Stop bolt won't go back in!

[Gord Baker]

Taking it to a dealer is not an option, it just threads in, I will re-tap to a larger hole and use a bolt that's the next size up. I never moved the shift after removing the bolt, so it can't be too far off from the swash plate being aligned now. Why would it need to come apart and how do align it?

Thanks for any help, and leave the wise ass comments to yourself, thus is supposed to be a place to get help, not "take it to the dealer" and what not jackals comments.

Take it to a Dealer is the Best Option given the complexity of the part and minimal knowledge of the owner.

 

[ptsg]

You should look up the cost of s replacement pump before you "try to make it work" with some cob repair. Be sitting down when you find the price.

I would be very surprised if there was a new HST unit available for a tractor that old. And these things, most of the times, are sealed units and it's not possible to get any individual parts for it.

 

[ruffdog]

Inside look:

Kubota b6100 B7100 hst 4wd 4x4 Hydrostatic Pump case | eBay

 

[oldnslo]

Yes I agree. Plus he will not be able to go up a bolt size. Hopefully he will post pictures and maybe we can see a solution. I hate it for him.

agree on pictures of the stop bolt would help. Unknowns, Did the stop bolt fit in a slot or hole in the swash plate? Was this hole or slot deformed while trying to force the bolt back into the tranny?
Could he possibly realign the slot or hole and then build a custom 3 piece assembly consisting of ground rod that is the correct diameter to fit into swash plate, hollow guide nut that could slipped over the guide rod and then threaded into housing while holding rod in place. Then a cap threaded onto the hollow guide nut to hold the rod in place. This would take some very careful and precise measurements to insure that the swash plate is held in the proper position during assembly and once fully assembled.

Bad situation for sure.

 

[MoKelly]

Reading this subject from simply an observational perspective - I have ask myself why in the world was that bolt placed there in the first place?

If just removing the bolt causes catastrophic results, why do it that way?

Couldn’t the parts be attached differently all inside the machine?

Bolts can come lose over time all on their own.

Just asking.

MoKelly

 

[K5lwq]

Reading this subject from simply an observational perspective - I have ask myself why in the world was that bolt placed there in the first place?

If just removing the bolt causes catastrophic results, why do it that way?

Couldn’t the parts be attached differently all inside the machine?

Bolts can come lose over time all on their own.

Just asking.

MoKelly

They don't anymore. The type 2 units use a registry pin on the housing. I am fairly confident the OP is not the first to make this mistake.

 

[MoKelly]

They don't anymore. The type 2 units use a registry pin on the housing. I am fairly confident the OP is not the first to make this mistake.

Thanks for the answer. Helpful.

MoKelly

 

[Tnkubotaguy]

Thanks for all the great replies, the bolt is actually fine, it's the threads in the case that I screwed up. The threads in the case got stripped as the hole was not where it should be before I forced it in. Thus since the bolt is a normal 10mm bolt with a small 1/4" shoulder on the end that aligns with the swash plate. I decided to re-tap with a 7/16 tap and use a 7/16-20 hardened bolt that I will grind a shoulder on the end equal to the original bolt. This should not cause a problem. Here is the problem: How do you manually move the fixed swash plate to find the alignment hole? The swash plate doesn't turn apparently so it had to shift forward or back from residual pressure when I removed the bolt as somebody eluded to earlier. Now that I know there is a hole, at least I have some direction. Hopefully a tech will chime in who has come across this before and knows how to move the swash plate.

 

[Tnkubotaguy]

Thanks for the answer. Helpful.

MoKelly

I agree, it is identical to a drain plug and even has sealing washer on it. What a ridiculous design to cause this much trouble for somebody who is trying to maintain the machine properly. I plan on grinding the head round so no wrench will fit on bolt so nobody makes the same mistake in the future. There is no mention anywhere in any manual..."never remove this bolt" as there needs to be that message somewhere and I agree that had to be one of the reasons the replacement HST does not have that bolt.

 

[Tnkubotaguy]

Inside look:

Kubota b6100 B7100 hst 4wd 4x4 Hydrostatic Pump case | eBay

Thanks

 

[K5lwq]

Without visuals it is hard for us to give good advice. My guess is you will have to lay directly under the hole and look with a flashlight. If you have a inspection camera you might be able to locate the hole you need to line up. Then use a small punch or screwdriver and try to line it up.

I would also assume the bolt will need to be machined fairly accurate in order to work properly.

 

[oldnslo]

Every piston motor that I have worked on has spring preload holding the cylinder barrel and piston slippers solidly on the swash plate and port plate. My suspicion is that when this stop bolt was removed this spring load pushed the swash plate towards end housing. What I do not know is how much force these springs produce nor how much the swash plate moved. Another problem is if you can pry it back into position how do you keep it there while installing the bolt.

K5L has the best suggestion in trying to see something though that small 3/8 hole and then making decisions based on that information

wishing you the best on getting this repaired

 

[nyone]

I would be very surprised if there was a new HST unit available for a tractor that old. And these things, most of the times, are sealed units and it's not possible to get any individual parts for it.

Exactly! Basicly if you screw this up your machine is parts.

 

[ptsg]

Exactly! Basicly if you screw this up your machine is parts.

Messicks does list the HST unit for $9,294 and I'm not even sure if they have stock. Is the tractor worth that much? Probably not.

On the other hand, they have the parts list for the HST unit with all the individual parts. Might be worth a look.

 

[oldnslo]

Kubota stopped making the B7100 in 1985 so doubt worth the cost of new tranny.
So suspect best option is repair what he has. Unfortunately this could be beyond the OPs capabilities.

he has some serious studying and decisions to make.

 

[Tnkubotaguy]

I'm still hoping some Kubota tech chimes in here and tells me how to move the swash plate forward or backward so the alignment hole appears. I've got a miniature snake cam in the hole and I don't see any alignment hole. The 7/16 -20 tap worked fine. Working on the new stop plug with my harbor freight grinder now. I really don't think I need I need a lathe as the tolerances can't be that exact from 1985. It's just an alignment stud, not a piston. I can't believe nobody had this problem before, I'm still hopeful as ol' Bessie still got a lot of life left in her.

 

[Cycledude]

I am very hopeful you manage to fix this issue !

 

[K5lwq]

This picture shows the hole.

 

[Henro]

I'm still hoping some Kubota tech chimes in here and tells me how to move the swash plate forward or backward so the alignment hole appears. I've got a miniature snake cam in the hole and I don't see any alignment hole. The 7/16 -20 tap worked fine. Working on the new stop plug with my harbor freight grinder now. I really don't think I need I need a lathe as the tolerances can't be that exact from 1985. It's just an alignment stud, not a piston. I can't believe nobody had this problem before, I'm still hopeful as ol' Bessie still got a lot of life left in her.

Just an uneducated idea, but might the unit shift if the directional pedal pedal was pushed? If so, maybe it would move enough to bring the hole back where you need it, if the pedal was moved towards the maximum in the right direction…

 

[ptsg]

Just an uneducated idea, but might the unit shift if the directional pedal pedal was pushed? If so, maybe it would move enough to bring the hole back where you need it, if the pedal was moved towards the maximum in the right direction…

That could possibly work if it was on the pump side, the one were the swash plate moves by pressing the pedal.

However, the bolt that the OP accidentally took off, is the one that keeps the swash plate on the hydraulic motor in place that is fixed and doesn't move.