Homokinetic Joint Disassembly - 300SD W126 - PeachParts Mercedes-Benz Forum

Richard Howard · #1 01-26-2009, 02:37 PM

After searching and looking at many threads here on rear axles and their boots, I need to ask for information I've not found so far...

The rear axles on my 82 300SD W126 are the homokinetic type and still had the original boots in place as oil drained when I cut the boots off the shafts. I've decided to reuse these original joints as they're noise-free and apparently still have much of the factory heat-treated surfaces intact where the balls ride. After disassembly of the joints and a thorough cleaning of all the parts in mineral spirits, I plan to reassemble with four of the Astoria Flexx boots - chosen because of their supposedly extreme flexibility and durability. For lube, I plan to use the supplied molybdenum disulfide MoS2 grease; the boot kits appear to be from somewhere in the EU.

Question: How are these homokinetic joints taken apart? I've found no snap rings and when looking at the ends of an axle shaft itself I think I see the ends of splines where they enter the "three-arm" castings that contact the housing when the joint is flexed to its limit.

I've used a brass drift and hammer to try to drive the "three-arm" casting away from the shaft (secured in a large vise) but haven't had any success so far. Does this joint disassembly require the use of a press? I have one available.

Thanks for any information on this disassembly precedure...

nlines · #2 01-26-2009, 03:54 PM

I do not think it is easy to disassemble these axles. I have seen a video on Youtube I think, which shows how to use a funnel to help slip the boot over the joint. it seems to work good.

Diesel911 · #3 01-26-2009, 04:46 PM

I believe the FSM shows using a Hydraulic press to press them apart. I also believe it shows that you un-crimp the tapered part (the part where the Boot clamps to) of what I call the Cans and remove them to get inside.
They sell kits that have new Cans that you have to find a way to crimp over yourself.

I think you are going into near virgin territory. I only read one post where a member used a press to take apart their axle. Don't forget to post some pictures.

If it was me and I was dead set on reusing the Axles and re-botting them I would buy a gallon of solovent (like mechanics use) and a solovent sprayer (cheap at Harbor Freignt). I would leave the Axles intack a shove the solovent sprayer inside the Cans and spray out all of the old oil.
After the solovent has completely dried I would find someway to pack the grease up into where the balls are in the joint. After which I would do the re-booting.

I did the above to a Chevy Citation and put on a Split Boot over 10 years ago and that CV joint is still OK today.

I also believe that if you do take the Joint apart it is a good idea to keep the same Balls in the Same space that the came out of and both parts of the Joint indexed to same place the came aprt from.

Nashvillecat · #4 01-26-2009, 05:29 PM

I am facing the same situation with an 85 300SD. I was going to upgrade to the newer axles but could not find the stub axle to install on the differential so I decided to clean, grease and reboot the original homokinetic axles.

I so far have not been able to get the axles out of my car. They will not compress enough to clear the wheel bearing. Does anyone have any suggestions for this increasing the clearance?

Also I found a product by Dorman UNI-FIT and Multi-Fit that are supposed to allow installation of the boot without disassembly. Part number 614-040 and 614-050. Around $75 saw on their website.

Richard Howard · #5 01-26-2009, 07:19 PM

Nashvillecat: I had a tedious time getting the first axle out... intend to do one first, reinstall on the car, then do the other. I also had almost no clearance between the outer splined end of the axle and the wheel bearing's grease seal.

Finally after raising the differential slightly higher I was able to get the axle end past the seal, got it to clear by going towards the parking brake's cable jacket and not towards the spring. I did produce some distortion at several places on the outer "can's" lip, where the shaft contacts it at its limit of flex. I expect to be able to reform the lip with careful use of a small adjustable wrench or small ball pein hammer.

I did not disconnect the lower shock attachment but will do so before the reinstall - it may, as other threads indicate, allow a bit more drop of the swing arm to allow the splined end to get past the seal and enter the hub a little easier.

Maybe some of the more experienced people here will soon post information on the actual disassembly of the joint. If this procedure seems too questionable, I may then flush out the old lube as mentioned above with solvent and relube the parts. It would however be great to be able to disassemble only one joint on each axle and install both new boots without the use of the expensive stretching tool. I also don't look forward to using gorilla-tactics along with a quart or so of silicone spray to stretch the Flexx boot's small end over the joint's housing/can - it seems like it's beyond the laws of physics!

Diesel911 · #6 01-27-2009, 11:44 AM

Decided to look up some stuff in the FSM.
The big part of the "Can" on the Axle is called the Protective Sleeve and the the part of the Can that the Boot clamps onto is called Stop Sleeve.
In the FSM they show a tool to cut off (the crimp that holds it to gether) the Stop Sleeve. After the Stop Sleeve is cut off you can pull the Axle apart.

