Differential for 1973 CS Automatic swap to Getrag 5 speed box,

I emailed Streetdriven and they didn't know if ,and couldn't confirm the 188mm LSD clutch kit they sell would fit in our sideloader diffs. You've used them before I assume Don?
 
I use Pete at Petes gear shop- maybe you should have him check it out?
 
I may have to do that. I was hoping to just buy the clutches and do it myself. Is that crazy? Anyone doing that themselves? The rest of the diff "looks" very nice inside I've heard Petes Gear shop is great, its just a long way for me to ship from Canada .
 
Its not out of the question to replace the clutch plates in a 25% lsd, the blue book has instructions, worth a read. If it needs complete bearing refresh as well may be worth a pro. The single use bolts you'd need are available from BMW, the hard part is finding the plates. I've been after plates for a 40% diff for some time now, and the trail is cold.
 
Ian, OK thx for the info. I've watched a few videos on replacing the clutch plates and it doesnt look hard. I'd be going with 25% lock up. I knew replacing the bearings requires more shimming etc. My bearings all look good ( I think). I've recently misplaced my blue book:mad:. Streetdriven has a 25% and 40% kit, I've be taking my carrier apart and confirming with them to see if their parts are right for these diffs. As with lots of things with these cars ( in this case a lowly e12) I like to try to do things myself when maybe I should just pay the experts. We'll see.
 
In all the work done at the shop-

We don’t do..

paint
body work
upholstery
windshields
machining
gears
alternators
powder-coating
zinc
polishing
chrome

amazingly- NONE of those great shops we use, put finished cars together and hand over keys to owners. Coincidence?
 
Ian C said:
Its not out of the question to replace the clutch plates in a 25% lsd, the blue book has instructions, worth a read. If it needs complete bearing refresh as well may be worth a pro. The single use bolts you'd need are available from BMW, the hard part is finding the plates. I've been after plates for a 40% diff for some time now, and the trail is cold.
Click to expand...
You can contact Al Traylor he used to sell LSD's to a builder who might have the parts you're after. [email protected]
Douglas
 
zinnocoupe said:
Ian, OK thx for the info. I've watched a few videos on replacing the clutch plates and it doesnt look hard. I'd be going with 25% lock up. I knew replacing the bearings requires more shimming etc. My bearings all look good ( I think). I've recently misplaced my blue book:mad:. Streetdriven has a 25% and 40% kit, I've be taking my carrier apart and confirming with them to see if their parts are right for these diffs. As with lots of things with these cars ( in this case a lowly e12) I like to try to do things myself when maybe I should just pay the experts. We'll see.
Click to expand...
The 25% and 40% lsd centres in these diffs are different animals, identified by either S25 or S40 stamped on the can. The blue book shows some of the differences in design and repair method. I can pm the lsd section from the manual if you like. I'd be really interested in the outcome with Streetdriven.
 
Douglas, thx very much for that contact info

Ian, That would be awesome. I do have the book but cant find it right now. Please do that when you have time. I'll have to try hubting up a digital copy of that manual. Im just busy with a project on a different car but going to try to get back on that diff pretty quick. Cheers

Dave
 
Well in the interest in keeping this post going, I took apart the LSD carrier and cleaned and oiled everything. No obvious damage, everything looks worn and stained but not terrible. Funny to see two clutch plates on one side and only one on the the other but its how it should be according to the page in the e12 service manual. Put it all back together and its now unlocking and spinning. 43 ft/lbs break away torque according to my fumbling efforts. comments??

By the way Ian C, you said preiviously 25% and 40% are very different animals, I believe the difference would just be a thinner spacer and another clutch plate? or something like that. I'll be measuring the plates and emailing results to streetdriven soonish. Need to take it all apart again.
 

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Sending the scans of the pages tonight, yours is another arrangement, similar to the 25% used on e9s.The early 40% have to be unbolted from the crown wheel to open, at least 2 versions with different types of plates, different number of plates, no belville plates no preloaded breakaway friction,and different depth of the can. Yours resembles the 25% much easier to deal with and a test by torque wrench possible. The 40% has to have the internal components places under a 200lb load from a press to take a measurement, then select thickness of plates to suit can depth. I'm hoping the dimensions and spline count of the plates from Streetdriven will match the early diff I have, then its a matter of the thickness. Ill be happy with any percentage of lock that's not going to make it feel like a drift car, really want the 3.45 :1 ratio.
 
Ian, Thx for the info. The more I hear and learn about these diff the more I realize I don't know much. LOL. Its all very interesting. Thx very much for the pages of service manual. I actually had a buddy txt me some pics of those pages but yours are much easier to read. After all this talk of ratios and 3.64 vs 3.45 vs 3.25 I think I'll try both of these diffs in the car with the 265/6 and see whats better.
 
FYI- my local gear shop does not rebuild early LSD sideloaders. Later e12 10 bolt versions are OK but not the 8 bolt version. Seals and bearings are not a problem but internals are the issue.
 
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