hydraulic cylinder repair

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The nut popped off the cylinder piston. Again. This happened last summer and the tractor dealer simply chased the threads and put it back together. This time I took it to the hydraulic shop and they kindly explained why that never works. They were busy and we had a load of haylage  to unload for some hungry cows. No way we could wait a couple days. As they explained the repair it sounded like I could do the repair myself. Basically they said it needed to be built up with the wire feed and re-threaded. Well I could do that.I originally planned on turning this between centers but the nut end was bent. So I set it up in the steady rest.Picture 1: The results of the nut popping off. They guys at hydraulic shop said the nut likely worked loose and hammered off during use.Picture 2: The rod setup in the lathe.Picture 3: The threads cut off ready to be welded.Picture 4: Thread area built back up and turned. I forgot to take a picture of the weld build up.Picture 5: I partially cut the threads on the lathe. I chose a 3/4-16 because my old lathe doesn't do metric. I also planned on finishing the thread using a standard die that I had. Attached Images
Reply:These are the rest of the pictures. Picture 6: Finished the thread with a die.Picture 7: Finished thread.Picture 8: I installed a nylock like the cylinder had originally.Picture 9: After I spoke with the repair shop again they recommended using a grade 8 nut with red lock tight... so I changed it out.It has been a week and the repair has held. I am very happy with the results. Hopefully this can help someone else save some money on the farm. Attached Images
Reply:Nice save!MikeConstans Fides et IntegritasLincoln Weldanpower 150 ACAirco Aircomatic MIGet CAV II w/ spoolgunMillermatic 30a wirefeeder
Reply:Thats a good fix!!!Its amazing what kind of repairs can be made with a lathe and a welder.
Reply:Nice fix, now since you saved yourself some bucks you can go and buy another fishing rod. Hey, that thinking has me up to about eighty rods and reelsGood job!"Where's Stick man????????" - 7A749"SHHHHHH!! I sent him over to snag that MIC-4 while tbone wasn't looking!" - duaneb55"I have bought a few of Tbone's things unlike Stick-Man who helps himself" - TozziWelding"Stick-man"
Reply:That looks like nice work.  I need a lathe! I'm about to start fixing a tractor bucket cylinder with a similar problem (but not quite as bad as yours).Now you'll just have to remember where that one non-metric nut is on your tractor . . .  - StixHobart Stickmate LXMakita 14" gas chopsawA whole mess of chainsaws
Reply:Man, I really envy the boys with the cool toys!Lincoln Power Mig 210MP MIGLincoln Power Mig 350MP - MIG and Push-PullLincoln TIG 300-300Lincoln Hobby-Weld 110v  Thanks JLAMESCK TIG TORCH, gas diffuser, pyrex cupThermal Dynamics Cutmaster 101My brain
Reply:Good job..I do that stuff all the time.....zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:nice what kind of lathe do you have
Reply:Very nice.  I can see it now."Honey, I need a lathe!""What for?""I can rebuild farm equipment, rebuild threads if I need to, turn metal, stuff like that!""You are a computer nerd."[I]LOL!  I do need a lathe though.  I've been on the prowl for a nice used one with tooling.  I wouldn't want to have to properly equip one  ($$$$$$$$$$$$$$$$$).
Reply:Dandy!Thanks for posting it up.Good Luck
Reply:Originally Posted by SimpleSimonVery nice.  I can see it now."Honey, I need a lathe!""What for?""I can rebuild farm equipment, rebuild threads if I need to, turn metal, stuff like that!""You are a computer nerd."[I]LOL!  I do need a lathe though.  I've been on the prowl for a nice used one with tooling.  I wouldn't want to have to properly equip one  ($$$$$$$$$$$$$$$$$).
Reply:Originally Posted by ed macnice what kind of lathe do you have
Reply:In another thread he mentioned it was a LeBlond.
Reply:Originally Posted by ed macnice what kind of lathe do you have
Reply:Another nice job, I have done the same thing my self but my lathe wasn't long enough so I had to add on to the threaded end after build up  and use the add on in the chuck and the the other end in the steady!I always tried to work with the oldest hand on the job to gain knowlege but now I can't find any.
