I went to NAPA to purchase a front wheel bearing kit for my 1984 300 D turbo and the Sales person told me he had a kit for it and it was for a 50 mm. He said he did not know what that meant other than there must be another size that might be the one that fit. He said if it did not fit, to bring it back...well, it did not fit (one look at the outer bearing and I could tell it was way too small). I took it back. I talked to a different sales person during my return and he told me the same thing the first salesperson told me. Bad thing...the only one they sell was the one that does not fit. Now, everywhere I look online, does not specify a size. Can anyone help me get the right wheel bearing kit??

Click on the "buy parts" link above, and check their catalog. If you aren't sure what you need, call Phil or Roy at the number on that page.

Nothing special about the wheel bearings (or the seals) for that vehicle. Buy a "Set 3" (outer) and a "Set 5" (inner). Timken and SKF are good quality brand names. My info says that the inner bearing is 50mm.

I just bought a front wheel bearing repair kit from this site, Phil was very helpful and the kit includes the seal. My local parts store would have to order the seal and the price, including shipping was very similar to buying the two sets of bearings and seal separately.

I purchased inner bearings BR5 and inner seal 19630
and outer bearing BR3 from Kragen online for $44 (both sides, all six boxes).
Picked up in store.

These are SKF numbers.

But the store application listed the WRONG OUTER bearing and I figured
out that BR3 by having them check other years around mine and matching
the one I removed (had it in hand) with the ones on their shelf for
other year Mercedes, including checking the bearings for the gasoline models with the same body. Like 380sel or 420sel or 280c, etc..

(can't remember if it was the W123 or W126 at the time, but
they both use the same bearings).

I can't say for sure the 84 uses same bearings as the 83 but the story of wrong size sounded familiar.

__________________
80 300D 340K Owned 30 yrs
83 300SD 440K Owned 9 yrs - Daily Driver 150mi/day
02 Z71 Suburban 117,000
15 Toyota Prius 2600 miles
00 Harley Sportster 24k
09 Yamaha R6
03 Ninja 250