Repair - how to open up clamp casting and release a thread?

[AcidReflux]

It's difficult to describe my problem in a short thread title...

I'm trying to screw a cast component (part of the steering linkage) onto a 1" thread on my classic car. The cast component has a split casting that's clamped up to lock the thread and keep the components together. I removed the component, lent it to a friend who needed one temporarily, and now I can't refit it to my car. I'm assuming that the casting deformed slightly on his car and is now too tight on the thread on my car.

I've reached the limit of the brute force I'm able to use on this awkwardly-shaped component.

The thread onto which I'm screwing this component (reference photo):



The component with the split that screws onto that thread (on the left of the picture) (reference photo):



The view of the component on my car. The gap that needs to open up is about 3mm wide.



Since it's now partially installed on the car and stuck solid, access to the gap in the casting is restricted - do tools exist that could open up a 3mm gap just a fraction to release the clamp on the thread? The tool would have to turn with the component as I screw it on. However, there are only about four more revolutions needed to get it into position.

I can't use heat on the component because of its delicate nature and limited access. (It's a power steering control valve and is full of grease and rubber seals.)

I've tried screwing the clamp bolt into the reverse side of the clamp hole with a washer in the split in the hope that the clamp bolt would press on the washer and open the split, but the bolt fouls on the 1" thread and never reaches the split.

Anybody got any ideas for tools or techniques I could try?

[Getragdogleg]

A small chisel knocked gently into the gap may open it up a bit, or a screwdriver used as a lever/drift to achive the same opening of the jaws effect.

I have a load of screwdriver bits that go into my Snap-on ratcheting screwdriver that i use as mini chisels when I get trackrod ends that do not want to fit properly, they use a similar set up, with a pinch bolt and a cut in the outer.

Basically put/beat/knock/hit/pry something in the gap to open it up.

And FFs grease it all a bit, it will help !

[perdu]

nasty

I thiknk you need a large screwdriver with a square shank that you can slam (gently of course) into the slot abnd then apply torque with a spanner or Mole Grips to twist the slot further open

But as you know already it will not be easy

Good fortune/luck/karma

[cambiker71]

Is there room to tap a small cold chisel into the slot in parallel to the thread? The chisels gradual taper should open it up, usually if it is driven deeply enough along the slot then the slot will stay open enough to unscrew the thread even with the chisel removed.

[AcidReflux]

Thanks for the suggestions. You're not the only ones saying that I need to force a wedge into the slit and open it up. I was hoping for a miracle tool but it sounds like there isn't one.

I think I'll remove the component plus threaded rod from the car so I can apply the full force of a lump hammer and chisel. No shortcuts for me today.

[WhoseGeneration]

AcidReflux said:

Thanks for the suggestions. You're not the only ones saying that I need to force a wedge into the slit and open it up. I was hoping for a miracle tool but it sounds like there isn't one.

I think I'll remove the component plus threaded rod from the car so I can apply the full force of a lump hammer and chisel. No shortcuts for me today.

Noo, don't go mad, I suspect with both components off and male one in a vice just inserting an appropriate tool into the slot and gently levering wil provide enough loosening, plently of Plusgas or similar might help.
Then, carefully check both male and female threads for burrs, flattened/distorted peaks etc.

[AcidReflux]

WhoseGeneration said:

I suspect with both components off and male one in a vice just inserting an appropriate tool into the slot and gently levering wil provide enough loosening

I get'cha. Inserting a thin lever into the slot and applying rotational torque will be self-regulating. Enough torque will open the casting and it'll be impossible to apply too much. I like your thinking.

I need to invest in a decent large flat-bladed screwdriver - none of mine is sharp/tough enough to apply much bending force.