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AJK
09-16-2007 04:07:14
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Re: uh125 main boom seal weep in reply to Al Wickheim, 09-15-2007 21:34:07
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This is no job for anyone that is not used to working on heavy equipment and does not have the tools to do the job, If you had a manual for your machine and you looked up resealing the cylinder it would tell you to remove the complete cyl and place it on a cylinder overhaul bench, it is unlikely you will have access to one of them, I have resealed lots of cylinders on large excavators and when on site with no bench the best way to handle them is to have a second machine to do the lifting and to use the machine itself as a bench, stretch out the arm so it at its lowest, curl the bucket so the tilt pin of the bucket is about a foot from the ground, remove the tilt pin from the bucket, retract the bucket cylinder rod, there is no seals fitted to the cylinder barrel so its the rod you need to remove, support the boom cyl rod and drive the pin out of the rod eye, lower the rod down till its level and support it, push the rod out within a couple of inches of its stroke, attach a lifting strap to the rod either end with a running loop so it will tighten, undo the cylinder gland nut, you are going to lose oil from the cylinder when the rod comes out so be prepared to catch the oil, have the top cut off a large drum for this purpose, take the weight of the rod slightly, start the machine and feather the boom up lever and the rod will get pushed out of the cylinder, look at the nut retaining the piston on the rod, it may be a nyloc or it may be drilled with a pinch bolt, if its got a pinch bolt it may need a drill to remove the punch blurs but they usually screw out, use a proper fitting Allen key and undo it, there maybe a steel ball under the pinch bolt so look out for it, put the eye of the rod into the tilt links place on the bucket and put the pin through it, use wood and block up the rod just behind the piston, the rod is now held solid to undo the piston nut, I use a 60" pipe wrench with smooth jaws,(If you have a socket and torque multipliers use it) it is a std thread, put two light punch match marks on the nut and rod for reinstalling the nut, put on the wrench and undo the nut, if you do not have a socket and multipliers you will more than likely have to use the second machine to press down on the wrench to undo it as the nut is savage tight, when the nut is off note the way the piston fits and remove it, remove the gland nut, clean all the parts, when you order the seal kit make sure that the bearing that fits in the gland nut comes too, it is important to replace that bearing because when it is worn the seal will not last, care must be taken to press the bearing into the gland square and without damage or distorting it, fit all the seals make sure that they are facing the correct direction, keep everything clean including your hands, reassemble the rod and tighten the nut to the match mark, put in the pinch bolt and put a couple of punch marks to blur over the hole a little, slacken the two hoses on the cylinder, smear liquid soap over the piston seals and gland nut o"rings, put the rod back in the cylinder and tighten the gland nut and hoses, push the rod in and out a few times to expel air from the cylinder, put the rod back in place, put bucket tilt pin in, top up the hyd oil, job done.
AJ
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