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Dropping rear axle carrier with the diff

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  • Dropping rear axle carrier with the diff

    I am preparing to remove the rear axle carrier with the diff, trailing arms and wheel hubs all together in one go. Looking underneath the car it seems that all parts have enough clearance to nicely slide off when supported under the diff with a hydraulic floor jack. I prepared a support plate for the jack to have a "table" to support the diff.

    The possible challenge seems to be whether the main drive shaft needs to be removed first or will there be enough space to first lower down the rear axle carrier with the diff to come off the main front bushes before it can be pulled backwards. The drive shaft has a limited space to move downwards as the exhaust pipe (cat section) is below the shaft.

    In other words, the whole rear axle thing needs first to be lowered + 10 cm to free it the main front bushes and only after that it can be pulled backwards and clear from the main driveshaft. The main driveshaft bolts seem to be integral with the driveshaft flange and cannot be removed.

    A little difficult to explain but if someone has done this, the question is simply that do I need to remove the main driveshaft first or is it enough that I just "unplug" it from the diff end ?

    br, Juha
    The older I get, the faster I was ...
    BMW HP2 Sport
    ex- BMW Z3 M Coupe - Cosmosschwartz Metallic

  • #2
    http://bmwfans.info/parts-catalog/Z3...el_suspension/

    The bolt requiring the subframe to be first lowered before moved backwards is bolt 2 that goes through the bushes.

    This fig shows the space availalble for the main drive shaft to move downwards : https://plus.google.com/photos/11351...64400707838815

    It seem that at least I should detach the heat sheald to get some more space for the driveshaft ...

    - Juha
    The older I get, the faster I was ...
    BMW HP2 Sport
    ex- BMW Z3 M Coupe - Cosmosschwartz Metallic

    Comment


    • #3
      I think I am slightly confused with the term driveshaft, normally we call the main centre deriveshaft the "propshaft". The universal joint on the end of it, plus the fact it is telescopic should mean it's possible to disconnect it there and give enough play to jiggle it out as you lower it.

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      • #4
        I removed the axle carrier from my MC about 7 years ago to fit polyurethane subframe bushes and to fit Ireland Engineering's Camber and Toe brackets.

        I was working off the floor and on my own, so I had to do this job safely and with parts that I could physically handle within the limited space and with a floor jack for lifting. I removed the diff on it's own before completely removing the subframe. There's no way that I would've been able to remove all the parts together, as one unit, as you're suggesting. I'm sure that you could get them to "fall-off" as one, but doing it without damaging the parts or injuring yourself would be just down to luck or otherwise. If you had two helpers to balance the hubs on each side whilst you lower the parts together on your jack would make it possible.
        /// Exdos ///
        "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

        Comment


        • #5
          That is true, but I'm sure with something appropriate like a gearbox jack assuming it's lifted in the air high enough it might be possible. Wheeler Dealers bloke dropped an engine from an Esprit in a similar way.
          Last edited by c_w; 26-01-2014, 09:06 PM.

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          • #6
            I made a wooden frame (as in the photo below) to lift the diff with a floor jack, but even with this and other balancing bits I found it tricky working on my own. Having said that, I've seen someone working with the car raised on a lift use his head as the jack for the diff!


            /// Exdos ///
            "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

            Comment


            • #7
              Love the wooden frame....think your napoleon quote perfectly represents your method for this.....

              Jim

              Comment


              • #8
                Thank you for the comments and point taken regarding the safety issues !

                I am preparing a special setup to support the parts and will also use extra hands while removing them from the car. I will not locate myself under the subframe while removing the last bolts :)

                If it proves necessary, I will remove the diff first to reduce load.


                http://v2tre.wordpress.com/2014/01/2...kakelkka-alas/
                The older I get, the faster I was ...
                BMW HP2 Sport
                ex- BMW Z3 M Coupe - Cosmosschwartz Metallic

                Comment


                • #9
                  Unbolt the diff mount ear, undo all plugs handbrake cables brake pipes etc, udo the rollbar from the shell, crack the 22mm nuts and place a jack under the diff remove the nuts fully, normally the axle won't just fall out will take some jiggling around to get the axle beam off the threads then drop the jack

                  Comment


                  • #10
                    Sounds like you've done it before! I'veseen plenty of E30 axles from breakers oer on ebay with the complete subframe with diff all attached so just a matter of makingsure it's balanced as it drops down.

