1994 Kubota B7100HST-D Strainer

[bobbyrhone]

Hello, we have a 1994 Kubota B7100HST-D with loader. Yesterday, it decided to stop moving while driving across our property with no load. The engine starts and runs fine, but pressing on the HST pedal (either forward or reverse) it does not move. We checked all the levers and made sure it wasn't in neutral - we checked the hi-low, 2wd-4wd, etc. The PTO works fine and the loader operates normally.

The fluid level is currently low (still registering on the dipstick). We wanted to service the hydraulics before filling the hydro fluid back up, but can't seem to locate the strainers? The "shop manual" we have doesn't seem to indicate the location of these. Any hints/photos? Does the low fluid sound like the problem with it not moving?

Thanks,
Bobby

 

[mrwitty_1]

Bobby

The strainers are two different locations, the best I remember the hydraulic pick up that runs the loader is located on the right side on the rear transmission housing and the hydro strainer is located in the left side, you should see a rubber hose about one inch in diameter attached to the pick up line. I can not remember the size of the hex on the banjo bolt but could check later for you if needed. I would just guess that something has stopped turning the hydro pump, but just a guess. Can you hear the hydro pump making any noise ? like starving for oil. There is also a filter located on top of the unit under the cover located in front of the seat. Hope this helps.

 

[Tig]

I think the strainer bolt is 24mm. I also seem to remember that I had to remove the each rear wheel to get the strainers out.
PM me and I'll send you a pdf of the parts guide. You'll see the strainer location in there.
Check the pedal linkage all the way back to the hydro input shaft. The input shaft clamps do get loose. It could be that you input shaft clamp has let go.
If low fluid were the problem I would expect it to be foamy when you check. Either way adding a quart would be a good idea.

 

[alchemysa]

Download the parts manual from here... Kubotabooks.com

Its for a 2WD but you'll still find it handy.

The strainers are part 040 on page 143 and 070 on page 145. The left hand stainer (page 145) supplies the HST. (I'm quoting pdf page numbers not actual page numbers)

Look for oil pipes each side of the tractor that terminate at large bolt heads. These bolts are the strainers. Take care of the O-rings.

A blocked strainer will bring your tractor to a halt although I would think its usually a gradual thing rather than a sudden and permanent halt.

This pic of the strainer was posted by another member a few years ago. As Tig said you may find it easier remove the rear wheels.

 

[bobbyrhone]

Thanks guys! We located the strainers. Since the tractor is in the middle of the property, we decided to see if adding some hydro oil would bring it to life and get it back to the shop. Kubota $ure is proud of their oil!

Anyways, adding oil didn't do the trick. One thing we noticed is that when the tractor is running, the loader and 3pt lift seem to have full power. However, the rear PTO barely turns when engaged. Also, when we pull off the top cover in front of the seat and expose the hydro filter, we can see the top shaft - this shaft is barely turning, if it does at all. If I push in the clutch, it starts turning a little, but release the clutch and the shaft stops.

Is this the shaft that turns the hydro pump? Do these symptoms sound more like a clutch problem?

 

[alchemysa]

Thanks guys! We located the strainers. Since the tractor is in the middle of the property, we decided to see if adding some hydro oil would bring it to life and get it back to the shop. Kubota $ure is proud of their oil!

Anyways, adding oil didn't do the trick. One thing we noticed is that when the tractor is running, the loader and 3pt lift seem to have full power. However, the rear PTO barely turns when engaged. Also, when we pull off the top cover in front of the seat and expose the hydro filter, we can see the top shaft - this shaft is barely turning, if it does at all. If I push in the clutch, it starts turning a little, but release the clutch and the shaft stops.

Is this the shaft that turns the hydro pump? Do these symptoms sound more like a clutch problem?

I may be wrong about this, but my recollection is that although the PTO is powered by a shaft that runs 'through' the HST, it basically bypasses the internal workings of the HST and is hard connected all the way forward to the clutch. In other words it doesn't rely on oil levels or the integrity of the HST.

So yes, if the PTO shaft is turning real slow and the tractor won't move then it could be a clutch problem, which means your HST may not be turning much either.

The loader and 3pt hitch are powered by a separate pump thats bolted to the engine.

If you have power steering check to see if it feels very heavy. Its often powered by the HST so heavy steering would also indicate the HST is not turning.

You mentioned you checked all the levers, but check them again. I think they all have neutrals. You could have bumped one with your foot while travelling. And I dont know if youve got any safety switches anywhere that would stop the tractor moving.

 

[bobbyrhone]

Talked to a local tractor repair guy today - he says that it sounds like a clutch problem and for $500 labor + parts he would replace the entire clutch. The Kubota dealer says that it would run $1700 - $2000 for the same job. If it's anything more than the clutch (transmission problem), the repair bill would be more than I'm willing to pay for that tractor, so I'll probably take the chance on the small guy. This way if it's a major problem, I'm only out $500 and will have a nice parts tractor. I'll post the results for future reference.

Thanks,
Bobby

 

[bobbyrhone]

Got a call from the repair guy today.. he confirmed that the clutch just blew out - no major repairs needed.

 

[grossgary]

very interesting information.
i have the exact same tractor so i'm curious. what exactly does the clutch do? i'm used to automotive clutches and "automatics", all of which i have worked on and replaced before. so an external clutch on an HST is not something i understand.

how frequently do these fail and is there any preventative maintenance for them?

side notes - i had no problem replacing the strainers without removing the wheels on mine and the B7100 doesn't have power steering.

 

[alchemysa]

very interesting information.
i have the exact same tractor so i'm curious. what exactly does the clutch do? i'm used to automotive clutches and "automatics", all of which i have worked on and replaced before. so an external clutch on an HST is not something i understand.

how frequently do these fail and is there any preventative maintenance for them?

side notes - i had no problem replacing the strainers without removing the wheels on mine and the B7100 doesn't have power steering.

Its nothing special. It works the same as a car clutch. When its pressed it disengages everything aft of the engine. (e.g.. the gearbox or HST, PTO, transmission etc.). Most HST tractors require the clutch to be depressed before it will start. As per a car clutch... don't ride it!