Repair BROKEN Hydraulic Cylinders for CAT D11 Dozer | Part 1 | Making a New Eye
hello how you going guys Kurtis from cutting edge engineering so for today's job we have two d11 ripper lift cylinder rods in for repair there's two of these on the back of a dozer used in tandem for lifting and lowering the ripper frames while it's in operation for digging the rippers in and then pull them back out of the ground once they finish their rip or their cut the issue we have with these two is they both off the same machine and they have both failed the first one failed they changed out the cylinder and within a couple of hours to my understanding the second one failed i found it very bizarre and unusual why they had both failed generally the eyes break off the rods but the eye has broken off one and the threaded part where the piston screws onto has broken on the other it's very uncommon for these to fail the way they did until we got them back to the workshop and we actually looked at both of them that we figured out why they both failed within a couple of hours of each other so it turns out that one of the cylinder rods has had an eye break off it at some stage of its life and it has been repaired which looks to be on the machine someone's just welded it back on it out in the field so it wasn't removed from the machine the cylinder disassembled and it repaired correctly someone hadn't taken a great deal of care when they were attaching the rod to the eye and they had damaged the chrome and you can clearly see there's a weld joint there after we worked that out it then said to me that maybe the rod is too long or too short which would have meant the two cylinders were fighting each other at its end strokes when the cylinders are in operation if one of the cylinders has been repaired and it is slightly shorter or longer than its partner what happens is one cylinder will stop once it reaches its end stroke and then the other cylinder will keep going until it reaches its end stroke or vice versa on the return or the push cycle of the cylinder and it is causing fatigue on the weakest point of the rod there's a relief machined into the threaded area there and that's where it has failed so over time fatigue has gotten to it because everything's starting to get kicked left or right or it's kinking or it's trying to push something into somewhere it doesn't belong over time they crack and then they break we do need to manufacture a new eye and two new rods but before we get into that we also have a seized nut on the end of the rod that holds the piston on i'd say it is seized on there because of the amount of forces that were applied to it and everything's been moving and everything's been stretched threads might have been rolled over so we do need to gas axe that nut off because we can't undo it the customer did have a go at it they couldn't get it i said look we're not going to spend any time doing it let's just cut it off it'll be cheaper in the long run the nuts already damaged and while i've got it apart i'll quickly put it back together throw a tape over it and we'll see whether this rod was too long or too short cool little fact about this particular crane this crane was the original one in the building it is mounted directly in the center of the workshop and it goes from one end to the other this is a i think it's a hitachi two ton hoist this crane was originally used for lifting helicopters from one side of the shed over to the other side of the shed been very handy that's why i put my press right in front of it right so we did perform a dye penetration test and it did reveal there is a crack forming in the same spot the other one broke so there you go i've sort of put the eye back together where the rod and the eye would be i have taken some measurements worked out a bit of an average and i believe this rod is about five mil longer than its partner which is the reason why everything failed the way it did five mil between two cylinders that are supposed to be a matching pair is a significant amount considering there's not that much slop in the pins and bushes to allow for that sort of discrepancy to be between the two cylinders so that's where it started and this was the end result of that one of the other signs that there was a problem here is there is a piece of chrome missing where it's been rubbing in the cylinder gland being that that damage is there on the rod i do believe we're going to find corresponding damage in the cylinder gland itself the rod has impacted the cylinder gland which sort of tells you one of them is longer than the other and we worked out the one missing the eye was the long one right so now that that's done we've got all that apart now we're going to get on to making a new eye piece of material we're going to be using is a piece of biz 80 so high tensile plate 110 mil by 250 mil in diameter it is a lot larger than what i needed it to be because this was sort of a bit of a surprise to us but it's all i have at the moment being that it's start of the new year and we didn't have anything ordered in for this job and being that it is only a round eye a piece of solid bar or a round bit of anything would be perfect for an eye so there's no weird shapes or contours to it so this will be fine but i do have a bit of work to do to this one so now i'm going to go set it up in my smallest lathe and start machining right so the piece of material is 250 mil in diameter i need to reduce it down to 210 not ideal to go and remove that much material but being that's all i have in stock at the moment that's going to have to work the smallest lathe that i have can't swing 250 over the carriage can only swing about 230 so i do have to sit here and work the face down and keep reducing it so i can get all the way up to the chuck the reason i don't pull it out and put it in my bigger machine is i've just finished cleaning that i've changed out all the coolant this machine's still really dirty so i don't want any of that rusty horrible dust and stuff going through a newly cleaned machine and the coolant's just been replaced so rather than dirty that up i'll dirty this one up deal with the little problem i've created for myself and moving forward will it fit we're good where is he righto guys now that we've completed the machining on the new eye we're now going to retrieve the good eye of the broken rod so we're going to go ahead and get that set up in the machine and start removing the eye just want to see if i've got clearance hang on a minute well there you go righto guys so that was a bit of a surprise i'd gone in to do my weld prep and i found i found a spigot which is very unusual it looked 100 percent genuine from the factory these rods and eyes are friction welded together someone did a really good job in blending everything and finishing off that rod so you couldn't actually tell it was a welded joint and that's why when you're doing stuff like this you should just take it easy when you're getting to your final sizes if i'd have been really hoeing into that and found that joint i could have damaged the machine or damage the tool something like that so just take it easy when you're getting into those final sizes so to be interesting now once we get the eye off to find out whether they put a spigot on the rod or they put a spigot on the eye definitely not genuine so after seeing the spigot and how it was attached to the rod this is 100 percent not a genuine part had me fooled i thought it looked pretty genuine to me this could be a factory remand part which would explain why it looked as good as it did so that's the eyes done stay tuned for part two where we're going to machine up the rods and fit the eyes go here come on it wasn't' even on straight now it's good so there's a relief machined into the area there into the end of the uh so one of the other tel tang tell right so now that we've got the alt uh done now now that so now now now that uh [ __ ] so now now i'm going to go set it up in the lathe and start chewing material off it [giggle] right so now i'm going to go set it up in our smallest machine [ __ ] off [squeak] [giggle] they do share oil oh who gives a [ __ ] [giggle] righto guys now [ __ ] bird [ __ ] off once the train [ __ ] off put them inside each other [giggle] spigot oh serious [giggle] you strong guy ah big guy can you imagine the [ __ ] damage that would do if it come hooking out of the machine it's going to hit oh dear [giggle] what are you recording me it's like hail [ __ ] not cold and sharp death hail [giggle] death hail jesus christ almighty i'll be back here oh my lord get on this side of me nah i'm the boss when you're not around i do what i want if Karen says it's okay on your bed go on on your bed on your bed hey good boy good boy lay down lay down good boy
2022-01-20 17:01
