How to change the rear speakers in a 318ti
By
Eric Miller As you probably know, the rear speakers in a BMW 318ti are not a standard size. The only aftermarket speakers that fit without modification are MB Quartz (size 4T), there may be others so don't quote me on that. This article describes my efforts (with pictures) to mount Eclipse 4" speakers in to the stock rear speaker mount.
First remove the side bolster from the back seat and carpet and trim from around the speaker, disconnect the wires for the tweeter mounted in the grill piece, then remove the speaker mount (4 screws) from the grill piece. This should be fairly self explanatory if you look.
De-solder the wires attached to the speaker poles, we will solder these to our new speakers. You can see that the speaker is held in place by 4 tabs around the edge that have locked in place under a tab, and secured with glue. Using a thin flathead screwdriver, carefully inch the blade around the edge of the speaker to unseat the glue (pic below).
You pretty much have no chance of rotating the speaker to get the tabs out of the way, so I just busted them off. You could still use the old rear speaker if you use glue, I suppose. Pry the speaker out of the mount.
A standard 4" speaker will not fit into the original mount location because of the mounting holes sticking out in the 4 corners. What I did is bend these corners back so the mounting hole is then perpendicular to the face of the speaker. Be careful not to bend the metal where the cone attaches.
(since the board limits the number of images per post, the write-up continues in the next post below.)