Today I was at the dealership looking at a 1998 with 5k hours, 753. It has been a one owner machine and while it has been used it looks to be maintained. The previous owner used it for breaking concrete and the front tilt ram on the quick attach side has a lot of free play, over 1/2"and most of it appears to be in the actual ram. The bushing is still present, and it appears if the hole has been egg shaped. The lead mechanic said that it definately was way to loose but that is what you get when it is used to break concrete. He recommended putting a new cylinder in the ram. Is there a easier way to fix this problem. Anybody have any ideas?
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As Luthor said, they are repairable it just takes a bit of work.
You will need to remove the ram and plug the usual things, hoses and ram plugs (remove the oil from the ram before working on it) You will need to bore out the hole at the back of the ram and maybee the end where it joins to the bobtach. Bronze is good, but on the one i'm doing at the moment i am making hardened pins and bushings, but bronze is a cheap easy alternative. When you re-bush it, make sure you give it new pins too, these will also be worn. Keep the grease up to them and they should last you a fair while. Make sure you put a groove around the bush and drill some holes so the grease can get to the pin before you push the sleeve into the ram. I can post pictures of what i mean if it doesn't make sense, as i'm currently making pins and bushes for mine.
Aluminiun nickle bronze is not a cheap alternative, it is in fact a very expensive material which is highly suited to heavily loaded slow moving applications and as long as the grease is kept up to it, will last a very long time.
The dealer said that the rod end ram is only a couple of hundred dollars. Would it be cheaper to just replace the ram? I really like the idea of a bronze bushing, however I do not have a lathe to make one with and I bet a machione shope would charge me 2 hours plus supplies to make a new bushing and pin pobably at 80 bucks an hour??
sterlclan
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I have seen some bushings made to fix out of round holes if I can find the company name Ill get it to you Jeff
That would be great, I would appreciate the help.
skidsteer.ca
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Just get a machine shop to make a new end for the cylinder ram. Cut of the old one and weld it on. I've had a local machine shop make me new chromes shafts for cylinders at times, and we have always cut the old end off and welded it to the the new shaft. Should be less then getting a new ram from bobcat. Ken
Does the ram need to be removed from the cylinder when it is welded on?
You could get away with not removing it. Remove all the oil you can from the cylinder by pushing the stick in and out from end to end, this should get 99% of the oil out. When it is being welded pull the stick all the way out, to keep the piston/seals away from the heat, leave it like that untill it cools. I doubt you will get enough heat into it to turn the oil to carbon.
Honestly, for the price i would replace the seals, they are cheap and they will stop the bobtach creaping down which i'm sure it would after its hard life. This way you can clean the cylinder out before and after welding and peace of mind that there is no junk inside the cylinder.
skidsteer.ca
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Generally we keep the chrome shaft cool by wraping a wet rag around it as a heat sink, may need to keep wetting it as you weld. Also keeps weld splatter from sticking to the chrome and ruining the smooth surface where the seal runs. It would be a good tim to repack the cylinder as well but this is up to you. To test the internal seals for leakage... Hook your air compressor to the cylinder port that retracts the rod, plug the port that extends the cylinder. Put the pressure to it. It will retract, if the seals are perfect it will stay retracted. If the are worn and bypassing it will retract and then in a few seconds to a minute it will begin to extend again. If it does the internal seals are leaking, the sooner it comes back out the worse the leak, (it does this becasue the surface area on the extend side of the cylinder is greater then the piston area on the retract side, (by the area of the crome shaft diameter))and the sooner you bucket will dump without you touching the tilt pedal. Ken
True, you must keep ALL weld spatter off the chrome bar, i used an old cardboard cylinder and cut it down the side to slip over the bar to protect it. As for heat, i have been told that if you get it hot not to quench it but to let it cool on its own. For the purpose of a ram rod i can't see any problems quenching it as you weld, as chilling it can harden the metal which for this is not a bad thing. Either way, the people at the machine shop that will be doing the work will know what their doing (well i hope they do!).
The only problem i can see, is when you get the new parts welded on is they must be straight! when i did mine, i had the ram attached to the machine and welded the rod to the pivot point while it was still attached to the bobtach. This way its in perfect allignment! I saw the bobtach on a block of wood and extended the chrome bar untill it was where i needed it, covered the rod and proceeded to lay a nice weld to it. Make sure the person thats welding it knows NOT to run the weld up the stick, as there is not much room between the eye on the end of the stick and the gland nut on the ram, you don't want it rippng your wiper seal apart when you pull the ram back! I had a 4 in one like that, a big ugly weld that went too far down and tore the top off the gland nut and killed the wiper seal.
skidsteer.ca
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I've usually let the machine shop weld these, as you have to be careful to weld equal amounts around the shaft , so that the weld "pulls" equal amounts and you end up with a rod end that is purpendicular to the ram centerline. But if you you "screw up" just cut it off and try again. Generally I try not to get the chrome to hot. Just weld one pass and let it sit for a few minutes. I don't usually at much extra water right after weld, but dampen the rag again each time before I start, after it has had say five mins to cool. I've only done a few times , but have never had one I felt i needed to remove. Ken
I spoke to a friend of mine that is a fitter and turner, i told him about the one i did and he said no no, do it this way!.
His way is to get the chrome bar and grind the top and bottominto like a flat chistle point, basically giving you room to weld the bar all the way through. Weld the top, then the bottom avoiding getting it too hot. Keep layering on welds untill you get to the top. This way the bar is attached to the eye all they way through from the centre of the stick outwards making it extriemly strong. The way i did mine was to weld around the outside and it worked fine for my work, i don't punnish it. He said if you have any air pockets in the way i did it, they will crack and continue around untill it breaks off.
The main problem is the tilt ram fully retracted doesn't leae you much room to do it that way. I'm sure who ever does it will do a good job.