Loader not lowering

[profitt]

My loader has suddenly stopped going down freely. Originally lowering the bucket was tricky because the valve opened very quickly allowing the bucket to drop too fast. It took a sensitive touch operating the lever. Now the loader drops very slowly, about 2 inches/second max. It doesn't mater if the engine is running or not, the thing just drifts down. Oddly the engine does seam to change pitch just slightly when opening the valve to lower the bucket. (could be my imagination) It lifts fine and the bucket rotates as before. This started after several hours of scooping dirt from root infested soil. I did my best to loosen things up with a rototiller first but it was just about all the little tractor could handle. Trying to level the soil with the bucket by backing up with the bucket lowered did not work because the loader just lifted up over the soil. Did I cause damage by putting back pressure on the control valve?

Reading previous posts on similar topics there is some discussion of quick connect fitting failing but all my connectors are old school. The oil is new and the pump seams to produce a lot of pressure. I once lifted with chains a 12' x 18" diameter tree section! Had to put extra air in the front tires for that one.

It is a 1958 Ford 851 with what looks to be a dealer add-on or a factory installed loader, if that was an option. I say this because it has what looks like original Ford safety stickers on the framing. The tin manufacturer placard on the loader frame reads:

Mid Western Industries Inc.
Wichita Kansas
Model 102 A
SN 19795

I can not find any numbers on the control valve so I am including a picture. I really do not want to tear into the control valve without knowing if replacement parts are available. An exploded view diagram would also be nice.

 

[Fritz Maurer]

The way the valve is plumbed it appears you have a gravity-drop loader, is this correct? It sounds like something is laying on the bottom of the cylinder (pieces of packing) covering the hole, acting like a check valve. Take the hose off the top of the valve and blow air through the valve, with the handle in the drop position, and if air blows freely into the reservoir the valve can be eliminated as a source of trouble. If the valve is clear, I would open the boom cylinders.

 

[Fritz Maurer]

When you get it figured out, you can install an adjustable check orifice to make lowering the boom more controllable.

 

[SkipperII]

By the picture, it appears to be single action (no down pressure). It is rare but; I have seen the inside of a hose start to deteriorate, and a piece start to act like a flapper valve. If you find nothing else, you might consider it.

 

[murray moore]

Hi Fritz,

I appreciate your comment. I have a Ford 703 Loader with a boom that drops very fast if I am not careful with the lever. Always felt this was unsafe and unpredictable. Can you or others point me in the right direction to a supplier so I can locate an adjustable check valves that will help me remedy this issue?

As always, thank you for the help.

 

[profitt]

Yes, the lift is single action. I was thinking a blockage in the cylinder line could cause this but I have very little experience with hydraulic systems. I will check the hoses and valve if needed next time I am at the property. Looks to be a messy day.

Thanks all for your suggestions.

 

[Fritz Maurer]

That is 110% correct. I first discovered that phenomenon in the '80s; that's when I learned to not let the front calipers dangle by the hoses on 1-ton Chevies.

 

[Fritz Maurer]

Baum Hydraulics, Kearny, Nebraska. It would go right where that 90 degree fitting is on the top of the valve. ( between the female swivel and the hose.) It doesn't necessarily have to be adjustable, that just makes the piece more expensive. You need free flow in one direction and restricted flow in the other direction. You may also want to try a couple local tractor dealers, it doesn't matter which brand, because all utility tractors with gravity-drop booms needed more or less the same plumbing.

 

[murray moore]

Great! Thanks for this, Fritz. Will look into this.

 

[Fritz Maurer]

I have a Baum catalog here with me, the thing you are looking for is called a "line throttle valve", made by the Gresen Co. They come in 3 different restriction levels, governed by the size of the orifice in the check ball. When you call those guys, explain your situation and they will know which one to give you. In 1989, they were $7.94.

 

[profitt]

What about something like this? It's a bit more but being adjustable may save having to purchase several to get it right.

Northern tool Item# 69832

https://www.northerntool.com/shop/tools/product_200746891_200746891

 

[profitt]

Oops, no flow in the opposite direction! That valve will not work.

 

[Fritz Maurer]

I couldn't see where it said no flow in the other direction. But you're right, it has to flow both ways. I should say at this point that you need to find something with FREE FLOW while raising the boom. A throttle valve that regulated in both directions would be putting an unnecessary load on the pump and drive shaft.

 

[Sean in PA]

It doesn't say that it doesn't provide flow both ways, but it will restrict the flow in both directions so the maximum speed while going up will be limited to whatever flow rate you set it to for comfort and safety when lowering.

 

[profitt]

Here is an interesting video on how a one-way throttle valve works. https://www.youtube.com/watch?v=KjnCCHV2RKM

I am thinking I may make one someday:

The GRESEN valves list $42 - $95: https://www.baumhydraulics.com/Search/Results?id=lt-50-12
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