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Difference M3 and other E30 half shafts

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  • Difference M3 and other E30 half shafts


    next weekend I am replacing the complete rear suspension (new subframe, new trailing arms, bushes, brake discs, wheel bearings,...), but I would like to keep the half shafts. I expect some problems removing the half shafts from the wheel hubs. Therefor I would like to buy a set of spare half shafts. Since I don't want to get ripped off by a second hand parts dealer, I would like to know what is the visual/measureable difference between the standard E30 half shaft with ABS ( 33 21 1 225 893) and the M3/325i one ( 33 21 1 226 901)? Is there a difference in diameter?



  • #2
    M3 v E30 Half Shafts

    Hi KoenC,

    If you are going to replace most of the items as mentioned, then I would consider upgrading some of the items en route, and the benfits to be gained.

    If you replace the Trailing arms with a pair from a Z3M, use the Z3M half shafts, hubs and bearings, you get bigger shafts and more robust rear bearings, are able to fit vented rear discs and either e36 m3 rear calipers or aftermarket bigger calipers.

    You have to use the E28 output flanges so as to marry the Z3M half shafts with the pick ups on the diff, but if you could source these parts from a salvage yard or car breakers, then I beleive you have a vastly improved rear suspension set up, much better rear brakes, and the labour stays the same, more or less.

    Handbrake still retains much of the same, and works in the same way.

    If not, then I belive E30 half shafts from an ABS car are the same, as are the shafts from a 3 Series compact, but not the rear hubs on the compact.

    I think somewhere in Jakes Brembo Brake Upgrade, there is a reference to this conversion, from a member in America.

    Hope this helps,


    The Gorilla.


    • #3

      Thanks for the advice, but I was already aware of this possibility. Anyway in my project car I preferred to do it differently. This means using new original components with uprated mounts/bushings.

      On topic again, I would be surprised that the driveshafts of a normal E30 and a 325i/M3 would be identical when they are having a different P/N. Nobody any idea about a visual difference?




      • #4
        The half shafts can be tough to get out, but you should be able to do it. Obviously begin by soaking with penetrant for a couple of days. You should be able to hammer them out of the hub with a drift and large hammer. Don't bother using a regular shop hammer, get a big one. I used a 3lb. hammer.
        If you can't hammer them out, get a torch and heat the assembly for at least 5 minutes and then repeat hammering. This should do it, but it takes patience, a big hammer, and a healthy repertoire of curses.
        I have done this twice recently and on my car they came out relatively easily, but they required the heating method above on my friend's car.
        Why do you necessarily expect problems removing them? Do you have the rear wheel bearing tool? If not, find one you can borrow or rent, because I wouldn't even attempt bearing replacement in the trailing arm without it. The tool makes pulling and replacing the bearing a snap, and it helps re-install the hub stub too.

        Hope that helps,

        Speed, as Iíve said many times before, makes you cleverer.

        -Jeremy Clarkson


        • #5
          I'd be the friend that Will is referring to above. When I was replacing the rear wheel bearings, the halfshaft came out very easily from the driver's side. Unfortunately, the passenger side wasn't going to budge. After many beatings with a hammer (regular, air, whatever), a can of penetrant, the only thing that got it out was a good heat soaking from a torch (cooked for about 10 min) and then some more hammering.

          Needless to say, I needed an new hub afterwards too. But, to answer your question, the normal 325 with ABS is the same as the M3 halfshaft. Since I needed one last minute, my local shop got me a remanufactured 325 one...there were no visual differences whatsoever between what came off my car and the "new" one except the much lower price.


          It will probably be much easier to do this with the trailing arms still on the car.


          • #6
            I have got new trailing arms with new wheel bearings with hub installed. I just want to use the current half shafts on the new trailing arm assembly, which means I don't have to worry so much about destroying the current wheel hub. Thanks for the tip on the torch.

            Concerning difference of E30 half shaft, I was referring to the difference between regular E30 (318, 320) half shafts and 325i/M3 half shafts. The half shafts of 325i and M3 are indeed identical.




            • #7
              I can only guess, but are smaller output plates used on the 318i? If so, maybe the inner end of the 318i half-shafts is smaller?


              • #8
                I think it may have to do with the ABS rings. I'm not positive though.



                • #9
                  Jake, that's what I thought, too. But the initial post led me to belive that there were 2 types of ABS half-shafts. There is of course a difference in the ABS/non-ABS half-shafts.


                  • #10
                    Indeed, it is not the ABS which makes the difference. Both part numbers from the first post are for ABS half shafts.