cheapie solution might be to just slip the clutch for a bit.. That should wear off the bond between the clutch plate and the disc or flywheel.. check to make sure the linkage is well greased and then try it..
Thanks Frency, I have made several trips to the local Clark forklift dealer for my other "rough terrain" forklift, and I have also frequented some of other forklift parts houses for the old CAT V50B that I had. I will make the 90 mile (each way) trip in the near future. The problem with the other Clark is that what the parts manual says and what exists on the forklift are not the same. One of the hazards of playing with old, nearly antique, equipment...
CaseyR
which model is it?
The plaque on the front states it is a FG15PII with a weight of 2545kg and max load of 1500kg. The plaque is in Asian characters except for the arabic numerals for the model, weight, load, and serial number.
CaseyR
I'm afraid you are in for trouble Casey, with asian writing it is most likely a Grey market lift ..
sold to who knows where and reimported to this country when it was no longer economically viable.. It's prime feature is lit's low cost
the real differance is grey market forklifts are not well served by parts since they don't habve the same comp[onants as American market forklifts.. As you mentioned the book and the forklift are differant!
Try to get someone to read the plaque and determine where it was sold originally.. see if you can buy parts from that country.. It's a real battle and the clark dealer won't be able to help at all (plus they get really upset about grey market lift trucks so they won't want to help) (PS that's a 3000 pound unit)
Yeah, that's pretty much what I figured, but the unit was the right size and about half the price of anything else I looked at (actually I didn't expect to get it as it was at auction so just gave a low bid and, perhaps unfortunately, it was mine). I think the Clark guys will help out they have been pretty good so far on my other machines. Oh, and if I remember my metric conversions correctly, 1500kg is about 3300 lbs, howeve, 3000 is close enough.
CaseyR
The metric versions also use a differant cube size when rating forklifts.
(I think a metre by a metre by a metre instead of 48"x48"x48")