How to repack an old steam shut-off

HarryL

Attached is a picture of the type of old Belknap valves that are leaking. When I took the packing nut off I didn't see what I expected. "B" is where I expected to find the remnants of a washer and wrap the graphite string. Instead "A" seems like a thimble that might be where packing material needs to be put, then the nut compressing the thimble and packing material.

Before I screw something up, is there any guidance or references to help on this?

Thanks,
Harry

Jamie Hall

Sounds about right. Get all the old packing out of there -- it's shot -- and make sure the stem isn't too badly scored and carry on.

Fred

I believe the packing is under that thimble. It should screw off. The packing needs to be wrapped around the stem. That's where they leak.

steaminboston

I also have Belknap radiator valves from 1937. I'm also repacking them but thought to repack "on top" of the brass piece due to its thickness and it appears to be designed to sit down in the recessed seat/groove with no room for packing....my brass piece looks a lot thicker than yours with no room underneath for packing.....any comments or suggestions?.....I've googled these valves and could only find a few patents from the late 1800's/early 1900's with little useful info. See 2 attached photos.

steaminboston

Photos...

Jamie Hall

I could well be wrong -- have been before -- but I'm going to bet that a relatively thin disk of packing -- I'd use small diameter teflon thread wrapped around flat, perhaps two layers but not as thick as the recess -- goes between that disk and the body of the valve, and then gets squeezed to form the actual seal.

steaminboston

Thanks I was thinking that....I'll try that with teflon tape....the 3/32" graphite rope may work too and just squish out....I had already used the graphite on the upper part of the disc around the stem....won't hurt to have both.