L4150DT Power Steering Quit

[CiscoRanger]

Happy Easter, boys and girls,

I've been meaning to get around to this for a little while...As some of you know about a year and a half ago, I came home with an abandoned and neglected L4150, and went through a number of repairs on it...that thread is here: https://www.orangetractortalks.com/forums/threads/l4150-repair-restore.60035/

Some of the earliest posts in that thread I noted that the power steering would steer hard one way, as soon as you started the tractor up. As I was working on it over that year, the power steering started acting normally - on it's own, I didnt mess with the P/S at all. Then, a couple of months ago, it quit all together.

So here I am looking for a little direction on this. I cracked open the service manual and read all about it in the general section, and also aboutit in the maintenance section. There doesn't seem to be a lot to it. An independent reservoir, a pump, a hydraulic steering gear assembly, and the associated lines between the two.

Unfortunately, the very first troubleshooting step is to test the pump with a flow meter and special connectors from kubota. Surprisingly, I do not own that special tool, or the special connectors.

Question #1 - Is there a shadetree mechanic way to test the pump, without the specific flowmeter? Such as "pull the pressure line off and if it shoots 10 feet over the fully raised bucket, you're good on the pump?"

Question #2 - Is there some "This happens to all these tractors, and this is what it is" secret jedi thing I should check even before that, like a stuck open relief valve that needs to be replaced?

Question #3 - The pump appears to be fairly new, just like the hydraulic TPH pump is new, and was replaced by the Prev Owner before letting it sit for years. Also looks easy to rebuild if that's what it was, but for the life of me find the pump parts on the Messicks diagrams. Any idea what I'm doing wrong here?

Question #4 - This cirulating ball (or whatever) style P/S gear box. Is it rebuildable by a non-professional? A replacement shows to be $3100.

I appreciate you guys, as always, and hope everyone is doing great. Gonna tag a few of the homies that helped me through the restore...

@North Idaho Wolfman - Yoda Himself
@TheOldHokie - The galactic wizard and gran poopah of all things hydraulic
@Nicksacco - The creative electrician
@PoTreeBoy - Who poured over transmission manuals with me
@rbargeron - Who probably loves this tractor more than I do.

 

[TheOldHokie]

Happy Easter, boys and girls,

I've been meaning to get around to this for a little while...As some of you know about a year and a half ago, I came home with an abandoned and neglected L4150, and went through a number of repairs on it...that thread is here: https://www.orangetractortalks.com/forums/threads/l4150-repair-restore.60035/

Some of the earliest posts in that thread I noted that the power steering would steer hard one way, as soon as you started the tractor up. As I was working on it over that year, the power steering started acting normally - on it's own, I didnt mess with the P/S at all. Then, a couple of months ago, it quit all together.

So here I am looking for a little direction on this. I cracked open the service manual and read all about it in the general section, and also aboutit in the maintenance section. There doesn't seem to be a lot to it. An independent reservoir, a pump, a hydraulic steering gear assembly, and the associated lines between the two.

Unfortunately, the very first troubleshooting step is to test the pump with a flow meter and special connectors from kubota. Surprisingly, I do not own that special tool, or the special connectors.

Question #1 - Is there a shadetree mechanic way to test the pump, without the specific flowmeter? Such as "pull the pressure line off and if it shoots 10 feet over the fully raised bucket, you're good on the pump?"

Question #2 - Is there some "This happens to all these tractors, and this is what it is" secret jedi thing I should check even before that, like a stuck open relief valve that needs to be replaced?

Question #3 - The pump appears to be fairly new, just like the hydraulic TPH pump is new, and was replaced by the Prev Owner before letting it sit for years. Also looks easy to rebuild if that's what it was, but for the life of me find the pump parts on the Messicks diagrams. Any idea what I'm doing wrong here?

Question #4 - This cirulating ball (or whatever) style P/S gear box. Is it rebuildable by a non-professional? A replacement shows to be $3100.

I appreciate you guys, as always, and hope everyone is doing great. Gonna tag a few of the homies that helped me through the restore...

