It is good practice to use plenty of safety jacks when working under a car, they have saved my life before.
Please look over this pdf from the factory disk before reading any further, it should help you with terminalogy. One may ask if this pdf is dedicated to changing the boot, why bother to make a site too? Did that pdf make sense to you? It didn't to me, if it did go ahead and close this window right now and best of luck on your rebuild, otherwise read on. Maybe it was because in every step they were using some fancy special tool, well the most advanced tool you will need here is a 12ton or higher press. Most shops can probably help you out if you don't have one and don't plan on buying one. I actually bought one because of this, well my previous axle rebuild (for my 84), it was less than $100 from a local tool shop. Maybe before you think to seriously about doing this you should look to see how many of the required tools you have.
Well this one is probably the most complicated DIY I've created so far, it really isn't very hard but takes quite a noticeable amount of time and certain tools to do it successfully. Mercedes only intended the outer CV joint to be disassembled as that was the only one they made the tools for, however it really doesn't matter the way we are doing it. Yet I have found that the outside joint is easier to reassemble, whether coincedental or not. However by disassembling the outer joint you will surely have it clean from anything that may of got in there while the boot was torn. To be quite frank about this, this replacement only applies to people who have decided to change it before the boot has torn or people who discovered their boot has torn in the last thousand miles or less. (If there is ANY torsional play in the shaft go ahead and order yourself some rebuilt axles, don't waste your time taking this apart.) Mercedes used oil to lubricate the joints, and when the boot tears obviously the oil all drains out. So far all of my joints I've rebuilt have been at least moist when I rebuilt them, one was still dripping of oil it was so fresh. I stopped driving my car as soon as I noticed this, if you continue to drive without proper lubrication you wear the spyder down, creating slop, hence ruining the joint.
Without further delay let us begin, obviously the first real step will be uninstalling the axles from the car. If you have torn boots your of course doing these steps anyway. Being this is in every manual I don't go in much depth here, but I still have a few words to share and some pictures for thought. Suspend car, remove rear tires, remove fill & drain plugs (14mm), drain oil, loosen axle bolt on each side, support diff, remove all 4 frame to cover bolts, remove all of the cover to diff bolts (you will have to lower it to get to the top ones), remove cover, raise diff to max height (Notice angle jack is at to the diff, does one side have an advantage? Do that side first then! I rebuilt this axle then installed it, repositioned floor jack, and then uninstalled the other axle for rebuild.) Try your best to not pry on the joint to get it out, if you push it to hard you can mess up the internals of it (overextending it). The outer must be removed before the inner, as soon as the outer is free you should have the axle in your hands ready to rebuild.
Decide which side you want to tear apart, MB wants you to rebuild the outer, and just put a new boot on the inner. I have done both but it seemed easier to reassemble the outer than the inner. Regardless let's assume you choose the outer, odds are your outer boot hasn't failed, so take a screwdriver and pry the clamp open, then off. Slide the boot down, you have a boot full of oil so be careful not to spill. Drain the oil into your favorite recycling container. After the joint and the boot are all drained of oil, push the boot back up just to keep it clean. The next step is to look at the lip, find the middle, maybe a little above the middle. Carefully touch the angle grinder with a cutting blade down there. ***BE VERY CAREFUL HOW DEEP YOU GO*** The metal you are cutting through is like thicker sheet metal so don't expect a whole lot, also after you get through the metal you will hit a rubber ring. Ideally you WILL NOT go through this rubber ring. If you do go through, and you are in a bad spot you will ruin the joint. Take your time. The first time I went around with a screwdriver and pried the weakened metal open, on my third and fourth axles I had it down pat cutting perfect depth, but like previously stated, WATCH THE DEPTH!! Ok so we have finally made our way through the boot, go ahead and slide the 'cup' up and off. You will now see the 6 balls, the spyder and all of the tracks they lay in. As you can imagine we have to take this whole assembly apart, without further adieu....
