B670 Backhoe Rebuild

[Lil Foot]

Re: Backhoe rebuild

Different view of locking pin, clip, & seat riser lifted.

Seat spun to the rear.

View from the front, right side.

 

[Lil Foot]

Re: Backhoe rebuild

My improvised seat support/shock absorber, and the spring-loaded pivot bolt.

I used a 3/8" elevator bolt with assorted washers & nuts to get the red automotive shock bushing to stay in place & sit at the right height. (press fit)

View from below showing the flat head of the elevator bolt. (necessary for clearance between the rotating & fixed plate)

View from below showing elevator bolt head & center pivot bolt head.

 

[Lil Foot]

Re: Backhoe rebuild

When I got the tractor, the PO knew the seat spun around, but didn't know it lifted. Because of that & outside storage, the lift mechanism was rusted solid, and it took forever to free it up. I ended up replacing the four rods the seat riser pivots on because the originals were too far gone. It also had no "shock absorbers/supports" at the rear (you can tell by all the scratching on the rear of the seat) and not knowing what the originals looked like, I improvised my own.

I tried to show as much as possible, but I'm sure I must have left something unclear, so sing out those questions.

 

[Lil Foot]

Re: Backhoe rebuild

Newly machined "glands w/o-ring", oh yeah.

 

[Bulldog]

Re: Backhoe rebuild

Those look nice. Good job.

 

[Lil Foot]

Re: Backhoe rebuild

Thanks, and thanks for my package, received it Saturday... fast shipping!

 

[Bulldog]

Re: Backhoe rebuild

That was fast. Glad you got it. I hope it will be of some use to you.

 

[morson82]

Re: Backhoe rebuild

Bill, thanks for the pics! Getting a new seat and having a couple of pins made up. Now I just have to figure out what to do to replace the missing rubber bumpers under the seat. Might try using some sort of spring set up. Not really sure what u did/ used but it looks good. Getting to rest of my hoses and pins today and can hopefully fire up the backhoe and fel. I also rewired the headlights (which were completely missing) and hooked up some rear taillights and flashers as well. Send pics when all done.

 

[Lil Foot]

Re: Backhoe rebuild

Glenn, the bumpers I made are shown in the first two pics of post #42. I used a 3/8-16 elevator bolt (just like a carriage bolt except with a thin, flat head), and then just added nuts & washers to get the polyurethane (rubber would also work) shock bushing to stay in place at the proper height for the seat to sit level. It doesn't have a lot of "give", but it's way better than the flopping around loose arrangement I had.
I have everything I need to finish mine. I only have to mount the curl cylinder & bucket, and mount the last 12 new hoses and I'm ready to go get the tractor & get it mounted. Oh, I guess I better get about 5 gal. of hydraulic oil.

I'm currently side-tracked on mine, my lathe went down last week, but i should have it up & running tomorrow.

 

[Lil Foot]

Re: Backhoe rebuild

Well, I finally got it completed. Even dug a couple of test holes, & it worked flawlessly, lots more power, and no leaks!

Dollars spent:

Bearing bronze (for machining) $26.00
Aluminum (for machining) 14.00
Oil filter 3.80
Paint 14.00
Assorted O-rings 10.56
Seal kits 170.70
Wiper seals & backup rings 13.00
Pump shaft seal 9.80
20 hoses 269.54
Turn, re-chrome, & regrind 1 ram 270.00
Misc hardware- bolts, nuts, cotter pins, springs, etc. 20.50
5 gal UDT 75.97

Total $897.87

As you can see, the single most expensive item was the re-conditioning of one of the stabilizer rams. Ouch!
Of course, this does not reflect my time, & the machining, which was quite involved. I consider my time as part of the hobby, but I'd hate to think what it would have cost from a regular machine shop. Perhaps Glenn (morson82) could enlighten us what he spent on his machining & fabrication.

Lesson re-confirmed: Grease is cheap, parts are expensive!

 

[horsehusband]

Re: Backhoe rebuild

I know this post is a little old, but I'm hoping to resurrect it. I bought my 7100 with loader and B670 backhoe back in October, and I am finally getting around to rebuilding it. This post has been extremely helpful!! I too am a victim of previous owner neglect Even though my top plate was also loose, amazingly there doesn't seem to be much damaged to the bronze bearing for the swing frame. The bronze bearing for the swing cylinders and the cylinder rods do have a lot of damaged due to it being so loose. My other big problem is that the 1" pin for the bucket is super stuck. (Any ideas for pin removal would be much appreciated) The pin and bucket holes are very worn because the pin hasn't moved (or been greased) in a long time. The grease fitting is also missing on my machine. I love Lil Foot's new placement! I also plan on rebuilding cylinders and replacing hoses. I do have a few questions about the rebuild:
Do I need to replace all of the snap rings, backup rings and the leather washers (on stabilizer cylinders) as well as the o-rings? which cylinder rebuild parts were you NOT able to find without buying the kits? packing assemblies? Any tips for removing and installing the bronze bearings for the swing cylinders? can you post pics of the hose routing? do you think I can use folded rolled steel to replace the pin for the bucket? which o-rings did you replace on the valves? what were the sizes? did you replace any other parts on the valve?
Thanks for all of the info you posted so far, and any additional info would be greatly appreciated!

