8n with Sherman Backhoe, Hydraulics fade after warmup

[TheOldHokie]

(quoted from post at 00:48:06 05/18/23) Excellent information.

Blue Jay - Got the info. Already learned a thing or two.

TheOldHokie - Thank you for the explanation. I will heavily consider the upgraded loader valve with power beyond. My original doesn't actually seem to work very well. It sticks in certain spots and makes the pump whine a lot, particularly when actuating the bucket, almost like it isn't always making the circuits complete inside the block all the time.


I suppose before I get too far down the road, I should put a gauge on the loader pump... I can only pick just shy of 1000lbs which seems light. It uses a Cross pump, so I assume this was a later addition but may mean it can either be rebuilt or replaced without too much grief.


I use in cold and hot weather out here so I will get my hands on some AW32.

8NChris - Very cool. I like the 12" (?) bucket.

Careful putting a gauge on the pump. You cant just deadhead it into a gauge.

Those P40 valves are fine but come from lots of sources - some are of questionable quality although probably all better than what you currently have. Also watch out for port threads - lots of them come with BSPP (G thread) ports rather than SAE. I prefer the ones supplied by Magister or Summit. At one time both sold the ones made by Badesnost.

Summit Hydraulics

Magister Hydraulics

The power beyond sleeves are sold separately.

TOH

 

[Jim.ME]

It may not bother some people, but I expect a loader valve to have a Float position on the lift spool, not just a direction control spool, which are all the ones in the OP's link show. No Float position, it's not a loader valve. JMHO. Summit Hydraulics offers the valves with Float position on the lift spool (as well as the power beyond and closed center options). I checked with Magister a while back, as I was looking for a valve for a loader, and they did not offer any valves with that option at the time, so one would need to ask to see if that has changed.

 

[TheOldHokie]

(quoted from post at 06:45:20 05/18/23)
It may not bother some people, but I expect a loader valve to have a Float position on the lift spool, not just a direction control spool, which are all the ones in the OP's link show. No Float position, it's not a loader valve. JMHO. Summit Hydraulics offers the valves with Float position on the lift spool (as well as the power beyond and closed center options). I checked with Magister a while back, as I was looking for a valve for a loader, and they did not offer any valves with that option at the time, so one would need to ask to see if that has changed.

Magister does not offer any directional valves with float but unless that Wagner loader has down pressure on the boom he won't have any use for it.

If he does have down pressure Summit's joystick model would be a nice upgrade and only $275 with float and power beyond.

He should also keep in mind that if his loader has single acting lift cylinders he will need to plumb the unused work port on any DA valve to tank.

TOH

This post was edited by TheOldHokie on 05/18/2023 at 05:01 am.

 

[Midwayman]

I am in the process of looking up what pump is on my machine now to see if everyone thinks it is suitable for the hoe. I see no reason to have more than one pump in this scenario, particularly when the sherman pump seemed to be under rev'd in this application. My one concern is that when I use the loader, particularly the bucket, I get quite a significant whine from the hydraulic pump. I don't know if this is the artifact of the pump or the valve or what.

My Wagner lift cylinder is single acting, the bucket is double.

So my original valve is a two stick valve. One my big gripes is I cannot readjust the bucket and the lift while driving (say, while loading dirt into a trailer). Seems like a single stick may be a better solution?

I understand what you mean with the gauge, I just meant see how much pressure I am developing in the system while operating.

 

[TheOldHokie]

(quoted from post at 10:56:47 05/18/23) I am in the process of looking up what pump is on my machine now to see if everyone thinks it is suitable for the hoe. I see no reason to have more than one pump in this scenario, particularly when the sherman pump seemed to be under rev'd in this application. My one concern is that when I use the loader, particularly the bucket, I get quite a significant whine from the hydraulic pump. I don't know if this is the artifact of the pump or the valve or what.

My Wagner lift cylinder is single acting, the bucket is double.

So my original valve is a two stick valve. One my big gripes is I cannot readjust the bucket and the lift while driving (say, while loading dirt into a trailer). Seems like a single stick may be a better solution?

I understand what you mean with the gauge, I just meant see how much pressure I am developing in the system while operating.

I think a single pump system is a good idea for multiple reasons.

