Kubota B21 TLB complete driveline rebuild

[yubby]

Hey Lucas....

I missed your B21 thread the first time around, but I read it all as soon as
MACHMETER pointed it out. I am glad nothing has broken since.

It is true that there were some assembly order issues for me as I did not
take the tractor apart first. I had some trouble with the HST pedal spring,
but not the one you had. I had to fabricate the part on the HST casting
as it was one of my missing parts. I DID make the mistake of putting the
2 halves of the tractor together before attaching the top hyd hard line to the
charge pump. This would not have happened if I had taken the tractor
apart myself.

Were your ROPS/FOPS support bolts on the rear axle as bad as mine?

Dave,

My ROPS bolts were tough to get off due to their location and penchant for attracting dirt. But they didn't have 10% of the corrosion I saw in your picture, good move replacing them.

Kubota has a dist'y center in Stockton so when you run short on parts you can will-call or have them drop shipped pretty quick.

-Lucas

 

[dfkrug]

Dave,

My ROPS bolts were tough to get off due to their location and penchant for attracting dirt. But they didn't have 10% of the corrosion I saw in your picture, good move replacing them.

Kubota has a dist'y center in Stockton so when you run short on parts you can will-call or have them drop shipped pretty quick.

-Lucas

I have worked with 2 local Kubota dealers in the past, but this time I gave
most of the parts orders to Messicks, as they honor the list prices, while
the locals add 10-20%. You know tractor parts are expensive and I will be
a bit over $3000 for parts for this project. Just a few minor parts are still
needed.

JD's warehouse is also in Stockton, and most anything comes in to the local
dealer in just one day after it is ordered. I did not know that customers
could do will-call pickups at either warehouse.

 

[dfkrug]

Now the last of the disassembly.

First pic is the 3-pt hydraulic cylinder housing, which covers the top of
the rear diff housing. No probs here, so I left it together.

2nd pic is the half-axle housing that also has the differential lock mechanism.
The crushed spring (shown previously) was found behind the largest gear.

3rd pic is a fully disassembled axle housing. These modern wet brakes are
amazing...no measurable wear. They work like motorcyle clutches and I can
see why they would outlast the tractor. The giant circlip was the hardest
part to remove or replace for this whole project. All ball bearings have been
discarded and replaced.

 

[machmeter62]

DAVE: After seeing the constant progress, and re-reading all the threads on it; the dealership has to still be "smarting" for giving up the B21. He probably gave the water company a fair deal on a new replacement tractor? The lost shop hours on the disassembly, then enough re-assembly labor, to give it hope at the auction, requiring more wasted shop hours; and then the final hit he took at the auction! There isn't many with your talent to challenge that project!

If you know the dealership you may have to be careful purchasing any parts or exposing your finished project there?!
I see a lot of attention to detail, including the meticulous clean components!

LEE

AFTER-THOUGHT: Maybe his labor force went to the auction, and was replaced after the bidding too?!

 

[dfkrug]

DAVE: After seeing the constant progress, and re-reading all the threads on it; the dealership has to still be "smarting" for giving up the B21. He probably gave the water company a fair deal on a new replacement tractor? The lost shop hours on the disassembly, then enough re-assembly labor, to give it hope at the auction, requiring more wasted shop hours; and then the final hit he took at the auction! There isn't many with your talent to challenge that project!

If you know the dealership you may have to be careful purchasing any parts or exposing your finished project there?!
I see a lot of attention to detail, including the meticulous clean components!

LEE

AFTER-THOUGHT: Maybe his labor force went to the auction, and was replaced after the bidding too?!

This tractor was sold and maintained by the largest Kubota dealer in NorCal,
and I was able to track down and talk to the several mechanics who worked
on it. The service dept also was willing to read to me all the records they
had on maintenance and repair. That was very useful to me, even though
my primary interest was just verifying the ownership history, so I knew I was
not buying stolen equipment. I am sure the sales dept was thrilled to sell
new equipment, rather than fix the old one. I have no idea what the
original owner bought, or what kind of trade-in allowance they got. Service,
parts, and sales depts don't seem to talk much to each other.

