hey everyone i was hoping you guys could help me with a couple questions. i've been searching through these and other forums on advice for repacking leaking hydraulic cylinders, but havn't been able to find answers to all my questions. 1. i want to repack my dipper cylinder. the cap screw torque specs say its to be torqued to 1800 ftlbs. i am also assuming it has 242 locktight on it. i have a torque mulitplier but it maxes out at 1200 ftlbs so i dont think it will be able to handle the job. i've read a 1" impact wrench works well for removing cap screws. so my question is what should i look for in an impact wrench? would its max torque have to exceed whatever 1800lbs + locktite equals? 2. what do people do to tighten the cap screws back on to the right torque specs? i've read stories of how 10' cheater bars and other heavy equipment have been used to loosen things, but what about putting it back together? i really appreciate any answers or general advice anyone has to offer :drinkup. i'm still very new to working on heavy equipment but i am leaning alot thanks to these forums. :notworthy thanks everyone.
repacking cylinders I learned a long time ago, if its a big cylinder (bigger than you can carry) take it too a hydraulic shop. The last one I did, it was about a 10" cylinder and I worked 6 hrs getting the gland nut out of the cylinder. It took me about 6 more hours to get it back together, the thread on the gland nut was mess up Its pretty simple too repack them, but that gland/barrel can be a problem and without the special tools, you are taking a big chance. It leaked from the time I installed it to when I sold the machine. We had to man handle everything and I guess we cut a seal going back together. if I had paid the hydraulic shop the $300-400 it would have had a warranty and I would be out of 10 hours in the hot sun. I also found that the local hydraulic shops are cheaper on the seal kits, when compared to dealers packing kits. When I refer to hydraulic shops, I mean shops that deal with hydraulic repair, not places like Cat, JD, Case, etc. In some cases they take cylinders to the hydraulics shop and get them to rebuild them, you just dont know it Just my 2 cents worth Good Luck
I agree with Willis 100% if it's a large cyl and hard to handle just take it in it's not worth the hassle to spend 6-8hrs and lots of cussing words over,my LHS charges $90 hr plus seals witch works out to about $100-200 per repack and IMO that's no problem to get the job done right and right away.
What kind of cylinder are you doing?
they make a 10-1 mulitipler..that will get you where you need to be,,,,i have done cat 345 dipper in field...pc400lc-6 and 8...it can be done.....make sur holes r tapped out..
its the dipper cylinder on a case 580e. i think the cylinder may be 5 or 6 inch diameter. definitely no where near as large as a cat 345 . in the end i'll probably end up in the local hydraulic shop. its just i already have a seal kit, have loosened the gland and would hate to let an excuse to buy a new tool go to waste . at times i think i have more fun working on the tractor than working in it. looks like ebay has some cheap import impact wrenches that claim to put out 1800 ft lbs max torque for around $250 or so shipped. would somthing like that work or am i still better off letting a pro repack it? how important is it to accurately torque these cap screws? is it safe to guess whatever means used to loosen would be good enough to tighten? thanks for the input so far guys. i'd love to hear any other thoughts.
I have a couple of 1" impacts and I find myself going back to my 1" bar, 6-point socket, and a long pipe. My Williams bar has long since broke, from bending too many times so I welded a piece of trans shaft on it. That has helped a lot but still a little heat is often required to soften the lock-tite, if previously used. Many backyard mechanics don't have the proper tools and rely on brute strength of some kind. I don't think the proper torque is ever applied to some of these rod bolts on reassembly and every once in a while I come across a loose one. I think some just get it as tight as they can, after using locktite, but of course there is always the risk down the road. Also a good way to get hurt. I had a pipe slip once while tightening a scraper cutting edge and hit me in the gut. I thought I was going to die, could not breathe at all. Phil
Firstly, where did you get the torque spec from? I can tell you now it won't be 1800 ft/lbs for the head bolt cap screws. Are you sure your not getting confused with the nut that on the piston? A 10.9 grade M30 bolt which is 50mm across the flats has a standard torque spec of about 1800 ft/lbs. For component torque specifications I recommend you follow the manufacturer specifications not the standard cap screw, nuts and bolts specifications. Same goes for the type of lubricant. I would imagine though the head cap screws require Loctite nickel anti-seize and the piston nut requires Loctite 242. In regards to your question about the impact wrench, yes it would have to exceed the torque specification due to the additional force required to break the threadlock compound. Loctite recommend that you apply heat before removal if you encounter trouble, obviously though this is situational and in some cases is not possible. Another thing to note is that the performance of your air compressor has a major role to play in being able to deliver the maximum breakaway torque your impact wrench can handle. They usually give you an air flow spec, so check first. A torque wrench will be fine for the head cap screws. Generally for the piston nut a mechanical torque multiplier is used. I strongly recommend you torque them to the required spec and not use the FT method. Not a problem, we enjoy helping, thats what we're here for. Let us know how ya go!
