B670 Backhoe Rebuild

[Lil Foot]

Not mine, just passing on the ad.
B670 Backhoe for sale:

Kubota Backhoe - farm & garden - by owner - sale

Kserial #3008ubota Backhoe Model B670, serial #3008, $1800.00 OBO. ONLY phone calls to Mike @ .

phoenix.craigslist.org

 

[Lil Foot]

Pretty disappointed, apologies for the long-winded explanation.

When I bought my second B670 Backhoe for parts, (from a B7100) I got a much improved, newer style of backhoe seat base. The seat base for this backhoe both raises and pivots to the rear. The seat base I already had does this, but the new seat base has some better engineering and nicer features.

The current base uses a spring loaded plate with a "tit" on the underside that locates in two wallowed out holes for indexing in the front or rear facing positions. It also has no adjustment to slide the seat forward or back for "legroom".

The new style base uses a spring loaded index pin which must be manually lifted to index the seat. It also has a forward/rearward sliding adjustment for that legroom adjustment. And it has "suspension" springs & rubber isolation for the front seat pivot. The base was all there, but in terrible shape. I have been slowly reworking/rebuilding it over the last year or so, and finally got it about ready to try out, and I have recently brought the tractor home for a couple jobs and some upgrades.

Now to the root of my disappointment. It stems from the fact that I'm mostly restricted to my home in the desert because of the caregiver thing, and the tractor lives 150mi away in the high country.

When I finally got around to bolting on the new seat base, I was crushed to find that it will not fit my tractor. Then it dawned on me that the donor B7100 was a HST, and mine is a gear. Crap.

The first problem was the new style has shorter "legs" and would not clear the rear fender brace. Crap.
(pic #1)
No sweat, I will fabricate a new lower fender support. While planning that, I found out that if mounted where it lives, the new style base will not index from forward facing to rearward facing because it hits the roll bar. Crap.

I'm pretty sure I could fabricate enough parts & workarounds to make it work, but it just isn't worth it.
I'm sure the base will work with the HST model, and may or may not work with another style roll bar. (or no roll bar)

I knew the HST was longer than the gear, but in hindsight, I should have test fitted it in advance of all that work.

Lesson learned. Crap.

 

[Lil Foot]

In the hopes that the info may help someone in the future, here are some pics of the two bases.
Gear style with the two red bumpers, HST style with the springs & slider.

 

[Lil Foot]

The above discussed seat base is for sale:

B7100 HST B670 Backhoe Seat Base FS

I have a B7100 HST B670 Backhoe Seat Base that I can't use for sale. $75 plus shipping Probably could be adapted to fit other tractors or backhoes. My sad tale of woe is here, posts #142 & #143: http://www.orangetractortalks.com/forums/threads/b670-backhoe-rebuild.5233/page-8 I put a ton of...

www.orangetractortalks.com

 

[Lil Foot]

SALE PENDING

 

[Lil Foot]

SOLD!

 

[Lil Foot]

Here is a link to a thread on swing speed:

B670 BackHoe swing speed

My B670 Hoe swing speed is WAY too fast- like 1 second from center to 90 degrees, if you just shove the lever over. This requires VERY careful, slow feathering when swinging side to side. I would like to ad restrictors to slow this way down, and was looking at the hose/valve/cylinder layout to...

www.orangetractortalks.com

 

[leno1]

This thread helped me rebuild /modify an old kubota B670 i purchased on FB marketplace. Thanks to all contributors.....

 

[Lil Foot]

Glad to hear it! Having a B670 puts you in a pretty exclusive club, and rebuilding one is even more exclusive!

 

[BradMW]

I know this is a relatively old thread but also see some relatively recent replies. There is a ton of great info here and thanks to all who have contributed!

I purchased a B7100 that came with FEL, a KUW200(B670) backhoe attachment and a PTO 3 point rototiller. The backhoe attachment was definitely used and quite possibly abused as many have mentioned.

