Backhoe 3720 rockshaft malfunction backhoe removal

[Yourkie]

I'm attempting to remove the 447BH from my 3720 for the first time. The BH was installed by the JD dealer early this summer. I'm discovering that the rockshaft will not lift (or lower). It seems dead in the water. I've tried adjusting the flow valve that is located in the middle under the seat and it makes no difference. Is there anything obvious I'm missing here? BTW I'm hoping that there is an answer that makes me really look stupid.

I've disconnected the BH and reconnected the bypass hyd hose on the power beyond. With a MMM and BH on it is tough to get under it to see if something is disconnected (espec >60).

This thread on 447 R&R http://www.tractorbynet.com/forums/john-deere-owning-operating/144188-r-r-3720-447-backhoe.html had some good info. Cocre recommended using the stabilizers to lift and then lower the BH instead of using the rockshaft.

My concern about using the stabilizers is that if they are used to raise the BH up and then move the tractor forward from the hooks, is there enough BH hose slack to lower the backhoe unit? It looks tight to me. The rockshaft method that the op manual recommends has the BH hoses disconnected and the bypass hose installed so hose slack isn't an issue.

As always thanks for any advice.

 

[Cocre]

My 447 backhoe has plenty of hose length. I can lower it all the way to the ground using the stabilizers. Often I do just that, then raise the stabilizers, turn off the tractor, disconnect the hoses, connect the PB hose to the tractor, crank up and drive off. I always make certain that the rockshaft control lever is all the way down also before lowering the hoe so they float down with it. The hitch lowers by weight, not by hydraulic power.

There is nothing underneath to connect up as far as the backhoe or rockshaft hydraulics are concerned. Make certain your quick connects are really connected. If not you will probably hear the hydraulic pump straining, and the lift will not work.

 

[CinderSchnauzer]

Is there anything obvious I'm missing here? BTW I'm hoping that there is an answer that makes me really look stupid.

OK - Here goes...............did you remove the two L-Pins?

Initially I had problems that mine would not raise high enough, but assuming the L-pins are out, the flow valve is open and the PB line has been properly reconnected, unless something is severely binding the weight of the BH should make it go down.

 

[Yourkie]

Thanks. The L bolts are still in. I can take them out if I use the stabilizers to lift the back hoe and take pressure off. But the main problem is that the rockshaft does not even try to lift the backhoe. It is not as though it is at the extreme or top of its travel as the hydraulics don't sound as though they are under pressure or in relief. The rockshaft does not lift or do anything when the lever is moved to the full rear. Is there something I'm overlooking that disables the rockshaft?

The power beyond bypass hose could not have been hooked up at the dealer as part of the install, as the male fitting needed loosened and swiveled so it could be facing and inserted in the female quick connect. Here is a photo of the PB after the BH was disconnected and before the bypass could be connected (and before it was connected).

 

[zr2blz]

Hello, I had problem taking off my 447 until I did the adjustment like shown in the 4th reply in this ==>> http://www.tractorbynet.com/forums/...g/158847-3x20-rockshaft-3pt-hitch-travel.html

This looks like its a known problem by all of us that had to do this small adjustment. (my dealer also didn't install 447 with rockshaft).

Goodluck, Glenn

 

[mjncad]

Hello, I had problem taking off my 447 until I did the adjustment like shown in the 4th reply in this ==>> http://www.tractorbynet.com/forums/...g/158847-3x20-rockshaft-3pt-hitch-travel.html

This looks like its a known problem by all of us that had to do this small adjustment. (my dealer also didn't install 447 with rockshaft).

Goodluck, Glenn

Hi Glenn:

Did you buy your rig from LPE?

Matt

 

[Cocre]

Yourkie is not talking about backhoe hook adjustment (not yet at least). sounds like his 3 pt hitch will not lift at all.

Make for certain that the PB quick connect is actually connected, it is not in your attached picture, and you say as much, just make certain that it really is. Trust me, it can look like it is, pretty much feel like it is, and not be. While you are at it, check the loader quick connects also.

