Greetings and happy new year.

I believe I have a noise which is due to a bad front wheel bearing on my '85 300TD. From what I have found in researching on the web shows that the disc needs to be separated from the hub when replacing the bearings. I'm wondering if that is indeed necessary. The rotors are ok at this time so I'd rather not mess with cranking on those rusty bolts that couple them to the hubs if I don't need to.

Can anyone confirm that the bearings and seals can be replaced without separating the rotors from the hubs?

Appreciated,

Jeff

In order to change the front bearings you need to detach the Calipers from the Steering Knuckle and hang them so they do not hang on the Hose. Then you remove the Hub from the Axle and the disc itself can remain on the Hub.

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84 300D, 82 Volvo 244Gl Diesel

Thanks. I was hoping so.

Do not hang the calipers by the brake hoses. Use a bungee cord or wire, even a wire coat hanger, to hang the calipers. Hanging the calipers by the hoses can potentially damage the hose.

I recommend using a dial indicator to adjust the end play after the new bearings are installed.

Attached Files

33-300 Adjustment of Front Wheel Bearing Play.pdf (613.1 KB, 271 views)

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84 300D, 82 Volvo 244Gl Diesel

One of those cheap dial indicators with magnetic mount from HF in USA, Princess in Canada, works well.

One thing that varies in the MB manuals, is just how to push and pull on the rotor. I seem to recall conclusion of another discussion was that that this should be done axially (in and out) rather than rocking from side to side. It takes quite a bit of in-out strength when grease and bearings are new!

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Graham
85 300D,72 350SL, 98 E320, Outback 2.5

I did this job a few days ago on my '81 TD. The tutorials all said to remove the rotor, but really it is not necessary. It makes it a little harder to secure the hub when driving out the races, but is doable.

Be sure to use the right punch when driving out the races. There is not much of an exposed race lip to drive against and it is easy to chip/distort the hub shoulder. I messed it up a little until I ground the punch to make better contact with the lip.

My HF dial indicator won't measure less than a thousanth inch, so I had to eyeball the max. .0008 endplay as the needle moved between the lines on the scale.

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1981 300TD 310k miles
1970 280sel 172k miles
1966 230 Fintail 162k miles

"Where are we going? And why am I in this hand basket?"

In the manual after the bearings are packed with grease, grease is in the Hub and the hub is installed with the axle nut and washer if it has a washer (don't remember a washer on mine).

Follow the Manual and tighten the axle nut and rotate the hub when it is tight. That squeezes the grease out so you can take the end play accurately.

You back off the axle nut and strike it the hub with a plastic hammer (a suitable heavy piece of wood also works) and that releases the Hub from the bearing taper.

Then follow the instructions on how to do the end play reading.

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84 300D, 82 Volvo 244Gl Diesel

They are very common bearings, no need to buy at a dealer. Timken SET3 & SET5 (National A3 & A5), I recall in my 1985 300D. Worse thing you can do is over-tighten them, since they could then bind and overheat. Same as changing tapered wheel bearings on any 60-70's U.S. car, though I like the nice pinch-design of the spindle nut. Best to install a new seal on the inner bearing. Pack them well by hand until grease extrudes. If the races look fine w/ no pits, I would leave them in and just replace the roller cones since you can mess up the hub if you botch the race replacement.

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1984 & 1985 CA 300D's
1964 & 65 Mopar's - Valiant, Dart, Newport
1996 & 2002 Chrysler minivans