Axle Shaft Inside Boot

[DerFuror]

I've discovered the right inner axle shaft boot next to the differential is cracked & getting things messy underneath. I see there is a repair kit (A1243500737), but this kit includes more items than I think I really need, & I believe this kit also applies to a removed axle shaft.

Can anyone confirm if there is just a replacement split boot to install in situ & what it's part number is?

TIA.

Inner_Boot_02.jpeg.jpg

[JC220]

I've discovered the right inner axle shaft boot next to the differential is cracked & getting things messy underneath. I see there is a repair kit (A1243500737), but this kit includes more items than I think I really need, & I believe this kit also applies to a removed axle shaft.

Can anyone confirm if there is just a replacement split boot to install in situ & what it's part number is?

TIA.

Split CV Boots are generally an aftermarket item only – and not recommended IMO. The MB Boot Kit will contain the necessary bolts etc to enable replacement of the boot which will require taking the axle shaft out. Or at the least you need to get the inner joint unbolted and away from the Diff. There is a circlip under a steel plate which will allow the inner CV joint to come off the shaft – then the new boot(s) can be slid into place. By undoing the one outer nut and hitting the shaft a smack the whole shaft will come out to work at it on a bench. Don't drive it until fixed as road dirt or water will quickly ruin the CV Joint.

I would order the other end boot too when you are at it since it all has to come apart.

[doolar]

Split CV Boots are generally an aftermarket item only – and not recommended IMO. The MB Boot Kit will contain the necessary bolts etc to enable replacement of the boot which will require taking the axle shaft out. Or at the least you need to get the inner joint unbolted and away from the Diff. There is a circlip under a steel plate which will allow the inner CV joint to come off the shaft – then the new boot(s) can be slid into place. By undoing the one outer nut and hitting the shaft a smack the whole shaft will come out to work at it on a bench. Don't drive it until fixed as road dirt or water will quickly ruin the CV Joint.

I would order the other end boot too when you are at it since it all has to come apart.

I recently removed and replaced an axle. Not a hard thing to do. You'll need apart from tools and bit, a torque wrench that goes to 70 Nm (for the 6 bolts at the diff end) and one (or the same wrench) that goes to 240 Nm for the nut at the outer shaft. New bolts and shaft nut are included in the kit.

I would not recommend replacing the boot with just the inner shaft part loose. It sure is tight in there, especially on the left side where the exhaust runs.

And I agree with JC220 on the split boots. They will not last the 20+ years that the original ones do. I also think you should get both boots when you do this job. Not fun to have to remove the axle again next year or so.

Maybe this is a thing that will start to happen to our cars now at this age, and should be added to the GVZ $5(6?,7?)k list of fun to do when you buy a 034/036?

[sheward]

I have two kits for a 400E, part A 124 350 08 37. Does anyone know what the difference between 034 and 036 is if any?

Drew

[doolar]

I have two kits for a 400E, part A 124 350 08 37. Does anyone know what the difference between 034 and 036 is if any?

Drew

Shaft diameter, the E500E have larger diameter shafts than the 400E.

[sheward]

Thank you!

Drew

[gsxr]

Minor clarification: The ASR shafts are larger diameter (32mm) than non-ASR (25mm). So, an 034 with optional ASR will use the same boot/shaft as the 036; however an 034 without ASR does use a different shaft/boot.

124-350-07-37 is for ASR, 32mm shaft, inner boot at the differential
124-350-08-37 is for non-ASR, 25mm shaft, inner boot at the differential <--what Drew has, won't fit 036

Interestingly, some very late production cars (i.e., produced after March 1995, approximately) use different boots. There's a note in the EPC with a VIN break, and also a note to measure the clamp width. If the clamp width is 9mm the "early" boot should be used, if the clamp width is 7mm the "late" boot is specified. The same applies to the outer boots, which are completely different part numbers.

I've never done this job, but I've heard that boot replacement is not fun. Another options would be to replace the entire axle shaft with a good used one, since they are rare failures (in USA), used axles are generally cheap and easily available. New axles aren't cheap, and be careful with rebuilt, if it's not an OEM rebuild (GKN/Löbro) stay away.

[nocfn]

Pretty much the same theory on the 126, new axels are relatively cheap and the labor is the same. New axel means old removal, same as oem boot replacement....just sayin.

