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Driveshaft replacement
Published by GoNuts
05-07-2013
Default Driveshaft replacement

So I'm replacing my drive shaft, just got it in the mail yesterday. I've found a couple diy's on it but just want to clarify that it is not a Ti specific process as I have only found them for regular e36's
Also, since I am taking the original driveshaft out and replacing the guibo center support bearing and the driveshaft will there be any alignment issues when reinstalling? (Something that a friend said would be a problem, I hope not)
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  #1  
By Mini M3 on 05-07-2013, 04:36 PM
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if your going to be seperating the driveshaft to replace the center support bearing be sure to mark it (input and output shafts) so the shafts go back together in the same place as they are balanced.Guibo is good to replace if it shows any rips.

All E36's process is the same. Difference is the DS length: Auto vs Stick, Getrag vs ZF and 4 bolt vs 6 bolt

Good luck
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  #2  
By GoNuts on 05-07-2013, 10:35 PM
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The drive shaft I got came with the center support bearing already in place. So it's just as simple as take the old one out and put the new one in?
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  #3  
By CirrusSR22 on 05-08-2013, 02:03 AM
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Quote:
Originally Posted by GoNuts View Post
The drive shaft I got came with the center support bearing already in place. So it's just as simple as take the old one out and put the new one in?
Essentially yes. You do need to preload the center bearing though. You will see that the two center bearing mount holes are elongated. Tighten the bolts until the bearing is almost tight against the body, then push the bearing assembly forward 4 to 6 mm. I usually push the bearing against the body in its "natural" position and make an etch mark on the body on each side of the bearing frame. Then measure 4-6mm forward and make another pair of etches. That forward etch set is your reference for final tightening of the bearing bolts.

In addition, the Bentley manual suggests just doing a visual check of the entire driveline to make sure it's lined up. Also the driveshaft should be centered in the tunnel. These would really be issues with the motor and trans mounts if it looks off, but it's something good to check while you're under there.
Last edited by CirrusSR22; 05-08-2013 at 02:05 AM..
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  #4  
By GoNuts on 05-10-2013, 03:38 PM
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Right on, sounds pretty straight forward. Any other things I should know before going for it tomorrow?
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  #5  
By Greg C on 06-09-2014, 05:12 PM
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OK, dumb question. My daughter had an issue with vibrations on her 318ti. Before she could have it serviced, the driveshaft ripped the carrier bolts out of the bottom of the car. Anyone know if the mount can be replaced? I'm hoping it is similar to the replaceable mount for the front sway bar.
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  #6  
By Eric on 03-01-2016, 08:20 PM
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Hi All.

I've just changed my driveshaft, and wanted to post up some information, as I was not able to find much out there when I looked.

First, to be clear, the common reason to replace a driveshaft is because the universal joints wear out.
The U-joints are pressed into the yokes and staked in place at the factory in a machine that places them in the best position for proper alignment and balance. There are no machined lands to locate the cup retaining clips, as there are on earlier American driveshafts, so replacing them yourself can be an adventure in fabrication and improvisation, with no certainty that you've done it correctly until it is installed and you find out whether it vibrates.

Quality-rebuilt driveshafts are available from several suppliers, but Driveshaft Specialists in San Antonio seems to be the place that comes most highly recommended. I bought mine there, it was about $375, plus a core charge, with free shipping, and it arrived in NY in 3 days.
You MUST also change the guibo, which WILL be in sorry shape. I bought a Febi/Bilstein unit from Pelican for a decent price, which had completely identical markings on it as my original BMW unit.

