Lil Foot
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Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
B670 Backhoe Rebuild
- Thread starter morson82
- Start date
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
When I began the rebuild process on the swing cylinders, I found a problem caused by a less than stellar design. The cylinders are single acting, meaning they only have hydraulic fluid on one side of the piston. The outboard end (ram end) of the cylinder has a hole in the end cap, which allows air to be expelled from in front of the piston as the ram extends. Great. The problem comes when the ram is pushed back in as the opposing cylinder extends.... the vent hole becomes a vacuum cleaner, sucking up any dirt or water in the area. In addition, there are no seals or wipers on the ram, so the ram & cylinders were very dirty and rusty. This vent was nearly plugged with crud, but when cleaned, measured .201 diameter. I hunted for suitable hardware to correct this problem, and came up with a suitable wiper seal for the ram, but had to fabricate the parts for the vent solution.
First, I tapped the hole in the end cap for a 5/16-24 thread. Then I pushed the bearing back .120, and pressed in the new wiper seal.
When I began the rebuild process on the swing cylinders, I found a problem caused by a less than stellar design. The cylinders are single acting, meaning they only have hydraulic fluid on one side of the piston. The outboard end (ram end) of the cylinder has a hole in the end cap, which allows air to be expelled from in front of the piston as the ram extends. Great. The problem comes when the ram is pushed back in as the opposing cylinder extends.... the vent hole becomes a vacuum cleaner, sucking up any dirt or water in the area. In addition, there are no seals or wipers on the ram, so the ram & cylinders were very dirty and rusty. This vent was nearly plugged with crud, but when cleaned, measured .201 diameter. I hunted for suitable hardware to correct this problem, and came up with a suitable wiper seal for the ram, but had to fabricate the parts for the vent solution.
First, I tapped the hole in the end cap for a 5/16-24 thread. Then I pushed the bearing back .120, and pressed in the new wiper seal.
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Lil Foot
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Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
I next made a couple of 5/16-24 X 1/4" hose barbs, and a tool to install them. (they are recessed, so a conventional wrench was not an option)
I next made a couple of 5/16-24 X 1/4" hose barbs, and a tool to install them. (they are recessed, so a conventional wrench was not an option)
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Lil Foot
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Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
Finally, the finished cylinder awaiting paint. I will bring Tygon vent hoses up higher on the hoe, probably under the control valve body, to some sort of vent box, yet TBD.
Finally, the finished cylinder awaiting paint. I will bring Tygon vent hoses up higher on the hoe, probably under the control valve body, to some sort of vent box, yet TBD.
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Re: Backhoe rebuild
Gentlemen, as many years as I have been a part of the internet I still become amazed, and on many levels. here we have two men who didnt not know each other before from completely opposite sides of the country sharing their knowledge, and understanding, and lives with one another to eachs benefit. but not only is it beneficial to them but to third parties as myself. I too have wanted this attachment for my B6000dt or b7100dt. I have learned that 1 they can be, and must be often abused by previous owners. secondly that repairs can be quite costly and time consuming. thirdly, if your dont have the money or skills be very careful about choosing to follow through with a purchase. with all that said, I have decided to keep my 57 cents, paperclip and half pack of chewing gum in my pocket til a later time.
No joke now, good work men and thanks for sharing with each other and thus all of us. Also thanks to Mr.K for the forum so us orangebloods can get a fix for our kubota addiction.
Keep posting guys!!
Gentlemen, as many years as I have been a part of the internet I still become amazed, and on many levels. here we have two men who didnt not know each other before from completely opposite sides of the country sharing their knowledge, and understanding, and lives with one another to eachs benefit. but not only is it beneficial to them but to third parties as myself. I too have wanted this attachment for my B6000dt or b7100dt. I have learned that 1 they can be, and must be often abused by previous owners. secondly that repairs can be quite costly and time consuming. thirdly, if your dont have the money or skills be very careful about choosing to follow through with a purchase. with all that said, I have decided to keep my 57 cents, paperclip and half pack of chewing gum in my pocket til a later time.
No joke now, good work men and thanks for sharing with each other and thus all of us. Also thanks to Mr.K for the forum so us orangebloods can get a fix for our kubota addiction.
Keep posting guys!!
