David Brown 990 PTO problem.

Several years ago while I was bushogging with a 6' Bushhog Squealer, the bushhog jumped on top of a large clump of cut weeds that had rolled up in front of the bushhog. I heard a noticeable pop sound underneath the seat in the gear box, and the PTO shaft started rattling, moving in and out.The factory Bushhog shear pin did not shear, and Bushhog refused to accept any liability for the damage this caused to my tractor. So I relegated this tractor to discing only, and used my DB 885 for bushhoging. But now I need for the PTO to work. I removed the small plate on the rear of the tractor where the PTO shaft passes through. I found that the outer snap ring was missing. I found half of it inside that cover plate. I replaced it with a snap ring that appeared to be the same size but it made no difference. The shaft still has about a quarter of an inch in and out play and makes the same rattling noise as before when I hooked up the bushhog to it. However, one thing I noticed is that when I pulled the PTO lever firmly forward, the rattling noise stopped. Before I tear it down, I was just wondering if any of you guys who know more about DB tractors than I do would care to offer an opinion about what is wrong and how best to fix it. Oh, one other thing: I discovered that the generator pulley was frozen so I tore it down and found that the shaft bearing was tore up. One wire alternators are a lot cheaper than a generator so I'm going back with one. As far as I know, I only have to determine which one of the original 2 wires going to the generator is hot, and connect that wire to the alternator?
 

The whole assembly the PTO shaft rides in comes off fairly easy. You probably lost a bearing or snap ring type thing on the inside of that case. Should be pretty evident when you pull the rear cover off.

When I got rid of my 3rd bad Lucas "dynamo" I used a standard 3 wire Delco alt. There are numerous diagrams on how to run the wiring. I would run new wiring if I was to do it.
 
What do you mean by "the rear cover". I already removed the small plate that the PTO shaft comes through and found that the rear snap ring had broken
but replacing it didn't help.
 
Which one?

Joe

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(quoted from post at 22:29:02 09/24/20) What do you mean by "the rear cover". I already removed the small plate that the PTO shaft comes through and found that the rear snap ring had broken
but replacing it didn't help.


You're going to end up pulling the whole assy off the rear end, the big round shaped thing in the diagram. That gives you access to both sides of the drive and the internals of the 2 speed gear box.
 
We did that today. We found 3 gears and 2 bearings with significant wear. One gear was badly chewed up. I'm going to try to find another whole
assembly like this. Thanks so much.
 
On of the guys on here is in Lafayette. Maybe he will see this and chime in if he has one. The email I have for him quit working a while ago.
 

Hi Rich & Walter. Yeah, that would be me. I live in Lafayette and I've been in contact with Walter. I have a couple of PTOs that were taken off junk 990s. I was going to keep the output shafts, but Walter you are welcome to the rest of the parts, if you ever make it out this way (I believe Amite is a good solid 2 hour drive from here. I am still unclear as to exactly which part(s) you need.
 
Hello from Texas, Since you all are into 990 Case tractors I was wondering if anyone knows the valve adjustment gap? I will be replacing a leaking valve cover gasket and have not adjusted the valves since I bought it last year and I would like to get it right. Can you help me and forgive for changing the subject because my question hasn't been answered in a while and I'd like to get it done.
 
My 990 is the only one I have ever owned, and it has always run perfect so I never had to adjust the valves. There is a company called Messick's that
specializes in David Brown parts. They sent me some things I needed. Maybe they can tell you about the valve gaps. Hope this helps.
 
(quoted from post at 03:13:12 12/05/20) Hello from Texas, Since you all are into 990 Case tractors I was wondering if anyone knows the valve adjustment gap? I will be replacing a leaking valve cover gasket and have not adjusted the valves since I bought it last year and I would like to get it right. Can you help me and forgive for changing the subject because my question hasn't been answered in a while and I'd like to get it done.

Use this link and go down the listings to the 990 Operators manual, and there are engine manuals further down. Should have everything you need. Bookmark the link, you can refer back to it!

https://sites.google.com/site/deerebrown/
 
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