Thursday, July 17, 2014
Jacking Up The E46
I've been meaning to give the E46 an overdue brake flush so I could use it the next few months as I take the E36 out of commission for paint and interior work. I've been dragging my heels because I long ago realized that I'd have trouble jacking the front end of the car but this week I concluded that I couldn't wait any longer and had to figure out a way around the problem that didn't involve using a lift.
The E46 was introduced in what I call the “beginning of the end” of the classic BMW era. In this era BMW at least gave a passing thought to how its cars might be used by its enthusiast customers in the real world, and made the cars relatively easy to service at home or at the track using tools and equipment that you might find in the average garage. Toward that end, the E36 and earlier models provided a front center jacking point that could safely support the weight of the car. Early E46's came with a center jacking point as well but it was removed on the 2001 and later models – including mine.
At the same time BMW installed a “flat” aluminum cross member designed to increase structural rigidity. Unfortunately, this cross member will not support the weight of the car and therefore cannot be safely used as a jack point. While this limitation is well known at this point (E46 production ended 8 years ago after all) this fact has not stopped self-proclaimed experts from posting videos entitled “how to jack the E46” only to clearly demonstrate the consequences of jacking under that support.
Of course it's quite possible to jack the front end of the E46 safely without a lift and people do it every day without issue, but it requires a slightly different approach as compared to the E36:
- Two jacks are required
- The jacks must be carefully set under the inner frame rails so the “approved” jack points close to side of the vehicle remain free to accept a pair of jack stands to support the vehicle for the duration of the work.
- The load of the jack pad must also be spread over a sufficiently large area of the rail. My AFF200 jack has a relatively large flat jack pad that is ideal for this purpose but many other jacks have a smaller metal pad, and still others have a “cupped” pad. Ideally a small section of 2x4 or other sturdy piece of wood should be placed between the jack pad and frame rail or the jack pad may deform the frame rail and considerably weaken it. It's a structural member so this is critical!
- The front wheels will need to be driven up on a couple 2x8's or other suitably dimensioned lumber as there is typically insufficient clearance to push the jacks far enough under the sides of the vehicle to reach the inner frame rails. You might be able to avoid this if you're jacking an Xi (AWD) model as the suspensions are typically an inch or so higher than the sport package cars, but more clearance is better generally speaking so it can't hurt.
- The jacks must be raised more or less simultaneously by pumping up each jack a few strokes at a time. If you try to raise one jack all the way and then set a jack stand on that side before pumping up the other side you risk the car falling off the jack stand. I've never seen this happen, but I've heard it can and does happen, so try that strictly at your own risk.
BMW also replaced the more or less flat jacking pucks mounted to the bottom of the E36 with hard plastic “receptacles” that are primarily designed to accept the factory “death jack” (the one in the trunk you might, ironically, think twice about using on the side of the road). If you try to use something other than a jack stand (or lift) with a flat jacking pad (like my Hein Werner jackstands designed for axles) the edges of these receptacles can be crushed due to the point loads. This explains why I have finally decided to splurge on a set of ESCO flat top jack stands.
I originally planned to order the stands from local supplier Ultimate Garage but Steve apparently stopped selling those some time ago and now has decided to get out of the BMW parts business altogether so I wound up buying them from long-time Roundel advertiser Reverse Logic. Incidentally, Reverse Logic offers a replacement post for the ESCO flat top jack stands that is designed specifically to mate with the E46's jacking receptacles but at $45 each (80% of the cost of a stand) I could not justify the expense. However, for those that want a positive, interlocking fit between the stand and vehicle and can accommodate the extra cost they appear to be well constructed pieces.