I clean the bores with a brass bottle brush on a drill while using transmission fluid for the cleaning solution then flush it all out with diesel fuel, kerosene or any light oil.
I attended a lecture at the David Brown tractors club last week given by Alan Kellett who was the hydraulic instructor at the DB training school. I recorded it on my phone so will watch it again tomorrow and hopefully get the answer.
Peter Flitcroft I could only imagine being an expert in DB hydraulics. I bet half the old timers in the countryside are well versed in these machines .
I have a 990 David Brown. It’ll raise and hold for weeks but will not lower. I checked the hold and bypass valves and they seemed ok but it’s like the pressure is bottled up right there at the valve. The second that I remove the valve, oil comes out real heavy and the 3 point lowers. Does this sound like the hold valve is my issue or do I need to be pulling the whole valve assembly? Thanks! Adam
Could be. It could also be an alignment issue with your control lever, especially if it was messed with before. That is one reason I took the entire assembly off as I did not want to mess with tolerances to get that correct. I'll look through my notes and see if I recall anything, it has been a while since I tore into this. When you say remove the valve, are you pulling just one or both?
@@jclaudii thanks for the reply! I didn’t even expect a reply because I seen the video was older. Yes I pulled both valves out and cleaned them thoroughly. I think you may be right. Yesterday I decided to adjust the nut inside the box that holds the lever to the rod, and i got a little bit of lowering action. It takes about 6minutes to lower all the way with weight on it. But... the nut is now backed out as far as I can before it coming unthreaded, and the lowering speed knob is also adjusted for maximum lower speed. So from here I’m not sure what to examine without pulling the valve body. I thought about changing filter and running diesel through the transmission to see if it clears anything up.
I have that thing still apart in a box. I found a few other issues with the tractor and our farm I had to tackle first, but I do plan on completing this series eventually!
Hello my friend. I have the same tractor with a problem that I don't understand. At first it works well. After an hour of work, the pressure on his plumbing slowly disappears. What do you think is to blame? i changed the oils but the problem remains. Thanks.
If it just won't lift anymore after a period of time it could be one of the following: 1. ) seals broke on the lift cylinder (cold oil is thicker and it works at it should for a limited time) 2.) pump is getting air somewhere causing suction issues and cavitation. Could even be a filter issue if the filter is extremely dirty it may not suck enough fluid 3.) worn hydraulic pump I mean with cold oil it will perform better and get worse with time. I would suggest to hop onto a dedicated David Brown tractor forum or page on FB and ask around more there.
Would you tell me where to add Dexron III Mercon for my steering on my Case 885? There is no actual photo of the reservoir in my manual. I think it must be a round cylinder on the side with a screw cap on the top. It seems empty. There is a rubber like filter at the bottom of this. I would appreciate it.
Hello , I have a q - cabbed 1490 with this valve block well & truly stuck , on certain valves , as it takes it an age to lower the linkage down , yet the spool valve " let back down " cycle seems unaffected , ( the big baler still slams shut well enough ) can this valve block be removed from the front of the right rockshaft bracket without taking the whole rockshaft assembly off , as there is a tin plate bolted on under the cab right outside it , just inside the right wheel ? , in short , what linkages or rods are connecting the selectamatic valve internally to the mechanisms inside the right rockshaft bracket that could get damaged if you tried to get it off without the rockshaft ? ..... anybody tried or done it ? we on here would love to hear & see about it . Best Regards from middle england .
Phillip, you may be able to do that, but I found a manual pdf file and read through it several times and ask the folks over at the David brown tractor forums on thoughts as well. I think one reason I left it all together is the requirement of some special tool or having to make one to get the spacing and align just about perfect mounting that valve body back to where it sets. That little kidney shaped plate will get you access to these two valves if you can work in that tight space.
Hello , thanks for replying so quick , I,ve been out & looked again at it , & the plate I mentioned is 9-1/2" x 7- 1,2 " , & it,s almost certainly for connecting the gearchange linkage up when fitting the cab , as it,s too far forward & too far up for access to the selectamatic valve , which you can just about see the right side of , this seems mounted on the front face of the back axle ,R.H. side , when the rockshaft right bracket is mounted on the back face of it , & it,s covered with a piece of black expanded foam with a cable clip holding it , so , I think I,ll be looking into joining the D.B. club here in england , to get the knowledge & put a video or two up if they have a forum for that ,( I could put the same video on here ! )The cab mounting bracket is directly above the selectamatic valve , so I think I,ll be phoning Mr Barcley Williams again for advice also , as he supplies most of the bits for these here in mid - england .Best Regs from across the pond .
