Repair BROKEN Hydraulic Cylinders for CAT D11 Dozer Part 1 Making a New Eye

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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

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