The loader valve is a potential source of pressure loss so you ccnt really test the pump as long as the valve is in the circuit. I can show you how to do an isolated test of just the pump if you want. If the pump is bad or you dimply want to get a larger displacement pump replacement cost is not bad - probsbly $200- $300

IMO joysticks are vastly superior.

TOH

 

[Midwayman]

Question 1: I am assuming this is a cheap knockoff of the Summit valve you mentioned: https://www.ebay.com/itm/11-GPM-2-S...4336?_trksid=p2349526.m4383.l4275.c1#viTabs_0
Not good quality wise or worth a shot?

Question 2: I have a 1.8cu in per rev pump for the loader. This would be around 10-11gpm at 1500RPM. I am also hoping that the pressure/lift problem is at the current loader valve relief. Seems like this should be plenty of flow for a small backhoe like this. Do you agree?

 

[8NChris]

(quoted from post at 14:09:28 05/18/23) Question 1: I am assuming this is a cheap knockoff of the Summit valve you mentioned: https://www.ebay.com/itm/11-GPM-2-S...4336?_trksid=p2349526.m4383.l4275.c1#viTabs_0
Not good quality wise or worth a shot?

Question 2: I have a 1.8cu in per rev pump for the loader. This would be around 10-11gpm at 1500RPM. I am also hoping that the pressure/lift problem is at the current loader valve relief. Seems like this should be plenty of flow for a small backhoe like this. Do you agree?

es it is a 12". According to this book they came with a 9", 12" and wider was optional. I prefer a pump for the backhoe alone so the fluid stay contained and the backhoe can be removed without disturbing the loader function and vice versa. Now an independent pump (not mounted to the equipment) stationary to the tractor with quick connects is a good idea. You can rig it up like a 50 year old and newer tractor would be. If I remember right the original backhoe pump is around 13 gallons a minute @ 1000 rpm. However it does work without overdrive. I installed my septic tank and half the lines before I broke the old garbled up patches upon patches. According to the manual Wain-Roy sold this model with 4 valves. This one has a dozer blade running off the backhoe pump.

 

[TheOldHokie]

(quoted from post at 17:09:28 05/18/23) Question 1: I am assuming this is a cheap knockoff of the Summit valve you mentioned: https://www.ebay.com/itm/11-GPM-2-S...4336?_trksid=p2349526.m4383.l4275.c1#viTabs_0
Not good quality wise or worth a shot?

Question 2: I have a 1.8cu in per rev pump for the loader. This would be around 10-11gpm at 1500RPM. I am also hoping that the pressure/lift problem is at the current loader valve relief. Seems like this should be plenty of flow for a small backhoe like this. Do you agree?

There are dozens of sources for those P40 style valves and Asia has recently started flooding the online market. .At that price its not much of a gamble but it has G thread ports and no power beyond sleeve. You can order the port adapters online and a PB sleeve from Summit will probably work but no guarantee.

I would think a 10 GPM pump is plenty. I sm told the BH77 OEM backhoe runs fine off the 7 GPM pump on my 37HP Kubota.

TOH

 

[TheOldHokie]

(quoted from post at 18:10:45 05/18/23)

(quoted from post at 14:09:28 05/18/23) Question 1: I am assuming this is a cheap knockoff of the Summit valve you mentioned: https://www.ebay.com/itm/11-GPM-2-S...4336?_trksid=p2349526.m4383.l4275.c1#viTabs_0
Not good quality wise or worth a shot?

Question 2: I have a 1.8cu in per rev pump for the loader. This would be around 10-11gpm at 1500RPM. I am also hoping that the pressure/lift problem is at the current loader valve relief. Seems like this should be plenty of flow for a small backhoe like this. Do you agree?

es it is a 12". According to this book they came with a 9", 12" and wider was optional. I prefer a pump for the backhoe alone so the fluid stay contained and the backhoe can be removed without disturbing the loader function and vice versa. Now an independent pump (not mounted to the equipment) stationary to the tractor with quick connects is a good idea. You can rig it up like a 50 year old and newer tractor would be. If I remember right the original backhoe pump is around 13 gallons a minute @ 1000 rpm. However it does work without overdrive. I installed my septic tank and half the lines before I broke the old garbled up patches upon patches. According to the manual Wain-Roy sold this model with 4 valves. This one has a dozer blade running off the backhoe pump.