Reply:Originally Posted by SimpleSimonVery nice.  I can see it now."Honey, I need a lathe!""What for?""I can rebuild farm equipment, rebuild threads if I need to, turn metal, stuff like that!""You are a computer nerd."[I]LOL!  I do need a lathe though.  I've been on the prowl for a nice used one with tooling.  I wouldn't want to have to properly equip one  ($$$$$$$$$$$$$$$$$).
Reply:Nice fix.
Reply:looks great!!
Reply:That's a really nice job.In the past, I have had a machine shop refuse to do just exactly what you did.  Building the metal back up with the welder.  I don't know the exact reason they refused, other than something about the metal not being able to be machined or hold the thread.I wonder if they didn't have the capability to do any welding, and just passed up on the job.And some machinists are kind of purist types too  No thinking outside the box.I gotta get my lathe set up one of these decades"Any day above ground is a good day"http://www.farmersamm.com/
Reply:Originally Posted by farmersammThat's a really nice job.In the past, I have had a machine shop refuse to do just exactly what you did.  Building the metal back up with the welder.  I don't know the exact reason they refused, other than something about the metal not being able to be machined or hold the thread.I wonder if they didn't have the capability to do any welding, and just passed up on the job.And some machinists are kind of purist types too  No thinking outside the box.I gotta get my lathe set up one of these decades
Reply:Plain steel or even mildly alloyed stuff can be welded with 'plain' filler.  ie: standard ER70 wire.One hint (if you didn't do it that way) is to weld the build-up passes -axially- (along the axis of the rod/cylinder, ie length-wise) and NOT round-n-round.  And then skip 'across' to the opposite side, and repeat until the item is all filled in with passes.  Doing it that way instead of round-n-round helps to minimize distortion due to all the welding.Yeah, that's a big ole lathe, for sure.Nice fix.    The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by MoonRisePlain steel or even mildly alloyed stuff can be welded with 'plain' filler.  ie: standard ER70 wire.One hint (if you didn't do it that way) is to weld the build-up passes -axially- (along the axis of the rod/cylinder, ie length-wise) and NOT round-n-round.  And then skip 'across' to the opposite side, and repeat until the item is all filled in with passes.  Doing it that way instead of round-n-round helps to minimize distortion due to all the welding.Yeah, that's a big ole lathe, for sure.Nice fix.
Reply:when you lean on the arbor press, doesn't the other end jump off the floor?
Reply:Next time you use your steady rest get yourself some cloth backed sanding sheets..Rip a piece about 1" wide as long as you need to go around the shaft..Put the sanding side down against the rest and cloth around the part..Forget the grease and just use spindle oil or some other thin oil..Saves the part finish from score marks..We save old sanding belts just for that purpose..Try it you'll like it!...zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.Originally Posted by zapsterNext time you use your steady rest get yourself some cloth backed sanding sheets..Rip a piece about 1" wide as long as you need to go around the shaft..Put the sanding side down against the rest and cloth around the part..Forget the grease and just use spindle oil or some other thin oil..Saves the part finish from score marks..We save old sanding belts just for that purpose..Try it you'll like it!...zap!
Reply:..That's a very nice repair on the Hydraulic  rod....I worked as a welder in a Machine shop for a while...we did lots of hyd cylinders...usually just cut of the rod end...made new chrome rod, weld the end back on.......but back at the farm....all different...do what you gotta do....  Thread chasers...they just smooth out the already partially 'removed' or stripped thread....if rod bent at welded-up area....sometimes best to weld the end solid....then drill new center...using the steady rest good for threading though...if you can't get the rod through hole in chuck....   The stuff we did weld for shaft repair...usually weld axialy...rotate 180, weld on the other side...pretty standard for any type shaft weld/repair...many cylinder rods are 1020 TGP carbon steel with .002-003" chrome on them......some 1045....don't weld them very well...   My only suggestion is to use a lock-nut, usual thing for this application...the ones typical for rods?...distorted-thread or 'prevailing' torque....you can always drill and cotter the thing if need be...Dougspair
Reply:..Old sanding belts..I got a big box of them, from #60 up to #400.....when the #400's get worn out...then I use them for polishing with some oil....my work sander is small though...1x42Dougspair
Reply:Hi  Nice job on the cylinder repair. You might want to drill and tap for small set screw on the side of the nut. When you tighten the nut,just screw in the set screw and the nut will never back off again. I do that all the time whenever I repair or repack a cylinder. You can buy a set screw with a edge on the end to bite into the threads on the cylinder
Reply:The cylinder broke again this morning. It appears the nut must have come loose and hammered itself off the rod. I'm gearing up to fix it again today. I used a grade 8 nut with red locktight torqued it to 320 lbs last time.Should I use a nylock or nut drilled for a set screw? What about a split lock washer? Any ideas?For comparison I re-uploaded the photo showing the last repair. It looks like the nut came loose to me and the piston acted like a slide hammer until it popped off the end. Again  Attached Images
Reply:Set screws thru the nut is not a good idea because the screw will eat into the threaded shaft and make a mess out of the threads..Now try to get it off...Nylock nut with a jam nut behind it is your best bet if there is room......zap!I am not completely insane..Some parts are missing Professional Driver on a closed course....Do not attempt.Just because I'm a  dumbass don't mean that you can be too.So DON'T try any of this **** l do at home.
