For the forum post mentioned in the description: As of January 2023, the David Brown Tractor Club site was hacked and the Forum post may or may not exist. Unfortunate situation where lots of knowledge on the forum was potentially lost.
Hi Shane, nice disassembly video. I would stone off the ridges on the bearings and remeasure the width, subtract that value from the center section, then mill off the right depth of material from the center section to arrive at a mid specification clearance when assembled.
Thanks for watching Glen! That's actually good advice and I cover that option in the followup to this video. ua-cam.com/video/IoJFH1rUJV8/v-deo.html Campbell in NZ sent along an email to us showing how he's going to do exactly this to one of his pumps. I'm interested to see if it gets back to full pressure. You can see what he sent by looking at the post on Barry's community area: ua-cam.com/users/postUgkxY2yFSPYVroys0MV5U0BZQeJUwwCyan6n I want to try the pump just resealed in mine to see what kind of pressure I get, but I'll likely need to sand the bearings and skim the body to get full pressure back.
Hi Shane what a brilliant video I must say well done to you you take the time to show and explain things properly and not go rushing on so pat on the back. Hopefully your get good news regarding a new pump. Also big thank you for your links regarding a load leveller finally I've found one which is designed for 900kg only £32.69 free delivery even my son said get one it's gonna make pur lives easier. Keep up the excellent videos
Thanks a bunch Jon! I've got some good news I think. Based on the forum post, errki says that it should be ok to seal up and use. The new seals tightened it up tremendously. I'll try to put out a video on it sometime during the week. Glad to see you're getting a leveler, it'll definitely be of help.
Hi Shane, another good video mate, O rings, don't use the Orings supplied in the kit for the oil outlet to camels humps they're to small of cross section and fail very quickly I think Cammeron said to try and get Orings of 3.5mm cross section and you should struggle to get the pump back on if you've got the right ones. Need still to change mine. keep up the good work Barry
@@path.of.discovery Hi Chaps, The OEM o-ring for the hydraulic pump outlet tube is specified as 5/8" ID x 3/32" 90 Duro, Class 6. That said, over time, the aluminium housing of the pumps often 'chatter' or wear away at the o-ring, and I believe that yours have probably done this. Carefully inspect the outlet hole in pump housing for wear caused by high pressure oil leaking past. O-rings should ideally have 25% compression between ID & OD so one quick fix that I have success with using is a slightly larger cross section o-ring - for example Metric 16ID x 3mm 90 Duro in either Viton (superior if you can get them) or more commonly Nitrile material which is much cheaper. When fitting the pump to the outlet tube, you should ensure the o-ring feels like a nice snug fit, otherwise prone to losing hydraulic flow/pressure. Recommend stay away from cheap o-ring kits in this application.. Also carefully inspect the pump inlet tube, they tend to crack under the hydraulic pump quite often letting air into the hydraulic system and may prevent oil entering the pump especially when the tractor faces downhill... just saying. Keep up the great videos!
@@CampbellBooth-gy8jv Thank you so much for this tip! So far from what I see in the pump outlet hole all looks ok. No discernable wear I can see or feel. I was debating with myself on using 1/8 cross-section but the metric size you specify looks to be great for "in-between" 3/32 and 1/8 cross-sections. I can't find Viton in the metric size you specify, so I'll settle with Nitrile 90 duro. I think I can get another 30 years out of that 🙂 My sons will have to worry about fixing it up then! Thanks again!
Great vid Shane. Lance @BundyBearShed put us onto your channel. I’m looking at an 880 selectamatic with a hyd fault so absorbing as much info as l can. Thanks for sharing. 🇦🇺
I agree with Glen . Clean up the bearings ( remove the ridge at the outside of where the gears run) , remeasure and mill the body to spec , either by polishing on emery paper or take it to a machine shop. and reassemble. It should be alright.
excellent video thanks, Im about to pull my pump again as I rebuilt the pump but may have put the wrong size o ring on the pressure outlet and it hasnt sealed, still have no real lift pressure. This time I will use mounting studs as it was a bugger of a job last time to get the cover back on
Hi there. I am in Canada and also have a 990 DB. No serial number but believe it’s a 1974 from the man I bought it from. I am also having the same issues with my tractor. Look forward to what you find out on a pump and how much they cost! Robin.
