(800) 853-2651
SHOP NOW

David Brown 780 Keeps Dying

K

KensDBT780

New User
I have a DB 780 which stutters and dies. She may run for an hour or 5 minutes before this happens. It appears it is a result of lack of fuel. I have replaced the fuel pump, had the injector pump rebuilt, pulled and cleaned the fuel tank, replaced the fuel filters and it still happens. I am out of ideas. While prime the system I get very good fuel flow at the injectors then suddenly loose fuel. Anybody have any ideas, I am at a lost......
 
Not sure what fuel system is on your tractor, if pump is C.A.V. DPA like MF with Perkins make sure the filter base constant bleed oriface is not plugged. It allows any trapped air in filter out before it can get to pump and cause a shutdown. Have seen the small hole get plugged on some MF models, can drive you nuts as it may run fine for an hour or 2 minutes when plugged. On Perkins the small bleed line is usually tied into injector top return line. Worth a look.
 
That is exactly whats happening! It is a C.A.V. pump. Im not sure though where to look for constant bleed oriface, is it on the pump itself or are you refering to the fuel filter housing? Wow sure would be nice if this were the problem...
 
The bleed fitting if you have one like Perkins used will be on top of a filter base. Some were a straight fitting threaded into the base with the line on top. May also be a banjo bolt oriface fitting. Some DPA pumps are not designed to handle any air at all at pump inlet, just one air bubble can shut it down until system is bled again. That's why Perkins used the constant bleed at the filter base. Let us know what you find.
 
Thanks Again, I will sure look for it and let you know what I find. Been banging my head for sometime on this one. I hope thats all it is, but then again after all the money spent so far, I wish I had asked the question sooner. Oh well at least the rest of the fuel system is new. :)
 
One more thing to check, if WIX/NAPA filters are being used make sure the top filter groove at outer base does not have an O ring in it. O ring goes in base groove only, not filter inlet groove. Have made service calls to correct this problem also. Does not apply to CAV filters.
 
Well I have tried all your suggestions and continue to have the same issue. The guy I am working with seems to think its an injector problem but I can"t see how that would cause air in the system. Bleed it and it runs for a few minutes then dies again. Every time there is air in the fuel filters. I will buy a new set and install them checking the placement of the gaskets. Does anyone have any other ideas?
 


This is a long shot but we had some DB tanks that the suction pipe cracked internal near the top. The tractors would run good while the tank was full over the fitting where the suction pipe goes then would load up with air when supply got below the fitting near the top of the tank. Just another avenue to consider, good luck.
 
Thanks for the suggestion. Can't see in there so I guess the best way to check would be to top off the tank and see how long it runs?
 
THE FIX! After trying everything listed in this thread, the last suggestion, a cracked pick up line in the tank, lead to the real problem. Although I had removed and cleaned the tank I never thought about the fuel pick up line. It turned out the line was clogged limiting the amount of fuel getting through. the clog was just inside the connection point of the external fuel line. When inspected some crud could be seen in the line, but after using air pressure to blow the line, a ton of crap came out, some the diameter of the line. By putting an air hose in the filler and blocking with my hand the pressure would move the blockage up the line until it could be picked out with tweezers a little at a time. Once a good clean air flow came through we added some fuel and used pressure again to check the flow, it worked. Cleaned the tank again, reinstalled it, primed, and everything is great. All this time I thought it was air in the line and it was really starving for fuel..... Cost me $2000 in other parts just to find crap in the pick up line. Lesson Learned!
 
You must log in or register to reply here.

Similar threads

W
David Brown 780 blowby
Replies
3
Views
243
woo003
W
W
David Brown 780 grill
Replies
1
Views
245
Joe Stewart
J
W
poor idle
Replies
3
Views
248
woo003
W
W
David Brown 780
Replies
2
Views
372
jean claude marleau
J
B
John Deere 3010
Replies
1
Views
235
Dieseltech
D
Tractor Parts Tractor Manuals

We sell tractor parts! We have the parts you need to repair your tractor - the right parts. Our low prices and years of research make us your best choice when you need parts. Shop Online Today.

Copyright © 1997-2024 Yesterday's Tractor Co.

All Rights Reserved. Reproduction of any part of this website, including design and content, without written permission is strictly prohibited. Trade Marks and Trade Names contained and used in this Website are those of others, and are used in this Website in a descriptive sense to refer to the products of others. Use of this Web site constitutes acceptance of our User Agreement and Privacy Policy TRADEMARK DISCLAIMER: Tradenames and Trademarks referred to within Yesterday's Tractor Co. products and within the Yesterday's Tractor Co. websites are the property of their respective trademark holders. None of these trademark holders are affiliated with Yesterday's Tractor Co., our products, or our website nor are we sponsored by them. John Deere and its logos are the registered trademarks of the John Deere Corporation. Agco, Agco Allis, White, Massey Ferguson and their logos are the registered trademarks of AGCO Corporation. Case, Case-IH, Farmall, International Harvester, New Holland and their logos are registered trademarks of CNH Global N.V.

Yesterday's Tractors - Antique Tractor Headquarters
Website Accessibility Policy

Back
Top