driveshaft woes

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  • More&Faster
    Member
    • Jan 2007
    • 61

    #1

    driveshaft woes

    this is my first rwd vehicle and when i pulled the driveshaft off i marked it in the wrong place, and before i knew it, it was on the floor and i don't know how to get it back together so it's balanced. i can see it has balancing weights on both halfs....maybe these are supposed to line up? sadly, i think i fucked myself here. so machine shops balance these? i dont think i can just throw it back in without being sure....

    please advise
  • euroshark
    No R3VLimiter
    • Apr 2006
    • 3491

    #2
    Don't worry, you will never notice if it's out of balance.

    Chances are the amount that it's out is small, and even if it isn't small, the shaft spins very slowly compared to the wheels.
    '88 528e /// '88 M5 /// '89 951 /// '98 E430 /// '02 M5

    Comment

    • Sam Lin
      Member
      • Nov 2006
      • 58

      #3
      Originally posted by euroshark
      Don't worry, you will never notice if it's out of balance.

      Chances are the amount that it's out is small, and even if it isn't small, the shaft spins very slowly compared to the wheels.
      Spoken by someone who clearly has never had one out of balance, and who also has no idea what the diff's drive ratio does.

      Sam

      Comment

      • More&Faster
        Member
        • Jan 2007
        • 61

        #4
        ok so i did some math and in top gear at high speed it'll be spinning about the same as the engine....so we're talking like 6000 rpm at the top. that sounds pretty fast. im gonna call a shop tomorrow and just ask how much they want to do it.
        Last edited by More&Faster; 04-02-2007, 07:31 PM.

        Comment

        • jlevie
          R3V OG
          • Nov 2006
          • 13530

          #5
          Take a careful look at the driveshaft. There should be a mark on each indicating the correct alignment. Most seem to have a small white dot on each half.
          The car makes it possible, but the driver makes it happen.
          Jim Levie, Huntsville, AL

          Comment

          • PeaveyBassist
            No R3VLimiter
            • Sep 2004
            • 3511

            #6
            If you marked it in the wrong spot or something, youll NEED to get it balanced. Youll definitely notice a vibration if its off, even just a little bit.

            Will
            RIP e30 (brilliantrot '91 325i) 11/17/06 Byebye: 8/21/07
            Welcome e30 (brilliantrot '90 325is) 12/23/06
            DaveCN = Old Man
            My signature picture was taken by ME! Not by anyone else!



            Originally posted by george graves
            If people keep quoting me in their sig, I'm going to burn this motherfucker down.

            Comment

            • More&Faster
              Member
              • Jan 2007
              • 61

              #7
              Originally posted by jlevie
              Take a careful look at the driveshaft. There should be a mark on each indicating the correct alignment. Most seem to have a small white dot on each half.

              YES i did notice those. one is definitely a dot....the other mayyy be some oxidation lol. i'm gonna try to line them up and install it. if it's off balance i'll just go pay someone to do it.

              thanks for the help everyone.

              Comment

              • Mike325
                No R3VLimiter
                • Mar 2006
                • 3685

                #8
                The driveshaft is two peices right? Right. Both parts are ballanced, right? Right. The only thing you are concerned about is DRIVESHAFT PHASING. This means that the two U-joints need to be exactly lined up with eachother. The two ends of the shaft have U-joints. They both need to be allighned in phase.

                This means that the two U-joints have to both be oriented in the same position. Like + + < thoes are the U-joints. Kinda hard to explain with out showing you. Both U--joints need to be pointing in the same direction.
                Originally posted by cabriodster87
                "Honey? What color is this wire? Is it the same as that one? Are you sure? I don't believe it. OK, it works. Thank you sweetie."
                Originally posted by Kershaw
                i've got a boner and a desire to speed.

                Comment

                • Mr.SWISS
                  E30 Fanatic
                  • Nov 2005
                  • 1251

                  #9
                  The white dot on the rear section is on the shaft itself, the one on the front is on one of the universal joint collars for the splined shaft.
                  Originally posted by 325Projectz
                  don't listen to the diagram... listen to mr. swiss.
                  :nice:

                  Comment

                  • Mike325
                    No R3VLimiter
                    • Mar 2006
                    • 3685

                    #10
                    Here is my explination in some pictures that I just took. The sticks are your U-joints.

                    The first picture showes your two U-joints in phase and ready to go.



                    There are two there. One in front of eachother. This is how you want your shaft to look.

                    This is them out of phase.


                    See how they are now out of phase? Just line your driveshaft up so both U-joints are allighned like in the first pic. Be exact about it.

                    Oh, BTW, your driveshaft spins at road speed, not engine speed.
                    Originally posted by cabriodster87
                    "Honey? What color is this wire? Is it the same as that one? Are you sure? I don't believe it. OK, it works. Thank you sweetie."
                    Originally posted by Kershaw
                    i've got a boner and a desire to speed.

                    Comment

                    • euroshark
                      No R3VLimiter
                      • Apr 2006
                      • 3491

                      #11
                      Spoken by someone who clearly has never had one out of balance, and who also has no idea what the diff's drive ratio does.

                      Sam
                      Sam, I have extensive experience with Alfa Transaxle driveshafts, something Im sure you know nothing about. The Alfa Transaxle cars have a driveshaft that is connected to the motor instead of the transmission, so it spins at engine speed all the time, not just in top gear.

