Conn 36K valve issue

[Radar]

I've got an older Conn 36K that I've owned a little over a year that I got off E-bay. The valves work good inside at normal room Temperature, but when I take it out in colder weather say 40 Deg. or Below, or hot weather say 80s or above the valves get really sluggish almost to the point where it isn't playable. I've had the valve section professionally chemically cleaned, and I've replace the valve springs. I took it out the other day for an outside gig and it was in the upper 30s and still have the same issue. Any idea what might cause this sluggishness in the valves at temperatures above and below normal room temp. I'm using Al Cass Fast Valve oil which is what I've used on all my horns for years and don't have this issue on other piston valve instruments I use it on.

[Radar]

puzzling...

I would wonder if the valves were SUPER-DUPER rebuilt (like by Dave Secrist, etc.) with SUPER-DUPER tolerances...(??)

Do the valves/casings have a "look" to them that looks "better than factory"...??

I don't think they look better than factory but they do look very clean with little to no wear. It is possible since the seller I bought the horn from had several horns to sell in various states of condition that these valves weren't original to this particular tuba.

[sousaphone68]

I think there should be a serial number under the felt on the top of each valve, on my 26K there is and they match the sousas serial number so it should be easy to see if the valves are original.

[Radar]

I think there should be a serial number under the felt on the top of each valve, on my 26K there is and they match the sousas serial number so it should be easy to see if the valves are original.

I'll check that, thanks!!

[Radar]

I think there should be a serial number under the felt on the top of each valve, on my 26K there is and they match the sousas serial number so it should be easy to see if the valves are original.

Well I did check the valve serial numbers and the 1st and 3rd Valves came from a horn very close in serial # and the 2nd valve was quite a ways off from the serial number on the horn, so none of these valves are original to this horn. I believe this group of Tubas came from a school that had several identical horns, and the seller mixed and matched parts to make some playable. So I'm guessing the next step would be to have these lapped into this horn, am I correct, in thinking that's the right thing to do?

[Dan Schultz]

... So I'm guessing the next step would be to have these lapped into this horn, am I correct, in thinking that's the right thing to do?

Yes.

[Radar]

... So I'm guessing the next step would be to have these lapped into this horn, am I correct, in thinking that's the right thing to do?

Yes.

Thanks for the reassurance, I'll get the horn down to my repair guy tomorrow.