Our car experts choose every product we feature. We may earn money from the links on this page.
Who knew replacing a simple set of mounts would be so difficult?
This past summer I went out and bought an E46-generation BMW M3 with an astounding 284,000 miles on the odometer. While the body and engine were in good condition when I picked it up, almost everything else on the car was not. The suspension was almost all original, with a vast majority of the bushings absolutely shot. The steering was in desperate need of a refresh, as were all of the rubber pieces holding the drivetrain to the car. In an effort to make my M3 feel a bit better going down the road, I decided to replace the engine and transmission mounts. What I didn’t realize was how hard it would be.
That’s what I was thinking going into this job. I ordered a kit specifically for the M3 put together by FCP Euro that included both engine and transmission mounts, as well as new bolts so I wouldn’t have to reuse the old ones. I’ve only replaced engine mounts once before on a BMW, and it took less than an hour. So I figured it would take a similar amount of time to complete on this E46. But I was dead wrong.
Getting access to the bolts that hold the mounts to the subframe and the motor wasn’t an issue. In fact, I barely had to remove any trim to get a socket and ratchet onto any of them. Getting the old mounts out wasn’t even a problem. I simply put the car on a lift and raised the motor with a ¾ ton under-hoist stand to get it high enough to where the transmission was actually pushing against the top of the firewall. The problem came, as you’ve probably guessed, when I tried to put the new mounts in.
The old mounts, likely the original units that came with the car from the factory, were permanently compressed roughly half an inch versus the new items from being in the car for so long. So while there was just enough space for them to come out, there was absolutely no room for the new mounts to go in. I fought for almost an hour to get the driver-side mount in, and another two hours to get the passenger side unit fitted. I was on the verge of giving up before I got the idea to use a gigantic four-foot pry bar sitting around the shop to get enough leverage to compress it into place. It was a nightmare.
The upside is, my E46 is now noticeably better to drive. It’s not some crazy night-and-day change, as most of the suspension is still trashed, but it’s clear the car feels tighter than it did before, with none of the sketchy weight-shifting over big bumps.
The transmission mounts were worlds easier to install, as I just had to drop the carrier that sits under the gearbox and place the new units in. Considering how deformed the mounts on the car were, they were likely original as well. The shifter is a bit less floppy than it was before, but there’s still a lot of play because the bushings attaching it to the linkage are shot.
If you read one of my past updates on this car you’ll remember just how off-center my steering wheel was thanks to new tie rods I installed myself. I finally got the time to take the car to get an alignment at a dealership. Before you accost me for bringing a car like this to a BMW dealer, here’s why I did it: I wanted to also get a diagnosis on my ABS and traction control lights, and the only way to do that was through a dealership, since I didn’t have the appropriate diagnostic tools. In addition to giving me an alignment, they also told me my steering angle sensor had gone bad, causing those lights to illuminate on the dash. Guess that’s another thing to add to the list.
I wanted to bleed the brake fluid when I replaced the front pads and rotors, but couldn’t at the time because I didn’t have access to a lift. I’ve since been able to get this car up in the air and immediately got to work bleeding the old fluid out. And as I suspected, it desperately needed to be changed. What came out looked more like Dr. Pepper than it did brake fluid. Gross. Unsurprisingly, the pedal feels a lot more solid now.
In addition to the steering angle sensor and shifter bushings I mentioned earlier, there are a handful of other small issues I’d like to address before moving onto the big suspension job. The flex disc that attaches the gearbox to the driveshaft needs to be replaced, as does the joint that secures the steering column to the rack. The sway bar end links are trashed, and need to be renewed. Plus transmission fluid needs to be bled and replaced.
After all of those things are done I’ll finally get to the shocks and springs. Then, if I have the budget, refresh the cooling system and get someone to weld some reinforcements into the subframe mounting points.