If something is not plugged into the PB supply line the hydraulics will dead head and you will know it, don't run the tractor long under those conditions.

Drop the backhoe using the stabilizers. Turn your tractor off. Disconnect your BH hydraulics. Connect your PB connect. Check to make ceratin you just did the previous step. Lower the hitch arm lever. Crank up, drive off. Adjust the rate drop valve to somewhere toward the rabbit and manually push down on the hitch to force them down. The 3 pt hitch will work.

 

[JB4310]

If your sure your pby is restored to normal 3pt function then it must be that height adjustment.

On my 48 BH the first few times I was able to do the swap by the book, with alot of fighting with the couplings in the tight areas. last time I couldn't even wrestle them in there without removing seat.

Now I just use the stabilizers, much easier, as far as the lift height on mine it was set right to the sweet spot for pin install no room for any less.

 

[jimgerken]

I own the same setup you do. I am betting your 3ph is working fine, but it is already to the top of its stroke (as it is adjusted) so it does not move when you move the lever. Moving the lever forward to lower the 3ph arms does nothing, since there is no weight on them. You need the adjustment made. The adjustment changes the the 3ph stop at its very top position. The manual explains how to do this. The problem is, if you get it set right to make the backhoe install and remove properly, the 3ph is adjusted so when its at the full up lever position, the arms cannot go that high so the relief valve is opening (heating your oil and ruining something within a couple minutes according to the manual). This is a bad way to leave your lever adjustment, 'cause if an operator does not realize the relief valve is opening after they raise the 3ph, eventually the hyd oil overheats. The real solution for this is a modification I wish to make to the backhoe. There are small bolt-on plates that allow fine tuning the fore and aft postion of the 3ph arm pin interaction with the backhoe. These small brackets are installed on the backhoe itself. The brackets are not made correctly, in my opinion. A simple change to them to make the backhoe raise a bit higher would result in allowing the 3ph to be adjusted correctly (so it didnt go into relief mode) and still lift the backhoe high enough. I plan to make this mod in the Spring 2010. I will post it under Customization when it is done.

 

[Yourkie]

Thanks again guys for your time and info.

This TBN forum is big time help and fixing problems in the end is all about details.

I did find other threads on this forum via Google that discussed my problem in depth, so (as someone said) this is a rehashed topic. I should have researched further before I rehashed it. Thanks it is a huge help having experienced support around. But having incompetent dealers is something you must judge for yourself.

http://www.tractorbynet.com/forums/...rating/88507-whats-sloppy-backhoe-mounts.html

http://www.tractorbynet.com/forums/...rating/146939-3320-rockshaft-doesnt-rock.html

Bottom line I'm going to use the stabilizers to remove the BH. Then I'm going to figure out how to adjust the rockshaft linkage so I can do it properly in the future even though JD keeps it a secret by referring users in the op manual to "the dealer" as if they will do it correctly.

As an engineer I'm a stickler for using factory documentation. Engineers have spent the time to evaluate and document this in the manual... which means something. Not that those engineers are always correct. Speaking from years of experience there is always a built-in friction between field techs and engineers. Some say engineers worry too much and some say they know nothing.

The bottom line here is that my dealer never bothered adjusting the rockshaft setting when they installed the backhoe and as much told me so, saying that they use the dipper and outriggers because it is easier. This works but it is more risky for the user manipulating hoses and multiple controls and requires being off the tractor. Why bother with manuals?

My dealer offered nothing to correct this except "have a good day". It reminds me of why I prefer doing things myself, as then I can be angry at only myself. We need to publicly evaluate dealers on this forum.

A concern is are the hoses long enough to allow it to set on a block and how much of a distance and angle of the dipper stick be required as space is limited where I park this? I'll find out shortly.

Our utility tractors are relative toys compared to real equipment but they are still heavy enough to do some personal damage if you don't think it all through.

Installing and removing implements for the first time is always a hassle. I told my dealer initially to add labor just to educate me on this BH r/r etc. but the guy that installed and understood it wasn't there and they dumped it off.