[doolar]

Yea that’s the route I’m taking for my 034, used axles from SL500, and in the process getting the larger diameter ones for my non-ASR car. They are usually in better condition in Sweden due to generally lower miles and little or no winter driving. I’ll clean and re-grease them, replace boots only if it is necessary.

New axles are not cheap for our cars. For my 034 it is €1200 for one.

Thanks for clarifying on ASR vs. non-ASR Dave.

[doolar]

Thank you!

Drew

The kit you have will probably fit a lot of R129’s if you want to sell them on, since one kit is around €100. I found out that the axle diameter varies seemingly random for the R129’s. I found V12 cars with the smaller axles, as well as V8 ones with ASR and small axles, without ASR and big axles, and the other way around. The shaft I bought came off a SL500 without ASR, and it was the thicker axle.

For the 036 it’s strict bigger diameter axles, ASR is of course standard. For 034 it depends on the ASR option. The 034 axles are off the shelf R129 parts, I would suspect it’s the same for the 036, but I haven’t checked and confirmed that.

Dave do you know perhaps?

[DerFuror]

Thanks for the feedback. Driving season is over & the car is officially in the garage. This torn boot is certainly not a condition to defer. I'll proceed with shaft removal & inspection after completing my planned brake work first. In the meantime, I'll compile the necessary WIS sheets & initial parts lists for the overall job.

Yee-ha!

[gsxr]

For the 036 it’s strict bigger diameter axles, ASR is of course standard. For 034 it depends on the ASR option. The 034 axles are off the shelf R129 parts, I would suspect it’s the same for the 036, but I haven’t checked and confirmed that. Dave do you know perhaps?

The ASR axles for 034/036 are p/n 124-350-87-10 and the EPC shows these only fitting the 129.066, with optional ASR.

The non-ASR axles for 124.034 are p/n 129-350-27-10 and again, the EPC shows these only fitting the 129.066, without ASR, which was optional on the 129.066 chassis.

Note the 129.066 is the early 500SL with mechanical injection and tall-deck 119.960 engine, offered as 1990-1992 model years in USA. 1993-up has completely different engine, differential, axles, etc.

[samiam44]

I just noticed this- Besides the MB part number kit, you can buy the boot kit from Lobro/GKN the oe manufacture. They run ~ $10 each. I believe, except for shaft length- this is the same as the Porsche 928. I ordered up some Oetinker clamps for the boots. Grease there are many options. Meissmitt, Lobro, Redline, MB. The inner joint is replaceable, the outer is welded on the shaft(just like the early 928's).
There are 2 or 3 tool options for the clamps. They need to be quite tight.

Did you sucessfully reboot and grease the joints?

M

[samiam44]

I think they are 190969 pn.

[Trae]

Well. . . after inspecting the 90 SEC, I found the inner axle boot to be MISSING.

EPC says new axle is Part No.: 126-350-64-10
AXLE SHAFT
Replaced by: 126-350-45-01 for $421.80.

There is a repair kit A 126 350 08 37.

I don't know how long it has been this way. . .may have water/road grime exposure.

What do the experts here suggest?

[nocfn]

Trae - I think the repair kit allows you to keep the axel installed. Maybe thats only the aftermarket, where the boot is split, and a chemical reaction closes and seals the rubber. But you need to inspect for wear prior to packing it and sealing.

Uncle Kent back in the day removes both and switches sides, maybe have a look for that.

[Trae]

I need to make sure that the area has not been contaminated with anything before I seal it if I go that route.

There is NO inner boot to inspect, it is completely GONE, nada, kaput, however, the car drives great and does not klunk or make any unusual sounds.

[nocfn]

I was referring to damage visible due to missing boot.

[samiam44]

I think the issue besides damage, is getting the joint clean. I personally am nearly 99% positive you can buy a new joint for <$100 from GKN/LOBRO. If you look at 928's on the net- you can replace the inner joint and boot without removing the axle. Guessing the 126 will be the same. I'd personally get a used axle, clean and get them ready- R&R.
The kits were just boots +clamps + grease.

[Trae]

found a 1990 560SEL donor car and had the axle replaced.

[nocfn]

looking forward to buying your spare! I will send a the shipping label when you are ready.