Broken pin-drive hub

[wolf k]

A customer brought his Backdraft in to our shop on a flatbed the other day, said he hit a pot-hole hard and then lost mechanical connection between engine and drive wheels.
Once on the rack, did some quick investigation and found broken pin-drive adapter. Not being familiar with Backdraft, where can this adapter be sourced from?
Also found that either the differential is an open unit, or that the limited slip function is non-functioning. Are LS differentials standard with Backdraft?

[spdbrake]

Looks like the BMW E36 (325i 1995yr) hub broke at the axle spline.
https://www.napaonline.com/en/p/NDP7707822 (L-R hubs are the same PN)

Was there a nut on the hub (inside the pin drive hub)?

I'd change the axle 1/2 as well ( L-R axles are the same PN)
https://www.napaonline.com/en/p/NMD951209
https://www.napaonline.com/en/p/ATM33411132565


Yes they can have Open and LSD diffs.
The aft cover of the diff should have a metal Tag. If the Tag starts with an "S" its an LSD (followed by the ratio)

[wolf k]

Thanks for the reply and info on the diff tag.
The Napa hub won't work because we need a pin drive hub that has the large threaded portion for the knock-off nut.
Axle actually looks good, there is a bolt securing it to the hub versus a nut.

[spdbrake]

Yes that would be the new style axle (uses a Bolt)
Backdraft Parts - Axle(New Type) - Rear Suspension - Suspension - Products

I'm not familiar with the Pin Drive hub that's integral to the Hub though.
Only with the stud and Pin that attaches to the Rotor Hat and hub like this
http://www.clubcobra.com/forums/atta...dapt-256-1.jpg

Jay with VintageMotorsports would for sure.

Hub looks like this on Mayhem
http://i235.photobucket.com/albums/e...pszxb8xrkp.jpg
http://i235.photobucket.com/albums/e...psnlphcsha.jpg

[Grey 65]

Contact Brian at Backdraft Parts in Miami....

Original BDR's had BMW hubs.
Then they had specially made hubs with pop in end caps.
Currently they have specially made hubs with screw in end caps.

About 2 years ago Backdraft switched the newer hubs with screw in end caps.

I broke the hub with pop in end caps and they sent me two new hubs with the screw in end caps.

Kevin.....

[wolf k]

Thanks, will do.
Current hubs have the pop in end caps.
Do the new hubs appear to be stronger?

[spdbrake]

Correct me if I'm wrong but that's half the axle bearing still attached to the broken Spline piece on the right side of the photo.
Where that hub sheared at the bearing the only thing that kept the wheel from exiting the car was the Wheel well tub and the caliper.
Since the caliper is aft and due to the rotation, the wheel could have jumped under the caliper and then exited. Was there any wheel tub/fender damage?

I'm not liking the metallurgy on those hubs.

[Grey 65]

Originally Posted by wolf k

Thanks, will do.
Current hubs have the pop in end caps.
Do the new hubs appear to be stronger?

I race my car and haven't sheared either of the two new hubs...

Kevin.....

[wolf k]

Originally Posted by spdbrake

Correct me if I'm wrong but that's half the axle bearing still attached to the broken Spline piece on the right side of the photo.
Where that hub sheared at the bearing the only thing that kept the wheel from exiting the car was the Wheel well tub and the caliper.
Since the caliper is aft and due to the rotation, the wheel could have jumped under the caliper and then exited. Was there any wheel tub/fender damage?

I'm not liking the metallurgy on those hubs.

Correct, the only thing keeping the wheel from departing was the caliper. He did have some light damage to the rotor, caliper, and parking brake assembly.

[wolf k]

New hub on right. Looks like there is a slight design change, Splines on the new hub extend all the way through hub ID. Whereas on the old hub, splines do not. That is where the old hub broke, where the splines ended.

[spdbrake]

Thanks for posting that. I now know what to look for if I'm ever in the market for another BDR.