Floor jack under oil pan OK?
 

Just wondering if it was ok for me to jack up the car using a floor jack under the oil pan. It's a 98 CLK 320. Thanks!

No !
 

Absolutely not! Use the jack points or a structural crossmember.

Also, on the rear, do not jack from the differential.

Jeff Pierce

Broken motor mounts and a damaged oil pan come to mind.

OK...how about under the lower control arms?

Those are usually ok but keep in mind that they will move as the car goes up. They will want to pivot downward, so keep that in mind.

Thanks
David

I wouldn't do it. The jack could slip and the car could fall. I would use the rubber pads under the car near the jack points. These are for when the car is raised using a four point lift. Btw, what are you trying to do?

jacking the car under the oil pan is what I did when I replaced the motor mounts, to raise the engine. However, I used a big piece of wood as a spacer between the jack and the oil pan (6x2, a foot long), and made sure the linkages were disengaged to make sure i do not break anything...

That's what I always do... why is it bad?
Bruno

No, no, no, no, no!!!!!!!!!! NEVER EVER JACK A CAR UP FROM THE OIL PAN!!!!!!

The only time you might need to touch the oil pan with a jack is if you are replacing engine mounts. But I would be carefull doing that because oil pans are pretty ting and you could bend it.

MB's have 4 jack points one on each corner or the car, thats where you jack from.

Jacking from the diff is also a bad idea you could damage the diff mount.

If you don't have to pull the wheels, it's a lot easier and safer to work on a car on ramps. A pair of plastic ramps is ~$25 at Wal-Mart. Don't put the ramps under the oil pan ;)

Sixto
95 S420
87 300SDL

The differential on an indepenent rear suspension car is mounted with rubber bushings and is designed to withstand twisting/lateral force -- not the upward force of the entire car.

Think of it like this: You have a vertical beam in your basement that's holding up the living room floor. You can invite 50 friends over for a party in the living room, and that beam is gonna hold them just fine. (if each friend weighs an average of 150 lbs, that's 7500 pounds.) But if you go in the basement and hit that beam with a 200 lb blow with a hammer, it's going to knock it out of place, and down comes your living room, with all your friends in it. That beam can handle 7500 lbs if it's coming from above, but it can't handle even a small load like 200 lbs if it's coming from the side. Same principle with your differential.

I don't know if that helps, but don't jack from the differntial -- it's a bad thing. (I do jack my '93 Volvo from the differential though, because it has a solid rear axle.)

Jeff Pierce

Along these same lines, if I use a floor jack to jack up the car at the jack point, where can I put a jack stand so I can move the floor jack to another jack point since there is not enough room at the jack point for both a floor jack and a jack stand? This refers to a C280 but I'm sure the answer will apply to many models.

Dan

Is a solid iron stand good or is a moveable one better? I saw ones that have an extendable leg that you can pry at a certain level (like when lifting weights, you put a pin on the heaviest and the entire set of weights from the pin will lift). TY!

My car is lowered. I got this response:
 

"Aaron
Moderator Join Date: Aug 1999
Location: Cincinnati, Ohio
Posts: 1,767


If the car is lowered, the only choice you have is to get a floor jack with a low-profile saddle which will slide underneath it so you can jack it up at the crossmember in the front and at the pumpkin in the rear.

------------------
Rgds,
Aaron Greenberg
MB technician
Precision Motorcars, Cincinnati, Ohio"

So, this is what I do.

So the million dollar question is....
 

What the ()&_&* is a pumpkin and a crossmember? Many thanks!

Was Aaron refering to a live (solid) axle car? I've only heard differentials refered to as "pumpkins" on live axles. In any event, I also jack the front at the cross-member, then put the jackstands at the jacking points. I would not recommend jacking the rear from the differential on an IRS car -- I also wouldn't trust a tech who says that it's OK to do so.

Just my 2 cents... arguably worth that.

Jeff Pierce

I hate to say it I repect Aaron but he is wrong on that one. Jacking a car with an IRS up by the diff is a very bad idea and you are asking for trouble. Ask any MB dealer they will look at you like you have two heads.

I jack up the front at the crossmember, and put the jacks at the jack pad.

I jack up each side of the rear end independently, using a couple of 2x4s on the sills just in front of the jack pads, and put the jacks at the jack pad. My car is a monocoque, so the sills should be structural.

I jack up the front of my 97 C230 at the designed jack points [rubber pads] .

I place the jackstands under the frame rails located inboard from the jack points. I use a 6x6 piece of plywood between the jackstand and the frame rail to provide a cushion >> no metal to metal contact.

Yea > it's easier to jack up the complete front end in one action >> but IMHO > "no" to jacking up the front via the oil pan.


I do use the "central" method in the rear though... >> maybe have to re-look

I assume the crossmember in front is the cross brace on tne sub frame. I can get all the way to the sub frame so I use that even though I have used the cross brace as well. I see it flex and it makes me nervous. I also assume the pumpkin to mean the differential housing. What else could it be?