Reply:Its a nice piece of work that. it sure saved then customer a lot of money. How old is that Lathe?¤If you got money, i've got time
Reply:If a Grade 8 nut torqued to 320 ft-lb and secured with red Loctite came loose,  wtf is going on there?  A 'lock washer' will do almost nothing.  Think about it, once the nut is tightened then the so-called 'lock washer' is nothing more than a flat washer with maybe a small burr at one place.  And as already said, a cross-drilled setscrew would most likely just bugger the threads even more.  Besides, do you realize how hard it would be to drill and tap a hardened Grade 8 nut?  Usually a nylock nut won't be any more or less resistant to backing off than decent thread-locking goop (aka Loctite).One possibility though might be that you put the Loctite on the end of the male threads on the rod or on the female threads on the nut and then assembled the two.   Which meant that most if not all of the Loctite was in the thread gooves out at the end of the male threads and not much was left in the threads where the nut was assembled and tightened, as evidenced by your photo showing a lot of red Loctite in the male thread grooves all the way at the end of the stud/bolt section.  Per the directions , you are supposed to apply the 'goop' in the area where you expect the final assembly to end up, ie not at the very tip of the male threads and then spin the nut down or run the male threads deep into a tapped hole.Also note that the Loctite usually works 'better' on clean non-oily metal and typically best strength is on plain steel.  Different metals (brass, stainless, etc) , different coatings on those metals (zinc dichromate vs plain steel, etc), different thread size gaps, and different curing temperature all have an effect on the strength of the thread locking 'goop' as well as how long it takes to develop that strength.  Ex, plain steel with a curing temp of 40C may take 1 hour to reach 'full' strength, while curing the same at 4C may take 24 hours for Loctite 277 Red threadlocking compund.  Using Activator 7649 with the Loctite 277 on steel specs out to give 100% strength at 6 hours, while Activator 7471 on the same specs out to only give a relative 75% strength after about 7 hours and with no activator used the relative strength specs out at only about 55% after 36 hours.  Taken from the Loctite 277 spec page PDF.  The best laid schemes ... Gang oft agley ...
Reply:Originally Posted by HGHS-CorpIts a nice piece of work that. it sure saved then customer a lot of money. How old is that Lathe?
Reply:Originally Posted by zapsterSet screws thru the nut is not a good idea because the screw will eat into the threaded shaft and make a mess out of the threads..Now try to get it off...Nylock nut with a jam nut behind it is your best bet if there is room......zap!
Reply:Did you talk to Art @ Fluid Power to see what they do or what you possibly overlooked? Loctite + double nut?Millermatic 200Hobart Handler 120Victor O/A & Ramco BandsawLincoln 225 ACSnapOn AD HoodMiller XMT304/22AHypertherm Powermax 1650 G3Lincoln Idealarc DC600 w/Extreme 12 VSMiller Digital Elite "Joker"
Reply:Originally Posted by MoonRiseIf a Grade 8 nut torqued to 320 ft-lb and secured with red Loctite came loose,  wtf is going on there?
Reply:Originally Posted by RaptorDunerDid you talk to Art @ Fluid Power to see what they do or what you possibly overlooked? Loctite + double nut?