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
Thank you for your kind words sir. I, too, am amazed at the amount of useful info that can be shared via the internet..... not that long ago we would have never known that anyone else was going through the same tribulations with our equipment and would not have been able to benefit from each other's experience. And there is apparently at least one other person as brave (or misguided) as we are.
http://www.orangetractortalks.com/forums/showthread.php?t=3374
Thank you for your kind words sir. I, too, am amazed at the amount of useful info that can be shared via the internet..... not that long ago we would have never known that anyone else was going through the same tribulations with our equipment and would not have been able to benefit from each other's experience. And there is apparently at least one other person as brave (or misguided) as we are.
http://www.orangetractortalks.com/forums/showthread.php?t=3374
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
The wrench I made for the curl, boom, & dipper stick cylinder end caps.
The wrench I made for the curl, boom, & dipper stick cylinder end caps.
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Lil Foot
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Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
When I got the tractor, the zerk at the end of the curl ram was broken off & the hole was packed with dirt. I extracted the remainder and installed a new zerk, which promptly sheared off on digging my 3rd or 4th hole. Looking at the paint (or lack thereof) on the end of the ram eye, it was obvious that every time the bucket was fully curled in a hole, the zerk was being dragged through the dirt, rocks, etc..
I put a 1/4-28 set screw in the original hole, and drilled, tapped,& installed a new zerk in a more protected location.
When I got the tractor, the zerk at the end of the curl ram was broken off & the hole was packed with dirt. I extracted the remainder and installed a new zerk, which promptly sheared off on digging my 3rd or 4th hole. Looking at the paint (or lack thereof) on the end of the ram eye, it was obvious that every time the bucket was fully curled in a hole, the zerk was being dragged through the dirt, rocks, etc..
I put a 1/4-28 set screw in the original hole, and drilled, tapped,& installed a new zerk in a more protected location.
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Lil Foot
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Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
The B670 has lots of seals, o-rings, backing rings, & wear rings to replace.
The B670 has lots of seals, o-rings, backing rings, & wear rings to replace.
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Last edited:
Lil Foot
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Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
And hoses...... I actually kept two that had apparently recently replaced to use as spares.
One of the previous owners had apparently noted the deterioration of the jacket on most of the hoses and peeled off the outer skin on most of the hoses- then he wound black electrical tape on them and painted the whole mess orange. With the hoses rotted to the point of being somewhat porous, that really didn't work too well, and was quite a mess to deal with.
Odd that electrical tape didn't hold up under 2000psi hydraulic fluid.
And hoses...... I actually kept two that had apparently recently replaced to use as spares.
One of the previous owners had apparently noted the deterioration of the jacket on most of the hoses and peeled off the outer skin on most of the hoses- then he wound black electrical tape on them and painted the whole mess orange. With the hoses rotted to the point of being somewhat porous, that really didn't work too well, and was quite a mess to deal with.
Odd that electrical tape didn't hold up under 2000psi hydraulic fluid.
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Re: Backhoe rebuild
Wow Bill, that looks great! You certainly go above and beyond.....might even dare to say your a "perfectionist" I have the main part of my backhoe back onto the tractor. Right now I am having pins made for the swing arm and boom. The bottom area of the swing arm, where it attachs to the weldment, is pretty screwed up, id say about 1/4 out of round. There were brass sleeves slid into the holes and then they had a bolt going through them. I am having my metal guy sleeve the holes back to 1" and having him make the spacers for where the cylinders attach to the boom/swing arm. By then, It should all be back together and ready to use, or should I say, in time to start redoing the front end loader. Will attach some pics later!
Glenn
Wow Bill, that looks great! You certainly go above and beyond.....might even dare to say your a "perfectionist" I have the main part of my backhoe back onto the tractor. Right now I am having pins made for the swing arm and boom. The bottom area of the swing arm, where it attachs to the weldment, is pretty screwed up, id say about 1/4 out of round. There were brass sleeves slid into the holes and then they had a bolt going through them. I am having my metal guy sleeve the holes back to 1" and having him make the spacers for where the cylinders attach to the boom/swing arm. By then, It should all be back together and ready to use, or should I say, in time to start redoing the front end loader. Will attach some pics later!
Glenn
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
Thanks Glenn.
I have run into a small setback- when I opened up the dip cylinder for cleaning & resealing I found this part, called a "gland with o-ring & backup" was badly pitted on the internal sealing surface. (Sorry about the quality of the pic, best I could do with my camera.)
Judging by the apparent screwdriver-like gouges, I think someone tore it up getting out the 6 piece seal set that goes in this recess, and then years of outdoor storage allowed water to corrode & pit it to this point. The boom cylinder is almost this bad, but the curl cylinder was in good shape. Go figure.
