low oil pressure L235

[ipz2222]

L235, eng, DH1100. only 1200 hrs.
At idle cold, pressure is only 5psi, at 2000 rpm only 10 psi.
Manual lists possible causes. Restricted oil filter or screen, pressure relief valve stuck open, rod, main or cam bearings worn and worn oil pump.
All of these are major except oil fliter which has been changed.
Where is the oil pressure relief valve? The manual has a drawing of it but does not show where it is or how to ck it.
Cking the screen and rod bearings require removing the oil pan. The front driveshaft runs under it and I do not see how to remove it. The manual has nothing about removing the shaft.
Thanks in advance.

[Service Dept Vic]

The Oil Pressure relief valve is located on the oil filter mounting assembly It will look like a large bolt head. Behind it is a ball bearing and a spring.

It's primarily designed to "open" in the event the oil filter collapses internally or becomes blocked, and in "bypassing" the filter, motor oil is sent to the internals of the engine, unfiltered, but it will save the engine from oil starvation.

Take it apart, clean the spring and ball bearing and reassemble. Replace the oil filter you have screwed onto the engine right now, regardless of how new it is, to rule it out as a source of your low oil pressure. It's doubtful that you have an internal engine issue given the low operating hours of the tractor.

I have seen plugged oil pick up screens due to poor overall maintenance and lack of regular engine oil service. Pull the valve cover and see if it looks like sludge in there.

If it does, then you may want to drop that oil pan and get a look at that oil pump pick-up screen, or at the very least, get busy doing a good long internal engine oil flush.

[ipz2222]

Thanks vic. I pulled the the oil filter houseing off last night. The screw in ck ball was not stuck open and had no transh under the seat. I removed it and applied regulated air pressure to the seat side, it took 60 psi to usnseat the ball.
There's another ball and spring in the houseing. What's that for??? It took 25 lbs of air to unseat it.
Can I get to the oil screen form the bottom pan? How do I get that driveshaft off? I'm a professional transmission mechanic, so I'm not afraid to tacke it. Just don't want to damage anything through ignorance.

[Service Dept Vic]

Uhhhhhhh???? Thats a new one for me! Were these piled on top of each other in the same galley?

I've only ever seen one check ball and spring in that bypass valve area. I would only be guessing if it was an assembly error or if there is some serial number change up involved. are you sure on that engine model number? The L235 was OEM with a D1102A engine. Is it possible that this tractor has been re-powered?

To drop that front drive shaft, unbolt the metal protective "tube" encassing the driveshaft. It will be held with a couple of bolts on either end of the tube.

Once the protective tube is loose, you should be able to move it a little to reveal inside it, a splined approx 2" long coupling. This coupling will be held in place with either a cir clip, or a roll pin. There will be a coupling at either end of the shaft.

Remove one, and the tube can then be slid off the driveshaft (which isn't very big by the way) . Once the tube is off, remove the coupling at the opposite end, and you'll have full access to that oil pan.

It will be interesting to see if you find anything. Personally, I'd internal engine flush the shit out if it first.

Drop all the engine oil, fill the crankcase with 4 qts of 5 litres of varsol.

Pin the cylinderhead decomp knob in the fully open position (so the tractor WILL NOT start!!, and then crank that baby over for many, many cycles.

Pull the oil drain plug to drop all that that dirty crap that will be comming comes out and repeat

Drain once again, replace engine oil , I'd be using 15W40, spin on a brand new oil filter of known quality, run the engine up to operating temperature, and then re-test.

Kubota issued a Technical Service Bulletins, TSB#79-07 in 1979 and TSB SB81-06 in 1981 outlining very low oil pressure in early B and L Series tractor engines.

An oil passage plug (there are two) on the end of the engine camshaft was known to dislodge or "pop" out. This of course dropped engine oil pressure to the basement. Kubota's TSB details replacing the plugs with stiffer steel plugs.

Might be worth checking this area as well. I'ts about a 3 hr teardown to get there for that look, but sometimes you have to cross that off a list of possibilites, right?

[ipz2222]

Thanks Vic. Yes thre are 2 ball and springs in the filter houseing. One is encapsulated, :Presssed together. The other is just a ball , about 5/16 and 1 inch long spring held in by a screw in plug with a recess in it for the spring. I'm makeing a tee to screw the encapsulated part into so I can read pump pressure straight off the pump. If Thats good then I know I have a leak in the bearings or the cam plugs you are referring to.
I looked at the front shaft and I see what you are refereing to. I'll get that off, then the pan to ck the screen. I'll put the pan back on then do the flush so I can tell if it does any good. Thanks again.

[ipz2222]

Just eliminated the oil pump. Took all my out of the box thinking to come up with a contraption to ck the pump. REmoved the filter houseing, spun the eng over to see where the oil came out. Tapped that hole with 1/8 pipe tap, spun the eng again to clean the metal out. Made a tee with a welded on metric nut that was the same thread as the pressure relief valve. Hooked a 100 psi guage to it and started the eng. Pressure jumped to 70 psi and started flowing out of the relief valve. Pump is good.
Now to pull the pan. Ouch!!!