Reply:I think you solved your own problem, assembly straight from milling and then straight to the tractor. Not enough cleaning for the locktite to grab good and the hydraulic fluid disolving the remaining locktite before it was set up. I've also wondered if the nut could be drilled and the end of the shaft drilled and using safety wire to secure the nut from backing off. We used this safety wire method all the time to prevent parts from backing off on aircraft. If it were me I would use both safety wire and locktite as I hate to redo a job for preventable reasons.MAC WS1110 Mig WelderWoodworker HobbyistDelta 10" Table Saw, Delta Planer, Bosch and Craftsman Routers, 48" Craftsman Lathe, drill press, 1/2" hand and cordless drills, scroll saw, skill saws, jig saws, etc, and too many hand tools to list, lol
Reply:At this point I'd be trying to figure why it tore itself up in the first place.Is there a bad twist on the assembly it powers?  Something causing a bind, or rotation, as the ram extends and retracts?  Excessively loose pins causing hammering?It might be a cause totally seperate from the internals on the cylinder"Any day above ground is a good day"http://www.farmersamm.com/
Reply:I would just use a castle nut and cotter pin but thats just me not sure how hard it would be to drill a hole in the shaft.
Reply:Plan "B" in action, very nice.Matt
Reply:Darn! I posted up at the bottom of page 1 and see now it went toes up again.MoonRise has good advice per the 277 threadlocker. Also did you get that 320ft/lb number from the hydraulic shop? It seems more in line with a "dry torque" to me and you can cause a failure with loctite as well as with oil or antiseize.Matt
Reply:Either cleans threads with no residue left behind..works great for using locktite!Also I have a LeBlonde  25" heavy duty...about the  same era as yours.
Reply:Originally Posted by farmersammAt this point I'd be trying to figure why it tore itself up in the first place.Is there a bad twist on the assembly it powers?  Something causing a bind, or rotation, as the ram extends and retracts?  Excessively loose pins causing hammering?It might be a cause totally seperate from the internals on the cylinder
Reply:Repaired and curing overnight. I cleaned it with loctite 7471 primer. Not sure why I didn't use it last time, it was within arms reach of the lathe. It contains acetone, isobutane, isopropyl alcohol, and mercaptonenzothiazole. A witches brew of cleaning. I opted for using a jam nut also. I used red loctite again but this time I will let it cure  Attached Images
Reply:Did the little bugger stay fixed this time? It looks good!Matt
Reply:Originally Posted by farmersammAt this point I'd be trying to figure why it tore itself up in the first place.Is there a bad twist on the assembly it powers?  Something causing a bind, or rotation, as the ram extends and retracts? . . .
Reply:Originally Posted by denrepI'm with Samm, there shouldn't be much rotational force on the piston.The problem now is that if it happens again the lock-nut will drop off before the piston quits working and then the loose lock-nut may cause havoc when the piston or rod finds it. Three strikes, he's out. The nut gets welded to the rod.
Reply:I've thought about this for a while, looking back through and noticing how little cylinder shaft is left remaining after the jam nut is installed, I see only one positive solution. Since there is obviously some vibration or rotational force coming from something, I'd replace the jam nut with a castlelated nut and drill and cotter pin the cylinder shaft. Then main nut would be torqued to specifications, the castle nut would then be run down untill it contacts the main nut then tightened until the cotter pin would fit through the hole. Tack welding the nuts together may or may not prevent the nuts from backing off, but the cotter pin will prevent the castle nut from backing off which in turn prevents the main nut from backing off. I didnt want to drill the main nut because it would put the weak spot from drilling closer to the working area of the cylinder shaft and you want the maximum metal to metal surface area under that main nut. I doubt that the main nut can tighten itself beyond specifications untill the seal deteriates but it would probably bypass and need rebuilding way before that would happen. I know I probably thought way too much into this, lol, but I hate doing things over when it could be prevented.MAC WS1110 Mig WelderWoodworker HobbyistDelta 10" Table Saw, Delta Planer, Bosch and Craftsman Routers, 48" Craftsman Lathe, drill press, 1/2" hand and cordless drills, scroll saw, skill saws, jig saws, etc, and too many hand tools to list, lol