Valve liner removal

[gclarke]

Hi all!
I have an 2 inside cylinder assembly with piston valves all out of bronze. The valve sleeves are 2 parts, presses in from each end. One of these parts needs replacing. There is some translucent green residue on the outside of one sleeve that is protruding from the cylinder block. this leads me to think that the sleeves have been loctited in place. 

given that the entire assembly is made of 1 material (bronze), what method do you suggest to remove one half of a piston valve sleeve? I would prefer to leave the rest of the sleeves in place.. 

I think the normal course is heat, but would this not loosen up all the sleeves? Any advice on how to proceed is greatly appreciated!
Gary

[ettingtonliam]

What is wron with that half sleeve?

[simon6200]

You could line it up true and bore it away.

[gclarke]

The previous owner made a boo-boo and drilled through the liner whilst drilling exhaust port.

[davewoo]

I once had to remove a bronze bush in a printing machine that the loctite had gone off as it was being fitted, the machine couldn't be heated as there were sensors and other bearings in the vicinity.Sawing/chiselling out would be difficult due to access problems and no one wanted swarf anywhere near the machine. I turned a bar to what I judged to be a good fit in the bush when red hot, heated it to dull red and held it in the bush (with tongs!!) after two applications of the hot bar the loctite started to smoke and was able to get it out with a slide hammer with a modified end. I did use a product called Cold Front which is a gel that keeps adjacent areas cool, came from a refrigeration supplier, fridge engineers use it when silver soldering valves and fittings in. I was hero for the day and the original culprit bought me a beer. This might be an idea you could adapt in some way maybe using wet rag to keep the other liners cool, good luck.
Dave

[oldnorton]

I think that you either have to break down the Loctite and remove all the liners, or carefully machine out the defective one. As well as this being very tricky you will inevitably cut a few thou into the cylinder block and need an oversize new liner.

Taking them all out will be a good idea as you can check the fit once cleaned up and see whether new Loctite will properly seal them in the block. Once you get the block heated to 200-230 degC the Loctite will have been destroyed and some white smoke will come off, but the white, powdery residue makes a liner difficult to drive out, easier while still hot. If you can drive the split liners though in one direction it will be easier, but I suppose that they are split because they have shoulders? That makes it difficult to get purchase to pull out the first of each pair. The residues seem impossible to wash off (cellulose thinner, brake cleaner) and need emery paper laps inside the bore.

I do like Dave's idea of a red-hot drift to locally destroy the Loctite.

Norm

[nick952]

If you have a large enough tap, tap the valve liner, screw in a bolt and then press or drift out from the opposite side. if that fails then move on to other methods.

[gclarke]

Thanks for the suggestions everyone.. sadly I think it may be necessary to use all three suggestions before the last resort of boring out the sleeve. The sleeves are in a block of bronze screwed to the cylinder block (like a sleeve valve steam chest). That block also appears to be loctited to the cylinders. I will try localised heat first and try to keep the other parts cool so the loctite doesnt soften everywhere. if I see any sign of that, I may have to take the whole thing apart, clean it and redo the loctite. 
Its amazing how a small repair becomes a big job. 

[Cro]

I had to do this to the 9f cylinders because the liners had been made badly with O-ring grooves but when it didn't work the guy loctited them in place.

I had to heat them up to break the loctite, I would do the same and then refit all the liners so you know its all done correctly.

Adam

[gclarke]

An update.. the badly machined sleeve is out and sitting on the bench! Either loctited parts are easy to remove when heated, or it wasn't well secured. the opposite sleeve shifted slightly during the removal process and I will make a brass drift to push it out and the remaining sleeves to inspect them and refit if ok. 

Thanks again guys for all the advice.. much appreciated!!

Gary
 

[simon6200]

Good to hear Gary. Must have been satisfying when it came out.