Right rear wheel wobble - 64 230SL

[paul_GB]

Hi, when I was driving slowly in a queue recently someone stopped me to say I have a buckled rear right wheel. I’ve since had the car jacked up an spun the wheel and it does wobble significantly (seems about 7mm at the rim). I’ve tried 2 other ‘known straight’ wheels on that corner and they wobble too.. so a buckled wheel is ruled out. Looking at the inside of the wheel whilst the wheel is rotating I can see the brake drum is wobbling too. So my natural thought is the wheel bearings need changing. Although I’ve not heard the typical failing bearing noise.. it runs quiet. Could a failed bearing cause this type of wobble? Anyone seen similar on their Pagoda?

Thanks
Paul

[rwmastel]

Fascinating!  I can't wait to hear from knowledgeable people on this one!  My uneducated guess is that a wheel under load with bad bearings would just ride in the same "place" as the weight would force it to one spot in its sloppy mount.  But, a wobbly drum!  Can an axle/drum assembly bend?  Are you enough of a DIY'er to pull the rear axle out, given proper list of precautions and instructions?

[paul_GB]

I hear what your saying re a very sloppy bearing.. would expect the hub to settle and run in one worn plane. I’m thinking, can the half shafts become misshapen.. that might cause a wobble motion. It’s odd the bearings aren’t making a noise. I could pull the axle out if it comes to (I did before about 10 years ago).

I took a short iPhone video clip but the format isn’t accepted on this site. The movement is exactly like a buckled wheel.

[rwmastel]

I took a short iPhone video clip but the format isn’t accepted on this site.

Do you have a YouTube account?  I've found that to be handy to have for posting videos.  Just posting the YT link for any format or length video is easy.

[Cees Klumper]

It's also possible your driveshaft is bent ...

[rwmastel]

Why would that make one rear brake drum wobble when spun on jack stands?

[Mike Hughes]

. . . axle shaft?

[Cees Klumper]

Axle shaft / driveshaft same thing - if it is bent then it will act on the brake drum and move it in and out according to the degree of bend as it rotates.

My 2002 Volvo S80 had a front vibration under load / accelleration. I replaced the inner CV joint that was worn out but that was only a temporary fix - it was the driveshaft that was bent that was causing the vibration and the CV joint to wear out as a result. Once I replaced the entire driveshaft the problem was gone.

[stickandrudderman]

Almost certainly a bent half shaft.

[paul_GB]

An update .. I swapped the Alfin brake drums left to right and it made no difference. So today I dropped into the local classic car workshop who crawled all over the axle and they suspect the drive shaft (half shaft) end plate is probably damaged. So I need to try and get hold of a decent replacement.

I believe the RH drive shaft part no. is 1103571501 (for an early 230SL)..? or I could be wrong.

BUT my axle has studs in the shaft end plates for wheel nuts rather than threaded holes for bolts (which I’m led to believe my car should have). Guess I next need to find the axle pt no stamped somewhere on the casing. Thanks for your inputs guys..

[stickandrudderman]

BUT my axle has studs in the shaft end plates for wheel nuts rather than threaded holes for bolts (which I’m led to believe my car should have). Guess I next need to find the axle pt no stamped somewhere on the casing. Thanks for your inputs guys..

Well, that presents a whole different set of problems! Are all four wheels like that?

[paul_GB]

Hi Colin, Rear wheels are nuts, front wheels are bolts.

I’ve had the car jacked up to try getting some ref numbers off the rear axle to find out what the axle is from.

There’s what appears to be 110 357 0017 stamped on the inboard end of the right cast ‘sleeve’(the tube that houses the half shaft). On a tab attached to the middle back of the diff casing (next to the rubber cuff) is A019285. Stamped into the rear diff casing is 3/9. Pics attached. The car chassis no. is 113 042 22 006285 so quite an early 230.

[Benz Dr.]

Looks like a mystery axle. To my knowledge the 113 never used a 3.90 rear axle. Could be a 3.92 or a miss-mash of parts.

Axles with studs tend to be used on drum brakes and mostly on 50's or early 60's cars.

[paul_GB]

Just my luck I have an odd ball axle.

Yes, it has alfin drum brakes on the rear

[stickandrudderman]

Without seeing the car it's difficult to know what you've got. Someone may have simply inserted studs through the threaded holes of the half shafts, or they may have fitted different half shafts to the original axle or they may have swapped the whole axle.
If the latter I do have 230 rear axles in stock.

[paul_GB]

Thanks. I’m inclined to think it’s a bit of a mish-mash at best or probably a swapped back axle from a saloon based on the what I am finding. The axle has performed happily for the last 30’odd years. That said, I might consider changing it to a known w113 axle.

[Benz Dr.]

Common 230 axles are 4.08 and 3.75 so not much gained by changing from 3.90  All 230 axles had alfin brake drums similar to front 190SL so yours are correct.

[paul_GB]

Thanks. The diff ratio I’ve got feels fine and makes for comfortable driving (I’m used to it). Other than the ratio it seems the only obvious difference is I have wheel hub studs rather than threaded holes.