I've been driving and fixing cars for a lot of decades, and have replaced U-joints a number of times over the years in American cars and trucks. I am accustomed to their typical failure signs, which include clunking with throttle, gear, or direction changes, and whining.
I was NOT accustomed to the signs of BMW driveshaft failure, which include exactly NONE of the above.
In my case, I spent a couple of months experiencing a harsh vibration that feels like it's coming from the rear of the car (occasionally left, occasionally right, usually middle), that I could feel mostly in my butt, like a back massager gone haywire.
No vibration in the steering wheel.
No vibration in the gearshift (MT).
The vibration was affected by throttle position and road speed - it was worse at steady throttle, better with acceleration or deceleration, worst at about 40mph and again at about 70mph (could be bone-jarring when it was just right), and smoothed out pretty well at about 80-85.
It was not affected by engine RPM.
There was no sound associated with it - no howling, growling, or grinding.
Taking sweeping turns in either direction did not change it.
I had gotten under the car and messed with the axles, wheels, and driveshaft, and I didn't notice any slack or problem (the rear U-joint is barely visible, and you can't get your hand fully around it, and the slack that there was felt to me like the slack I would expect to find in the differential, so I didn't think anything of it).
My best guess was a rear wheel bearing, because of the relation to throttle position, but, of course, I was wrong.

The driveshaft could be changed on the ground, on jackstands, by the determined, strong, and young, but I would highly recommend using a lift.

In order to change the driveshaft, you need to first remove both the catalytic converter and muffler sections of the exhaust system. I have never been able to get the downpipe flange nuts off without first heating them to orange-red, except in cases where I had previously replaced them with stainless. This applies to both plain steel nuts, and to BMW factory copper nuts. You do NOT want to really whale on these nuts to remove them, as the studs sometimes have been corroded away to some extent at their bases, and too much of a pull can shear them off, which would then oblige you to drill them out and replace them. I always chase the threads with a die (M10x1.5 if I recall), as they are always crappy. You will need a new flange gasket for reassembly.

Unless they were recently replaced, you WILL destroy the two 85-100mm bolts that hold the two pipe sections together at the flare joint, so have a new pair, as well as nuts and washers. Again, stainless is your friend. The springs are often stainless, and if so will be fine (they aren't cheap to buy).
You may have to drill or drive parts of the old bolts out of the flanges - heat helps here, too.

The two heat shields covering the driveshaft have to be removed - this usually goes well, but if you live in a rock-salt area, this is a good opportunity to replace the little washers with larger washers and even larger plastic spacers (cut from coffee can lids), because otherwise galvanic action will eat little holes in the heat shields exactly the size of the washers, and they will begin to fall off.

The driveshaft is attached to the differential by 4 screws with 16mm hex heads. 16mm is the size that is not included in any socket or open end wrench set. ⅝" is the same size as 16mm, so grab an American box wrench (a socket won't fit). You will need to apply the parking brake, loosen 3 screws, release the parking brake, rotate the driveshaft 180°, and loosen the fourth screw.

The driveshaft is attached to the guibo, which is attached to the transmission by 3 nuts and bolts. These fasteners all have 18mm heads. This is the other size that is uncommon in wrench sets, and there is no American substitute.
You will need to use a deep extension from the rear, with an open end on the nut on the front.

Don't forget the center bearing's 2 nuts, and the little steel support bracket for the rear heat shield, which also have to go.

Once all the fasteners are off, the driveshaft just drops out.
Right.
Actually, after 1- to 200,000 miles, its spline joint will be frozen, and it will be locked in place. You will need two good prybars to work the ends off, and then manipulate the thing out.

The new driveshaft will come sans vibration dampener, so you will have to swap yours on (unless it's destroyed, in which case you will need a new one, for over a hundred bucks). The bolts that fasten the guibo to the front of the driveshaft have round flat heads and splined shafts, and are splined into the driveshaft flange holes, after going through the balancer's holes. A few good shots on each bolt with a sledge will pop them out - screw the nuts back on to just above the ends of the bolts, to protect them.
I replaced all 6 of of the nuts, as they are special lock nuts, but I'm not certain whether that's necessary.
Once the bolts are out, the balancer can be rotated 60° and removed.

Installation, as they say, is the reverse of removal (only easier).

To be continued...
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  #7  
By Eric on 03-01-2016, 09:02 PM
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Continued...

With the driveshaft out, you have an excellent opportunity to install a short shifter and replace all the loose bushings in your shifter assembly.
Do that now.
A hook-shaped hose-remover tool with a screwdriver-type handle is an excellent tool for unclipping the "bastid clip" that holds the gear shift carrier to the back of the transmission.