[ipz2222]

Vic, I forgot to answer you're question. Yes the eng is a dh1100. It's stamped on the block where the fuel pump is.

[Service Dept Vic]

Starting to sound more likley that it's a cam plug service issue.

Nice work on the adapter for the oil pump pressure! I'm going to pass that along to the "R and D" Department here at Orangetractortalks so Mr. K can "Rip off and Duplicate" that shop tool for us schmoes in the shop!

[ipz2222]

I forgot to mention the threads for the oil sending unit on my tractor is metric. Most prssure guages are 1/8 pipe thread. 1/8 th starts in the thread but starts getting tight within 1 turn. I have an adapter from working on foreign vehicles that allows me to use the 1/8th thread on my guage.
The hole in the block was allmost to big for 1/8 pipe thread but it was enough thread to hold the guage in long enough to ck it.
If I knew how to take pictures and post them, I'd get you one of the contraption I made.
It may be a while before I get the front end off the eng, but that's where I'm going next. I did do an eng flush and changed the filter and oil but it did not help. Thanks again for your help.

[ipz2222]

I finally got some extra time and dicided to pull the pan off the eng hopeing to find the cam plug in the bottom to confirm that is the problem. You can forget that.!!! There are 2 bolts on the front of the pan that are above the houseing of the front diff, only about 1/16 of an inch clearance. No way those bolts are comeing out unless the front end is removed first.

[steve01]

Not sure if this will work for you but on my B7100D I removed the bolts that hold the front frame to the motor and jacked the tractor up from the center(mine has a loader on the front) brackets until I had enough room to remove the oil pan over the drive shaft.

[ipz2222]

I'm back on this problem and have run into a snag. I'm down to getting the front axle assy away from the front of the eng and cannot get it off. There 3 studs on the left side and 2 on the right (that I can see). All 5 have been removed and I can't get the assy to move away from the eng. It is somewhat loose but feels like another bolt somewhere.
Hopeing one of you guys that just removed yours will remember what was there. The wsm is about as useless as tits on a boar hog. There are only 2 half page lines on how to get this axle housing off. Waiting for help!!!

[ipz2222]

Got it off. Was able to insert small screw driver into top edge that was slightly open. Jacked the front end up and it pulled the bottom open a very little bit. Kept repeating this until it came off.
I had purchased the 46 mm socket earlier but did not have a 1 inch to 3/4 adapter for it. Had a 1 7/8 deep socket with the right square drive to fit my impact. It was a little loose on the nut. Figured I'd hit it just a little bit and see if it would break the nut loose. It did.
I now have the front cover loose and out about 3/4 inch. There is a spring inside the houseing that hooks to the throttle lever. It's inside the houseing and I can't get to it. Thinking, take the throttle lever loose from the top of the cover???

[ipz2222]

Was able to get the spring off with needle nose plires. Should have taken the throttle lever houseing off, there was another spring inside that I did not see. When I finished pulling the cover off, I stretched it. buuuuutttt.
""""FOUND THE PROBLEM""""
It was the cam plug missing.
There is a bullitin on this but it does not tell how to verify other than pulling the front cover. It's #sb79-07
Hope the local dealer has the parts.

[ipz2222]

Man, what a pain. I've scraped many gaskets before but this was the worst. My arms and shoulders were aching. And to make matters worse, while I was blowing the gsket material off the front of the eng, I blew one of those little springs off and did not know it. Got ready to put the cover on and noticed the spring mssing. Spent 2 hours looking for it on the floor, in the drain and every where else. Could not find it.
Thought it might have went back into the block where the fuel pump is. Got a flexible magnet and could not find it. I now have to pull the fuel pump and fuel cam out to make sure it's not in the cavity.
Now have a new delima. The idler gear has 3 different places on it that has marks, a 1 dot, a 2 dot and a 3 dot. The eng cam gear has a 2 dot and the fuel pump gear has a 3 dot. The wsm shows the 1 dot lineing up on the crank gear and the 2 dot on the cam gear and the 3 dot on the fuel pump.
Mine does not line up. Not sure what to do now. Where's the Excedrin?????

[ipz2222]

Got it back together. Got 50psi at idle and 75 at high eng speed. Don;'t have to worry about mains anymore.

[Service Dept Vic]

Hmmmm, in reviewing this post I see that we kicked that cam plug idea around pretty good in June 2009!


Damn! I wish I had that kind of success picking the lottery numbers!

You know, I've been chipping in $5 a week to Mr. K for the last few years so he'd let me participate in the shop lottery pool. I fould out a month ago he's been buying himself a large double-double three days a week on with my fin! And he wonders shy I hide the odd Kubota trade-in under a tarp in the back of the shop!

Grrrrrr!