Backhoe Hydraulics for Backhoe

[mrkool]

Here's my setup (valve) on a 3500 with either a 735 or 740 FEL, it's old and pretty loose, but will have to do till I can get some different handles.

I'v been meaning to ask if anyone can tell me if it has PB? because I found a used backhoe
that, I think came with this tractor, just not sure how it was connected to the system.

Another issue that just came up, Hydraulic pump or line noise, it's a hum, sometimes loud and sometimes not, louder at higher rpm's and when I raise the bucket. I think I read somewhere that it could be:

1. Pump fluid low or bad
2. Pump itself going bad

Should I check for anything else?

Thanks,
Paul

 

[montejw]

I'v been meaning to ask if anyone can tell me if it has PB?

How many lines coming from the valve? I think an even number (2 per circuit, in, out) would mean no, odd (2 per circuit, in, out, pb) would mean yes. But don't quote me on that.

Can you get another picture from a different angle showing all of the connections?

Monte

 

[herringchoker]

mrkool - The Ford setup has the power beyond function in the backhoe valve, so that fluid goes from the pump to the backhoe valve and then to the loader valve. The attachment to my post #43 in this thread shows the oil flow diagram for the 740 FEL with backhoe. The 735 is similar except there is no surge reservoir on the tractor itself (the loader frame is the entire reservoir) and the filters are different. If the backhoe you found was made for the 3500, the PB function should be in the backhoe valve.

 

[mrkool]

OK, my oil reservoir is in the loader towers (frame(s) and I believe my valve
(Bucket Hyd 5 & 77.jpg) has 7 lines in/out of it, 5 on the side and 2 underneath, does that mean it has PB?

or is my PB on this loader? (BH1 & BH2)

also, was I right about the Hydraulic noise at high rpm? the fluid is 13 1/2 in.
from the top of the tower, if that's full, then it's either the filter/screen or pump right?

 

[JerryG]

There should be these hoses for the loader.

pressure to lift
return from lift
pressure to dump
return from dump
pressure to valve
return from valve

If there is PBY, there will be another hose for that.

Most of the small tractors that owners have here on TBN have the PBY in the loader valve. Large tractors have a higher percent that have the PBY in the backhoe valve.
Look to see where all of the hoses go, then you will know more about the system.

 

[herringchoker]

That backhoe looks like what I had on my 4500. It was a model 755, 15 ft. digging depth. The 3500 mounted either the 750 hoe (10'6" depth) or the 753 (13'4" depth). All hoes were identical except for dimensions and cylinder sizes.

I'm no hydraulics expert, but as Monte and Jerry say, I think 7 lines at the valve means PB is installed at the loader valve. Check the backhoe valve - an odd number of lines coming from the valve (I think there should be 15: 6 pairs of work ports plus inlet, power beyond and return to tank) should mean PB is installed there too.

Digging further into the shop manual, I found where the PB plug can be removed from the backhoe valve (it appears to be simply a pipe plug installed internally in the valve body and is accessible through the outlet port). This would allow you to feed the FEL first, if indeed the FEL valve has PB.

Is that a selector valve on the side of your FEL valve? In the shop manual it says "The power-beyond port supplies oil to the loader valve, when a loader is installed on the tractor. All pumped oil is supplied to the backhoe main control valve before it reaches the loader. This eliminates the necessity of using a selector valve."

I wish I could help you more. We're sure missing MadReferee now.

 

[FULLPULL]

On our 730 loader the filter screen is like a wood fiber filter .Setting on the seat our's is on the left under the loader in the loader frame about a 12 inch long filter.13 1/2 inch sound's right that's where we fill our fluid level to.We cleaned the filter on our loader after 20 year's of service and it was stopped up with gunk and the hose's that delaminated from the inside.I cleaned it with thinner and it worked alot better almost to good we busted a few weak hoses because of the presure increase.

And we are going to miss MadReferee in this thread

 

[jgbanshee]

I talked with people from Bradco some more about the 11 HD valves and they said that the max flow the Gressen valve can handle is 20 GPM. So I think that I am going to route the hydraulics to the backhoe power beyond and then to the loader and see how it performs.

 

[jgbanshee]

I came across the same tractor and backhoe the other day on the internet and called the dealer and they told me that the hydraulics were routed from the block off plate on the top cover under the front of seat with a fitting and the return line was fitted to one of the filler plugs on the rear axle housing. Anyone know if that is okay to do?

 

[jgbanshee]

Well today I did it. I routed the backhoe valve in series with the loader valve and for everyone out there, it does NOT work. I ended up splitting the loader valve body in two pieces. Hydraulic fluid everywhere and need to replace the valve quick like. I guess I will buy a valve with power beyond and I wont have any problems. One question, the pump is rated for 26GPM and most of the valves I see that come close to fitting the physical area on the loader are rated at max flow of 25GPM. What should I do?