At this point with the FSM method of replacing the Boot you would put the Axle into a Hydraulic Press and press off the Spider from the Axle. Slide the new Boot on. Press the Spider back onto the Axle.
Of coures int is not necessary to press anything off if you have another way to expand the boot but if you want to take apart the Axle CV joint to take a look you need to cut off/remove the Stop Sleeve.
If you cut the Stop Sleeve Off you will need a new one and have to find some way to crimp it back on.

It maybe possible with a lot of careful work to uncrimp the old Stop Sleeve so that you can reuse it; but, i have not read anythig as to how to do this.

burford · #7 01-27-2009, 08:07 PM

Richard, These joints are big. Use twice the amount of grease. MB says use 310
grams I think. Anyway, I did this job with the flexx boots developed some noise after 3k miles, used more grease and no more problem.

waybomb · #8 01-27-2009, 08:17 PM

I cut my cans off when I needed to replace cracked boots and tig welded the new ones together. I ground the flange off, and welded. No need for special tools.

Diesel911 · #9 01-27-2009, 09:31 PM

Quote:

Originally Posted by waybomb

I cut my cans off when I needed to replace cracked boots and tig welded the new ones together. I ground the flange off, and welded. No need for special tools.

A Tig Welder; not a special tool???

I one of the Posts I read they crimped on the now Stop Sleeve with a Channel Locks.

waybomb · #10 01-27-2009, 09:37 PM

Ok, it is special, but can be used for many things. That's what I meant - not a dedicated one-use tool.

When I did the job, I though about using a pliers, but I was concerned about getting the crimp tight and consistent. The welder is always available, so, went and welded it together. For sure it will not leak nor come apart on its own.

Richard Howard · #11 01-27-2009, 10:08 PM

Diesel911, Burford, and Waybomb:

Thanks for the additional information, especially what the FSM says about cutting off the can from the heavier metal... sobering thoughts. The procedure demonstrated on the internet using a funnel and dishwashing liquid or similar for a lube to install a boot over the joint housing now looks more appealing than before.

Since I really want to use these original axles that have given noise-free operation and they just need fresh lube and new boots, I think I'll look for a suitable funnel to modify and try the brute force method of installing boots. I do have some doubt about the boot's small end passing over the joint housing... I may end up using boots that require adhesive to secure a lengthwise junction of the boot material, but that sure seems a way to get problems in the future.

Diesel911 · #12 01-28-2009, 12:58 AM

Quote:

Originally Posted by Richard Howard

Diesel911, Burford, and Waybomb:

Thanks for the additional information, especially what the FSM says about cutting off the can from the heavier metal... sobering thoughts. The procedure demonstrated on the internet using a funnel and dishwashing liquid or similar for a lube to install a boot over the joint housing now looks more appealing than before.

Since I really want to use these original axles that have given noise-free operation and they just need fresh lube and new boots, I think I'll look for a suitable funnel to modify and try the brute force method of installing boots. I do have some doubt about the boot's small end passing over the joint housing... I may end up using boots that require adhesive to secure a lengthwise junction of the boot material, but that sure seems a way to get problems in the future.

There are several thread on what boot will work with the funnel method and many threads on people looking for the Split Type Boots.

No one so far (including me) has been able to find a Split Boot that works on my 84 300D. I even was in contact with a person on Ebay who was selling them and the Seller checked his supplier and found no Split Boot for it. Still there is a possibility that there is one out there that will fit but so far no one has found one.

My understanding is that as long as you use the Flexx boot like the Utube video shows that the funnel method works. You might look up some threads and see which lube worked the best. Search the words Flexx Boot and I think you will find the threads.
However, I have never done this mself.

Richard Howard · #13 02-04-2009, 03:40 PM

More info to all those interested:

After finding a suitable funnel, I gave it a good try with the Flexx boot (part number FB3001) attempting to get the boot over the joint housing... In my opinion, there's no way this procedure will work with the homokinetic joint we have - the housing is just too large.

With some regret due to the cost, but still wanting to continue using the original factory joint/axle assemblies, I ordered the Flexx gun to use to install the four Flexx boots I have. It was 9 degrees in the garage here this morning, and UPS is not delivering in the area today because of the cold and ice on the roads, so maybe soon this phase of the W126 rehab will be completed.

TylerH860 · #14 02-04-2009, 03:50 PM

Trying to stay mature...

Diesel911 · #15 02-04-2009, 06:55 PM

Quote:

Originally Posted by Richard Howard

More info to all those interested:

After finding a suitable funnel, I gave it a good try with the Flexx boot (part number FB3001) attempting to get the boot over the joint housing... In my opinion, there's no way this procedure will work with the homokinetic joint we have - the housing is just too large.

With some regret due to the cost, but still wanting to continue using the original factory joint/axle assemblies, I ordered the Flexx gun to use to install the four Flexx boots I have. It was 9 degrees in the garage here this morning, and UPS is not delivering in the area today because of the cold and ice on the roads, so maybe soon this phase of the W126 rehab will be completed.

I hope you had the Boot and Axle somewhere where it was around 70 derees F when you attempted to install the Boot; I think they would stretch better when warm.