David Brown 990 removing the rockshaft and hydraulic lift cylinder #22

[@ChatlesHall]

You deserve a great praise for teaching the kids how to work with their hands and tools

[@manfromthemist1958]

Hi Chatles, I fear we are on a loosing wicked with the younger generation in general, few of them like getting dirty unfortunately. To many like sitting playing computer games. many thanks

[@DanieOpperman-s7w]

Hi Barry, thank's for lot of info, have also DB 990 standing in garage and have not the knollege to let it work again. My Granny inport rond 4 of DB 990 to Namibia and we used it for many year's on the farm. Mine is still standing on block's and in vry good condition, l wil look to ather vidio's, talk later again

[@manfromthemist1958]

Hi Di2ri, thanks very much for the support, I'm pleased you found the video's useful, please let us know how you get on with your tractors, many thanks Barry

[@phillipcleaver7063]

Many thanks mate , I didn,t want to attack stripping mine down until I,d seen a knowledgeable guy do it , I,d have blundered on disconnecting the pipe manifold on the front of the selectamatic valve , because I,d never seen one before , also well worth checking the "copper" pipes inside the back axle have not got twisted around & severely restricted , The workshop manual I,ve got misses a lot that you show up . All the best .

[@manfromthemist1958]

many thanks Phillip, don't forget to loosen the lubricatrion (return) pipe via the 7/16" bolt in the drivers side of the axel case good luck let us know how you get on Cheers Barry

[@mr.traider7429]

Hey Barry, I was wondering if you could help me again with a missing part on the DB 990? The bleed valve is missing on the hydraulic cylinder. It just has a screw stuck in it. Not a good way to bleed the system after I try to fix it. All the valves on the valve chest are stuck. Sigh, I have tried looking in several places but with no luck at getting one. What would be a good replacement for the bleed valve? You and Shane have helped me with the knowledge and confidence through your videos to try to fix this tractor. Many thanks.

[@manfromthemist1958]

Hi mrtraider the part your looking for is item no 25, part no K910104 vent screw i'll upload an exploded diagram to this link, go there download it and look for item 25 drive.google.com/file/d/10yr9wqbdVg9F7b79znY9rFOPPOGSLL-1/view?usp=sharing for your valve chest watch my video and shanes video on the the valve chest, if you need to buy on try Barclay Williams UK tell them you got the link from me. hope this helps Barry

[@mr.traider7429]

Thanks again barry. I will give that a go.

[@jimmymannion6874]

Great video

[@manfromthemist1958]

Thanks! Barry

[@tombruce6398]

I very much aprecate your video

[@manfromthemist1958]

Hi Tom,many thanks, I'm so pleased they are of use to you. Barry

[@docterjan5841]

Hello Barry Nice videos I have a David Brown 990 selectamatic built in 1965, a very early selectamatic, my Ram cylinder is stuck Do you have any idea how I can get this out?

[@manfromthemist1958]

Hi Jan, I'm assuming it's your lift piston stuck in the lift cylinder, do you have access to a compressor or a set of hydraulic pumps, the type you couple up to those hollow lift rams and spreaders? If so remove the lift arms, rock shaft so as to expose the piston in the lift cylinder, remove the threeway valve from the front of the cylinder or the connector across the feed pipe and input to the cylinder, you may need to fabricate some method of connecting either the air or hydraulics to the input of the cylinder and start pumping, cover the rear of the cylinder with some heavy cloth, old douve etc as when it lets loose it will move very very quickly and you need to catch it , definately don't stand behind it. lets know how you get on Many thanks Barry

[@ChatlesHall]

Hello Barry what is the function. Of the latch valve

[@manfromthemist1958]

Hi Chatles, the latch valve, when your lift arms are in the raised position and have an implement on them, any leakage in the ram cylinder circuit will allow the linkage to lower slowly and gradually place the spool valve in to raise position, The latch valve will then snap shut, providing a sharp response of by-pass valve. I'll put the extract from the manual on my FB page and also in the community area for you to read. many thanks Barry

[@kentkent537]

Very interesting video👍

[@manfromthemist1958]

many thanks for your support Barry

[@David.Monkhouse]

Hi Barry. I didn’t see the missing disc you mentioned in your last video but if it was on top of the valve chest, could it have been the sealing washer between the dump valve and the top of the valve chest? Your valve chest looks to have had some interference in the past. Mine was the same and wasn’t even the original part. They are date stamped underneath and mine was newer than the tractor. Anyway, I don’t believe there are any serviceable parts inside the chest and although mine appeared to work ok, I took it to Barclay Williams who is just down the road from me and he tested it. The spool valve was worn and there were various leaks where there shouldn’t have been. So whilst it wasn’t cheap, I bought a refurbished valve chest from him and fitted that. Although I’m not painting my tractor until it’s mechanically sorted, I didn’t want to risk finding that I had hydraulic issues and have to take it all back to bits again. Finally (!), there are at least a couple of real hydraulic experts on the DBTC forum if you get stuck.

[@manfromthemist1958]

Thanks David, I've stripped the valve chest off the selector casting today and found some more damaged parts as you'll see in the next video, it's a good job I've got a spare, as for the valve chest I'll have to talk to Paxtons in Alnwick and see if they have any spare parts, the needle valve for the lowering speed was missing, make's you wonder what else isn't there. In the next video you'll see the cam from the end of the rockshaft could you please let me know if that's excesive wear or deliberate profiling? Many thanks for your support Barry