one of the bearings i got came in a dodge box, it's the self aligning one that's on the feed chute side of the disk. it was the much more expensive bearing. The other was just a standard bearing. there isn't room on the feed side to fit a standard bearing, that's why they used this smaller one. it's also partially cut down to be able to fit.
For anybody attempting this job, here are some tips in no particular order;
blow off your chipper before attempting the job and give it a wash down too. spray all the bolts with penetrating oil a few days beforehand, it'll make the job go easier.
You start by removing the drive belt cover, slacking off the engine and hydraulic pump and removing all the drive belts. Remove the discharge chute (it's heavy!) and the top half of the disk box. Moving the fuel tank makes removal of the drive pulley on the disk shaft a lot easier, so try to make sure you don't go filling the tank up just before attempting the job. The pulleys are taper lock; you break the lock by taking the three bolts out and inserting them into the 3 empty holes, then gradually tighten them up until it pops. The taper lock itself can be taken off the shaft by driving a large flathead screwdriver into the wedge cut in the taper with a mallet. You need to open it up quite a lot before it will slide off. Jack up the feed rollers and fit the safety locking pin. Remove the blades and anvil.
The bolts on the discharge side of the disk should come out easy. The bolts on the feed side are the ones exposed to weather and will often be sheared or seized. Try a small amount of heat on them in case someone used loctite. if you are lucky the previous assembly used anti sieze and they come out easy. Do not apply excess heat to the bolts, you will only harden them.
I lifted my disk out using ropes, pulleys and a block and tackle. Sling in the hole where the blades sit, rope tied to a very stout branch then down to a pulley on the sling for a 2:1, back up to a branch to another pulley, then into the tree to a third pulley, back down to the base of the tree for a redirect pulley, then attached to a 1 tonne chain block connected to a heavy truck. If you've got a crane, or a well built garage with beams that will hold the weight your set. an engine hoist won't lift high enough.
Once you've lifted the disk up enough you can either drive the chipper out or work on it suspended. Driving out is the safer option.
Getting the old bearings off will generally require cutting them off. It's an easy thing with an oxy, but don't try it unless you know how to cut bearings off, there is a trick to it and you don't want to have your first attempt on the very expensive shaft. If you don't have an oxy or have not tried cutting bearings out before then you can do it with a grinder and cutting disk. cut carefully and slowly, don't try to cut the whole thing in one go. Cut through the housing on both sides and break it off, then cut through the outer race on two sides and break that off, then very carefully cut the inner race. You can cut it almost all the way through then crack it with a cold chisel to not damage the shaft. The infeed side bearing has one or more spacer rings which align the disk. do not cut the spacer rings you will need them for reassembly later. They locate the disk in relation to the anvil. Without them the disk will be too close to the anvil. Keep the extended grease nipple hose off the discharge side bearing to use again on the new bearing.
The shaft will need cleaning up with emery tape, 80~120 grit is fine and you may need a mill bastard file to put a chamfer on the end. Wipe down with solvent, then test fit the new bearing. If it wont go on try twisting it as you slide it on. do not use more than your hands, no hammers here. If it won't go on, work the shaft with the emery tape again. Once you get a nice slide fit, apply anti seize and fit the infeed side bearing and tighten it up. Do not tighten the grub screw on the discharge side bearing yet.
If you have infeed bearing bolts seized or sheared (you probably do) then your life is about to get less pleasant. If they've been seized a long time penetrating oil, heat and easy outs aren't going to cut the mustard. You also can't get a drill straight on to the hole, so heli coils require cutting the mounting plates out and re-welding them which is a major job and not to be undertaken lightly. Your best bet is to start drilling them out. The top 2 bolts are through-bolts and go into the disk housing, the bottom two are blind. If it's the top two, then you're in luck; they're easier to get out. Start from the inside, and centre punch the bolt. Take your time and centre punch it exactly in the centre. Now, using a brand new 1/8" bit in a right angle drill or adapter, very carefully line up your drill to be straight in all planes. Take your time here and get someone to watch/guide you if needed. If you get that first hole out of straight or off centre then your life will be in jeopardy! Drill it straight and take great care not to snap the bit off in the hole. Have a few brand new 1/8" bits on hand, it's tricky enough to drill a hole at a right angle as it is; no need to make it harder by using a blunt bit.
Apply penetrating lube, and step up to 1/4" and drill again. Use the lowest speed setting on your drill. A drill with a gearbox will be a great aid, or a cordless dewalt with a 3 speed box or similar. Apply lube and step up to 3/8, then 1/2". At that size, the bolt may well come out with use of a punch to turn it, particularly if it's not too badly seized. Do not drill a larger hole if you are off centre - you will damage the threads of the hole. If you have drilled off centre, or you've got to a 1/2" and the bolt still won't budge then you'll have to change to a dremel with stones and burrs. Go slow, use good lighting so you can see what's going on. Ream the bolt out further until you can collapse it. If you're losing patience, put the job aside and come back to it later. It's going to take time.
Once you've got the bolts out, re-cut the holes with a tap. The size is 5/8"UNC. Get a bottoming tap if you can, it will make the blind holes easier to cut. Not many shops carry bottoming taps, so order ahead of time. You may also like to pick up all new bolts for the chute etc ahead of time, and washers to go with them. Yours are probably already flogged out.
I chose replacement high tensile bolts that were oversized, so they had an unthreaded portion the same length as the thickness of the bearing mount holes. This makes the bolts act more as dowels which helps. I had to cut the thread to length and re cut the threads to make them tidy at the end, but it's worth the small extra effort. Get bolts in both bearings to line everything up, but tighten the infeed side bearing first, then check the anvil clearance. Finally, slide the discharge side bearing hard up, bolt it down tight, then tighten the grub screw. If you tap the grab screw with a light ball peen hammer you can tighten it just that little bit more.
Allow yourself two days, and have one other person to give you a hand. Be sure and pickup your bearings, bolts, anti seize, penetrating oil and a 5/8" tap well ahead of time. You can easily get the job done in a day if all goes well, but allow extra time especially if you live far from stores or if you'll be working on a weekend when stores are not open.
Re-assembly is pretty straightforward. Use anti seize on everything. Replace worn bolts, and this is also a good time to lube up the rotating section of the discharge chute. If it's rusted out give it a rub back and apply grease. You may also like to replace your drive belts if they are worn/slipping.
Job done, have a beer.
![IMG_0098[1].JPG](https://cdn.imagearchive.com/arboristsite/data/attachments/6/6357-a43e46e6ad3699bd1e35ee882fac9d30.jpg "IMG_0098[1].JPG")
