990 Injector Pump Leak

I'm new to this Forum but I've had a 990 David Brown for 30 years. It was built in England in 1956 - at least that what it says on the tag.

I've develop a slow drip (leak) on the backside of the Injector Pump housing. It leaks when the tractor is running or when it's not. It leaks a bit more when running. I can't determine exactly where the leak is at because I can't see it.

The tractor runs ok other than the idle is higher than it should be. The main problem is that after the tractor sits for a long period of time I have to bleed the injectors to get to start.

Any help in determining the cause of the leak, and what the solution might be will be appreciated. I've not been able to find a seal/gasket kit.

The 990 wasn't built till 1965ish. If it is a 56 it would be a 900.

Either way they both have a CAV dpa injector pump. The seal kits are available on eBay and a number of other places(under $50). If it is still a good tractor for you it might be worth the money to have the pump and injectors serviced by a pump shop.

I'll double check the tag... it may be 1965 instead of 1956.. wouldn't be the first time I made that mistake. Thanks

I have never seen a DB tag with a date of manufacture on it. If you get the serial number I can get it close.

1965 would be a red tractor with yellow wheels, 66-73 or so would be white tin/brown chassis, 74-80 white tin, orange chassis.

Leaks are common on a CAV DPA pump that has seen some age. They are what I call a bomb proof pump that seldom has much trouble,just leaks once in a while. Pull it off and have a shop reseal it. If the pump is leaking on the outside it may start leaking past the drive seal and put diesel in your oil pan. Call around and check on prices. Some shops will hit you hard. I would suggest taking it to someone who can run it on a test stand when done to check it over correctly. buying a kit on ebay isnt allways the best answer. Sometimes a warranty is worth a few extra busks. I usally get $450.00 to reseal the pump and go through the nozzles. Good luck. 231/757/0064

(quoted from post at 18:09:23 02/04/14) I have never seen a DB tag with a date of manufacture on it. If you get the serial number I can get it close.

1965 would be a red tractor with yellow wheels, 66-73 or so would be white tin/brown chassis, 74-80 white tin, orange chassis.

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As it turn out I haven't seen a tag on a DB with a date of manufacture on it either. I don't know where I got the date from.
I think I've uploaded a photo that shows the tag off of this tractor and the tag on the Injector Pump. This old tractor is white on brown.

Let me try those two picture uploads again.

It is a 1973 model with a faster than normal gear set. Most common is 10/49.

(quoted from post at 19:36:03 02/04/14) Leaks are common on a CAV DPA pump that has seen some age. They are what I call a bomb proof pump that seldom has much trouble,just leaks once in a while. Pull it off and have a shop reseal it. If the pump is leaking on the outside it may start leaking past the drive seal and put diesel in your oil pan. Call around and check on prices. Some shops will hit you hard. I would suggest taking it to someone who can run it on a test stand when done to check it over correctly. buying a kit on ebay isnt allways the best answer. Sometimes a warranty is worth a few extra busks. I usally get $450.00 to reseal the pump and go through the nozzles. Good luck. 231/757/0064

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Thanks I will do that. I'm a fairly good mechanic but I've never had an Injector pump apart. Wish that I could see where this drip is coming from. I know that it's originating on the back side of the pump but I can't see where.

Speaking of fuel in the crankcase oil pan. I get crankcase oil into the power steering reservoir, especially when the weather is cold. I mean it will fill up the reservoir and overflow. The shaft seal on the power steering pump must be bad and somehow letting the pump suck oil out of the crankcase. I probably should start another thread on this.

Thank you very much for the information - RGMartin.

(quoted from post at 15:25:42 02/04/14) [

Speaking of fuel in the crankcase oil pan. I get crankcase oil into the power steering reservoir, especially when the weather is cold. I mean it will fill up the reservoir and overflow. The shaft seal on the power steering pump must be bad and somehow letting the pump suck oil out of the crankcase. I probably should start another thread on this.

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The seal on the PS pump goes bad and draws engine oil through the seal rather than oil from the reservoir. Change the filter while you are at it, a plugged PS filter seems to make it worse.

I have seen it many times. It is utterly confusing the first time you see it as it doesn't make any sense at all. Case sells the seal kits for $30, they are available aftermarket for $10 or less.