LeverFever wrote:After cleaning it all up, i see exactly what you mean.

Reassembled the spring and piston today.

Two questions -

The service valve screw - whats the procedure for tightening this? Ie, inner shaft hand tight, out nut spanner tight?

The nut and dome nut of top of group - Is this purely for setting the resting height of the piston?

Thanks

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Back the inner stem out so as to not drive it into the seat and screw the packing gland nut in to compress the packing slightly and then screw the service valve in and out several times while adjusting the packing compression so you do not have any leaks.

Thanks to both of you.

Groups on today, and seals in.

The large hex nut compresses the upper and lower seals - whats the general rule for this? Hand tight?

In regards to the service valve - Is this to cut the flow to the group and allow servicing without shutting the machine down?
If so, i really can't see how that'd work. What exactly is it for?

Service valve cuts off flow when closed it is not a flow rate adjuster. Should be wide open unless group disassembly is desired on 1 out of many groups in service without depressurizing the machine.

Seal compression is tweaked to no leak point and quit.

On the versions I've had of this group with the O-ring inset there has been a rather heavy duty spring that sits on top of the inset below the big hex nut. I see the profile of the inset is a little different to mine though, so I guess another variant. The service valve can cut off the group supply altogether (if you are lucky, its not a good enough fit on all my groups) but it can also limit the flow rate by almost closing it off. I set mine as a bit of a flow limiter, maybe quarter of a turn from fully closed. Certainly not enough to cause a hydraulic lock on the lever though.

Hex nut I think a little tighter than by hand if you can. If its not tight enough water can get above it and rust, or oxidise zinc coated spring etc. I've had that happen.

Well i did the large hex as tight as i can by just my hand. No spanner.

Im happy to report, no leaks from the group after running up to pressure

There seems to be a fair range of possible final positions to set the piston at the bottom - ie. you can use the top crown nut or screw the whole piston assemble in or out.
I set the top crown nut best part down the rack thread and I've ended up with this final position.

I'm a bit stumped as to what the tap 2nd from left is - circled red in the picture. Am i missing something obvious?

**Edit - is it a cup warmer for the top?

Those 3 fitting with chalk marks in the picture are still leaking slightly under pressure.

Are there any little tricks to sealing these? I'm probably going to use some emery paper on the face to clean it up..

Use flint or garnet paper as embeding emory into soft metal causes problems.

That small tube looks like it is the pressure tap for the pressurestat.

Thanks for the tip.

Why would i have a tap to the pressure stat? Wouldn't that need constant pressure?
The stat you can see in the pic was just temporarily added while i fired it up (although i didnt need it as there is a tap)

The pix lacks sufficient detail to actually answer the question.