                      On two occasions I was forced to install different driveshaft halves that were put together from different cars. In the Alfa world this is a HUGE no-no because the shafts are balanced at the factory, they are special, and nobody in the world is willing to try to re-balance them. Even though on my first attempt the shaft was out of balance, it was not enough to warrant buying a new one. On my second attempt two years later with a different motor, the shaft from that car was disassembled and put back together in a different order than stock (I can almost guarantee this as Alfa used washers and bolts to balance the shafts, not just weights... damn Italians...) and the car ran with NO problems. 140mph flat out with no vibrations that would seem out of place at such a speed.

                      BMWs, in contrast to my Alfa, aren't as scientific in this area for a DIYer. Chances are that the paint on the shaft itself will throw it out of balance due to thickness variations more than assembling two halves that don't match.

                      I think everyone is making this complicated... The boys at Bimmerhaus (a race shop with many titles under their belt) never indicated that they gave a shit about phasing, I've never had problems, my dad's never had problems, and I've never heard of problems with driveshaft balance on a BMW due to the orientations of one half versus the other half. The reality is that the balance must be pretty damn good, or at least good enough that you won't notice.

                      So in regards to what you said Sam, you are correct that I have never had an out of balance driveshaft even though by all indications I should have. I see this as proof that it's not much of a thing to worry about. You are incorrect about my understanding of the "diff's drive ratio", but since you seem to be such a smart guy and have added so much advice that is based on experience to this topic, please enlighten me.
                      '88 528e /// '88 M5 /// '89 951 /// '98 E430 /// '02 M5

                      Comment

                      • Mike325
                        No R3VLimiter
                        • Mar 2006
                        • 3685

                        #12
                        All he needs to do is put his driveshaft back together so the U-joints are in the same orientation.

                        /thread.
                        Originally posted by cabriodster87
                        "Honey? What color is this wire? Is it the same as that one? Are you sure? I don't believe it. OK, it works. Thank you sweetie."
                        Originally posted by Kershaw
                        i've got a boner and a desire to speed.

                        Comment

                        • Sam Lin
                          Member
                          • Nov 2006
                          • 58

                          #13
                          Funny you mention the transaxle Alfas - these last 10 years their value has been brought up with the general resurgence of interest in collector cars, and I was looking at a couple GTV-6 as investments. The very first thing I was told when I talked to multiple specialists was to look for driveshaft issues.

                          Quoting Sports Car Market's article found here: http://www.sportscarmarket.com/affor...meo-gtv-6.html

                          Originally posted by Sports Car Market
                          The health of the driveshaft is the first thing to check. A careful visual inspection will reveal the condition of its three rubber donuts (one inside the front bell housing). A vibration at idle, or at about 3,500 rpm, indicates that the driveshaft is not in balance.
                          Based on the feedback I got from them, I'd say you had a unique experience, and either got lucky or had other factors, whether it was road noise or exhaust noise or simply better vibration damping, that kept you from feeling the unbalanced driveshaft.

                          That said, my response to your original post was because the post is wrong.

                          Originally posted by euroshark
                          Don't worry, you will never notice if it's out of balance.
                          Just in this forum alone, numerous posts ask about driveshaft alignment and vibrations, so people are clearly noticing. The fact that BMW marks and aligns them from the factory serves to confirm that. Long term imbalance only serves to destroy transmission and CS bearings, and joint misalignments tear apart guibos from repeated angular loading.

                          Originally posted by euroshark
                          the shaft spins very slowly compared to the wheels.
                          The shaft spins faster than the wheels, 300-400% faster depending on gearing. That's how the ring and pinion in the diff work.

                          Sam

                          Comment

                          • More&Faster
                            Member
                            • Jan 2007
                            • 61

                            #14
                            wow, thanks for all the good posts :)

                            i'll let you know how it works out when i get the thing back together in.....oh about a month LOL

                            Comment

                            • PeaveyBassist
                              No R3VLimiter
                              • Sep 2004
                              • 3511

                              #15
                              Originally posted by euroshark
                              Sam, I have extensive experience with Alfa Transaxle driveshafts, something Im sure you know nothing about. The Alfa Transaxle cars have a driveshaft that is connected to the motor instead of the transmission, so it spins at engine speed all the time, not just in top gear.
                              1. Why are we talking about Alfa Romeos??? This is a forum for BMWs, this thread is about a BMW, who cares about Alfas?

                              2. Why do we are about Alfas and their transaxles? So you're saying their transaxle is in the rear, engine in front, and torque tube/driveshaft between them to connect them? In THAT case, of course the driveshaft spins at engine speed... again, we are talking about the BMW e30. Front engine/trans and rwd. Driveshaft comes after the transmission, then goes to the final drive(differential) and then to the wheels. In THAT case, Sam is correct. The driveshaft does NOT spin at engine speed. So I have no idea why you are bringing up anything about Alfa Romeos and their transaxles.

                              Will
                              RIP e30 (brilliantrot '91 325i) 11/17/06 Byebye: 8/21/07
                              Welcome e30 (brilliantrot '90 325is) 12/23/06
                              DaveCN = Old Man
                              My signature picture was taken by ME! Not by anyone else!



                              Originally posted by george graves
                              If people keep quoting me in their sig, I'm going to burn this motherfucker down.

                              Comment

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