I am to do an oil change and caliber painting on my 2004 525i.

1. My jack stand is shapped like a "Y" shape (like with two "heads"). I noticed the two side rails are flat with the rest of the car except where the 4 jack points. So, once I jack up the front of the car, shall I place the jack stand so that the two heads go front and back, or side to side? On my Honda Accord, the rails are lower than the rest of the car and thus they can sit securely as long as the jack stand's two heads go side to side instead of front and back. But this 525i's rails are flat to car's belly, so I am confused how the jack stands should support the rails.

2. Can somebody help explain where exactly is the jack point for the rear of the car, other than the two rear jack points along the side rails in front the rear wheels. I am looking for the rear jack point along the center line of the car. Someone mentioned rear differential is the place, but I don't really know how they look like, and what part of the differential should be used vs. avoided.

Thanks!

 

1. Not 100% sure what you mean - perhaps a picture will help. If I understand correctly, I'd place the jack stands so the "Y" goes front to back on the jack points.

2. The rear differential is the rear center jack point. Some E60's have fins on the diff - don't put the jack on those fins or you could rip them off the diff. Also, I wouldn't jack up both ends at the same time (i.e. a 4 point jack); I'd do the front, then lower it, then do the rear. More stable that way.

 

Thanks.

I looked the rear end of the car, and saw a silver metal block with layers of metal shelfs (vertically orientied I think). Is that the fin?

What I am not sure is what exactly the differential look like. Is it the whole piece running from left rear wheel hub to the right rear wheel hub? And the fin is an extention at the center point of the differential? In that case, I need to jack up exactly at the center of the differential, but must make sure the hydraulic jack does not touch the fin?

 

If you draw a "T" using the driveshaft and axles to the rear wheels, the differential is the meeting point of those three lines - the big bulbous hub that converts the driveshaft's rotation into rear wheel rotation.

It makes me a bit nervous when you say "I need to jack up exactly at the center of the differential"; well, yes and no. You need to jack at the center of the rear part of the differential - not the smack dab middle of the whole unit itself. In other words, imagine that you're sitting at the rear bumper and can see under the car. You'd be looking at the back of the differential, which (most likely) has a whole bunch of bolts surrounding it (which attach the back plate to the differential housing). Assuming your differential doesn't have any fins, you'd place the jack such that the pad contacts the differential at the 6 o'clock position of that back plate. Hope that makes sense.

If your diff does have fins, you may or may not be able to jack using the diff. Some fins are even with the diff (in which case you can jack from there), and others actually hang down below the bottom of the diff (in which case you can't).

If you're unsure about what to do, do what I did: go to the dealer, walk into the service area, and ask a tech to show you exactly where to jack from. If you don't do that, you may be visiting the service techs anyway if you screw up your diff.

Another (easier) solution: just jack up each rear side using the jack points on the side of the car, and do each side one at a time. No muss, no fuss, no chance of messing anything up.

 

I finally got some pictures from underneath the car. Here are my questions and I have marked in one of the picture where I am refering to for each of the questions below:

1. Is this the differential, or the heat sink behind the differnential, or something else?
2. In another word, does driveshaft and two rear axles meet IN FRONT OF or AT this heat sink?
3. The silver beam (made of multiple segments) behind the heat sink seems to be better place than differential for jack point, right?
4. Is this a good location for jack point as well,
as long as bolts and this round soft piece are avoided?

 

1. Yes, that's the differential. The "fins" are the heat sink at the back of it.
2. Driveshaft goes from front of diff to engine. Rear axles go from sides to tires.
3. GOOD GOD NO!
4. See #3 above.

The only rear jack point is the rear differential, but not on the heat sink.

These pictures might help. Note: my car does not have the fins on the rear of the diff.

 

Why "3. GOOD GOD NO!" to my question #3? What is this silver metal beam running from side to side? I seem to remember a friend of mine jacked up the rear passenger side of his Benz by jacking that bar close to the rear passenger wheel.

 

Well, the easiest answer is "Because it isn't the right place". Can it handle the weight? Maybe. Try it and let us all know.

Are you sure that the bar on your friends car is the same as the one on yours? Willing to pay the price if it isn't? You don't know what the bar is, and "seem to remember" something with a friends car? If you're not right, it could be Very Expensive.

 

I used that beam instead of the differential when I did my rear spring swap.

 

If i'm not mistaken those axle stands are on the CV joints, dangerous for two reasons:
They turn so are not solid or fixed and they are not designed to withstand any sort of torsional load, the joint will fail or the diff bearings will shatter.