Ford 4600 very slow pulsing hydraulics

[gregrsv]

Hello
Im new to the forum, so this is my first post apart from the introductions post.
I've been looking at a 4600 (1981-82 model) with Q cab.
It has a 3pt linkage and a front end loader fitted , it has a ford distribution ( single spool i think) valve with one control handle and 3 detented positions.
Ive tried the pressure guage in the out put to the FEL and also tried the port for the tipping trailer, the syptoms appear the same for both ports.
With engine running i select the aux valve distribution lever to the required port , nothing happens for a second or two then you hear the pump building a bit of pressure, the pressure sits around 40-50 bar then surges to 115-120 bar for a short spike then back down to 40-50 bar , this continues until the aux valve is deselected.
Using the hyds on the loader or the 3 pt linkage shows corresponding symptoms, the loader lifts ultra slowly in short jerks of an inch or two at a time, the 3pt link is the same.
Another thing is the PTO is not working either it has a hid pro engagement i believe.

I'm not sure if anything in the aux valve distribution block could cause this and i tried to measure pump pressure at the port on the actual pump casing to see if there is any pulsing down there. but i don't have an adaptor of the correct thread to go in there, it looks like the same coarse thread as a mini mess connector on some test points but the test point i had wouldn't start easily so i didnt want to continue and damage the thread.I was trying to eliminate whether the problem was up in the aux take off housing or down at the pump end. I'm not all that clear about this system even after reading the workshop manual it doesn't seem to have a hyd schematic.

I have since taken the pump out an inspected there was a little light scoring on the internal pump face but not much and not measurable in depth of wear for instance. The pump relief valve was actuated a few times and flushed out, that seemed fine.

I then went to take the spools out of the flow control (speed adjuster) and the spool labeled as cooling valve in the manual had no piston or spring inside its chamber when i stripped it! this seems strange unless its omitted on some models as the owner says the hydraulics have worked before and no one has been in around the flow controller.

I did notice when selecting the hydraulics to loader or 3 pt link there is a rushing sound in the hoses and top cover area and i wondered if theres an o ring between top cover and main case that may have let go.


Oh by the way its a single pump machine
thanks very much
Greg
gregrsv is offline Report Post

 

[DieselBound]

Almost sounds like the pump is dead-heading: that flow control valve maybe?

Air in system?

How's the fluid (contaminated, water)?

 

[TractorTech]

Is the oil pickup screen clean and was there an oring on the pump where the pickup tube goes in?

 

[gregrsv]

Is the oil pickup screen clean and was there an oring on the pump where the pickup tube goes in?

Tractor Tech
I took the pump out and checked the O-rings and connection to pump suction port, I also stripped the pump to see howm much wear there was in the gear cavities which dint look bad.
The pump suction port connects to a s shaped aluminium pipe which in turn is connected to a spigot that leads out to the suction filter at the other side of the transmission casing.
THe o rings in both ends of the transfer tube were good and connections secure, the spin on filter is new.
After rebuilding and re filling the symptoms were the same, i took the large plug on the fwd side of the flow control valve out and there is nothing in there , the manual shows a plunger and spring - something to do with a cooling valve ...do you know if this is ommitted from some models.
I am offshore working on a ship at present but when i get home i'll try and lift the top cover and see if anything is not right in there , i wondered if there is an o ring or something that ports the pressure up to the top cover from the flow control that may be damaged or is there any other valves in teh top cover that can mis behave. Also is there anything in the auxiliary presure take of housing ontop of the casing that could cause this.
I dont think the system is dead heading as when observing the guage whilst activating the loader or 3pt hitch , the hydraulics pressure alternates from low pressure then spikes to high pressure 120 bar and that is when you movement (slow and short duration) at the loader or 3pt , then the movement stops as the pressure subsides back to 30-40 bar.
thanks for your replies
Greg

 

[sixdogs]

I don't have a lot to offer here but there are a number of threads that make references to Ford of that series having a sump screen that's accessible from a cover on the side of the transmission . Mine was round with three bolts. Not sure if your model has one but thought it worth the mention.

 

[gregrsv]

Hello
Its a long time since I've been on here and i'm back looking at this ford 4600, i'm still at a loss with what is happening with it , I've had the pump out and checked the o- rings for the suction side of the pump and they look fine , when operating the loader or 3pt linkage the function does nothing for about 20-30 seconds then i can feel the pressure "buzzing" in the hose feeding the FEL spool block , then the loader creeps up an inch or so , the cycle then repeats. you can see it on a gauge also the pressure drops to next to nothing then you get a spike for a second or two up to about 140 bar. then back down to hardly any pressure for 20 seconds or so.
Ive checked the spool in the flow control and it seems free enough , also i noticed the cooling spool was missing , i wasn't sure if this is omitted on some models.
cheers
greg

 

[gregrsv]

Hello
Its a long time since I've been on here and i'm back looking at this ford 4600, i'm still at a loss with what is happening with it , I've had the pump out and checked the o- rings for the suction side of the pump and they look fine , when operating the loader or 3pt linkage the function does nothing for about 20-30 seconds then i can feel the pressure "buzzing" in the hose feeding the FEL spool block , then the loader creeps up an inch or so , the cycle then repeats. you can see it on a gauge also the pressure drops to next to nothing then you get a spike for a second or two up to about 140 bar. then back down to hardly any pressure for 20 seconds or so.
Ive checked the spool in the flow control and it seems free enough , also i noticed the cooling spool was missing , i wasn't sure if this is omitted on some models.
cheers
greg

Latest on the hydraulics I've renewed the near new spin on filter and the hydraulics function now , must have been collapsed

 

[DLTTrekkers]

Yes...always do the cheap stuf first !

 

[sixdogs]

Yes...always do the cheap stuff first !

That is so true. Always start with the easy answer and work up. Good advice on most every mechanical issue.

OP--thanks for the update.

 

[daniel20vm]

Hello. At the beginning I want to apologize for the spelling, but translators are translate google translate because I'm from another country.
*
I have not bought a FORD 4600 tractor for a long time and I have a problem with plumbing from the very beginning

The oil and filter in the hydraulics was changed half a year ago (he worked 200 mtg), and the fact that the previous owner assured that recently when he used the lift (ie about 2 months ago) everything was ok.

I noticed that under load when the lift lifts up everything is ok (floats smoothly, does not tug) but when it reaches the required height, it gradually descends and raises again. As a result, raising and lowering the tractor trembles so that it can not withstand it. What could be the reason? I will add that the tractor is equipped with a front loader that goes flawlessly .... (for those who do not know I'll add that this tractor has a lever under the seat to change the hydraulics (works or jack or turn)). I also know that the tractor has the regulation of the pace of the hydraulic pump, but if I did not set it all the time the front loader works without changes (it's ok) and the lift bounces ...

The oil condition when I check on the dipstick is ok (the tractor has the one behind the rear left axle).

I read was similar when the oil filter was changeable (but then they wrote nothing about the front loader) and in my case it was changed six months ago. Others wrote that in the manifold the valve was stuck (I think it's No. 27A or 24 in the picture No. 3). Still others that the manifold under the seat has been damaged (hydraulic switch for lift or turn).

I am surprised that the front loader works properly, and the lift tugs ... If the filter (No. 71 in picture 3) was to blame, would it be possible for the front loader to work properly and the lift tugged?

What can cause the lift to tear?

1. The interior of the tractor (from white plastic comes the lever to change tur / jack)



2. I have such a hydraulic distributor (except that I have a working pace in the cabin) (photo borrowed from the Internet)



3. Diagram of hydraulics and distributor (photo borrowed from the Internet)