Hydraulics quit working

ukcatfan · Apr 15, 2018

I was using my box the other day and my
hydraulics just bottomed out and quit
working, brought my tractor to a halt.
Pulled the inspection plate and started
the tractor. I don't see anything going
on in there around the pump. My question
is, how does the control rod attach to
the pump control? Mine just kind of flops
around down there. I can move the pump
control in and out by hand but it doesn't
appear that the touch control is.

ukcatfan · Apr 15, 2018

Sorry, it's a 51 8N.

Caryc · Apr 15, 2018

(quoted from post at 07:25:43 04/15/18) Sorry, it's a 51 8N.

The control rod has a ball end on it. This ball sits in a cupped socket on the pump control. Someone here has a pretty good picture of that. I'm sure he will be along soon to post it.

When you have that side cover off, you should be able to just reach in there and feel if the end of the control rod is still in the cup at the bottom. Then move your touch control and feel if the control rod is actually moving the pump control in and out. Do this with the tractor not running or course.

Sometimes control rods get bent or even broken.

Caryc · Apr 15, 2018

Actually, you can see that picture in this post.

http://forums.yesterdaystractors.com/viewtopic.php?t=1350259&highlight=control+rod

HCooke · Apr 15, 2018

Picture is from the FO4 manual. Control rod fits into a rocker which then opens and closes the intake and exhaust valves. If the control rod is flopping around down there, you are going to have to drain the fluid so you see what happened.

Caryc · Apr 15, 2018

Here's an example of how much a control rod can get bent. Yes, they're supposed to be straight.

ukcatfan · Apr 15, 2018

It's not bent. I've drained the oil, looks like the picture. There is some slop and it moves up and down slightly but due to the manner in which it quit, I believe my problem lies deeper. Just going to pull the pump, the fluid is very nasty anyway.

Caryc · Apr 15, 2018

(quoted from post at 11:26:38 04/15/18) It's not bent. I've drained the oil, looks like the picture. There is some slop and it moves up and down slightly but due to the manner in which it quit, I believe my problem lies deeper. Just going to pull the pump, the fluid is very nasty anyway.

I was driving my 8N up to it's parking place when the box blade suddenly dropped. Exactly like your symptoms. I pulled the top cover off and discovered that bent control arm. The pin in the control arm had also slipped completely off the cam and was on the side of it. It was very worn. I put a straight replacement control arm in it and replaced the pin with a longer one. The linkage was also a little sloppy with side play and I fixed that with a washer as a spacer. Works good now.

I'd be more inclined to pull your top cover and have a look than the pump.

ukcatfan · Apr 30, 2018

Ok, I rebuilt everything in the pump, except the intake and exhaust valves and bushings. Still didn"t work. I believe something is going on with my exhaust valve. Does the intake spool suppose to push in to go up or what? I can only pull mine out, seems backwards. The taper on the spool should open the port correct?

ukcatfan · Apr 30, 2018

I need somebody with some experience to
tell me how the intake and dump valves
work. Every pic I see, the valve control
is touching or almost touching the pump
housing on the exhaust side. Mine does
not and it will only let me pull the
intake spool out which looks to me like
that does nothing as far as the taper on
the spool opening the port in the
bushing. Looks to me like when you raise
the lift the spool should move in instead
of out. I'm going to try and remove the
dump assembly.

Caryc · Apr 30, 2018

This is a pretty good DVD on repairing the Fords hydraulic system.

https://www.amazon.com/Hydraulic-Re...draulic+repair+for+ford+and+ferguson+tractors

JMOR · Apr 30, 2018

(quoted from post at 13:31:09 04/30/18) I need somebody with some experience to
tell me how the intake and dump valves
work. Every pic I see, the valve control
is touching or almost touching the pump
housing on the exhaust side. Mine does
not and it will only let me pull the
intake spool out which looks to me like
that does nothing as far as the taper on
the spool opening the port in the
bushing. Looks to me like when you raise
the lift the spool should move in instead
of out. I'm going to try and remove the
dump assembly.

he intake loop as shown in the posted picture from the manual is supposed to touch housing at full lift command. "It will only let me pull the intake valve out" is all wrong. If left free, it will be pushed out rather forcefully be the spring behind it, resting in the dump/lower position.

ukcatfan · Apr 30, 2018

Then I have an exhaust valve spring
problem. It seems to be jacked up. I
guess you have to press these out or hit
it with a punch?

JMOR · Apr 30, 2018

(quoted from post at 15:19:24 04/30/18) Then I have an exhaust valve spring
problem. It seems to be jacked up. I
guess you have to press these out or hit
it with a punch?

hy do you say, 'exhaust valve spring problem"? I said that it is the intake valve spring (spring behind intake valve ) that pushes it out. So, to me it looks a lot more like intake valve spring problem, if it is not pushed out when unconstrained.

ukcatfan · Apr 30, 2018

The travel of the intake spool is not
enough for the taper to open the ports.
The exhaust pin/spring is what is keeping
this from happening. This is on a bench
working it by hand.

JMOR · Apr 30, 2018

(quoted from post at 15:38:35 04/30/18) The travel of the intake spool is not
enough for the taper to open the ports.
The exhaust pin/spring is what is keeping
this from happening. This is on a bench
working it by hand.

ou can not push the exhaust valve in?

ukcatfan · Apr 30, 2018

I'll post some pics when I get home and
explain further. Sitting on a bench out
of the tractor, out is the only way it
will allow me to move. It's almost like
the pin in the exhaust side is opposite
of how it should be, very weird.

ukcatfan · May 1, 2018

It was the exhaust spool, it was frozen.
I didn't realize how the spring and pin
worked. I didn't realize the spool was
supposed to move in and out like that. I
started to knock the bushing out and it
came loose, well crap. Now I know. I feel
stupid but I learned from it. Thanks for
putting up with my rambling. Hopefully I
can pay it forward someday.

JMOR · May 1, 2018

(quoted from post at 08:08:50 05/01/18) It was the exhaust spool, it was frozen.
I didn't realize how the spring and pin
worked. I didn't realize the spool was
supposed to move in and out like that. I
started to knock the bushing out and it
came loose, well crap. Now I know. I feel
stupid but I learned from it. Thanks for
putting up with my rambling. Hopefully I
can pay it forward someday.

on't feel too bad, as that exhaust valve construction is not well understood by many. Glad you got it fixed.

ukcatfan · May 1, 2018

I read in the old training manual that
they fixed this freezing problem with a
valve in a spiral configuration but I
can't find anything else about it. At
least I'll know where to start looking if
there is a next time.

Hydraulics quit working

New User

New User

Well-known Member

Well-known Member

Well-known Member

Well-known Member

New User

Well-known Member

New User

New User

Well-known Member

Well-known Member

New User

Well-known Member

New User

Well-known Member

New User

New User

Well-known Member

New User

Similar threads