Chris - wrecd has a backhoe built in mid 80's - not a 30ton excavator! they dont have head cap screws - but does have a bolt holding the cyl piston which needs 1 7/8" inch drive socket & 10' pipe after heating the head to a dull red & an almighty grunt from a 130kg monkey...... Done dozens of 'em mate
I never said anything about a 30 ton excavator! They must have got either a bolt or cap screw to hold the head on which is what I assumed he meant by the cap screw comment.
you guys are the best! i'm glad i asked here before i started buying stuff. i got it from my service manual, you are right i had it confused with the nut on the piston. i was calling it a cap screw from the picture in my manual. i didnt know cap screws were something else srry for the confusion. thanks for the tip on the air compressor Chris5500. doesnt look like mine would be able to power a big enough impact wrench. i think i might try alrman's method, a big breaker bar and heat. if you guys think these two tools would work i might try the job myself. http://www.northerntool.com/shop/tools/product_200328359_200328359 http://www.northerntool.com/shop/tools/product_200315001_200315001 thanks for all your help and patience everyone :drinkup
Well if you have the glan nut loose aready i think your half way there! so i say keep going!! I think someone here said it has a 1 7/8" nut, so if you have one and a 1" or 3/4" drive socket and bar thats all you ll really need! Also if you like buying new tools (that you will only us once in a while like me) check out these spanners i got from MSC J&L for opening glan nuts, got a few different sizes great job. Also some where on this forum, i think someone posted a thread with step by step how to repack cylinder on a case 580! search for it, it may help you out! CPS
Wrecd....you must mean the bolt that holds the piston on...yes that in fact is 1800ft lbs. of torque...$250.00 bucks is a good deal i say buy it and do it your self....dipper on backho is a can do job...good luck...242 loctite i ok don't cover the threads just a small bead on one side...
My breaker bar :drinkup I also used the oxy to heat the bolt head and break the loctite bond, before using the breaker bar. Whoever did the last lot of cylinder rebuilds on my machine, must have been applying the loctite with a shot glass! (These stabilizer piston bolts are 1 1/4"UNF)
:iagree Don't forget to clean the threads of the bolt and threads inside rod before installing bolt with loctite. I just use starting fluid and compressed air to clean oils from threads. If your kinda new to doing cylinders, one thing I haven't seen anyone mention is the piston ring. Sometimes you run across a Urethane or Teflon piston ring. You usually have to stretch the piston ring somewhat to install it on the piston, and urethane and teflon rings don't like to return to their original diameter once stretched. A trick I do is heat the piston and piston ring in warm water on a hot plate, heating the two helps the ring to stretch easily when installing on piston. Once installed, I take an automotive type piston ring compressor, fit it over the piston and piston seal, and tighten the ring compressor to compress the piston ring. Then I chunk the assembly in the freezer to cool the piston and piston seal. Makes a nice compressed piston seal.
why to go dude......
Looks abit like mine to Ando:drinkup
Hi, I'll add my 2 cents, anytime I had repack a cylinder on the Case machines I always heated the head up on that bolt, you don't have to cherry the whole head of the bolt. You just get the center alittle cherry and then let it cool for about 2 minutes. Then you get your 3/4 or 1' gun and whiz it out, works every time. LETTING IT COOL for those 2 minutes is the trick!
thanks for all the help guys. i chickened out a little and repacked my less leaky boom lift cylinder. i though it might be better to cut my teeth on a smaller cylinder first. following all your tips made the job go smoothly. :drinkup i have the cylinder back on the tractor and it is working great with no leaks! i'll be repacking most of the other cylinders too. thanks again everyone for being so generous with your knowledge and experience. :usa
Looks new like you painted it?
Good Job, Another tip,treat your all you cylinders like gold. Spicifically your Stabilizers, those tend to get abused, the rods get bent for one, number two most common problem, Denting them, one dent can cause you to have to replace the whole cylinder so be nice to them.
yep, its new paint. i picked up a few gallons of cat yellow for $5 a gallon at a local sherwin williams. the sales guy said it had been on the shelf for years and he just wanted it out of the way. i have the engine panels prepped for the spray booth today. i like the case yellow better but for the price my hoe will be sporting cat yellow for a while.
i'll definitely be taking that advice. when i first got my hoe i sorta had the idea these machines were near indestructible. later i found it's not that hard to break stuff (at least on my hoe). :bash
You can add a few drops of black and get the Case Yellow. Just use a small amount first to get ratio that matches. then mix away.
Cheater Pipes This thread has got a lot of great tips in it. I read this before we repacked a couple of big tilt cylinders on our Dresser. Here's a tip you probably already know... Our piston nut was to be tightened to 1500 to 1550 ft/lbs. If your using a cheater pipe here's a quick way to find out how to tighten to proper spec rofessor Torque = Force x Distance If you apply 200 lbs (Force) on the end of a cheater pipe thats 10' (Distance) you're putting out 2000 ft/lbs of Torque. If you need to know where to grab the pipe to apply your force, use this: Distance = Torque/Force So if you need to torque at 1550 ft/lbs. Take 1550 and divide by 200 (Force). This will give you the distance you need to apply force = 7.75 feet from the nut. This should give you 1550 ft/lbs.
Sorry, meant to say ft lbs not ft/lbs. That's what I get for trying to be smart :duh
Thanks to Boone this is an old thread, but have to say thanks to Boone for stating the obvious. Instead of buying an expensive tool, I can just hang my 200 lbs at the right point on a 10 foot pipe.
If you want to get real fussy you would need to factor in the weight of the pipe too! Let's see schedule 40 2 inch pipe is 3.65 pounds per foot so a 10 foot section would be 36.5 lbs. Have to average the force over the 10 feet so that comes out to 18.25 pounds of torque applied just by the weight of the pipe alone so better move that 200 lbs a couple inches closer to the nut! Also be sure to apply the weight nice and smooth no bouncing as the inertia will throw things off even worse!