In the last nine months I’ve replaced all the hoses on the backhoe. Last week I snapped the pin slot off at the weld on the end of one of the swing piston rods. I was able to weld it back on but found the lower king pin hole being worn 1/4”+ and the mating surface of the king pin itself being worn down 1/8”+, was the contributing factor to the broken piston rod.

The upper king pin plate bolts were loose or missing but some of the bronze bushing was still intact. The mating king pin surface at the upper end had minimal wear but overall the upper probably had about 1/8” of slop in its movement.

I’ve taken the down time as an opportunity to do some other maintenance on the attachment. I dropped 4 piston pins off at my local hydraulic shop to have new ones (they had pitted chrome with rust spots) made and to get new seals for all pistons.

I feel like I could pretty easily fix the bolt-on upper king pin plate. My real issue is how to proceed with repairing the lower king pin plate and mating pin surface. The king pin has a lot of weld holding it to the boom swing carriage. I am away from home this week and left the carriage and upper plate with my local Kubota dealer parts department. They can often come up with creative cross parts for otherwise unavailable discontinued items. I’m wondering if any here on this thread has any helpful suggestions though.

Thanks in advance!

 

[Lil Foot]

I (and several others) tried a wide ranging search for all of the hard parts for this BH, with no luck.

Seals, o-rings, and such (and to a lesser extant, cylinders) are readily available because they are all standard SAE (US) sizes, but the hard parts are all gone.

There are probably only three options;

1) build up the worn parts with weld & re-machine back to original sizes, then machine new bronze bushings.

2) have new replacement parts & bushings fabricated/machined from scratch. This is what morson82 did)

3) machine worn parts to clean up, & machine new steel & bronze bushings. ( I did a combo of #1 & #3)

I had the advantage of having the equipment & knowledge to use it, morson82 had a very capable machine shop nearby that was willing to tackle the job.

I wish there was an easy, quick fix, but I think you will have to bite the bullet like the rest of us did.
Maybe your dealer can come up with something.....
Keep us informed.

 

[BradMW]

I (and several others) tried a wide ranging search for all of the hard parts for this BH, with no luck.

Seals, o-rings, and such (and to a lesser extant, cylinders) are readily available because they are all standard SAE (US) sizes, but the hard parts are all gone.

There are probably only three options;

1) build up the worn parts with weld & re-machine back to original sizes, then machine new bronze bushings.

2) have new replacement parts & bushings fabricated/machined from scratch. This is what morson82 did)

3) machine worn parts to clean up, & machine new steel & bronze bushings. ( I did a combo of #1 & #3)

I had the advantage of having the equipment & knowledge to use it, morson82 had a very capable machine shop nearby that was willing to tackle the job.

I wish there was an easy, quick fix, but I think you will have to bite the bullet like the rest of us did.
Maybe your dealer can come up with something.....
Keep us informed.

Someone earlier in the thread linked to an Aeroquip site that was suppose to cross reference to compatible John Deere parts. The site seems to, unsurprisingly, no longer be up. Do you know if anyone had luck with finding bronze/steel bushings using that search?

 

[Lil Foot]

I contacted Aeroquip when I did mine, 10+ years ago, and they were sympathetic, but could not help at all, except to send me a print of the hose routing. It is posted somewhere here in the thread, I think.
They said they had stopped supporting that line 20+ years previously, and everyone who worked on that series had retired about the same time.

I know of no one who had any luck finding any parts at all.

That is why I bought a second one, for parts; but I think that it is in worse shape than my original. But if I need to, I can rebuild/re-machine parts from the 2nd while I keep using the original. If I ever get time, (fat chance) I plan on rebuilding my second one, and maybe sell it.

 

[markscorner]

I see this is an old post, Can anyone tell me the dimensions of the main boom, It looks like maybe 2" x 4"

 

[Lil Foot]

Mine is 150mi from here, not sure when i will go there next.