I haven't decided yet whether to machine new parts from scratch, or maybe just bore out & sleeve the old ones.... it's nearly the same work either way, if you figure fixturing & multiple setups. Might have a problem with leakage past a sleeve, even with an interference press fit.
Opinions?
P.S. Once these cylinders are rebuilt & painted, it will just be a matter of assembling the boom, dipper stick & bucket, and installing 12 hoses. Everything else is done/cleaned/replaced/etc.
Thanks Glenn.
I have run into a small setback- when I opened up the dip cylinder for cleaning & resealing I found this part, called a "gland with o-ring & backup" was badly pitted on the internal sealing surface. (Sorry about the quality of the pic, best I could do with my camera.)
Judging by the apparent screwdriver-like gouges, I think someone tore it up getting out the 6 piece seal set that goes in this recess, and then years of outdoor storage allowed water to corrode & pit it to this point. The boom cylinder is almost this bad, but the curl cylinder was in good shape. Go figure.
I haven't decided yet whether to machine new parts from scratch, or maybe just bore out & sleeve the old ones.... it's nearly the same work either way, if you figure fixturing & multiple setups. Might have a problem with leakage past a sleeve, even with an interference press fit.
Opinions?
P.S. Once these cylinders are rebuilt & painted, it will just be a matter of assembling the boom, dipper stick & bucket, and installing 12 hoses. Everything else is done/cleaned/replaced/etc.
Attachments
Last edited:
Re: Backhoe rebuild
Bill, it might be easier to just try and order a new glad w/O-ring. The part number is 70020-00839 and according to Messicks its cost $40.61. I would recommend contacting Tracy at Big Orange Parts either by email or phone, he has helped me a lot with the backhoe rebuild and is the cheapest price by far. I was able to order 2 NOS cylinder pins, guides and even a bare cylinder for the backhoe. Check him out. As a matter of fact, I'm about to place an order with them today. Let me know how it works out. Any luck with the seat pics?
Glenn
Bill, it might be easier to just try and order a new glad w/O-ring. The part number is 70020-00839 and according to Messicks its cost $40.61. I would recommend contacting Tracy at Big Orange Parts either by email or phone, he has helped me a lot with the backhoe rebuild and is the cheapest price by far. I was able to order 2 NOS cylinder pins, guides and even a bare cylinder for the backhoe. Check him out. As a matter of fact, I'm about to place an order with them today. Let me know how it works out. Any luck with the seat pics?
Glenn
Lil Foot
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Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
Glenn, wow, thanks for the research. But I've decided to make new parts from scratch- I bought enough stock for 2 parts for $14 today, and it will probably take me ~6-8 hrs of machine time, when I can fit it in between other stuff.
If I still had access to larger, more precise equipment, I could probably halve that estimate, but the lathe I have now is smaller, less rigid, and I sometimes have to adapt my larger tooling.
No seat pics yet, but we are tentatively planning to go to the high country this weekend.
Bill
Glenn, wow, thanks for the research. But I've decided to make new parts from scratch- I bought enough stock for 2 parts for $14 today, and it will probably take me ~6-8 hrs of machine time, when I can fit it in between other stuff.
If I still had access to larger, more precise equipment, I could probably halve that estimate, but the lathe I have now is smaller, less rigid, and I sometimes have to adapt my larger tooling.
No seat pics yet, but we are tentatively planning to go to the high country this weekend.
Bill
Re: Backhoe rebuild
It's somewhere in a box but I have a brand new hyd pump for one of those little backhoes. I had one years ago and it came with a extra pump when we bought it. If either of you guys need one give me a shout.
It's somewhere in a box but I have a brand new hyd pump for one of those little backhoes. I had one years ago and it came with a extra pump when we bought it. If either of you guys need one give me a shout.
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Lil Foot
Well-known member
Lifetime Member
Equipment
1979 B7100DT Gear, Nissan Hanix N150-2 Excavator
Re: Backhoe rebuild
Ok, slight shift in focus.... Glenn (morson82) had some questions about the lifting/reversing seat for the B670, so today I went up north & shot some pics.
Rear view of seat showing lock rod & hair pin clip.
Same except seat tilted forward.
Seat riser lifted.
Different view.
Locking rod & hairpin clip in place.
Ok, slight shift in focus.... Glenn (morson82) had some questions about the lifting/reversing seat for the B670, so today I went up north & shot some pics.
Rear view of seat showing lock rod & hair pin clip.
Same except seat tilted forward.
Seat riser lifted.
Different view.
Locking rod & hairpin clip in place.
