David Brown Tractor Forum

To get better access to the diff lock, its better to remove the flange, on which the oil seals are fitted. Use right size of bolts and a strong flat bar to the job, just in order to avoid the flange damages. To put the things back together you need a rod, slightly thinner than the drive shaft, on wh...

I have an 990 which has got the engine from a 1390. That means that swapping the engine between 1390 and 996 should be more or less a bolt-on operation. 990 has dual clutch but both stages on pedal, so I suppose my tractor has original 990 clutch assembly. I cant be sure if 1390 and 996 have interch...

I have seen one 990 (very identical fuel system with 996) which suffered of a dirt particle in the tank pipe. It did run a while but then stopped. After bleeding it did run a while again and stopped. The dirt was found after loosening the connection from tank line to the fuel line to the lift pump. ...

OK. Broken/disappeared 0-ring is probably the explanation. Now, when the pump is on desk, it could be a good idea to check if it needs new gasket rings. At least Dowty has replaceable seals which can give up and weaken the pressure output. I do not know about Plessey, but I guess that it has about t...

If your tractor has double acting valves on the RHS of the seat, they are independent of rear lift.

W.B.R erkki

As far as I know tightening the bearing is a simple job. The parts inside are rather robust, so they don't break up easily but still I think that investing a while for the job is the way to go.

There can be a few reasons to low pressure but first clean the by-pass valve on the valve chest. If the valve is clean, it is time to check the pump.

W.B.R erkki

Agree Olle,

I haven seen non-sychro gearboxes which have experienced lots of abuse with the result that the gear of 2:nd and 3:rd are worn out over half of their original width. The problem grows gradually when changing gears in move by crunching the rotating gears against each others.

RGDS erkki

Hmmm. 674 IH is close to same power class and weight class than 6711 Zetor. Maybe 1390 David Brown is about same size. It is very advanced tractor on PTO because of large variety of speeds. The rest of the tractor is conventional. 674 is rather agile with compared to 6711. Good luck.

W.B.R erkki

If the water level raises to level of cooling fan, it will certainly cause belt slip and in the worst case damage to the fan. Factory recommendations are true, of course. I know from experience that specific fuel consumption is higher when driving on the road by 2400 rpm with compared to 2000 or 180...

If the rear lift hold when the three way valve on th eleft hand side in in position "1" or "2" the ram piston seal is ok. The system has probably a leak in dump valve (if your tarctor has one, a stud sticking up on the cover just behind the main control lever) or the control spool valve. First aid t...

2300...2400 rpm is fine on road. Depth of water? Depends on model but I would not hesitate to cross two feet deep water by my 1200.

W.B.R erkki

Snowfish, David Browns have different ratios in final drives depending of the model. some 850 implematics had 9/37 as well as 885. They have good road speed even if the rear wheels are not that high. 990 and 1200 with 6 speed gearbox had 9/50 in order to keep the 1:st gear slow enough for rowcrop an...

Agree joeproctor. 990 came available with three liter long stroke wet sleeve engine, which is durable and has very good lugging properties. The same engine is found in early selectamatics also. Later selectas have 3.2 liter short stroke engines with bores made straight to the block.They have more po...

With slasher its better to use low speed PTO. The implement is not made for 1000 rpm PTO, which is a natural reason to avoid using high speed. Low speed with 1400 rpm in the engine does a brilliant job.

RGDS erkki