JD 450B

WAYNE-N-TX · Post by **WAYNE-N-TX** » Mon Mar 25, 2013 7:48 pm

I have a JD 450B Dozer. My project this winter was to install brake bands on it. I finished this past week, brought it out of the shop using it for a while (approx 20/30 minutes). Needed to make more adjustments, brought it back to the shop and made the adjustments. Tried to crank it and check if I needed more or less. It cranked right up as usual. Died in just a short time.

Figuring it was out of fuel, no, not the problem. Checked the fuel filters, changed both as they needed it. Bled the system after changing the filters, still no go. The outlet valve at the tank, no problem, blew the lines out with air, have flow all the way to the pump, Roosa-master pump. The electric shut off seems to work, disconnected wire, would not crank at all. Hooked it back up, cranked and died just like out of fuel.

I’m not a mechanic but don’t mind working on things. Fuel looks good. What am I missing, Pump? Injectors? Trash somewhere? What’s next?

Scottyb · Post by **Scottyb** » Tue Mar 26, 2013 5:24 am

It does sound like no fuel is getting to the injectors. have you tried bleeding the injectors while turning it over?
Scott

WAYNE-N-TX · Post by **WAYNE-N-TX** » Tue Mar 26, 2013 6:03 am

Yes, I loosen one at a time and turned the engine over. Diesel come out I tighten it back up and went to another.

JRF253 · Post by **JRF253** » Tue Mar 26, 2013 12:11 pm

Figuring it was out of fuel, no, not the problem. Checked the fuel filters, changed both as they needed it. Bled the system after changing the filters, still no go. The outlet valve at the tank, no problem, blew the lines out with air, have flow all the way to the pump, Roosa-master pump. The electric shut off seems to work, disconnected wire, would not crank at all. Hooked it back up, cranked and died just like out of fuel.

What style pump do you have? Can you give the model number? Also, when you say you disconnected the wire and it would not crank at all are you saying you disconnected the solenoid and the engine would not crank?? Or just that the pump was not pushing fuel?

How much fuel, if any, is coming out of the injector lines?

When the machine shut off, did it sound like someone just turned off the key or did it sputter and then shut down?

WAYNE-N-TX · Post by **WAYNE-N-TX** » Wed Mar 27, 2013 10:30 am

The book I have says the pump is a DB model. The tag has been painted and still on the dozer so it's hard to read, this is what I seen. One box/place has a long number and I can't see half of it. Beside that number is "250" and a box just below (toward the back of pump) that one has "AR-51?47" & the third number could be a 7.

When I crank it, it starts just like it suppose to. Very shortly it gets slower and dies just like the key is turned off. The wire I removed was the wire to the pump, wouldn't crank, put the wire back on, cranks but won't run.

It started this before I changed the fuel filters. Like I said before, I used it 20/30 minutes after working on the breaks, drove it back to the shop, after that, it will crank but will not run.

jtrichard · Post by **jtrichard** » Wed Mar 27, 2013 11:09 am

starts and then slowly losses power and dies its the flex ring in the pump.... sounds like its time for a rebuild ...most re-builders don't use that style of flex there is an up grade

JRF253 · Post by **JRF253** » Wed Mar 27, 2013 12:33 pm

Your pump is probably a JDB435AL2442 if the part number is AR51747.

I agree with jtrichard, it is probably time for a rebuild. A guy around here once said that those flex rings wear out in about 10 years and if they are not replaced you can ruin the pump. Best to get it done before that happens, if the rotor seizes up then you get little or nothing for a core value.

WAYNE-N-TX · Post by **WAYNE-N-TX** » Wed Mar 27, 2013 1:34 pm

Thanks guys for helping on this machine. I was on another site asking the same question. A gentleman come on and said his 350 did the same thing and the problem was the return line. Where the return line comes out of the pump, the first fitting has a glass type bead/ball and if it gets plugged it will crank but will not run. Cleaned it and it cranked right up. Thanks again

jtrichard · Post by **jtrichard** » Wed Mar 27, 2013 2:17 pm

yes it will ......the reason its plugging is the ring is exploding ...i have a 580c case and it did the same thing and to get the job done i had to take that check ball out ..but that is only a very short term fix and not a real fix at that

LeonardL · Post by **LeonardL** » Wed Mar 27, 2013 4:41 pm

Jtrichard is right!! Your flex ring is leaving as we speak. Your injector pump should not be putting anything but clean fuel through it... period!! Out the injector lines or the return it doesn't matter. There shouldn't be any debris at all. If there is, then there is a problem and 99.9999999% of the time it will be the flex ring. If you want it fixed you need to listen to what he is saying.

JRF253 · Post by **JRF253** » Wed Mar 27, 2013 5:00 pm

Sure the pump will run with the ring being gone, but your pump will be trashed eventually. I had no idea about this until it happened to my pump, found pieces of metal inside that were roughly half the size of a dime.

If you doubt any of this then there are two things you could do:
1) pop off the timing cover, if you see little black hard pieces under there then its time to take it off for a rebuild.
2) take off the top cover where the shut off solenoid is, its 3 bolts, look in there for any metal shavings or flecks. there will probably be some aluminum, brass, and steel flecks along the edges. if you see anything then it is REALLY time for a rebuild.

WAYNE-N-TX · Post by **WAYNE-N-TX** » Wed Mar 27, 2013 6:18 pm

Thanks guys, I'll get the pump reworked.

Now can you tell me, can I pull the pump myself (not a mechanic) or do I need to carry the whole machine to the shop?

JRF253 · Post by **JRF253** » Wed Mar 27, 2013 6:48 pm

You should be able to get the pump off yourself if you have some mechanical skills. I have not worked on your particular machine model before, but the basic idea is still the same.

-set the engine at TDC cylinder 1
-clean the pump area so it is free of grime and dirt
-turn off the fuel supply at the tank
-disconnect fuel supply, return, and injector lines and plug them so dust can not get in
-set throttle to wide open (this will help hold stuff together in the pump)
-tie throttle lever on pump into wide open position and once secure remove throttle cable
-remove solenoid wire
-note any timing marks where the pump is bolted to the engine
-remove the nuts that secure the pump and carefully remove it

I'm not sure if the driveshaft will be removed with your pump model or if it will be secured into a timing gear, I'm thinking it will be the latter.

That should basically be the procedure to follow. Rebuilding services should be around $350 I think.

For exact procedures for your crawler you should refer to the TM. It's not always a bad idea to have a TM for your own reference...

jtrichard · Post by **jtrichard** » Wed Mar 27, 2013 7:36 pm

don't be surprised if its closer to 800 for rebuild ....yes you want to make sure it is TDC #1 before you take the pump off and when you put the pump back on MAKE sure that you don't miss any of the injector line washers i speak from experience it will be costly if you do

JRF253 · Post by **JRF253** » Wed Mar 27, 2013 8:14 pm

I found this rebuild service on ebay

I have not done business with them, but its an option. There are others on ebay if you search "JDB pump"

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