 

[Lil Foot]

Re: Backhoe rebuild

Wow, never thought this old thread would come back to life!
OK, normally folks ask me questions about my tractor when I'm home, and the tractor is at my place in the mountains.
This time, I'm with the tractor, but all my notes, manuals, receipts, & pics are 150 miles away at home. Go figure.....
This is all from memory, so forgive me if I miss something along the way.
The stuck pin..... Where is it stuck? In the eye at the end of the ram? Might have to cut it & press or drive the remnants out after some PB Blaster or Kroil. Did you mean cold rolled steel for the replacement pin? If so, yes that will work, the company that built the B670 told me that is what they used originally.
On the valve, the easy answer is that I replaced all the o-rings; I don't have the sizes handy, but I just took some samples to an o-ring supplier, & they measured them & set me up with new ones. Seems like there were only two or three sizes. I replaced nothing else in the valve, just cleaned and polished away some rust in spots.
I bought complete kits for all the cylinders, and used everything except the new nuts on the end of the rams..... They seemed very loose, so I re-used the originals with Loctite. Several people have told me that because the sizes are standard, I could have just taken the parts (leather cups, backing rings, o-rings, etc.) in to a hydraulic shop & they could supply new ones.
Do you mean the bronze bearings that the swing rams slide in? Or the bearings at the eyes on the ends of the cylinders? The bearings that the rams run back & forth in are easy to press
out, see my post (#22) about adding a seal in that area- I pushed them back (easily) to make room for the seal.
I have a drawing that shows the original hose routing that I can e-mail you, (too big to post here) but I found it pretty useless, as the old original hoses were much smaller outside diameter & more flexible than modern hoses are. I pinched & scraped a couple of hoses & had to re-route some of them. I can shoot some routing pics tomorrow, but I have not had any luck posting pics from this tablet so far, so you might have to wait a few days till I get home.
Hope I touched on all the points you asked about, I've got to quit before typing on this tablet drives me completely batty.

 

[gpreuss]

Re: Backhoe rebuild

I still have a K650 backhoe that I bought new with my L185DT, 35 years ago. There was nothing similar to yours, other than the plate holding the upper bearing being bolted to the frame. About the third time it worked itself loose - probably the 6th or 7th time I used it - I drilled it and the frame for alignment pins in 4 places and put 5/8" cold-rolled dowel rod through them, welded at the top plate. They have held fine ever since.
Generally, the K650 was a poor design. The newer models seem MUCH better...

 

[horsehusband]

Re: Backhoe rebuild

so glad you replied! The pin is stuck in the dipperstick weldment not the ram. The sleeve in the dipperstick weldment for the pin does look like it has hit a few rocks so I'm not sure if it is pinched inside the sleeve. I was thinking of cutting it then pressing it out. I wish I could get it to turn first. Thanks for the info on the cold rolled steel. I should be able to make a replacement pin.

was there a specific reason you rebuilt the valve? leaking or sticking? my valve seems to be okay so I might not touch it.

is loctite recommended for the nut on the ram when rebuilding the cylinders?

The bronze bearings that I was referring to are for the upper and lower swing links that get pressed into the swing frame. I was surprised that I didn't see anything about them in your post since mine are pretty bad. The pins on the upper swing links also have some wear, but I'm hoping that they fit okay into new bonze bearings.

I would really appreciate any drawings or pics on the hose routing! My before pic attached. Thanks!

 

[Lil Foot]

Re: Backhoe rebuild

PM me with your e-mail address & I'll send a drawing on the backhoe in general & it's hose layout, it's too big to post here.
I rebuilt my valve because it was leaking in places, (still functioned well) and I am kind of a perfectionist- couldn't see re-doing everything except that.
The swing link bearings & pins in mine were almost without wear…. surprising, considering how bad the top plate, pivot pins, & pivot bearings were.
The nuts on the rams have nylon locking inserts, and because I re-used my old ones, I used some 242 blue locktite. (but I use it on almost everything anyway)
Later I'll post some pics of the hose layout on mine.

 

[Lil Foot]

Re: Backhoe rebuild

Please excuse the dirt, just got through with two major digs, haven't had time to clean up yet.

 

[Lil Foot]

Re: Backhoe rebuild

More pics:

 

[Lil Foot]

Re: Backhoe rebuild

And more pics:

 

[flynavy]

Re: Backhoe rebuild

I would like to THANK everyone who posted to this "Backhoe Rebuild", I can't begin to tell ya'll how much info/knowledge I received form all the chatter and photos. Thanks Guys, here I thought I did great just changing my fluids & filters.

 

[Lil Foot]

Re: Backhoe rebuild

I keep getting questions on things I didn't cover in this original thread, so I'm going to add some of the questions & answers to this thread. Hopefully, if someone has the same questions in the future, a search will lead them here, a sort of encyclopedia of B670 factoids.
If I miss something, please feel free to jump in.