Before you install your new driveshaft, you need to install the vibration dampener.
This is not as easy as it might first appear.
There is probably a correct way to do this, but if so, I do not know what it is.
The splined bolts have to end up pulled all the way into their holes, up against the dampener, with the dampener tight against the driveshaft flange.
When I have encountered bolts like this in the past, I have seated them by either a few sharp blows with a sledge, or by pulling them in by tightening the fasteners. I tried both and neither provided a satisfactory result.
In the end, I pulled each one in using an air wrench, then gave the nuts a good pull with a long ratchet, then gave them another eighth of a turn with the air gun. This is probably the wrong way, but it was all that would work.

Once the driveshaft is assembled, note that the splined connection will act like a shock absorber: It will move either in or out, but very slowly, and with cruel disregard for the amount of force you put on it. This means that if you hold it at an upright angle, it will slowly get longer, then when you are trying to put it in place over your head, it will be too long and won't shorten no matter how hard you push it, then once you've gotten it shorter, it won't lengthen again as you pull on it with all your might. It won't wedge in place and stay there long enough for you to reach the handful of bolts that's just sitting a few feet away unless you've gotten it to the right length.

Reassembly from here appeared to me to be completely straightforward.
Cirrus, above, described a procedure for preloading the center bearing.
I knew nothing about that, and just tightened it in its least-stressed position.
I am not sure whether this is a bad thing or not.

BMW gives torque values in a lengthy technical bulletin that applies to all models in the time range, and they all seemed rather low. I just gave everything a good strong pull, and probably made them 50% tighter than BMW would have.

In addition to a new exhaust flange gasket, new muffler hangers (2 rubber thingies, and one rubber whositz) are never a bad idea, as the old ones slowly stretch over the years.

Once my car was reassembled, I found that it drove amazingly smoothly, and, in fact, some slight vibrations that I had attributed to the engine lugging were also gone.

This is a repair that I should have I done a long time ago, and I'm glad that I finally did it now.

- Eric
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  #8  
By Eric on 03-01-2016, 09:09 PM
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Incidentally, this is the only visual sign that this was a bad U-joint - you can just see some of the silver of the bearing surface, which is ribbed from the needles wearing against the surface, before they all fell out, sometime several months ago, at least.

This would have been almost impossible to see with the driveshaft installed.

This is the read U-joint - the front U-joint and the center bearing both appeared to be fine.



- Eric
Attached Images
File Type: jpg Rear U-Joint 318ti.jpg (97.7 KB, 94 views)
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  #9  
By Eric on 03-01-2016, 09:12 PM
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Finally, I will ask this question in a separate post, as the preceding posts are a bit dense:

How important is it to preload the center bearing, as Cirrus described, above?

Do I need to take the whole darned thing apart again to do this, or is it no big deal?

Personally, I don't see how it could be necessary, having examined the whole system, but I'd like to know what others' experiences have been.

Thanks,

- Eric
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  #10  
By Eric on 03-10-2016, 11:16 PM
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An update:

I cannot yet answer my question, above.

I have read that the reason for preloading the center bearing is to prevent some sort of chattering or un-smoothness on takeoff from a stop, but I ran my center bearing un-preloaded for about 2,000 miles and noticed no problems.

Yesterday, I caught a good day and preloaded my center bearing. Here is my report on that process:

In answer to the burning question that I'm certain is in everyone's mind who is reading this:
Yes, you can move your center bearing without dropping the exhaust system.

Here's how:
  • Remove four fastening screws from each of the two exhaust heat shields.
  • Remove the bracket that holds the back of the front shield and the front of the back shield.
  • Carefully roll the rear shield out by pulling a bit forward and rolling around to the right side of the car.
    You will need to pull down on the exhaust system pretty hard for a second or two to get it to move down just a bit, to get some clearance.
  • Slide the front shield backward.
    It will move enough so that the center bearing is just uncovered.

After this, it is a simple task to loosen the center bearing nuts, confirm its neutral position, measure and mark 5mm (3/16") forward, move the bearing, and tighten it down.

Installation of the shields is the reverse of removal (bracket goes on after shields are both back in place).
Once everything is together, reach up to the top of the front of the front shield, and make sure it's not rubbing on the driveshaft, and pull it down a bit if it is.

Since making this change, I have noticed exactly NO change in how the car drives.

- Eric
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