This is on a Massey Ferguson 240. Perkins Diesel. The steering control valve leaks..a lot. There are two O-rings on the spool that account for this leak. And of course, the one that needs replacing is the one I cannot get to.



The red parts are the ones in question. You can see the split 'yoke' in the big circle unthreads. It has loctite and hasn't moved in 40 years, so it's not going to 'just unscrew'. The o-ring I need to replace is under the stack of springs and washers.

Here is what it looks like in real life:



As you can see, there is no where to grab the spool itself to hold it steady so I can apply enough force to the yoke in my fingers in the pic. Anything you grab will gall and destroy this part and it is not replaceable. It's a $500 dollar error if I gall it. I have ruined three pairs of leather gloves trying to clamp it tight enough in my vice. It won't hold. It slips. I have heated the end as well, but I can't do that much because of the springs, they may lose temper. I tried putting it in wood where I cut a hole and a kerf so I could clamp the hell out of out. No dice.

So, I am down to thinking maybe the only way to do this is to clamp where the green arrows are. Only thing I have to do this would be a pair of modified vice grips that fit in those slots without damaging everything around them. I think that if this area is galled, then it won't matter anyway. This is the only way I can see to hold it.

The little ports would work but I cannot find anything that fits them that is strong enough to withstand the force required to unscrew the other end.

How would a rebuilder get this done? Surely this isn't rocket science, but damn if I can't get it apart.

I understand wanting to do it yourself, but there are hydraulic places that will make short work of that for a reasonable price.

Never took them apart. Just use a pick to take the old one off over everything, and went back with the new one the same way. O-rings will stretch quite a bit. Some times some tape over the spring will make it easier if it's not compressed so that the o-ring might slip in between.

The O ring causing trouble is UNDER that washe/spring stack. It must be disassembled to remove. I'll probably haul it down the road to my hydraulic guy and see if they can take it apart for me. The damn o-rings are .80 a piece. LOL.

TMfrisco said:

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I understand wanting to do it yourself, but there are hydraulic places that will make short work of that for a reasonable price.

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You are totally right, and that is very likely the direction I will go. I was frustrated over the ass pain required to replace 2 dollars of parts.

Jason. You think you could try a barrel vice to hold it? They are made to hold gun barrels very tightly for unscrewing and not mar them. Just a thought.

Yes, I see that. I also know that you can stretch and roll the o-ring on from the small end. Have done it numerous times. But if you have a hydraulic shop near, I'm sure they can also do it for you.

AHA! Now that's an idea I didn't consider.

What does the opposite end of the spool look like (right side looking at picture)? It looks like the relief in the spool has been gripped before. If you can get your hands on some v or contoured blocks that fit in the slot you could put in a vise.

Gunny456 said:

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Jason. You think you could try a barrel vice to hold it? They are made to hold gun barrels very tightly for unscrewing and not mar them. Just a thought.

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Good idea. Two hard wood blocks and rosin. Hydraulic press or strong back.

Roger that!

Can those side holes be used as keys to prevent it from turning?

Looks like a small hydraulic end cap wrench might work, the kind with the tiny post that keys into the hole and wraps part way around the shaft?

https://a.co/d/fyjLkFQ

I was thinking something like that as well. Do those holes go all the way through?

I any case bet you could find a nail that is basically those dimensions and put them in all 4 sides to hold from twisting with the vice. Can even cut some blocks of wood and drill a hole to let the nail through and hollow out some to hold the valve assembly better in the vice.

Shoot even just rounding out a couple pieces of wood to clmp on wtiehe side might give you enough friction to turn it out. Assuming that's steel then would shouldn't gaul or screw it up much at all.

Yeah, using wood blocks as a clamp with a sawed off nail or screw as a key matched up to fit in one of the holes might work.

I see you have also used heat to try and make it easier, but have you tried COLD.

CRC makes an aerosol called "Freeze Off". You might also try putting it in the freezer for a while. Realize you have to be able to HOLD it as well, but the cold may help.

(I once had an AR15 receiver/barrel I couldn't get apart. No luck with heat, but the freezer trick did the trick.)

I'm assuming you've also watched this video:




(Good stuff is from 7:00 to 7:30 mark)

Ok, so that is THE video I watched and it would be the ticket except the port holes on his are about 3x bigger than mine. If they were larger, a screwdriver would work in the holes. My holes are 1/16 inch or something so small that I don't have any metal picks or punches that are strong enough to hold without bending.

V Block is probably going to be the ticket next. I just need some material that won't mar my spool.

And yes, the holes go all the way through but they are very small. The only thing that I have that will go in them is a fine finish nail and it's not strong enough to secure.