4610 PTO stopped working

   / 4610 PTO stopped working #1  

tallyho8

Elite Member
Joined
Aug 1, 2004
Messages
4,998
Location
Who Dat Nation west of Westwego east of Ama south
Tractor
Kubota L4400, Kubota ZD326
I have had nothing but trouble with my 4610SU since I got it last month. The lift had quit working and I dismantled it and found the control valve sticking and fixed it. Then I bushogged about 3 acres and it really ran great and did a very good job. I wondered why the previous owner had got just a 6' mower for it because this one could easily handle an 8' or larger mower.

I moved it to the next field to cut and pulled up the handle to start the pto and it made a little clank and stopped turning. This is an independent pto where when you engage the lever it sends hydraulic pressure to the pto clutch to engage it and pressure to the pto brake to release it. When you disengage the lever it relieves the pressure from the clutch and allows the brake to stop the pto.

I don't have any gages to check the hydraulic pressure as the manual instructions state to do and I suspected a stuck pto control valve so I again removed the lift cover and inspected the valve which seems to be working fine and I replaced the cover.

I need to get a gage and adapters to check the pressure as my manual states but before I go any farther but I have one question first. I can turn my pto shaft easily by hand with the engine off as it is supposed to do and with the engine running the pto brake is supposed to be on. With the engine running I can still turn the pto shaft with my hand but it is difficult to turn. Should a person be able to turn this shaft by hand while the pto brake is on, even if it is real hard to turn? Or does this signal that my pressure regulator valve may be bad?

I am hoping that it is not a broken pto clutch because the tractor would have to be split to repair it and I could not do this procedure by myself especially with no shop to work in and it would be very expensive to get it fixed by our only New Holland dealer.

I am sure the pump works fine because it easily lifts my 6' bushhog and I just put a new filter and new oil in it.

I hope someone has some suggestions for me.
 

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   / 4610 PTO stopped working #2  
I have had nothing but trouble with my 4610SU since I got it last month. The lift had quit working and I dismantled it and found the control valve sticking and fixed it. Then I bushogged about 3 acres and it really ran great and did a very good job. I wondered why the previous owner had got just a 6' mower for it because this one could easily handle an 8' or larger mower.

I moved it to the next field to cut and pulled up the handle to start the pto and it made a little clank and stopped turning. This is an independent pto where when you engage the lever it sends hydraulic pressure to the pto clutch to engage it and pressure to the pto brake to release it. When you disengage the lever it relieves the pressure from the clutch and allows the brake to stop the pto.

I don't have any gages to check the hydraulic pressure as the manual instructions state to do and I suspected a stuck pto control valve so I again removed the lift cover and inspected the valve which seems to be working fine and I replaced the cover.

I need to get a gage and adapters to check the pressure as my manual states but before I go any farther but I have one question first. I can turn my pto shaft easily by hand with the engine off as it is supposed to do and with the engine running the pto brake is supposed to be on. With the engine running I can still turn the pto shaft with my hand but it is difficult to turn. Should a person be able to turn this shaft by hand while the pto brake is on, even if it is real hard to turn? Or does this signal that my pressure regulator valve may be bad?

I am hoping that it is not a broken pto clutch because the tractor would have to be split to repair it and I could not do this procedure by myself especially with no shop to work in and it would be very expensive to get it fixed by our only New Holland dealer.

I am sure the pump works fine because it easily lifts my 6' bushhog and I just put a new filter and new oil in it.

I hope someone has some suggestions for me.

Dudley,

It is pretty late here but please don't grab the pto while the engine is on, especially if it is independent and hydraulically activated. I'm not familiar with the inner working of your tractor, but would think there is always potential for pto to engage suddenly if the clutch pack somehow engage. There is no way to have response time fast enough to let go off the pto shaft in time. I'll try to look at the ford site tomorrow to see if there is something there to see what's going on. I'm sure there is plenty of guys here know what exactly is going on. I just bought a hyd gage from northern for $12 and it works great and seems to be well built. I suggest for you to wait for some response here while you are getting a gage before any attempt in repair. below is the link for the pressure gage.

Valley Instrument 2 1/2in. Stainless Steel Glycerin Gauge — 0-3000 PSI | Filled Gauges | Northern Tool + Equipment

JC,
 
   / 4610 PTO stopped working #3  
I have had nothing but trouble with my 4610SU since I got it last month. The lift had quit working and I dismantled it and found the control valve sticking and fixed it. Then I bushogged about 3 acres and it really ran great and did a very good job. I wondered why the previous owner had got just a 6' mower for it because this one could easily handle an 8' or larger mower.

