Power valve problem!

[shaunthe2nd]

Just when things started looking up......

Took the power valves out of the barrels on my 31k project, and on stripping them down one of the long M5 screws that keeps the 2 halves of one valve together broke inside.




You can see the difference in length of the 2 screws. The upper one in the pic has sheared leaving about 20mm inside the valve on the right.
Its recessed so very difficult to get to the the bit inside. Grrrrr.

Anyone had this before? Any suggestions?

Thanks, Shaun

[midlifecrisisrd]

This may sound a bit rough but usually works if you can see the broken bit

You may have to drill the valve from the other end to get access

Drill a small hole in the bit of broken bolt. Pic a drill size just below the measurement across the points of an allen socket or torx socket

Tap it into the hole and hopefully screw it out. Once you get it moving change to the handle of an allen key to get more length if you have went in from the other end

Be carefully the allen/torx is not too much bigger or it can splat the bolt and make it thread bound

Steve

[Deleted]

As Steve suggested

Also try putting the valve in the freezer over night then plonk it directly into boiling water

Hopefully the thermal shock may be enough to crack any corrosion on the broken thread to make it easier to remove

You could then put it in penetrating fluid too, overnight as well, the fluid may be able to creep up the thread again hopefully making it easier to extract

Last resort is a machine shop to see if they can accurately drill it out and run a machine tap down it

Good luck either way

[shaunthe2nd]

Thanks for the suggestions.

I've had a few battles and successes/failures with broken bolts in the past, but never with anything that is so small and so far recessed so that I can't get to it to either centre pop and drill, or dremel a slot into it to get a flat screw driver onto it.
The break is at an angle too so would be difficult to drill centrally by hand.
Freeze/heat will no doubt loosen it but I will still need to get something on it to turn it.

I'm taking my barrels to a good machine shop in next week or so for re-boring so I'm planning to take the valve with me to see if they can do anything.
Seems the least stressful solution at the moment and I have plenty of other things to be getting on with.

Unless anyone has a decent S/H one they would part with?

[muttsnuts]

pop it in the post and I'll sort it for you Shaun

[shaunthe2nd]

Jan 15, 2021 20:07:26 GMT 1 muttsnuts said:

pop it in the post and I'll sort it for you Shaun

Thanks Dave I will do just that, cheers.