Loader Issues

[b:ef6bc11cc9]Still fighting with my loader on the '55 300RC. Goes up and down great under no load, will lift the front end off the ground. When the loader has any weight on it I can't lower it without it dropping quickly at first. The bucket still operates fine as does the up, it's the down portion that's the problem. If I try to really slowly move the lever the pump will sort of squeal, the loader will start to barely move then whoosh...a big drop then a controlled descent. I'm starting to think I have a valve problem in the two main cylinders. Any thoughts?

Bruce[/b:ef6bc11cc9]

Switch the loader and bucket remotes. If the loader arms work properly now, it's the valve. If the loader still drops, it's something in the loader cylinders.

Air in the system?

I think air can be a factor in the dropping. Remove the cylinders (one at a time and work the air out of them and reinstall. (a guess, as are all others.) Jim

Air in the cylinders is most likely the cause. Not only is this a pain in the @(# it can be very dangerous. The simple thing to do is just loosen the line that feeds the side of the cylinder that is causing the problem (as you are sitting on the tractor either the front or back fitting) and work the up and down lever until oil is coming out of the fitting without air bubbles just be sure and do both sides of the loader at the same time or it will just push the air from one side to the other. If this does not fix it then take a look at the valve system.

It could be air, but I'd be surprised if it is, unless you have had the system open recently, meaning a hose changed or something similar. However, if it is air, try driving the front wheels of the tractor up onto something so the loader cylinders will retract all the way. If there is air trapped in there, running it fully up and fully down a few times should get more of it worked out. If that doesn't help, there is sometimes a "pilot operated check valve" built into a loader, depends on the loader, where when lowering the loader, the pilot check needs to have pressure applied to open the check and let the loader cylinders retract. the fact you are hearing pressure for a moment before it lowers is an indication it may have one of those checks, and it may be taking too much pressure to open it and therefore building too much down pressure before the check opens. If there is a block in the line going to the cylinders and both the up and down lines go through that block, this could be the problem.
There is many times a check block in the bucket cylinder lines and is usually mounted somewhere behind the bucket on the loader frame cross-member.