David Brown 880 Selectamatic Hydraulic issue

DGS

Member
Hi I recently bought a David Brown 880 Selectamatic tractor 66/67 model.
The 3 point linkage (hydraulics) will not lift if the tractor is pointing downhill, even on the slightest slope. It’s fine if tractor is uphill or on level ground. Both filters are new and oil level is correct. If I raise the 3 point linkage on level ground and then back the tractor slightly up an incline or drive it downhill, so tractor is pointing downhill. While on that incline I can lower the 3 point linkage but it will not raise again while on the downhill. It does not appear to be starving of oil, because it makes no noise. I have tried overfilling about 3 litres and it made no difference. If I have to dismantle it, I would first like to have some idea what I should be looking for. Has anyone experienced this issue and or have some constructive input on this? Cheers DGS
 
Hi I recently bought a David Brown 880 Selectamatic tractor 66/67 model.
The 3 point linkage (hydraulics) will not lift if the tractor is pointing downhill, even on the slightest slope. It’s fine if tractor is uphill or on level ground. Both filters are new and oil level is correct. If I raise the 3 point linkage on level ground and then back the tractor slightly up an incline or drive it downhill, so tractor is pointing downhill. While on that incline I can lower the 3 point linkage but it will not raise again while on the downhill. It does not appear to be starving of oil, because it makes no noise. I have tried overfilling about 3 litres and it made no difference. If I have to dismantle it, I would first like to have some idea what I should be looking for. Has anyone experienced this issue and or have some constructive input on this? Cheers DGS
All the lift problems I’ve had with an 880 were caused by water getting in the oil via the gear lever gators,this then softens the cardboard filter element that in turn breaks up and plays havoc with your hydraulics,the main problem being the dump valve blocking.
 
Thank you my friend... That could well be causing the issue. I recently changed the oil and both the filters and the sump filter was not in very good condition. Cheers
 
Hi I recently bought a David Brown 880 Selectamatic tractor 66/67 model.
The 3 point linkage (hydraulics) will not lift if the tractor is pointing downhill, even on the slightest slope. It’s fine if tractor is uphill or on level ground. Both filters are new and oil level is correct. If I raise the 3 point linkage on level ground and then back the tractor slightly up an incline or drive it downhill, so tractor is pointing downhill. While on that incline I can lower the 3 point linkage but it will not raise again while on the downhill. It does not appear to be starving of oil, because it makes no noise. I have tried overfilling about 3 litres and it made no difference. If I have to dismantle it, I would first like to have some idea what I should be looking for. Has anyone experienced this issue and or have some constructive input on this? Cheers
When you changed the lower filter, how bad/dirty was it? The upper filter is a return filter and I’ve seen a few DB 880s with the upper filter permanently discarded so it’s not strictly essential. What type of oil did you refill with? 10W 30 would be the correct oil, less than ten gallons in total if I remember correctly. Also on the selectamatic switch, which position have you got it in? Try it in the right position (spring loaded to rise lift) and when it’s fully lifted can you hear the relief valve blowing? Possibly the suction pipe may be cracked and when the oil is tilted away it may be starving. The DB has lots of rubber seals and a leather seal on the lift piston, both Dowty and Plessy pumps were used on the 880 during production.
 
Hi The lower filter was pretty bad when I changed it and the gauze filter was also very clogged. I used Hi Tech 15W/40 Farm oil which is what they recommended as it's mostly hotter in OZ. I now have a manual for it which says SAE 20W/30 or SAE 20W/40 motor oil, so the Hi Tech fit's in there fine. I have only used the selectamatic switch in the normal centre position. I think your cracked pipe theory is more likely the issue or perhaps an o ring. Ok when I get a chance I'll check out your suggestions, thank you. Cheers DGS
 
Id chance looking at that filter again 1st. Had a 35 here onetime that let water into backend. Had to drain oil and I put diseal in then and went up the lane and let it out again to rinse the crap out. Don't work the lift or PTO doh
 
Hi The lower filter was pretty bad when I changed it and the gauze filter was also very clogged. I used Hi Tech 15W/40 Farm oil which is what they recommended as it's mostly hotter in OZ. I now have a manual for it which says SAE 20W/30 or SAE 20W/40 motor oil, so the Hi Tech fit's in there fine. I have only used the selectamatic switch in the normal centre position. I think your cracked pipe theory is more likely the issue or perhaps an o ring. Ok when I get a chance I'll check out your suggestions, thank you. Cheers DGS
The bottom paper filter may need changing again, just check it carefully when the bowl is removed. You may be able to pressurize the pick up pipe with air to help find a crack. The selectamatic system is very sensitive to dirt and with so many O rings in the system it’s a tricky one to troubleshoot. The positive thing about yours it that it works correctly some of the time so rules out certain components. Check the hyd pressure if you can get a gauge, max pressure on the 880 is around 2000 psi.
 
Id chance looking at that filter again 1st. Had a 35 here onetime that let water into backend. Had to drain oil and I put diseal in then and went up the lane and let it out again to rinse the crap out. Don't work the lift or PTO doh
Thank you my friend, that's good advice that I've taken onboard
 
The bottom paper filter may need changing again, just check it carefully when the bowl is removed. You may be able to pressurize the pick up pipe with air to help find a crack. The selectamatic system is very sensitive to dirt and with so many O rings in the system it’s a tricky one to troubleshoot. The positive thing about yours it that it works correctly some of the time so rules out certain components. Check the hyd pressure if you can get a gauge, max pressure on the 880 is around 2000 psi.
Thank you again for your friendly advice also taken onboard. Once I can get to it I'll let you know how I go.
 
Had the same problem with a 995, never did get to the bottom of the problem.
Changed oil and filters many times, only thing I can think of is valve trouble or linkage trouble.
Having lived with it for years sold her and bought a 4000.!
 
I recall seeing a steel oil pipe hanging from the wall of the workshop back in the 90s, it had a few sharp bends and a flange on one end with O rings on the other end. It was from the 880, going from the pump to the valve chest and I presume it was either cracked or a spare. The two pipe connections on the pump have seals, the one on the wall here was side mounted and held with two bolts but this would be pressure side so it’s more likely the main suction flange that bolts underneath the pump and it also has a seal on it which may have failed or the mounting worked loose. Remove the ring of bolts from around the rear lift housing and slide it off, the pump will be obvious then.
 
Any hydraulic issues that I had with my 880 all related to the valves under the selector dial. Screw them out and clean them and see if it improves. The manual or youtube will show you what to do. Be careful with the springs etc.
 
Any hydraulic issues that I had with my 880 all related to the valves under the selector dial. Screw them out and clean them and see if it improves. The manual or youtube will show you what to do. Be careful with the springs etc.
Thank you my friend, good advice taken onboard
 
I recall seeing a steel oil pipe hanging from the wall of the workshop back in the 90s, it had a few sharp bends and a flange on one end with O rings on the other end. It was from the 880, going from the pump to the valve chest and I presume it was either cracked or a spare. The two pipe connections on the pump have seals, the one on the wall here was side mounted and held with two bolts but this would be pressure side so it’s more likely the main suction flange that bolts underneath the pump and it also has a seal on it which may have failed or the mounting worked loose. Remove the ring of bolts from around the rear lift housing and slide it off, the pump will be obvious then.
Thank you also my friend, that's good advice taken onboard
 
Any hydraulic issues that I had with my 880 all related to the valves under the selector dial. Screw them out and clean them and see if it improves. The manual or youtube will show you what to do. Be careful with the springs etc.
Thanks also good advice
 
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