One of our nieghbors is cleaning up his junkyard, and he has offered us a pair of Drott 50s - a parts machine and one he used up to about late 2008. They are a bit on the tired side - the running one (50D) has badly worn track chains, and the owner drained the hydraulic system after he parked it because the swivel motor was leaking rather badly. The parts machine (50B) was a log loader. It is missing the valve bank, grapple, and the tracks, but is otherwise intact. Both have 6V71 engines, and the owner claims both ran. What are the specs on the Drott excavators? Were they good machines?
They had their day. The pumps were Commercial Shearing and available most anywhere a while ago. The early machines had mechanical linkages and you used levers and pedals. If you wanted to change the controls it was a pain. All the 50s that I worked on had 6V53 engines in them. I've never seen any of those with a 71 series. Good luck with getting one of them running. By this time they would probably have a lot of crap throughout the systems.
Old, tired iron... Yeah, I think they are actually 6V-53 engines. The one we are looking at that might actually run (the other is definitely a parts machine) has pilot controls. Its a 50"D" model but we haven't been able to find what years it was made. The attraction to me is that the machine hydraulics are dead simple: gear pumps and gear motors. They are relatively cheap to fix and maintain. Probably at the expense of smooth, fine control? For a stump rancher, a 1000$ gear pump beats a $15K Kawasaki pressure compensated servo pump!! John C, did the 50's have any "warts" that you care to comment on? For example, I noticed that the track drive sprockets are mounted on a couple of pillow block bearings--dead simple but probably prone to wear out quickly? Did they have fragile booms or pins that wore out quickly? Was the tilt turntable a plus or just a pain? Your experiences would be welcomed!! How about the controllablility of the machine while digging? With gear pumps, the controls have to be open center, so that if you were using one function on a valve the other functions don't work very well, if at all. The machine has two pumps but I don't know how the pumps are split--does one pump go to the tracks and swing; the other to the boom? Did the track drives have adequate power? We can't afford a real excavator but we figure we might get 75% of the usability of a 200-size machine with one of these 50's. The "stump ranch" would probably benefit with the addition! If nothing else we would end up with 50 tons of scrap metal ready to go to the Toyota factory. And the 7" bore lift cylinder would make a heck of shop press!!! Jon.
I spent a few yrs in 40s and drott 50s, many hrs clearing, running a hammer, as well as digging. They were indeed simple and basic machines. The tilt rams are prone to leaking but simple to rebuild, less than an hr. The rotater manifold (center swivel) is an easy fix, just O rings and seals. They were a bit weak in the swing, but you could compensate by using the tilt feature to help out. They are by no means fuel sippers. All that being said to have one for a pet to use on your own place absolutley, if the cost to get it up and running again is not to great.
Wait until you spin the splines off an axle and sprocket , you'll be glad you have a parts machine. jr
jrtraderny: Yeh, I don't expect to buy real live parts!! (they are still shown on the Case website!) I am blessed with a fairly complete machine shop so if a spline spins out it has a good chance of getting turned into a plain old fashioned keyway if I don't have a spare on hand!!! On a stump ranch, time is on your side. Cash isn't. I gather you had the joy of having this happen to you at one time? What's the best guess at their age...late '70's? Would I be too optomistic to suggest early '80s? ddigger: I like the suggestion that they are pretty simple! I love the term "pet" Har!! " Honey, I bought another pet for the ranch " Did they have decent power in the lift and digging functions? Gads, the lift and crowd cylinders are both an impressive 7" bore--even at the low 1500-2000 psi pressures they ran back then the push forces are 60-80,000 lbs!! Keep your observations coming!! Thanks a lot, Jon.
Yeah, I had a 40 . You can normally get 2 sprockets to 1 axle wearout ratio. Did the keyway thing once , worked ok as long as the sprocket was a press fit. Also welded an axle back together after it broke in two pieces. The pillow blocks will really make a believer out of you, if Case still has them they are real proud of them $$$ wise. jr
The final drives were simple and needed to be because they didn't like working in the mud. The final is a linear drive which means there are no planetary gears, just shafts and gears that mesh. The pillow blocks could be found at a bearing supplier far cheaper than the dealer. The swings were a pain also. The box had to be shimmed to get the correct backlash on the pinion so if you pull that box don't lose any of the shims and make sure to get them back in the right place. The circle bearings were usually good for five to six thousand hours and the machines that we converted to loggers went about half that. It is correct that those hydraulic systems were simple but as I recall some of them had what was called horse power summation. It was the first try at reducing the work load on the engine. As I recall it was a valve that dropped off some of the flow of the pumps when the engine was being drawn down. It came out at about the time I got laid off from that job so I don't even know what else to tell you about it. I do remember the pilot controls on the 50 now that you mention it. I remember those being sold by the dealer I worked for at the time which was the late seventies and early eighties. If you get it running and coax some use out of it, more power to ya. Good Luck!
We had customers who used the old Drott just for their breakers. Dead simple hydraulic system and why wreck a good machine when you can pound the hell out of the old Drott. Final drive splines tend to be a problem but if you have a machine shop then no problems. We use to weld the sprockets then run a broach through them with 100 ton press. Splines were like new.
Rebuilding Tilt or Leveling Cyclinders Can you explain how to remove the tilt/leveling cylinders on a Drott 40 D? We need to rebuild them, but can't tell how they come out.
diesel833, The cylinders come out from the top, they are a single acting that has down pressure only to each side. A single hyd hose runs from a check valve/load holding block to each cylinder barrel end. Oil is static in both cylinders with a load check holding them. As pressure is sent to either side to tilt the carbody, the side that is raising, forces the other to unseat the check to allow tilting and keep the system from losing it's static oil on that line.This keeps it from flopping back and forth after releasing the control lever.
Care must be used to remove the cylinders. I would park unit outside, turn the boom over the cyilnder to be removed, tilt machine up with the leveler, lower the boom/ stick/bucket. Remove sheet metal guard, if still there next to the track at the tilt cylinder barrel. Go under the machine, there will be a access hole for each cylinder. Most had 4 bolts/washers/lock plate that held the lower cylinder in the bore, remove them. Place floorjack/porto power in the center of the base, may need a 4x4 block 18" long for the floorjack to reach it. Jack up ontill snug, place cribbing in leveler area, remove hyd hose to the barrel end, plug line. Use jack to push up on cylinder (may take some work due to crud packed in the area around it) all the way up. Install cap on the fitting where line was removed. Remove the large pin at the barrel end and bring cylinder out from the top. Once out the cylinder can be pulled apart if it diden't already come apart during removel since it just slides in. The piston has a snap ring/chevron type packing/wiper seal and is easy to pack, tube can be rechromed if needed, more if needed. The other cylinder can also be done in the same manner.
Sheepfoot, thanks for the response. I have taken the (4) 1/2" bolts out of the bottom of the cylinders. There are 4 other holes that look to be bigger (5/8" maybe) on the bottom side as well. How do you get the cylinder to come out the top, do you need to use bolts or thread-all in the bigger holes to push it up through?
Like said in the last post, use a floorjack with a 4x4 from the bottem to push it up with the hose unhooked to remove the oil and retract the cylinder, Once retracted remove the pin in the barrel end (top). Let your jack down a small amount 3". You should be able to lean it out and raise/pull it out of it's hole. Cab needs to be tilted up to gain the extra clearance, it will not come out the bottem.