I moved it to the next field to cut and pulled up the handle to start the pto and it made a little clank and stopped turning. This is an independent pto where when you engage the lever it sends hydraulic pressure to the pto clutch to engage it and pressure to the pto brake to release it. When you disengage the lever it relieves the pressure from the clutch and allows the brake to stop the pto.

I don't have any gages to check the hydraulic pressure as the manual instructions state to do and I suspected a stuck pto control valve so I again removed the lift cover and inspected the valve which seems to be working fine and I replaced the cover.

I need to get a gage and adapters to check the pressure as my manual states but before I go any farther but I have one question first. I can turn my pto shaft easily by hand with the engine off as it is supposed to do and with the engine running the pto brake is supposed to be on. With the engine running I can still turn the pto shaft with my hand but it is difficult to turn. Should a person be able to turn this shaft by hand while the pto brake is on, even if it is real hard to turn? Or does this signal that my pressure regulator valve may be bad?

I am hoping that it is not a broken pto clutch because the tractor would have to be split to repair it and I could not do this procedure by myself especially with no shop to work in and it would be very expensive to get it fixed by our only New Holland dealer.

I am sure the pump works fine because it easily lifts my 6' bushhog and I just put a new filter and new oil in it.

I hope someone has some suggestions for me.

Pressure testing the PTO clutch circuit will be preferred to blind disassembly. Test with the PTO both engaged and disengaged. A 400-500lb gauge is much more appropriate for this test when connected to the proper port in the hyd pump cover.
 
   / 4610 PTO stopped working #4  
I am sure the pump works fine because it easily lifts my 6' bushhog and I just put a new filter and new oil in it.

I hope someone has some suggestions for me.

Dudley,

look at the pic below. It shows your hyrdaulically activated clutch pack for your pto system. You see two control valve #42 #35. #42 is attached to #57 connecting link. I make sure manipulating the connecting rod fully stroke or turn the hyd valve stem/spool. the reason that your clutch can not maintain gripping power to the pto is that the clutch pack is not squeezed together tight.The quizzing action is done by flow from two valves #42 and #35 to clutch pack piston assembly #1. If the sealring #4 is leaking by constant pressure can not be applied to the clutch pack hence no pto.

I don't know how the manual recommends diagnostic for your tractor but I think either the spools are not directing flow to the clutch pack, clutch plates are worn out (unlikely) or the sealring is bad.

You also have tubes #s 41,72,34,40 that direct flow to and from the clutch pack. I'd make sure I check them for may be crack or tightness where they are connected with tube #66 to return unused hyd fluid back to the reservoir.

indptohs5.jpg


Where you able to see the stuff on the drawing attached when you pulled the cover off?

Is any part of this contraption outside and on the side of the tractor?

Where do they recommend to check pressure for the pto system?

Can you pm me scanned sheets of the repair manual for the pto system to take a look at?

Good Luck,

JC,:)
 

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   / 4610 PTO stopped working
  • Thread Starter
#5  
Dudley,

look at the pic below. It shows your hyrdaulically activated clutch pack for your pto system. You see two control valve #42 #35. #42 is attached to #57 connecting link. I make sure manipulating the connecting rod fully stroke or turn the hyd valve stem/spool. the reason that your clutch can not maintain gripping power to the pto is that the clutch pack is not squeezed together tight.The quizzing action is done by flow from two valves #42 and #35 to clutch pack piston assembly #1. If the sealring #4 is leaking by constant pressure can not be applied to the clutch pack hence no pto.

I don't know how the manual recommends diagnostic for your tractor but I think either the spools are not directing flow to the clutch pack, clutch plates are worn out (unlikely) or the sealring is bad.

You also have tubes #s 41,72,34,40 that direct flow to and from the clutch pack. I'd make sure I check them for may be crack or tightness where they are connected with tube #66 to return unused hyd fluid back to the reservoir.

indptohs5.jpg


Where you able to see the stuff on the drawing attached when you pulled the cover off?

Is any part of this contraption outside and on the side of the tractor?

Where do they recommend to check pressure for the pto system?

Can you pm me scanned sheets of the repair manual for the pto system to take a look at?

Good Luck,

JC,:)

JC
42 is the pto control valve and 35 is the pressure regulator valve. I removed, inspected, reassembled and tested the control valve and it seems to work perfect. The linkage to this valve works fine. I did no checks on the pressure regulator valve yet.

