Ed's 77 Terex 72-41 Wheel Loader

[LouNY]

Hmmmm, like this.

Yes, but that one looks better then mine;

 

[Xfaxman]

For Terex manuals, this is where I ordered a parts manual for my Dumper: Sycamore – Your technical publishing source

 

[GLyford]

the only thing keeping that from happening now is the leak on the steering control valve directly above it. The leak is the valve itself, and already has new o rings in it. It is available, but at a price I can only categorize as ridiculous. I do not know if it was used on other stuff. As long as I am buying it as a Terex part it will be ridiculous. The wheel cylinders had a manufacturer name and part number on them, I could get them at a reasonable price that way. I do not remember a manufacturer name on the control valve.

If you have a clear view of it, compare it to an Eaton (Char Lynn) or similar "orbit" valve. Most appear to function in about the same way, and the length of the bottom rotor section seems to determine the amount of fluid moved per revolution, so you can probably get close even if it is not quite the same. There are two sub-types, "load reacting" which gives feedback to the driver through the wheel, and "non load reacting".

Caveats:
1. if there is anything else in the steering circuit, you may need a "power beyond" version (5-port vs 4).
2. if the existing valve has a pressure relief, a generic replacement may not and you'd have to add one ahead of the valve.
3. Eaton steering valves aren't cheap either...but least there seem to be a lot of them. Surplus Center has a small selection Power Steering Valves | Hydraulic Valves | Hydraulics | www.surpluscenter.com

 

[mountainguyed67]

For Terex manuals, this is where I ordered a parts manual for my Dumper: Sycamore – Your technical publishing source

I got the parts manual from Sycamore last year. A friend that runs the service section of an equipment repair/rental business got me a service manual earlier this year. I have already found some info in the service manual I wouldn’t have known otherwise. For example the planetary gear oil level is not the bottom of the filler hole. They want you to set the level line, by rotating the wheel until it is horizontal. Then leave out the next lower cover plate bolt, and add oil through the filler plug until it runs out the bolt hole.

 

[mountainguyed67]

Well, only a couple of those prices are more reasonable. Maybe that is just what they go for. The steering control valve is in the middle of the image, with the two Allen head bolts holding the top cover on. It is bolted to the steering gear box under the floor.

 

[mountainguyed67]

These are new valve pics I found.

 

[GLyford]

"bolted to gearbox" implies steering assist, rather than full hydraulic, yes? In that case, an orbit valve probably isn't going to work for you.

I don't see a power assist valve on the list at surplus center at the moment, I know they used to have one for a while. I guess that leaves ebay.

I wonder if there is a tractor valve (older JD perhaps) that might be "close"?

 

[mountainguyed67]

This might help explain it.

 

[mountainguyed67]

Some detail on the valve itself, and mounting.

Edit: We have already replaced (in the valve) #5 qty 2, #9, and #11. I had someone say he thinks the o-rings are twisted or torn. The same guy did it that did the bucket control valve, steering manifold/unloading valve, and 1 steer cylinder. And none of those are leaking.

 

[mountainguyed67]

This might help explain it.

I am thinking the control valve is on the gearbox just to send the fluid to the correct steer cylinder, turning the steering wheel opens the correct valve. And the follower link is not needed, it is just to give “road feel”. So it is full hydraulic, there is no drag link pulling the wheels this way, and that way. Steering is accomplished by hydraulic fluid only.