Ok we are doing great now, here is where cleanliness starts to pay off. You want a nice clean area, preferably with some towels laid down so when the balls come loose they don't bounce away, or get damaged AT ALL. Turn the joint a little bit and pull at the same time, all of the balls just fell out. Make sure they stay clean, and you don't lose any. Look at the spyder now, is there a groove there where the ball has unevenly wore away? If yes how bad is it? A little we can gladly live with, a lot and well sorry but you just wasted your time. You drove to long on a unlubricated joint!! To be quite honest, even my factory sealed joint which was always lubricated had some wear in it, maybe even more than the joint that the boot tore on. Anyway the next step is to take a screw and screw it into the plastic cap at the end of the axle, just keep screwing until it begins to come out, ie the screw bottoms out and pushes the plastic out of the hole. Be careful with this piece, it does serve a purpose. Remove the screw from the plastic in the least evasive way you can think of, the plastic can and will break if you clamp down on it to hard. Ok so we are now looking at the spyder on an almost half empty shaft. As you can clearly see the spyder was pressed on from the factory, it will need to be pressed off. There isn't much if any chance you can get it off without a press, setup the press as pictured below.
Ok the spyder is off, excellent, let's remove both boots, drain the inner joint now, or if it was torn, we have to take some rubber freindly brake cleaner and try to get all contaminates out. Make sure to let it dry nicely before sealing it up. Ok you've waited a while and you know for a fact that the inside of the inner joint is 100.000% dry, so we can procede to start putting the grease in there. As stated in the pdf file you read a while ago you know that you should use approximately 230 grams, how convient, Febi supplied us with two tubes of 250 grams. Now I hate the idea of metal on metal, after all we just cleaned all of the oil out of the inner joint too. So your mission is to get as much grease as deep in there as possible, preferrably on each ball and its track. Go ahead and slide the boot (which you already made sure is perfectly clean) on the clean cup and clamp both ends with either the factory type of a squeeze clamp, or the one with a screw that febi gave you. If you use the screw one get it as tight as you can, make sure to use *RED* lock tite on it as well. We do not want this to come lose, I even distorted the threads a little too. You can align the clamps two different ways either exactly 180 degrees opposite of each other or aligned straight as the factory manual suggests.
Use the special clamping tool to tighten your mercedes style clamp or just a simple screw type clamp is fine here but if you do go this route, please use some red locktite to be sure it doesn't come off on accident. Ok slide on the new clamp, new boot, new seal, and new inner cup for the joint which we took apart. Now we have to get the spyder back on and start reassembling. I've found if you use a socket to fit in the middle so the spyder isn't risk damaging that you can beat it back on with a 2lb hammer, just make sure it is all the way back on like it was before. Carefully reinsert the plastic insert into the hole and reinstall the 6 balls. The first 5 aren't that bad but sometimes that 6th ball is fun.
Fill the joint up with as much grease as you can, the boot will always hold a little more than we can cleanly get in there so fill the whole joint up then put the new top seal and top can on. Slide the bottom can up to the top, the boot will help you out here by holding it in place for you while you start crimping. I found it easiest to start crimping with the vice grips, then I go to the channel locks to do most of it, then back to the vice grips for one last turn by hand. At this point it is looking pretty nice, but let's make it look and work proffessional, go ahead and stick that lip in the vice and go around like this in the vice several times until it is perfectly flat. Voila, now you just need to reinstall the half shaft and start with you other one.
After both axle shafts are rebuilt installation is pretty much the reverse of disassembly, remember to use blue locktite wherever the factory did. After this I went ahead and cleaned the cover up, put some Mobil 1 75W90 in there to help clean it out, I changed the fluid again about 5k miles later. It came out semi-dirty so the differential must be a bit cleaner now.
Supplies:
Terry Towels
Lock Tite, Red & Blue
Gear Oil (Mobil 1 75w90)
Tools:
AT LEAST:
12Ton Press
4" Vice (6")
large set of 1/2" Sockets (3/4")
set of 3/8" Sockets* (1/2")
4" Angle Grinder (4-1/2")
10" Vice Grips
14" Vice Grips
22" Channel Locks
3/8" Torque Wrench* (1/2")
2+ 3Ton Safety Jacks* (I used at least 2)
1 2.5 Ton Floor Jack* (I used 2 and a bottle, but you could function with just 1 floor)
18" Breaker Bar* (25")
Circlip Pliers* (inward pressure)
Nice to have:
~450ft/lb Impact Wrench
*- required for axle change.
Back