# Ford 4600 pulsing slow pulsing hyds



## gregrsv (Aug 25, 2016)

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.

Our next plan is hopefully test pump pressure ( does the pump offload itself when not selected by the aux take of valve or should i see pressure all the time there?)
Then possibly remove pump to see if there is any way it could be drawing air in the suction side ( is that the spigotted connection inside as you pull the pump out of the transmission housing?) 
Can i get to the pump suction gauze without taking the top cover off?
We are hoping not to need to take the top lift cover off due to the q cab and it looks pretty space restricted.

Has anyone seen similar symptoms with this model that may reduce my fault finding route as i am just finding my way around this machine?

Oh by the way its a single pump machine
thanks very much 
Greg


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## sixbales (May 18, 2011)

Howdy Greg, welcome to the tractor forum.

The pressure test port for the pump is on the lower side of the flow control valve plate. Your manual should have a picture illustrating it. That's probably the same port you were referring to. You will need a 285 bar gauge, a shut-off valve, and a length of hose long enough to return fluid back to the reservoir. Your manual should illustrate the setup.

Your pump pressure should be near 178 bar (2500 psi).

PS: If your 4600 is equipped with an accessory selector valve (see your manual) disconnect the line going to the valve, and install plug prior to doing the pressure test.

This is all covered in your manual, but sometimes you can miss a detail.


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## gregrsv (Aug 25, 2016)

Thanks six bales 
That test port is the one i cannot find an adaptor to fit the thread its a very coarse thread that i haven't seen before. I've had the gauge in the accessory ports they are 9/16 thread for sae type fittings , thats where i could see the pressure pulsing , i'm desperate to try a pressure test at the port next to the pump to see if the pulsing is evident down there also.
regarding the manual they say to put a shut off valve in line with the gauge and a run off hose to the tank ? i'm not sure why they are doing that as surely you'd want to test the pressure that they system is making to open the system relief valve i'm guessing it'll be downstream of the pump test port.
cheers 
greg


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## gregrsv (Aug 25, 2016)

*4600 slow intermittent hydraulic loader*

Hello all 
I am back looking at the problem on this tractor , I'm not sure if there is anything i can do externally to check before i take the top cover off , can i remove the top cover if needed with a q cab fitted.
cheers 
greg


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## gregrsv (Aug 25, 2016)

hello all 
latest on the hydraulics changed the near new spin on filter and alls well!! so ware collapsed filters!
cheers 
greg


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