I think it can too... eventually. I've got everything back together and tested now. ua-cam.com/video/Ncps8Du3Vz0/v-deo.html got in the neighborhood of 2300 PSI! I was impressed. We'll see how long it'll hold up though.
I can only speak to my experience. My family has two 990's. Both have worked hard with minimal maintenance and issues since new. Only in the past few years have they started to have issues. The main issues with mine is the o-rings in the hydraulics have started to fail. The other 990 has the spool valve seized. If properly maintained these tractors are amazingly long lived, as mine is over 50 years old at this point. Minimal repairs. However, each tractor will be different due to environmental factors such as how it was stored, frequency of maintenance, etc. They are simple to work on and parts availability is still fairly good if you're looking for a project tractor.
Have owned two 770As. my experience is that the selectamatic system is too clever by half. More sophistication than needed for most users and finicky, extremely sensitive to less than perfect fluid and adjustments, and hard to find parts for, exp here in the States. This is a great video series but do a quick search and see how many DBs are for sale in the US that run great but have hydraulic issues.
put the main body of the pump flat on a sheet of glass or flat surface with some fine emery cloth or p800 paper and gently rub to bring the body width back into tolerance before you condemn the pump
Thanks for watching dr jay! That's a great idea, and will save some money on getting it machined to get it back into tolerance. There's a followup to this video where I use the new seals and it tightens it up tremendously. ua-cam.com/video/IoJFH1rUJV8/v-deo.html I've already put it back in the tractor and refitted the PTO housing and will experiment to see just how much pressure just a resealed pump in the condition mine was in will build up. If it's not close to 2000psi I'll take it all back apart and try what you've outlined in the comment. I've got to finish getting the Valve Chest cleaned up and reinserted before I can test everything though. Thanks for the idea!
For the forum post mentioned in the description: As of January 2023, the David Brown Tractor Club site was hacked and the Forum post may or may not exist. Unfortunate situation where lots of knowledge on the forum was potentially lost.
Hi Shane, nice disassembly video. I would stone off the ridges on the bearings and remeasure the width, subtract that value from the center section, then mill off the right depth of material from the center section to arrive at a mid specification clearance when assembled.
Thanks for watching Glen! That's actually good advice and I cover that option in the followup to this video. ua-cam.com/video/IoJFH1rUJV8/v-deo.html
Campbell in NZ sent along an email to us showing how he's going to do exactly this to one of his pumps. I'm interested to see if it gets back to full pressure. You can see what he sent by looking at the post on Barry's community area: ua-cam.com/users/postUgkxY2yFSPYVroys0MV5U0BZQeJUwwCyan6n
I want to try the pump just resealed in mine to see what kind of pressure I get, but I'll likely need to sand the bearings and skim the body to get full pressure back.
Hi Shane what a brilliant video I must say well done to you you take the time to show and explain things properly and not go rushing on so pat on the back. Hopefully your get good news regarding a new pump. Also big thank you for your links regarding a load leveller finally I've found one which is designed for 900kg only £32.69 free delivery even my son said get one it's gonna make pur lives easier. Keep up the excellent videos
Thanks a bunch Jon! I've got some good news I think. Based on the forum post, errki says that it should be ok to seal up and use. The new seals tightened it up tremendously. I'll try to put out a video on it sometime during the week. Glad to see you're getting a leveler, it'll definitely be of help.
Hi Shane, another good video mate, O rings, don't use the Orings supplied in the kit for the oil outlet to camels humps they're to small of cross section and fail very quickly I think Cammeron said to try and get Orings of 3.5mm cross section and you should struggle to get the pump back on if you've got the right ones. Need still to change mine.
keep up the good work
Barry
Ok thanks for that. I've written it down in my "Book O' Tips" and will get some of those thicker o-rings.
@@path.of.discovery Hi Chaps, The OEM o-ring for the hydraulic pump outlet tube is specified as 5/8" ID x 3/32" 90 Duro, Class 6. That said, over time, the aluminium housing of the pumps often 'chatter' or wear away at the o-ring, and I believe that yours have probably done this. Carefully inspect the outlet hole in pump housing for wear caused by high pressure oil leaking past. O-rings should ideally have 25% compression between ID & OD so one quick fix that I have success with using is a slightly larger cross section o-ring - for example Metric 16ID x 3mm 90 Duro in either Viton (superior if you can get them) or more commonly Nitrile material which is much cheaper. When fitting the pump to the outlet tube, you should ensure the o-ring feels like a nice snug fit, otherwise prone to losing hydraulic flow/pressure. Recommend stay away from cheap o-ring kits in this application..
