JD 790 with JD#7 bachoe question

[sixdogs]

I recently purchased a JD 790 with 419 loader and #7 backhoe combination. Does anyone own one of these that can comment on the effectiveness or durability of the backhoe? I figure the tractor and loader are OK but know little of the backhoe. I just plan to use it around the house so lighter duty is OK. It only had 100 hours on it.
I have owned a Woods 750 before and it was tough as they come. The #7 looks more fragile in some regards but I am not sure and wonder if there are any other owners are out there?

 

[gordon21]

I have that combo and it has proven itself a solid performer. I have used mine for about 60-80 hours of actual digging. We cut into the side of the mountain so we could recess a full basement. It has worked great. Even though you normally think of a backhoe digging holes, most of my use was digging above ground level in front of the unit. We would reach up and dig into the hill above our heads and drap material down. You then use the FEL to scoop and remove about 8-10 buckets at a time. Repeat the process another 8 million times. I have not had one problem at all. It is very well built. The styling is from 20 years ago, but that doesn't bother me.

Watch the boom speed when swinging left or right if you are running over 1600 RPM. It can get fast.

Safety tip: Make sure no one enters the 180 degree arc of potential boom movement. If that boom comes around and hits you, there would be broken bones or worse.

 

[RobS]

I too have a 790 with the #7 backhoe, though my setup includes the older #70 loader. I use mine around the house and it's been great. I have no real complaints. Mine was used as well (the hoe anyway) and the swing cylinders leak a bit. I've heard this is common due to their location. I have the rebuild kits but have not yet messed with it. Had one leaky stabilizer cylinder and did the rebuild on it. It's been fine ever since.

It's not a powerhouse, but for the uses you described you should be fine. As Lewis mentioned, keep people, and anything valuable away as you are working.

One more thing, the quick-attach is great. Not as good as the 47/48 and later, but it's so easy that I generally leave the hoe on to keep it in the garage and remove it everytime I need the tph. Only takes me about five minutes for each install/removal.

 

[sixdogs]

[
One more thing, the quick-attach is great. Not as good as the 47/48 and later, but it's so easy that I generally leave the hoe on to keep it in the garage and remove it everytime I need the tph. Only takes me about five minutes for each install/removal.[/QUOTE]

Just how easy is it to remove the backhoe? I had a Woods 750 3-pt hitch that was a bear to take off and install. I have the owner's manual for the JD#7 but it seems confusing.
This only takes five minutes to remove or install?
If so, I'm on easy street as I sure would like to use the tractor for other things with 'hoe removed.

 

[RobS]

Taking it off is super easy. Getting it back on is dependant on how well you line the tractor up to the hoe. Practice helps I guess as I really can do it in five now pretty consistently. It almost takes longer putting the tph hardware back on than taking the hoe off.

I don't recall the manual but I'm sure it is confusing. Once you've done it a few times it will be a snap. I remove mine on a gravel pad but if you had a hard surface and could lower the hoe onto a wheeled dolly it would be even easier.

 

[cabover4us]

RobS
I was reading your post, and you got me interested in knowing the steps in removing your #7 backhoe. I have a #7 mounted to a 855, havent used it much at all, bought it last fall late in the season, my son dug a three foot hole just to try it, no effort at all...

greg

 

[RobS]

RobS
I was reading your post, and you got me interested in knowing the steps in removing your #7 backhoe. I have a #7 mounted to a 855, havent used it much at all, bought it last fall late in the season, my son dug a three foot hole just to try it, no effort at all...

greg

OK, I'll see if I can remember the steps:

1) Back up to wherever you want to leave the hoe. Level and smooth is good.
2) Lower the boom to the ground to unload the top link and remove the top link pin at the tractor and the pin halfway along that link. With both pins out you can flex the link to fold it up and out of the way. I put both pins back in to not loose them.
3) Raise the boom back up a bit to unload the subframe. Pull the pins at the front of the subframe, under the operator platform. Mine are spring loaded but the 855 may be different.
4) Lower the stabilizers and the boom to put the whole weight of the hoe on the ground. Now the trickiest part, work the boom and stabilizer controls to lower the front of the subframe and keep the rear subframe mount at about the same height. Do this from beside the hoe, not on the seat. You'll move the boom down to lower the front of the subframe, then tweak the stabilizers some. The subframe will end up at an angle, lower in front than the back. Also, the hoe seat will rotate forward and probably hit your tractor seat.
5) At this point, you can pull the tractor forward a few inches to clear the subframe but not stress the hoses. Take a good look at the rear subframe mount to the tractor, below the PTO. This is what it needs to look like when you hook back up.
6) With the tractor clear, lower the hoe to the ground using the stabilizers and boom contol. Watch the hoses though there should be enough slack.
7) Once it's on the ground and steady, shut the tractor off and disconnect the hoses (have a good look at the routing before unplugging). Plug the tractor end back into the tractor and hook the two hoe hoses together. It is most important to plug the tractor hose back into the tractor otherwise you dead-head the hydraulic pump.
8) Restart the tractor and pull away.
9) Remove the strut that keeps the rockshaft arms up and put the tph hardware back on (this can be harder than you think due to the subframe bracket below the PTO, it obstructs the tph hardware some).
10) Installation is essentially the reverse. The rear subframe mount has some clever stops built into it that help guide everything back together.

I've got this down to the point that I actually keep my hoe on my tractor most of the summer, so it can be in the garage. I pull the hoe off everytime I need to use a tph implement. With practice it literally only takes five minutes. On the other hand, if you don't get things lined up pretty well, it can take quite a bit longer with plenty of adult words to help!

 

[cabover4us]

RobS, thanks a million, now thats some good info, on wednesday I'm going to remove it and put on the box scraper and get to our pot hole roadway...
thankyou again, i think i'm going to print that out..
greg

 

[slaveToHorses]

I owned and used a #7 for about 5 years on an 855, before I got my 3720/447.

Mine was heavily used before I got it and I used it hard. One of my swing cylinders leaked a bit also. But it was no big deal and it never bothered me enough to rebuild it. Otherwise I never had a lick of problems with the hoe.

It was on the tractor most of the time. In fact I rarely removed it. The only issues I had with mounting it was getting the tractor straight with the backhoe subframe. I finally made a home for it on a level surface and painted markers to made it butt-stupid for me to line up to.

Learn to use it with your throttle set at about 1500. At a point where the hydro pump doesn't load down your tractor but the hoe controls move slow and smooth. I wish someone had told me that back when I first learned to use a backhoe...

Oh one more very important piece of advice.
When you are working the hoe, and ask it do do something it doesn't have the power to do, it goes into bypass mode, bypassing hydraulic fluid; Don't keep pushing it. Back off a bit and try something different. Otherwise you will damage your hydraulic pump. It heats up when it is in bypass.

 

[sixdogs]

Thank you s-t-horses--

I too have found 1500 to be a good operating RPM and have been careful not to overload it. That's good advice.
I've been moving trees and such as well as general cleanup. I just love this little tractor-loader-backhoe. I can get into corners with the backhoe or loader and it's light enough not to leave ruts on the lawn. I've owned a lot of tractors over the years but this is one of the best. It looks small and inadequate but wow it sure isn't.

Having raised a lot of horse hay over the years, I understand the slave part. Then again, Bob Dylan wrote that "Everybody's got to serve sombody." Might as well be horses.