I have just purchased a 73 C500-50 automatic trans. It's my first forklift, I've never worked on any forklift so this is new territory for me.
here are the issues it has;
1. It barely moves, takes a moment to go into gear.
It would not drive up the tilt deck low boy trailer I have.
Trans fluid level is good, fluid does not smell burnt.
Engine oil kinda looks like water contamination, but coolant looks fine.
2. When the inching pedal is depressed trans does not go into neutral.
I'm wondering if the inching valve is stuck partially putting the trans into neutral, causing it to slip. I tried disconnecting the line going to the inching valve, it would not go into gear when I did that. Reconnected the line and it goes into gear.
3. It hardly runs, occasionally backfires out the intake.
Will not rev up much.
I'm giving it a tuneup now to see if that helps.
4. Service brakes do not work, only the parking brake works.
Update; changed plugs, cap, rotor and I'm letting it run until it gets to operating temp. When I try to hold it at higher rpm's it is still backfiring. Wants to die at idle despite turning up idle speed by 1/4 turn in the stop screw. Seems the longer I have it running it is slowly running better at idle. After idling for 20 minutes it died and will not start.
Trying to find the point gap before changing points.
Did a compression test. All were between 80-95 dry, all improved by 5-10 when wet.
Any helpful ideas are appreciated.
Showing items 1 - 9 of 9 results.
There are two master cyls. on mine. One for the service brakes, and one for the inching pedal.
I know of a welding equipment company that, back when these were new, eliminated the inch function on all their fleet of 50+ c500 Clarks (not because of leaking brake fluid into the trans, but because they didn't want that function in their operation), and the trucks lasted a LOT longer than most C500s in daily 24/7350 operation.
Depending on the size of your truck, you may have a 2 master cylinder setup, and you MAY just have trans clutches that have been contaminated by brake fluid leaking from the left master cylinder reservoir, into the transmission, through the inching circuit.
Partsguy5- Thank you for the info. I do understand the legal ramifications, and I don't dismiss them. One would think I would be under the same legal obligation if it were to fail or something go wrong after I've repaired it. So I'm kinda damned if I do, damned if I don't.
BREWSKI- Thanks for the points gap spec, I planned on checking valve lash next. Possibly pull the head check it out, and lap the valves.
You need to adjust the valves. Your compression is too low. Should be about 125. Point gap is.019.
Even though it is for personnel use you are removing something that was part of the original design of the truck and if something were to happen you would be held liable.
Maybe I'm missing something safety wise. Is there a reason to leave the inching valve system in place?
I'm the only operator, it's for home shop use only. I figure eliminating the chance of contaminating the trans & subsequent damage is a good enough reason. I got a quote of $3000 to rebuild the transmission.
Yea it is i guess but i wouldnt advise or say yes to it...is a fairly easy repair if the inching valve just needs a new cup in it
Thanks Kevin,
Is it possible to remove that whole inching function?
The inching valve could be stuck/sticking from gunk....or the piston cup in the valve is worn and hanging up...is a simple device really,just a single brake line going to a valve with a piston and cup the push down on a pin in the transmission to put it in neutral...it can be accessed fairly easily from the wheel well on the leftmside...should take a 7/8 wrench to unscrew it out of then trans...lcan rebuild them with regular brake piston cups that youncan get at NAPA or any other quality auto parts store...
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