                    Disconnect the dampers too obviously!

                    Comment


                    • #11
                      Just a thought....what about getting it all back on...it's one thing taking a heavy load off the car but when you need to put it back on and line up connections that could be the main difficulty ?

                      Comment


                      • #12
                        Originally posted by redrobin View Post
                        Just a thought....what about getting it all back on...it's one thing taking a heavy load off the car but when you need to put it back on and line up connections that could be the main difficulty ?
                        The rear subframe is very flexible on its own, but when you attach the diff to it and then the trailing arms it becomes very rigid. It's one thing letting gravity help you remove the subframe off the pins, but relocating the pins through subframe bushes when the whole subframe is completely assembled, especially the polyurethane bushes, would be extremely difficult.
                        Last edited by exdos; 30-01-2014, 09:55 AM.
                        /// Exdos ///
                        "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

                        Comment


                        • #13
                          Took today the subframe down with the diff. No problem there.
                          However, I took some time to make a decent support on the jack.
                          The "table" on the jack is bolted onto it to prevent any tilting or sliding.
                          In addition, I attached a metal bar to hold the jack itself from tilting and falling over. A safety belt is holding the diff on the table.

                          Some figs here :

                          https://plus.google.com/photos/11351...64400707838815

                          https://plus.google.com/photos/11351...64400707838815


                          The OEM bushes are really very soft :

                          https://plus.google.com/photos/11351...64400707838815

                          It is easy to see that those soft bushes allow too much movement and put stress onto the rear bush in the diff and to the floor.

                          I do not expect any big issues when putting this back with new PU bushes.
                          I am considering to lift the frame into correct position just the upper part of the bushes in place and then push the lower part of the bushes in place afterwards.. This should make the alignment easier than when trying to lift the whole thing at one go. I think that the PU bushes should slide much easier in place into the subframe compared to rubber bushes. Will test this before reassembly.

                          br, JuhaV
                          The older I get, the faster I was ...
                          BMW HP2 Sport
                          ex- BMW Z3 M Coupe - Cosmosschwartz Metallic

                          Comment


                          • #14
                            Originally posted by JuhaV View Post
                            Took today the subframe down with the diff. No problem there.
                            However, I took some time to make a decent support on the jack.
                            The "table" on the jack is bolted onto it to prevent any tilting or sliding.
                            In addition, I attached a metal bar to hold the jack itself from tilting and falling over. A safety belt is holding the diff on the table.

                            Some figs here :

                            https://plus.google.com/photos/11351...64400707838815

                            https://plus.google.com/photos/11351...64400707838815


                            The OEM bushes are really very soft :

                            https://plus.google.com/photos/11351...64400707838815

                            It is easy to see that those soft bushes allow too much movement and put stress onto the rear bush in the diff and to the floor.

                            I do not expect any big issues when putting this back with new PU bushes.
                            I am considering to lift the frame into correct position just the upper part of the bushes in place and then push the lower part of the bushes in place afterwards.. This should make the alignment easier than when trying to lift the whole thing at one go. I think that the PU bushes should slide much easier in place into the subframe compared to rubber bushes. Will test this before reassembly.

                            br, JuhaV
                            Well done!

                            I used AKG polyurethane subframe bushes and they were a VERY tight fit inside the housings: they needed hammering into place and there's no way they will come out easily. I believe the Ireland Engineering ones can be easily removed. Good luck putting it back.
                            /// Exdos ///
                            "Men who try the impossible and fail spectacularly are infinitely superior to those who reach for nothing and succeed" --Napoleon Bonapart

                            Comment


                            • #15
                              Seems that the links above in my earlier posts to those individual pictures are not stable for some reason.

                              So here is a link to the whole album, please scroll down to see the pics related to this rear frame project :

                              https://plus.google.com/photos/11351...LXkmuWj46W42wE

                              Hopefully this link works better.

                              - JuhaV
                              The older I get, the faster I was ...
                              BMW HP2 Sport
                              ex- BMW Z3 M Coupe - Cosmosschwartz Metallic

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