[AT] hydraulics question

[Dudley Rupert]

-----Original Message-----
From: at-bounces at lists.antique-tractor.com
[mailto:at-bounces at lists.antique-tractor.com]On Behalf Of Tom
Sent: Tuesday, January 11, 2005 6:43 AM
To: Antique tractor email discussion group
Subject: Re: [AT] hydraulics question


Dudley
        I've got to take issue with a couple of your statements above.
        A hydraulic control valve relies on the fine clearances achieved
        at manufacture to perform. To hone a valve body is going to only
        increase internal leakage unless one is in a position to fit
        oversized spools. O rings are fitted to prevent low pressure
        external leakage as there is generally a gallery back to the return
        inboard of the O rings.

Tom,

Agree ... from a theoretical standpoint I would take issue with what I said
too!

However, sometimes the practical world surprises me although usually not
favorably.  I was amazed that I could take probably 50 year old valves
(these are the "Christmas tree" valves that were an aftermarket Farmall
option for the H & Ms) that were frozen and corroded inside and do to them
what I did and, at least for the two that I've mounted, see no evidence of
leaking after a couple of years of infrequent use.

My point for relating my experience with valves (and I am sorry I didn't
make it clear) was that if these old valves don't leak in the center
position then the new ones that Cecil brought most certainly should not.  I
did not mean to imply that honing a hydraulic valve was something that
anyone would normally want to do.

Dudley