JD 530 - Gasoline in the crankcase oil

[rScotty]

Well, it finally happened. The old JD 530 needs a repair. Runs just fine, but leaving a trail of gassy oil behind so I checked it and found that the crankcase was overflowing with gas in the oil!

I swapped out the needle and float, changed the oil and filter, replaced the aftermarket manual gas shut off valve I had added to the fuel line to the carb 20 years ago, - all to the tune of about $125 - and then drove it around to see what happened. Everything worked like it has for the past 30 years, so I shut it down, closed the aux. gas tap and left it. A few days later I for no good reason went over and to check the oil and it was gassy and the crankcase full to nearly overflowing again!

Wonder what's going on here? I think I know, but thought I'd ask first.
rScotty

 

[raheimdal]

You mention that you installed an auxiliary gas shut off valve, but does it still have the original sediment bowl? If so, most of the later two-cylinders had an automatic shut off for low oil pressure. As part of the sediment bowl there is a diaphragm where oil pressure turns on the flow of fuel.

Over the years those two rubber disks wear out. Any JD dealer that has two-cylinders in the area should stock them. You might also want to get the flat o-ring that goes on the automatic shutoff as well.

To replace is quite simple. Drain the tank of fuel. Remove the oil lines. Take off the glass bowl for clearance. Unscrew from the tank. With a pencil mark the orientation of the center cast disk that the oil line attaches to. Take out the screws holding the stamped steel top onto the cast body. Take the clip off the fuel shut off plunger and remove the spring.

Replace the flat o-ring and reassemble with the two new rubber disks. Make sure to include the small button that goes between the two rubber disks in the hole of the cast piece that the oil line attaches to. If yours is missing, replace it. Then matching up the mark you made earlier finish putting back on the tractor.

 

[rScotty]

You mention that you installed an auxiliary gas shut off valve, but does it still have the original sediment bowl? If so, most of the later two-cylinders had an automatic shut off for low oil pressure. As part of the sediment bowl there is a diaphragm where oil pressure turns on the flow of fuel.

Over the years those two rubber disks wear out..... .

Yes, I've still got the original sediment bowl with the oil pressure-controlled diaphragms. I added the inline manual shutoff about 30 years ago twhen the auto shutoff feature failed in a way that kept pressure on the carb float. Yes, rubber parts do have to be replaced periodically, and I've wondered if it's just me or is the time interval becoming shorter between replacement? Possibly today's gasoline is different from the older type. Anyway, it's much better to be able to shut off the gasoline feed when it's not needed.

Thanks for the very complete post on replacing the diaphragm. I agree that's a good bet about what is going on. I'll be replacing those parts when the weather clears up. It's -22F today.

Say, it looks like you have quite a few old JDs. We sure do like ours. It's a family member.
Back in the 80s we even subscribed to some of the JD magazines and they were read eagerly here.
The Kubota is a more handy machine - there's no denying that. I hope it lasts half as long as the JD, although to be honest it has done fine so far. Only another JD guy can really understand how devastated we felt when we went down to the JD dealer to buy a new JD and came back with an Orange Machine!!
I do wish our newer tractors had half the support groups that the old JDs do. IMHO, that 530 represents all the best in 2 cylinder development. With the power steering, 12 volt electrics, quick-attach #46 FEL, hydraulically suspended seat, aux hydraulics, independent PTO, and awesome traction it compares suprprisingly well against today's Ag & chore tractors. Several times now the JD has been called on to rescue a smaller and modern 4WD machine. Cars and tractors both. Usually stuck somewhere they shouldn't have gone.

 

[raheimdal]

Two cylinders are a bit of a passion in my family. Between my dad and I we have over 30 tractors and lots of matching implements and almost all of them are pre 70's. We've collected everything from plows to elevators, hay rakes to corn pickers. My dad also accumulated a pretty extensive range of toy tractors and original JD literature over the years. It is fun to look at the sales pamphlets or ads in the Furrow for the equipment when it was new. The Two-Cylinder club has released the original JD Day videos on DVD and it is neat to see what farming was like back in the day. My dad has said when he was young, you only needed one A JD for every 100 acres. Now lawn mowers have more horsepower.

The "30" series two cylinders are still a handy machine. We have four 630s, one that has a restored 227 corn picker on it, and another that has all the options, factory square wide front, air precleaner, dual hydraulics, flat top fenders, 3-point, and full set of weights. My 530 I answered an ad in the paper and just had to have it. Came with a 45 loader, and instead of going and getting the trailer, I drove it 30 miles home. Just a fun tractor to have around for pulling wagons, or backing machinery in the shed.

I know what you mean about the new ones having their place as well. My 4720 CUT was the first and only tractor we own that has a cab. I finally decided that when moving snow in the wintertime we deserved to do it in comfort. Our local dealer sells both Kubota and JD in the CUT size range. The orange ones are nice, but we had to stay green. Not that Kubota doesn't make a nice tractor. There was one where my dad worked and they used it for mowing, snow removal, and running the auger. The hour meter only went up to 999 and they rolled it over twice before finally breaking a camshaft. Replaced if and I'm sure it is still running strong.

 

[rScotty]

You mention that you installed an auxiliary gas shut off valve, but does it still have the original sediment bowl? If so, most of the later two-cylinders had an automatic shut off for low oil pressure. As part of the sediment bowl there is a diaphragm where oil pressure turns on the flow of fuel.

Over the years those two rubber disks wear out. Any JD dealer that has two-cylinders in the area should stock them. You might also want to get the flat o-ring that goes on the automatic shutoff as well.

I thought I'd take a moment to close out this thread. Yes, you were entirely correct. Gasoline was leaking internally in the OEM sediment bowl.....that's the sediment bowl peculiar to the last of the two cylinders and it features an set of internal oil-pressure driven diaphrams to automatically open or close the fuel feed to the carb. It saves the operator from remembering to manually turn the gas flow on/off.

One of those diaphrams had a split in it which allowed gasoline to backflow through the oil pressure pipe and down into the sump when the engine wasn't operating. That's a slow process, but give it a few weeks and it will fill up the sump.

The fix was simple: new diaphragms and a sediment bowl rebuild. Which I did. Then I took my dealer's advise and replaced the entire fuel sediment bowl assembly with JD's manual replacement featuring a good old finger-operated on/off switch. The rebuilt OEM unit is now on the shelf in the barn!
rScotty