BMW Diff Removal

[BigCol]

My BMW LSD is FUBAR (well, I hope not BAR but it is F'ed) so needs to come out (probably to get a Tracsport unit fitted).

Having searched, on the face of it this topic has been covered in a number of threads but each seem (contrary to Just a Minute) to deviate from the subject without a simple overall guide as to how to get a BMW diff out relatively  easily.

On one thread John Vine offers this, for a Ford diff:

Is this transposable (with the addition of the removal of A-frame and rear ARB too?) for the BMW unit?

 

 

 

 

 

[Jonathan Kay]

I can't remember ever seeing anything that clear.

There's a diagram in the current pictorial Assembly Guide.

There's rather more in the last text-heavy version from 2016. Please let me know if you'd like a copy.

John Vine identified that the location of the Schnorr washers was incorrect in some guides. I don't know if that is now corrected.

Jonathan

[BigCol]

Thanks Jonathan

I built my car in 2013 and have the contemporaneous Assembly Guide.  

Applying the Haynes manual principle, I fitted the diff before the DeDion tube...  suggesting that the latter should come out to.allow removal of the former (which I'd prefer to avoid)!

[ScottR400D]

I've sent you a PM that you might find useful, BigCol.

 

 

[BigCol]

re #4

Thanks Peter... was hoping for a knowledgeable contribution from you given the frequency with which you've had to remove your diff!

[StevehS3]

Peter's notes worked brilliantly for me. They gave me the confidence to swap the diff myself and helped enormously with the miserable diff situation. 

[ScottR400D]

#5 Ha! Yes, it's ingrained on my memory, but at least I don't have nasty dreams about it any more.............

[BigCol]

You went for a Tracsport unit if I recall...(?)

[ScottR400D]

Yes. The process after my Titan blew itself to bits was:

Strip out diff for rebuild at RRT.

Refit and test to find it intolerably noisy.

Strip out diff for another rebuild at RRT.

Refit and test to find it better but still unacceptably noisy for me.

Strip out diff for final rebuild at RRT.

Purchase new open diff from CC, sent to SPC for fitting of Tracsport. 

Refit Tracsport and test to find no discernible diff noise, and an LSD that unquestionably works better than the Titan, IME.

Other than the occasional spanner and rotation check and one precautionary oil change, haven't touched it for over 2 years now. Still quiet, still functioning, runs nice and cool. 

The rebuilt BMW/Titan sits in my garage unused on the little wooden jig! 

[BigCol]

Diff out, boxed up (a variation of ScottR400D's jig) and now en route to Steve Perks.

[John Vine]

#1:  I'd forgotten all about that post.  How much (if any) applied to your BMW diff?

JV

[Dan R]

I have just installed my TracSport diff into my car after having it built by Steve.  The drive has been completely transformed.  He is excellent at what he does! 

[BigCol]

re #11.  ScottR400D provided me with a not dissimilar list of actions to yous - main differences were the addition of removing the ARB and A-frame too.

[ScottR400D]

.....don't forget the miracle of precision engineering that is the jig, BigCol!!

[John Vine]

#13: Thanks. BC.

#2:  John Vine identified that the location of the Schnorr washers was incorrect in some guides. I don't know if that is now corrected.

This refers to the error I reported back in March 2019.  The Assembly Guide failed to show the required Schnorr washers under the heads of the lower diff bolts (green arrows):

Having just looked at the current AGs (Duratec and Sigma), the error is still there.

JV

[Jonathan Kay]

Thanks for checking.

Jonathan

[Geoff Brown]

Might be a bit late to the party BUT one can remove the BMW Diff independently of the support frame. 

Leaving the frame in avoids the unnecessary nause of re shimming & the dreaded top bolt removal/refit.

Having done the job previously- two years & counting - I can honestly say that the sans frame method is straight forward.

 

 

[ScottR400D]

You're right Geoff, and it saves having to mess around with the handbrake cable too. I did both. First couple of times left bracket in, removed the whole lot when I replaced the original with a new SPC assembly. 

One potential issue, I am told, though it wasn't the case for me, is that the brackets aren't all that accurately made and removing the diff from the bracket, leaving that in place, can lead to issues getting the diff-bracket bolts back in. Apparently that's why the diffs tend to come from CC with a bracket already bolted up. 

[StevehS3]

I had no choice with mine. The top bolt was locked-in solid; no way would it come out. Fortunately the new diff fitted perfectly into the existing cradle. 

[Geoff Brown]

ScottR400D - There is little error for judgment when refitting the Diff to the frame, mine was quite tight so the lift had to be adjusted slightly to 'scrape' it in. What helped was the jig I made up. (below). Without this the casing is quite unwieldy to handle. Balancing on the jack out of the question.

Dropping out on the other hand was ably assisted by gravity!