@North Idaho Wolfman - Yoda Himself
@TheOldHokie - The galactic wizard and gran poopah of all things hydraulic
@Nicksacco - The creative electrician
@PoTreeBoy - Who poured over transmission manuals with me
@rbargeron - Who probably loves this tractor more than I do.

You should not need a flowmeter to test the pump. A pressure gauge should be sufficient but if steering works fine in one direction but not the other I would suspect the steering valve not the pump.

EDIT

Should have read a little more carefully. If its completely dead pull the pressure line off and use a bucket to look for flow. If you have flow check pressure. If you have flow and pressure coming to the steering valve the problem is not in the pump.

Dan

 

[Nicksacco]

Hi Cisco!
Happy Easter to you too.

A couple things I'll add to Dan's thought is to also check fluid level and check for suction leaks in the path from tank to pump (as long as you're checking things.)

 

[CiscoRanger]

You should not need a flowmeter to test the pump. A pressure gauge should be sufficient but if steering works fine in one direction but not the other I would suspect the steering valve not the pump.

EDIT

Should have read a little more carefully. If its completely dead pull the pressure line off and use a bucket to look for flow. If you have flow check pressure. If you have flow and pressure coming to the steering valve the problem is not in the pump.

Dan

Thanks guys. Some more clarity.

Steering does not work at all anymore.
I'll remove the pressure connector at the pump and check flow. The pressure line is a hardline with banjo connector on one end and the kubota round 3 bolt o-ring connector at the pump so I’m not sure how I’d check pressure on that. Is there a good way?

@Nicksacco Its full of fluid, but thats a good idea about checking supply hose for suction leaks.

 

[PoTreeBoy]

Happy Easter ! I think you could get an adequate pump test by loosening the discharge line (make sure the spray won't hit you). When the steering hits some resistance, you should get pretty good pressure, up to 2000 psi.

I'll just add that this system is not like the hydrostatic systems on most/all more recent Kubotas.

If you jack up the front end to take the load off, with the engine off does it steer reasonably easily and equally in both directions? If the pump checks out, I suspect you're looking at removal and overhaul. It could just be trash in a valve passage, I'd guess.

 

[North Idaho Wolfman]

Happy Easter, boys and girls,

I've been meaning to get around to this for a little while...As some of you know about a year and a half ago, I came home with an abandoned and neglected L4150, and went through a number of repairs on it...that thread is here: https://www.orangetractortalks.com/forums/threads/l4150-repair-restore.60035/

Some of the earliest posts in that thread I noted that the power steering would steer hard one way, as soon as you started the tractor up. As I was working on it over that year, the power steering started acting normally - on it's own, I didnt mess with the P/S at all. Then, a couple of months ago, it quit all together.

So here I am looking for a little direction on this. I cracked open the service manual and read all about it in the general section, and also aboutit in the maintenance section. There doesn't seem to be a lot to it. An independent reservoir, a pump, a hydraulic steering gear assembly, and the associated lines between the two.

Unfortunately, the very first troubleshooting step is to test the pump with a flow meter and special connectors from kubota. Surprisingly, I do not own that special tool, or the special connectors.

Question #1 - Is there a shadetree mechanic way to test the pump, without the specific flowmeter? Such as "pull the pressure line off and if it shoots 10 feet over the fully raised bucket, you're good on the pump?"

Question #2 - Is there some "This happens to all these tractors, and this is what it is" secret jedi thing I should check even before that, like a stuck open relief valve that needs to be replaced?

Question #3 - The pump appears to be fairly new, just like the hydraulic TPH pump is new, and was replaced by the Prev Owner before letting it sit for years. Also looks easy to rebuild if that's what it was, but for the life of me find the pump parts on the Messicks diagrams. Any idea what I'm doing wrong here?

Question #4 - This cirulating ball (or whatever) style P/S gear box. Is it rebuildable by a non-professional? A replacement shows to be $3100.

I appreciate you guys, as always, and hope everyone is doing great. Gonna tag a few of the homies that helped me through the restore...

