I'm going to look at a David Bradley ( British ) 990 backhoe this weekend. From what I gather it is realy a farm tractor with a 3 pt hoe attachment, is this true? The 990 seems to be a ~ 6,000 LB 60 ish HP tractor made from 1960 to 80. The motor supposedly has rod noise but no hole in the block ( yet ) Case was the American sales point for these tractors, were there any other machines that used the same motor? ( 4 cylinder diesel ) Early tractors used a AD 4 / 47 ( 188 cid ) diesel , late units were AD 4 / 49 ( 196 CID ) . I've found a good way to roughly ID motors, look at the water pump. Water pump pictures are widly available. I've taken a look at a 188 Case diesel ( supposedly made by Continental ) but water pumps are wildly different. Aftermarket Thanks
I'm no expert on farm tractors, but if it's the same tractor that I've had experience with then watch out. I had 2 David Brown 990's once, and although a very nice quiet running unit they have an engine with only 3 main bearings and seem to have a lot of crankshaft problems. Most wrecking yards have exhausted their supply of crankshafts, although good blocks without the hole are not hard to find. They have an usual design in that the frame serves as part of the oil pan and the engine oil dipstick is actually in the frame. The older red and newer brown/white tractors have the same engine. Crankshaft bearing manufacturers have joined in and charge double the price for just this model of crankshaft bearing set. It would have to have an external hydraulic pump as the internal Dowty pump would be too slow for the hoe and too expensive to risk using for anything else other than the 3-point hitch. Phil
Crank problems as in worn journals or crank breakage?
As I recall it was #4 rod bearing failure that was always the problem. Most wrecks I found at the time all had a hole in the block near the back on the left side. If rebuilt and looked after, not abused, the engine is fine. I enjoyed owning the 990 and still have a fondness for them. The engine is very quiet and the tractor has a unique final drive that gives it more ground clearance. There was a transmission gear that was very prone to wear, and sought after by tractor wreckers, as with the crankshaft. One can easily take the trans cover off to check this gear. A crankshaft that is not worn too much from a failed bearing, can still be rejected because of heat cracks, and many are. Years ago I broke a crankshaft on my red DB hauling out logs from a bush, and I had a very hard time finding one. I took the 'new shaft' to an auto machinist for magnafluxing before installing. He did the hammer test on in and it did not ring at all. Not good he said, I'm right 99% of the time, but it passed the flux test. I don't recall the 995 or 1200 models having similar problems, it was just that model of engine. Phil
Where can I check the differential oil level and where can I drain it on a 990