Thanks for your efforts , I,ll join the D.B. club here , & then do it your way anyway so as you say , not to upset the relationship between the R.H. crossshaft box & selectamatic valve , it might be dowelled , but until you get it off you can,t tell , so be able to scribe around the valve body first before undoing the fasteners , & get it back into the same position . Best Regards .
Frank I never got it back together yet. I had to chase down a broken part and it has sat in a box in the house for a while. Basically other fish to fry. I have some footage of me smoothing the bores that I need to put up sometime.
@@jclaudii Where are you finding parts? I need that valve that had the screen in it because the screen is out of mine. I also need the plate that goes on the bottom of the hydraulic filter. without it the oil isn't forced through the filter media thus causing those little valves to plug.
Michael Persinger I have no knowledge of the db1200, if it looks similar to the 885 you can see if there is an access hole above the valve area. Mine had that but was rusted up so I had to pull. I joined one of the UK David brown forums for more info, you may have to do the same as well.whats yours doing? Good luck!
Well when you start it up the lift arms lift right away and the handle that lifts the arms goes to the up position right away and when you try to lower the arms the handle seems like its got a heavy spring on it and goes right back to the up position ... there is a top cover there where the valves are i just wasnt sure if there was springs and ball bearing on the top of them ? anyway thats for the information ...
The 1200 series is just like the 995, 996 etc. Which has a top access cover held on with 2 screws. Under the cover there are 2 screw in caps over the valves, lefty loosie, righty tightie.
I clean the bores with a brass bottle brush on a drill while using transmission fluid for the cleaning solution then flush it all out with diesel fuel, kerosene or any light oil.
I attended a lecture at the David Brown tractors club last week given by Alan Kellett who was the hydraulic instructor at the DB training school. I recorded it on my phone so will watch it again tomorrow and hopefully get the answer.
Peter Flitcroft I could only imagine being an expert in DB hydraulics. I bet half the old timers in the countryside are well versed in these machines .
great video hydraulic s can be tricky on these david brown mainly caused by water ingress at gear stick gators ,
I have a 990 David Brown. It’ll raise and hold for weeks but will not lower. I checked the hold and bypass valves and they seemed ok but it’s like the pressure is bottled up right there at the valve. The second that I remove the valve, oil comes out real heavy and the 3 point lowers.
Does this sound like the hold valve is my issue or do I need to be pulling the whole valve assembly?
Thanks!
Adam
Could be. It could also be an alignment issue with your control lever, especially if it was messed with before. That is one reason I took the entire assembly off as I did not want to mess with tolerances to get that correct. I'll look through my notes and see if I recall anything, it has been a while since I tore into this. When you say remove the valve, are you pulling just one or both?
@@jclaudii thanks for the reply! I didn’t even expect a reply because I seen the video was older.
Yes I pulled both valves out and cleaned them thoroughly.
I think you may be right. Yesterday I decided to adjust the nut inside the box that holds the lever to the rod, and i got a little bit of lowering action. It takes about 6minutes to lower all the way with weight on it. But... the nut is now backed out as far as I can before it coming unthreaded, and the lowering speed knob is also adjusted for maximum lower speed.
So from here I’m not sure what to examine without pulling the valve body. I thought about changing filter and running diesel through the transmission to see if it clears anything up.
to late now, but for viewers later, Talcum powder works well for a very high grit (12000or so) polishing compound
I just welded the bolt that fit the valve body threads to a nut that fit my slide hammer shaft and it came right out.
I'm not sure why I did not think of a slide hammer :)
PS, that only works for one of them . . . The other one needed the anchor bolt like he is showing but i put that on my slide hammer too.
thank you for your videos. I have an 885N that isn't lifting. Were you able to get the hydraulics to work again?
I have that thing still apart in a box. I found a few other issues with the tractor and our farm I had to tackle first, but I do plan on completing this series eventually!
@erikanderson hopefully it helped get your valve body apart.
@@jclaudii It helps to know what l am working with by seeing what is inside...
Hello my friend. I have the same tractor with a problem that I don't understand. At first it works well. After an hour of work, the pressure on his plumbing slowly disappears. What do you think is to blame? i changed the oils but the problem remains. Thanks.
If it just won't lift anymore after a period of time it could be one of the following:
1. ) seals broke on the lift cylinder (cold oil is thicker and it works at it should for a limited time)
2.) pump is getting air somewhere causing suction issues and cavitation. Could even be a filter issue if the filter is extremely dirty it may not suck enough fluid
3.) worn hydraulic pump
I mean with cold oil it will perform better and get worse with time. I would suggest to hop onto a dedicated David Brown tractor forum or page on FB and ask around more there.