@North Idaho Wolfman - Yoda Himself
@TheOldHokie - The galactic wizard and gran poopah of all things hydraulic
@Nicksacco - The creative electrician
@PoTreeBoy - Who poured over transmission manuals with me
@rbargeron - Who probably loves this tractor more than I do.

I would start with clamping off the return line to the tank (Blue).
Disconnect that hose from the output of the steering unit.
Then add a new line (Red) that you could put into a bucket, secure it into the bucket so flow will not force it out.
Then start it and see flow, if you have good flow then the pumps working.

Next I would pull the pressure relief valve out and check it for anything out of the ordinary.
Before you remove it document the length of the adjustment.

Next I would be checking my wallet / bank account to see if this is an option.

Used Power Steering Gearbox fits Kubota 32530-16100

Power Steering Gearbox. Replaces Kubota OEM Number(s) 32530-16100.

www.tractorpartsasap.com

It's not looking good for steering rebuild parts, looks like most parts are discontinued and no longer available.
So a DYI repair is going to be really tough.

I would carefully disassemble the unit and you might get lucky and find a single parts that might be able to be crossed over to generic parts.

One other outside the box fix if all else fails is to change it to hydrostatic steering.

 

[rbargeron]

This may be old news but in 2020 somebody here asked @007kubotaguy whether he had received "that L4150" that he was expecting to get - dunno if he got one or has any steering parts but its worth an ask......

And to Cisco Ranger - no doubt about it - I'm still a major fan of the L3's - Take care, Dick B.

 

[Nicksacco]

Another thought; You didn't mention anything about fluid other than it was full - e.g. no leaking or anything.
So fluid's got to be going somewhere eh? Or not. I'm thinking pump is not putting out pressure or pressure going right past the relief valve.

I can't wait to hear! Hopefully not something too expensive!

 

[CiscoRanger]

Thanks guys. I'll do a return hose flow check as soon as possible and go from there. I appreciate all the input, as always.

 

[CiscoRanger]

Hey guys, just a quick update. It’s been a busy few months. My older son informed me he’s about to be a dad, and I’m about to be a grandpa, which is so exciting! And been trying to get my younger son off to college. Life is full right now.

I did get back around to the tractor over the weekend and this power steering issue…

I pulled the return hose off the tank and drained it, and zip tied a np glove to the inlet.

I refilled the tank and redirected the return hose into a bucket.

it was darker than fresh hydraulic fluid, but the pump flowed well. I would say it was similar to a lower pressure garden hose with nothing on the end.

I refilled the tank again and tried to turn the wheel while it was pumping out and did not see any change to the flow.

I guess best case scenario at this point is the relief valve could be stuck open. The gear and RV are buried under the front console so I’ll have to tear it apart more to get to it.

Question: what am I looking for when I pull the RV? Would it be obvious that there’s a problem with it?

thanks!

 

[TheOldHokie]

Hey guys, just a quick update. It’s been a busy few months. My older son informed me he’s about to be a dad, and I’m about to be a grandpa, which is so exciting! And been trying to get my younger son off to college. Life is full right now.

I did get back around to the tractor over the weekend and this power steering issue…

View attachment 130621

I pulled the return hose off the tank and drained it, and zip tied a np glove to the inlet.


View attachment 130622

I refilled the tank and redirected the return hose into a bucket.


View attachment 130623

it was darker than fresh hydraulic fluid, but the pump flowed well. I would say it was similar to a lower pressure garden hose with nothing on the end.

I refilled the tank again and tried to turn the wheel while it was pumping out and did not see any change to the flow.

I guess best case scenario at this point is the relief valve could be stuck open. The gear and RV are buried under the front console so I’ll have to tear it apart more to get to it.

Question: what am I looking for when I pull the RV? Would it be obvious that there’s a problem with it?

thanks!

Have you tested the delivery pressure?

 

[CiscoRanger]

Have you tested the delivery pressure?