You can easily deal with detaching the hoe.
Its just a power beyond loop - nothing special needed.
Have a look at any modern quick detach hoe.
In the case of removing that Sherman digger from an 8N the hydraulic connectios are the least of your worries.

TOH

This post was edited by TheOldHokie on 05/18/2023 at 04:10 pm.

 

[8NChris]

(quoted from post at 16:08:01 05/18/23)

(quoted from post at 18:10:45 05/18/23)

(quoted from post at 14:09:28 05/18/23) Question 1: I am assuming this is a cheap knockoff of the Summit valve you mentioned: https://www.ebay.com/itm/11-GPM-2-S...4336?_trksid=p2349526.m4383.l4275.c1#viTabs_0
Not good quality wise or worth a shot?

Question 2: I have a 1.8cu in per rev pump for the loader. This would be around 10-11gpm at 1500RPM. I am also hoping that the pressure/lift problem is at the current loader valve relief. Seems like this should be plenty of flow for a small backhoe like this. Do you agree?

es it is a 12". According to this book they came with a 9", 12" and wider was optional. I prefer a pump for the backhoe alone so the fluid stay contained and the backhoe can be removed without disturbing the loader function and vice versa. Now an independent pump (not mounted to the equipment) stationary to the tractor with quick connects is a good idea. You can rig it up like a 50 year old and newer tractor would be. If I remember right the original backhoe pump is around 13 gallons a minute @ 1000 rpm. However it does work without overdrive. I installed my septic tank and half the lines before I broke the old garbled up patches upon patches. According to the manual Wain-Roy sold this model with 4 valves. This one has a dozer blade running off the backhoe pump.

You can easily deal with detaching the hoe.
Its just a power beyond loop - nothing special needed.
Have a look at any modern quick detach hoe.
In the case of removing that Sherman digger from an 8N the hydraulic connectios are the least of your worries.

TOH

This post was edited by TheOldHokie on 05/18/2023 at 04:10 pm.

'm not the least but worried. It is a matter of preference. Just keep in mind that cylinder volume will decide how many gallons per minute are needed. Chances are these old Wain-Roy / Sherman diggers have larger cylinder volume than your unit. Something to consider before deleting parts and plumbing new ones in.

 

[TheOldHokie]

(quoted from post at 20:11:22 05/18/23)
I'm not the least but worried. It is a matter of preference. Just keep in mind that cylinder volume will decide how many gallons per minute are needed. Chances are these old Wain-Roy / Sherman diggers have larger cylinder volume than your unit. Something to consider before deleting parts and plumbing new ones in.

Nobody said you were worried. I said there were far bigger worries than hydraulic cinnections when it came to detaching the hoe. Three hydrsulic hoses with quick couplers is bothing.

And its more than a matter if preference it is a matter of engineering. I have done literally dozens of hydraulic conversions on old iron and I can compute hydraulic loads. Thats how I work.

If you have some actual hard data perhaps you could share it to aid in those calculations. Reservoir capacity is usually a limiting factor in hydraulic systems and the hoe only holds 8 gallons. The 1.8 CID loader pump produces 13 GPM @ 2000 engine RPM so we are already pushing best engineering practice there. Can you tell us what the actual displacement/flow rate of that little 540 RPM PTO gear pump is? To simply match the loader flow rate it would need to be roughly 3X bigger.

TOH

This post was edited by TheOldHokie on 05/19/2023 at 08:07 am.

 

[Midwayman]

Well this could be part of the problem:

It looks as if this had a paper element on the filter at some point and it ultimately broke down to pulp over the last few decades.

I already assembled back together and it helped a lot. I still may be looking at consolidating pumps for higher pressure, but this is much more workable than before.

 

[8NChris]

The pieces you have there are what the manual shows.

 

[8NChris]

Nope, I'm just an average washed up field technician. Never worked at one place for more than 5 years. To be fair 70% of my hydraulic experience was getting man lifts, crane and sign trucks to go up, down and around. The other 30% was mainly farm and construction equipment. Probably forgot half of it so maybe I'm below average. I didn't invent anything nor have any cad or desk work to back it up. You win.