@@jclaudii thanks my friend.
Good job
Would you tell me where to add Dexron III Mercon for my steering on my Case 885? There is no actual photo of the reservoir in my manual. I think it must be a round cylinder on the side with a screw cap on the top. It seems empty. There is a rubber like filter at the bottom of this. I would appreciate it.
Hello , I have a q - cabbed 1490 with this valve block well & truly stuck , on certain valves , as it takes it an age to lower the linkage down , yet the spool valve " let back down " cycle seems unaffected , ( the big baler still slams shut well enough ) can this valve block be removed from the front of the right rockshaft bracket without taking the whole rockshaft assembly off , as there is a tin plate bolted on under the cab right outside it , just inside the right wheel ? , in short , what linkages or rods are connecting the selectamatic valve internally to the mechanisms inside the right rockshaft bracket that could get damaged if you tried to get it off without the rockshaft ? ..... anybody tried or done it ? we on here would love to hear & see about it . Best Regards from middle england .
Phillip, you may be able to do that, but I found a manual pdf file and read through it several times and ask the folks over at the David brown tractor forums on thoughts as well. I think one reason I left it all together is the requirement of some special tool or having to make one to get the spacing and align just about perfect mounting that valve body back to where it sets.
That little kidney shaped plate will get you access to these two valves if you can work in that tight space.
Hello , thanks for replying so quick , I,ve been out & looked again at it , & the plate I mentioned is 9-1/2" x 7- 1,2 " , & it,s almost certainly for connecting the gearchange linkage up when fitting the cab , as it,s too far forward & too far up for access to the selectamatic valve , which you can just about see the right side of , this seems mounted on the front face of the back axle ,R.H. side , when the rockshaft right bracket is mounted on the back face of it , & it,s covered with a piece of black expanded foam with a cable clip holding it , so , I think I,ll be looking into joining the D.B. club here in england , to get the knowledge & put a video or two up if they have a forum for that ,( I could put the same video on here ! )The cab mounting bracket is directly above the selectamatic valve , so I think I,ll be phoning Mr Barcley Williams again for advice also , as he supplies most of the bits for these here in mid - england .Best Regs from across the pond .
Thanks for your efforts , I,ll join the D.B. club here , & then do it your way anyway so as you say , not to upset the relationship between the R.H. crossshaft box & selectamatic valve , it might be dowelled , but until you get it off you can,t tell , so be able to scribe around the valve body first before undoing the fasteners , & get it back into the same position . Best Regards .
Do you have any more videos? How did it end up working?
Frank I never got it back together yet. I had to chase down a broken part and it has sat in a box in the house for a while. Basically other fish to fry. I have some footage of me smoothing the bores that I need to put up sometime.
@@jclaudii Ok, looking forward to seeing them when the come.
These are actually some important videos. A common problem for us DB owners.
@@jclaudii Where are you finding parts? I need that valve that had the screen in it because the screen is out of mine. I also need the plate that goes on the bottom of the hydraulic filter. without it the oil isn't forced through the filter media thus causing those little valves to plug.
That is a David Brown hydraulic valve removal tool, that's what that is called.
Could you tell me if i can take the valves out of the valve body with out disassembling the back of the tractor of a 1200 David brown ?
Michael Persinger I have no knowledge of the db1200, if it looks similar to the 885 you can see if there is an access hole above the valve area. Mine had that but was rusted up so I had to pull. I joined one of the UK David brown forums for more info, you may have to do the same as well.whats yours doing? Good luck!
Well when you start it up the lift arms lift right away and the handle that lifts the arms goes to the up position right away and when you try to lower the arms the handle seems like its got a heavy spring on it and goes right back to the up position ... there is a top cover there where the valves are i just wasnt sure if there was springs and ball bearing on the top of them ? anyway thats for the information ...
Michael Persinger my 995 does the same thing. You ever figure what it was?
The 1200 series is just like the 995, 996 etc. Which has a top access cover held on with 2 screws. Under the cover there are 2 screw in caps over the valves, lefty loosie, righty tightie.
Thats called a DYNA Bolt,,, yes a concrete anchor
Don't mix the springs up. They are different tensions. Two are 60. One is 70.
Peter Flitcroft hmm good to know I think I put all the parts in separate baggies, if not is there anyway to identify which ones are which?