Hey Dan,

No, I don't have anything to do that with. Other than @PoTreeBoy suggestion to crack the pump output connection and see if I have "pretty good pressure". The manual directs to a special adapter that bolts to the pump and goes to a flow meter. The only other thing I could think of is I might be able to purchase a new delivery line and make an adapter to a pressure guage. Or maybe there is a banjo style adapter that could be placed inline on the gear side? But currently I dont have the correct tools for that.

 

[CiscoRanger]

Have you tested the delivery pressure?

Is there a weld on pressure port I could install on the steel delivery line?

 

[TheOldHokie]

Is there a weld on pressure port I could install on the steel delivery line?

I would think an ordinary banjo on the pump discharge gets you hooked up. Ypu will be eliminating the relief and testing the pump directly.

For the pressure test you need a gauge, a tee, some hydraulic hose, and a needle valve to simulate a load. EZPZ and inexpensive.

Dan

 

[Nicksacco]

Hey @CiscoRanger Congratulations to you and your son!

Hopefully your steering issue will be a simple fix (crossing fingers).

 

[CiscoRanger]

I would think an ordinary banjo on the pump discharge gets you hooked up. Ypu will be eliminating the relief and testing the pump directly.

View attachment 130626

For the pressure test you need a gauge, a tee, some hydraulic hose, and a needle valve to simulate a load. EZPZ and inexpensive.

Dan

@TheOldHokie

Dan, maybe my brain isn't quite working today, but I'm struggling to understand how to plumb those items up to the pump. Is this what you were thinking? Or a banjo bolt straight into the bottom (delivery side) of the pump? Or something else?

 

[TheOldHokie]

@TheOldHokie

Dan, maybe my brain isn't quite working today, but I'm struggling to understand how to plumb those items up to the pump. Is this what you were thinking? Or a banjo bolt straight into the bottom (delivery side) of the pump? Or something else?

View attachment 130680

I am the one that's confused. I should have looked closer at the parts diagram. I mistook the 4 bolt flange on the pump end of the pipe for a banjo.

That said if you have a drill press making a test adapter should be pretty easy - block of aluminum and five holes. Use the pipe as a template and an endmill to counterbore the oring recess. If you can give me bolt circle and outlet port dimensions I can knock one out for you.

Then connect the gauge and needle valve test rig to the pump outlet just as you diagrammed.

Dan

 

[CiscoRanger]

I am the one that's confused. I should have looked closer at the parts diagram. I mistook the 4 bolt flange on the pump end of the pipe for a banjo.

That said if you have a drill press making a test adapter should be pretty easy - block of aluminum and five holes. Use the pipe as a template and an endmill to counterbore the oring recess. If you can give me bolt circle and outlet port dimensions I can knock one out for you.

Then connect the gauge and needle valve test rig to the pump outlet just as you diagrammed.

Dan

Thanks Dan, that helps. Also, that is a very kind offer. I also had an idea of drilling and tapping the head of a different banjo bolt (they're like $5) for a real-time pressure measure, or having a threaded block at the end of the banjo bolt (instead of the bolt going into the steering gear) that the rig could attach to.

Let me get the console removed so I can take the pipe off and measure from there.

Thanks again.

 

[CiscoRanger]

Update:
Good morning gents!

Got back around to the power steering issue today. @TheOldHokie thanks again Dan for offering to make me a plate. I ended up just getting a couple of $3 banjo bolts and drilling and tapping them to use to test.

The first one is straight through and just measures the system pressure.

I got almost no pressure reading on it while the tractor was running and also while trying to turn the wheel.

So I welded up the other bolt on the output end to isolate and test the pump pressure.

Closing the needle valve I see that the pump is making good pressure up to ~2600psi. I didn’t try and go any higher.

Seems to mean the pump is fine and something is wrong on the p/s box. I think @North Idaho Wolfman mentioned checking the relief valve, so I guess I’m doing that next.

what would I be looking for? Broken or warped spring? Trash in the needle/ seat? Also do I need to be mindful of the adjustment if I can use the inline gauge to set pressure later?

thanks guys.