The economics of this kind of purchase must factor in a lot of risk. The
fact that it was partially dismantled and slapped together for sale was a
huge impact to its value. The hoe is in great shape, but would have to
be adapted if used on anything but a B21. I assumed the worst about the
transmission, but I also gambled that the engine was OK. Fortunately,
the motor had no sign of dismantling and it purrs like a kitten. I paid $5500
for the "complete" TLB from a used equipment dealer. He bought it from an
auction company which refuses to release the original sales price. The guy
I bought it from was originally trying for $10K, but he was glad to get
what I gave him and I had no competition.

I do prefer to work on clean machines, so I pressure wash first!

 

[machmeter62]

Dave: Thanx for the reply.

When the HST in smaller tractors arrived, and proved reliable. I had already made my last purchase of a GST. But again, I was interested in the longevity of the HST, and any further improvements. I am not too informed on the latest Kubota upgrade with the throttle control working with the HST? I think this is a definite plus to reduce the constant noise when the power isn't required?

Was the HST failure premature on your B21, because of lack of service or some other reason; I would think the life cycle should be longer? Kubota always does a lengthy field tests? Maybe contamination of some kind or sabotage by a disgrunted person?? Have you been able to determine the cause of damage, or was it more than the HST that caused the rebuild?
LEE

 

[dfkrug]

Was the HST failure premature on your B21, because of lack of service or some other reason;

Lee, as I showed in the earlier HST part of the project, the HST itself is
in fine serviceable condition. Gears in the main gearbox and rear diff are
what broke. It is plausible to me that the tractor was run for a while with
an oil-fouled clutch, which caused lots of chattering and vibration. This
led to driveablity issues and difficulty shifting. The operator forced the
MFWD lever so hard the fork broke, releasing the detent spring, which got
caught in the diff, shattering the ring and pinion gears. That's my guess,
based on the evidence I have seen and how the detent spring is retained.

If anything, this project convinces me more than before how robust these
HSTs are.

 

[john_bud]

Your assessment sounds plausible. I also agree that the HST's are probably the most robust transmissions you can get.

Your $5500 gamble looks like it will pay off nicely for you! Were you able to get a used back half or is parts and pieces cheaper? I've found that on 30+ year old iron, used whole assemblies are often much cheaper than repairing what's broke.

Good luck and keep up the very informative posts.

jb

 

[machmeter62]

Dave: Thanx for the reply.

When the HST in smaller tractors arrived, and proved reliable. I had already made my last purchase of a GST. But again, I was interested in the longevity of the HST, and any further improvements. I am not too informed on the latest Kubota upgrade with the throttle control working with the HST? I think this is a definite plus to reduce the constant noise when the power isn't required?

Was the HST failure premature on your B21, because of lack of service or some other reason; I would think the life cycle should be longer? Kubota always does a lengthy field tests? Maybe contamination of some kind or sabotage by a disgrunted person?? Have you been able to determine the cause of damage, or was it more than the HST that caused the rebuild?
LEE

DAVE: When you opened the HST and said things were "within limits:" meaning to me; it was warn, but would "maybe" need rebuilding in the distant future too?

This goes back> than 5 yrs here, but one of the members had a fleet of Kubota HST's for side road maintenance somewhere in Canada, towing small trailers, and complained of poor performance in fuel and capability on long steep pulls, (high fluid temps) I think?...that got my attention? I believe he traded-out for gears? I may buy a small new HST in the future for mowing and gardening.

 

[dfkrug]

When you opened the HST and said things were "within limits:" meaning to me; it was warn, but would "maybe" need rebuilding in the distant future too?

The manual has wear limit ranges for the pistons and bores of the pump
and motor, as well as thickness of the brass slippers, and the brass end
plates. All were on the good side of their limits....maybe I should have said
"well within limits", rather than within limits. I should also state that one
needs a micrometer that measures in 10,000ths to see any meaningful
measurement variation. Also, I should note that the swash plates
themselves are a shiny hard steel alloy that I am sure is quite a bit harder
than the slippers....thickness variation form side to center was maybe
1/10,000".

I saw a post maybe 4-5 mo ago on TBN where the owner of an HST tractor
ran out of oil. He posted pix of the HST swash plate and it was spalled
badly. Basicly, if your HST never runs out of CLEAN oil, I do not know what
its failure mode would be.

Following is a photo of Kubota's new and sophisticated HST+. This is a
different beast entirely. I would like to see what's inside that.