[AT] hydraulics problem

[Lew Best]

Thanks Cecil

Guess I wasn't clear enough; this is a rotary valve in the steering
shaft.  When putting pressure on the wheel to say the right it sends
pressure to the cylinder to "help" push the wheels one way.  Once you
release the steering wheel (or stop because you've reached the point you
want to turn it to) the valve drops back to neutral.  For a pic you can
go to http://img.photobucket.com/albums/v707/lewbest/steervalve01.jpg.
The top & bottom hoses go to the cylinder; right goes to pump pressure &
left to pump suction.  The gearbox on the steering still functions;
hydraulic power just "helps" move the steering knuckles.   

Lew

-----Original Message-----
From: at-bounces at lists.antique-tractor.com
[mailto:at-bounces at lists.antique-tractor.com] On Behalf Of Cecil Bearden
Sent: Thursday, February 09, 2006 10:51 PM
To: Antique tractor email discussion group
Subject: Re: [AT] hydraulics problem

Lew
you mentioned that the roll pins had been replaced.    Check to see that
the 
control valve can move in and out.  My old Massey had a slot that the
roll 
pin in the control valve shaft slid in and out to regulate the fluid.  I

reamed it out to pin it solid. and had no more Power steering...

Cecil in OK
----- Original Message ----- 
From: "Lew Best" <bee_keeper at earthlink.net>
To: <at at lists.antique-tractor.com>
Sent: Thursday, February 09, 2006 6:25 PM
Subject: [AT] hydraulics problem


>
> Hey guys
>
> Got a problem; (so what else is new)?
>
> On an old John Deere 420 power steering it's doing something crazy!
> Solved a few problems yesterday; got it to turning pretty good one way
> but not near as good the other.  Had a bad leak on one of the rotten
old
> hoses coming from the control valve to the cylinder so replaced the
hose
> today thinking that would fix it.  Well, that made things worse!
Seems
> that when it had pressure on the good hose that the leak let the
return
> fluid from the cylinder out so it worked.  Now (with no leak for the
> return flow) no turn either way.  Someone had obviously had problems
> with this steering before (had sheared keys & roll pins, etc.) so now
> I'm kinda grasping at straws.  What is obviously supposed to happen is
> when you turn there should be pressure to one end of the cylinder
making
> it push & the fluid from the other end be allowed to go back to the
> suction side of the pump.  Is there a check valve inside of the
control
> that could be stuck? I've removed the hoses one at a time (right, left
&
> return) & all seem to squirt fluid "when they should."
>
> BTW I wanted to replace one of the shafts in the valve (pretty well
> mutilated) but the shaft is no longer available thru JD.  Asked about
a
> complete valve & same response.  Hate to tear into it not knowing if
any
> parts available (seals, etc.) but guess I'll have too.  No good the
way
> it is!  Anyone got one (or know of a source) without having to give an
> arm & a leg for it?
>
> Any ideas appreciated!!!!!!!
>
> Lew
>
>
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> Remembering Our Friend Cecil Monson 11-4-2005
> http://www.antique-tractor.com/mailman/listinfo/at 

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