Ford 600 hydraulics Problem

RMV

New User
I have a 1955 Ford 640 Tractor that I traded for three old suburban riding mowers that needed restoration. The Tractor engine has been rebuilt and everything works but the hydralic system. I have been reading alot from this site from people that had the same problem. So far I know the outside mount piston pump is putting out 2500 psi at the bleeder plug by checking it with a guage and plugging number 7 hole on the accessory port. But I get no pressure out of the accessory test port #2. I check the unloading valve and it was stuck ands I free it, but it didnt help. Any body have any Ideas? Thanks in advance.
 
No I didn't check it. Is it possible this could be the problem? I have no lift at all and when its running I can't see anything leaking when looking threw the dip stick cover.
 
Bad linkage or badly worn or broken cam follower pin could cause your problem. Other possibilities too.

When you look in the dip stick cover hole, can you see the linkage attached to the control valve? If yes, get someone to move the touch control lever while you watch. Does the control valve move in and out. Tractor does not need to be running to check this.

Post back if you don't understand the terms I used.

Another thought, make sure you are in position control mode
 
When I was checking the unloader valve, I was moving the control lever to see what it moved and it did move the control valve back and forth not a lot but it did move. I notice that it was connected in kind of in slight angle and was wondering if this is the way it should be.
 
Here's what my 660 looked like.



And a look from inside the dip stick hole.



Does that help at all.

If my memory is any good, the control valve moved about 3/4 inch.
 
The best place to get the adjustment procedure is to buy a copy of the I&T service manual for the hundred series tractors. Tractor Supply usually stocks it.
 
No O-ring on the control valve, its a metal on metal seal. If they leak it is minor and results in hiccups, not a total failure of the lift.
 
Thanks Kurt for helping me.
I know the pump is working, but why can't I see any flow?
Its flowing somewhere because the guage on the bleeder on
the pump is zero
 
(quoted from post at 13:27:25 07/13/13) Thanks Kurt for helping me.
I know the pump is working, but why can't I see any flow?
Its flowing somewhere because the gauge on the bleeder on
the pump is zero
ou have a 3000# ?? gauge on pump bleeder port and if valving is unloading via backpressure valve, that sets system pressure to about 40# and you can't see that small pressure on your high pressure gauge. Where is the flow? Out the unloader/backpressure valve.
 
When I free up the unloading valve I didn't change the o-ring
could that be the problem?
 
(quoted from post at 15:40:04 07/13/13) When I free up the unloading valve I didn't change the o-ring
could that be the problem?
ot really possible to say. It has to befree enough to move with only low pressure (~40#) applied but yet tight enough to seal, so???
But remember too, that control valve must be in correct position (think linkage adjustment) to control flow into & out of unloader valve in order to make it move. Not a solo act.
 
Ok I am going to order the manual.
The control arm that you move to make the 3point go up and
down moves free until it gets close to the last part of the lifting
end and has a little resistance, is this normal?
 
(quoted from post at 16:12:20 07/13/13) Ok I am going to order the manual.
The control arm that you move to make the 3point go up and
down moves free until it gets close to the last part of the lifting
end and has a little resistance, is this normal?
s best I remember & thinking, that depends on how high the arms are and also whether in Draft mode or Position mode. But it at least isn't uniform over the full range, so for today, call it normal. :)
 
One of the problems of working on an old tractor is that you don't know what was done before you got it. I've seem some really crazy stuff. That just means you have to be really careful and check everything out.

If I where going to pull that top cover again, I would be really careful at going over it. Its also time for a new piston o-ring and backup washer. I would definitely replace that unloader valve o-ring. These come with a top cover gasket kit, but I prefer to get mine from CNH. But that's my preference, others use the kit.

Do check that cam follower pin. If its not perfect, then replace it. The I&T manual will show you how to adjust the linkage. I would also pull the touch control lever hub and replace the cork friction washer under it. That could be the cause of resistance you feel at the upper end of travel.

That is the bare minimum I would do. If you pull a plow, plan on doing some work on the draft control system.

Sure does get complicated in hurry.
 
Anybody know where I can purchase the original o-ring for the the unloader valve on the ford 600 tractor? Part number NCA 8 36B
 
(quoted from post at 13:02:49 07/17/13) Anybody know where I can purchase the original o-ring for the the unloader valve on the ford 600 tractor? Part number NCA 8 36B

external_link and partspring.com both claim to have them in stock. partspring only sells them in bags of 4 for $7.32, while messicks sells them individually for $2.21, which is about 39 cents a piece more, but how many are you going to need in your lifetime?
 
Try Messick's

www.external_link

or direct to hundred series

https://www.external_link/NH/60170.aspx
The choose hydraulic system - lift cylinder

The unloader valve o-ring is part number 7

Shipping is probably more than the part!
 

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