Visual inspection of all the tubing while it is in place reveals no defects, however, if it had a crack somewhere on the bottom it would not be detectable. I would have to have some way to pressurize the tubing to inspect it for leaks.

All parts in your image are inside the housing except for the control lever and many are visual after draining some of the fluid.

Attached is page 77 of my IT manual which shows where to connect the gage in fig. 227. This is a poor, dark photo and I am not positive if I see the correct place but I also attached a photo of my tractor and I believe that this is the test port. Does anyone know if this is indeed the test port?

I can get a gage anywhere but it may be harder to get the 2 adaptors I need to hook up the gage. It is in a difficult area where a simple straight attachment will not work. Did I mention that it is a 50 mile roundtrip to my NH dealer who seems to never have anything in stock and does not answer his phone, you have to go to his shop. :mad:

I will email you the pages of my manual about the pto.
 

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   / 4610 PTO stopped working
  • Thread Starter
#6  
One thing I did not mention was that I always let my engine idle down fully before I engage the pto, but it engages suddenly like if you were to "pop" the clutch up suddenly on a tractor with a clutch operated pto instead of slowly engaging like when you let the clutch up slowly.

Is this normal on these types of Fords with the independent hydraulic operated ptos or should the pto engage more smoothly?
 
   / 4610 PTO stopped working #7  
One thing I did not mention was that I always let my engine idle down fully before I engage the pto, but it engages suddenly like if you were to "pop" the clutch up suddenly on a tractor with a clutch operated pto instead of slowly engaging like when you let the clutch up slowly.

Is this normal on these types of Fords with the independent hydraulic operated ptos or should the pto engage more smoothly?

Dudley,

I'll try to read up on your manual. I don't reckon the "sudden engagement" is normal. May be of you have a fast acting solenoid to open up the flow rather than a spool valve would be more of a shock load. That probably happens with tractors that have electro-hydraulic pto clutch (pushing a switch) to activate pto. On other hyd applications, I know that a ****** chamber or an orifice plate is used to slow down the hyd flow to avoid sudden engagement.

This may be caused by pressure relief device that works intermittently and may be is diverting flow from your clutch pack, just a bit of food for thought.

Jc,
 
   / 4610 PTO stopped working #8  
Dudley,

Read parts of the manual you sent me, wished you could have scanned it in to PDF rather than JPEG with a better resolution. it was little hard to see the details. Trouble shooting on page 77 generally summarized the suggestions I had earlier although it is always easier said than done:( The work involved can get a bit hairy and take a lot of patience if you have not done it before on the same make or mode to avoid further dorking it up. Your best bit would be to get the pressure reading to see where things are, basically doing all non-destructive things you can do. I don't think there is any way to avoid using of the pressure gauge and the adapter tool they mentioned. I suppose one could use a piece of 1/4" hyd hose with the proper fitting on the ends to be able to connect the gauge to the fitting (due to lack of room and not being able to get the gauge directly on the pressure nipple fitting). The problem with the hose is that you have to bleed the air before you can read accurate pressure (air compresses and screws up the reading). Their adapter most likely have very tiny hole in the pipe just to get a pressure reading. I hope you don't end up changing the ring seal on the pto clutch piston:eek: If you are forced to do it, I then for sure put a new set of clutch disks in it to. I hope the problem is some blocking the control valve or relief keeping the clutch pack from receiving adequate oil flow and pressure.

Good luck and keep us posted.

JC,
 
   / 4610 PTO stopped working #9  
Abrupt engagement is normal for Fords of that vintage. Engage at low ERPM's and feather the lever carefully, it can be done. The brake pad is weak, it is best to throttle down before disengaging the PTO so as to lessen wear in the PTO brake pad. If you don't want to visit the dealer, remove the test port plug and match the thread diameter, pitch and sealing device with an adapter to JIC, then use a short hose from JIC to 1/4" NPT which is your typical gauge thread size. It's all generic stuff available at a (very)good auto parts house that does hydraulics, or a hydraulic supply house, or industrial/ Ag dealership of almost any brand. Don't worry about a column of air in the hose, we are not troubleshoting a nuclear reactor. Check the pressure with the PTO both engaged and disengaged; that will give you an indication of the clutch piston seals' condition. Replacing the piston seals is good practice if you split the tractor for any reason. Replacing the piston seals without replacing the friction and unlined clutch discs is perfectly fine if the discs are flat and linings serviceable.
 
   / 4610 PTO stopped working
  • Thread Starter
#10  
I did not think about throttling down before disengaging the pto and am glad to learn this. I will probably get a chance to get a gage and adaptors Monday and do some checks.
 
 
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