318 drum to disc conversion

[Group A]

ok, before anyone bitches about 'search' i did and i did get some info, but want to be 100% before going into this project.

from what i understand all you really need is:

rear trailing arms and disc brakes (caliper, brackets, rotors)
and possibly new m/c and e-brake line

am i correct? everything should just be straight forward and bolt right up with little to no fabrication needed, right? i'll also appreciate it if someone can link me to a good write-up for this too.

Thanks

[PiercedE30]

Sounds about right.

[Jean]

To do this conversion on my 318i, I purchased a complete set of trailing arms with calipers and e-brake cables.

I disconnected the e-brake cables from inside the car and pulled them out from under the car, then removed the trailing arms. On the passenger side you'll need to disconnect the rubber fuel hose that goes to the fuel tank as it's in the way. Now would be a good time to replace rear brake lines, as they are easily accessable. Also think about replacing rear trailing arm bushings at the same time.

One thing I didn't do is get rear abs sensors, you might want to just keep them in place and just remove the wires going to them, otherwise you'll have holes where they would normally be. Probably not a big deal, but I don't know how much dirt could get in there....

Replace the trailing arms, brake lines, install new rotors and/or pads, feed the e-brake cables from under the car , connect at the e-brake inside the car.

I also got a new 325e (non abs brake master cylinder) just in case, I haven't compared it to the 318i mc though.

[Brinkley]

nice work. I'm in the middle of this myself. Did you replace the 318 diff? i pulled my arms with axles diff still attached as i couldnt the axles out of the hubs. I thought the e brake cables were the same from what i could tell.
please compare the master cylinders if you would that would be a big help!

[Jean]

Yes, Sorry forgot to mention. I pulled the trailing arms complete with the half shafts attached and did swap the 3.64 open diff for an LSD.

[Brinkley]

cool i wasnt planning on getting this involved but the subframe bushings on mine are shot worthless
OP I would go ahead and replace my subframe bushings while you are at it if yours are gone
I angle grinded my brake lines free :) as they were being bitches then got the arms off. youre going to need a 19 open end wrench and a generous breaker bar to free the trailing arms.
Get car in the air free E brake cable
disconnect shock
use a prybar and pull spring out
put a jack under the diff, remove the 4 subframe bolts (i put a pipe on my ratchet and used it as a breaker bar) and get the rear diff bushing bolt out, lower diff
pull gas tank hose on the passenger side, remove trailing arms with diff in one piece
DO YOUR SUBFRAME bushings now i wouldnt want to have to do this again
reassemble!

[Brinkley]

the only thing im worried is reconnecting the e brake cable it was easy to disconnect from the drum doesnt look so easy to reconnect for the disc park brake

[Jean]

the only thing im worried is reconnecting the e brake cable it was easy to disconnect from the drum doesnt look so easy to reconnect for the disc park brake

Leave the e-brake cables connected to the trailing arm assembly, just disconnect from inside the car and pull them out with the trailing arms. Then feed the ones connected to the disc brake trailing arms from under the car into the cabin. No need to disconnect or mess with them ...