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Old 11-19-2012, 08:36 PM   #68
WDE46
Registered User
 
Join Date: Sep 2012
Location: Virgo Supercluster
Posts: 8,726
My Ride: 2004 330Ci OBM
Quote:
Originally Posted by FenderGuy05 View Post
Lifting the rear so high to get a stand under the front seems pretty dangerous though...imo
I lifted my car today using Mango's method. I did this because last time I bent my front reinforcement plate using that spot. It worked, but I don't want to try it again. Anyway, Mango's method works, but it was sketchy at one point

First, I lifted the rear right and placed a jack stand under the front right pad. I then lowered the car onto the jack stand. Second, I lifted the left rear of the car. I lifted it to the limit of my jack and the front tire wasn't off the ground. I realized I was actually lifting the entire rear of the car instead of just the left side. Luckily, I merely had to pull up with about 30 lbf on the front fender and the car slowly tilted and put the right rear tire back on the ground (it was almost perfectly balanced). I put the jack stand under the left front, then I lowered the car. It was safe, but the seesawing I did was strange. I had to rock it back to remove that same jack stand later. With a full tank of gas, this would not happen probably, but neither the front or the rear of the opposite side will have much load on it until you lower the rear back down.

I would also recommend not applying the parking brake. Honestly, I would just put it in neutral w/ no brakes and double chock (front and back of the rear wheel) the wheel on the side opposite of your current lifting point. I recommend this because the rear suspension needs to be able to settle and the rear wheel needs to rotate to allow it to do this. If you leave any brakes on, then release them when the car is on the stands, it will shift itself backwards quite a bit.

My final conclusion on Mango's method is that it works just fine. The lateral forces on the jack stands are kept to a minimum provided you don't have on any brakes. I didn't lift the rear, but Mango just recommended the same place everyone else knows to use. As a side note, your jack needs to be capable of at minimum 16 inches of lift for this method to work. 16 inches at the rear will give you about 12 inches at the front. Luckily I could do 18 inches with the jack I bought.

I thought maybe I'd include some credentials though I won't prove my claim. I am a Mechanical Engineer who works in the automotive industry. I do have a very deep understanding of forces, both static and dynamic. In this scenario I simply visualized the applied forces and it seemed safe to me, so I continued (even with the seesawing action).

Last edited by WDE46; 11-19-2012 at 08:40 PM.
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