Also carefully inspect the pump inlet tube, they tend to crack under the hydraulic pump quite often letting air into the hydraulic system and may prevent oil entering the pump especially when the tractor faces downhill... just saying.
Keep up the great videos!
@@CampbellBooth-gy8jv Thank you so much for this tip! So far from what I see in the pump outlet hole all looks ok. No discernable wear I can see or feel. I was debating with myself on using 1/8 cross-section but the metric size you specify looks to be great for "in-between" 3/32 and 1/8 cross-sections. I can't find Viton in the metric size you specify, so I'll settle with Nitrile 90 duro. I think I can get another 30 years out of that 🙂 My sons will have to worry about fixing it up then! Thanks again!
Great vid Shane. Lance @BundyBearShed put us onto your channel.
I’m looking at an 880 selectamatic with a hyd fault so absorbing as much info as l can.
Thanks for sharing.
🇦🇺
Thanks! Welcome to the channel and thanks for watching! Glad to have you!
I agree with Glen . Clean up the bearings ( remove the ridge at the outside of where the gears run) , remeasure and mill the body to spec , either by polishing on emery paper or take it to a machine shop. and reassemble. It should be alright.
Agreed!
excellent video thanks, Im about to pull my pump again as I rebuilt the pump but may have put the wrong size o ring on the pressure outlet and it hasnt sealed, still have no real lift pressure. This time I will use mounting studs as it was a bugger of a job last time to get the cover back on
Thanks John! I used 3mm CS x 16mm ID O-ring for the pressure pipe. Much tighter seal than using what's specified on the parts diagrams.
Hi there. I am in Canada and also have a 990 DB. No serial number but believe it’s a 1974 from the man I bought it from. I am also having the same issues with my tractor. Look forward to what you find out on a pump and how much they cost! Robin.
Hi Robin! I've got some inquiries out on availability and cost. Will see how bad the hit to the ole wallet will be.
Get someone to pressure test the pump before you pull it down
That ring looks like a backup ring.The actual oring is gone.
You're probably right
I think it can be resurfaced to the factory specs.
These OEM pumps would be better than replacing it with aftermarket.
I think it can too... eventually. I've got everything back together and tested now. ua-cam.com/video/Ncps8Du3Vz0/v-deo.html got in the neighborhood of 2300 PSI! I was impressed. We'll see how long it'll hold up though.
Hello. I have the opportunity to buy case david brown tracktor are they a good tracktor to have as dar as quality, longevity?
I can only speak to my experience. My family has two 990's. Both have worked hard with minimal maintenance and issues since new. Only in the past few years have they started to have issues. The main issues with mine is the o-rings in the hydraulics have started to fail. The other 990 has the spool valve seized. If properly maintained these tractors are amazingly long lived, as mine is over 50 years old at this point. Minimal repairs. However, each tractor will be different due to environmental factors such as how it was stored, frequency of maintenance, etc. They are simple to work on and parts availability is still fairly good if you're looking for a project tractor.
@@path.of.discovery Thankyou so much for sharing with me.
Have owned two 770As. my experience is that the selectamatic system is too clever by half. More sophistication than needed for most users and finicky, extremely sensitive to less than perfect fluid and adjustments, and hard to find parts for, exp here in the States. This is a great video series but do a quick search and see how many DBs are for sale in the US that run great but have hydraulic issues.
990,Brilliant tractor,mine is well over 50 yrs old and it's only the last few yrs it's giving little problems,it would rings around a mr 135/165.
put the main body of the pump flat on a sheet of glass or flat surface with some fine emery cloth or p800 paper and gently rub to bring the body width back into tolerance before you condemn the pump
Thanks for watching dr jay! That's a great idea, and will save some money on getting it machined to get it back into tolerance. There's a followup to this video where I use the new seals and it tightens it up tremendously. ua-cam.com/video/IoJFH1rUJV8/v-deo.html
I've already put it back in the tractor and refitted the PTO housing and will experiment to see just how much pressure just a resealed pump in the condition mine was in will build up. If it's not close to 2000psi I'll take it all back apart and try what you've outlined in the comment. I've got to finish getting the Valve Chest cleaned up and reinserted before I can test everything though. Thanks for the idea!
Just replace o rings and go with
Yep! It's been working fine!