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1973 450 SL
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Discussion Starter · #1 ·
You all know that I know dick all about mechanics, but I am trying.

I am in the process of cleaning up the undercarriage of my 73 450SL and would like advice on the proper jacking points for a floor jack and the proper placement of the Jack Stands.

Front End:

Any problem with options 1 and 3, or is it highly recommended that the proper place is a 2x4 between the jack and oil pan?

The Jack Stand points appear to be quite obvious.



Back End:

Jack point under the differential.
Jack stand points as shown in the photo?



Loren
 

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'72 350 SL
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375 Posts
I bought a pair of jack stands on Saturday, Loren!
Thanks for bringing this up - I just assumed they just went on opposite sides where you would put the car jack if changing a tyre.
 

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1986 560 SL
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Maybe I have been doing it all wrong, but I have always placed my hydraulic jack under the side sills near the jack tubes, with a piece of wood between the jack and the sill. Jack stands go close by.
 

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1981 380SL - Lorinser bodykit w/16x7 LOs - AKA "Frau Blau"(Lady Blue)
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I just had the 380 up on stands the last four nights in a row.
Saturday and Sunday was doing the fuel system inspection and filter replacement in the back.
The jack point I used was in the last pic, just to the right of the arrow, a circular nut and bushing. Jack stand positioned between edge of the A-arm and the bottom shock mount.
Yesterday was working on the front, replacing vac fittings on air pump.
Jack point exactly where the arrows are. Jack stand immediately behind that toward the rear of the car.
If I was to want to jack up the whole front end, I would use #1 as the jack point, centered with jackstands at either side at the last red arrows in the first pic.
I NEVER jack on ANYTHING that is not related to the frame.
A jack/stand point ALWAYS has to be able to support the weight of the car.
I ALWAYS have a BACKUP. I leave the jack supporting the car with it barely resting on the jackstand(so you can't accidently kick it out of it's position)
Can't be too careful when it comes to safety!
 

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bandit96 said:
If I was to want to jack up the whole front end, I would use #1 as the jack point,

That whole piece flexes in an upward twist when used as a lifting point. Can't be good.
 

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1973 450 SL
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Discussion Starter · #7 ·
But surely position 3 has to be ok. What your saying with position 1 is that the metal itself will twist, and if that's the case I would have to agree.
 

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1981 380SL - Lorinser bodykit w/16x7 LOs - AKA "Frau Blau"(Lady Blue)
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^Really? That's not tied into the frame? It looks like a frame crossmember. Good to know. Although I try to never have more than one wheel off the ground anyway...
 

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82 380SL 96 SL500 03 SL500
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think subframe
 

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2010 Mercury Milan Hybrid, 1993 BMW 325i convertible
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When I jack up the car, I position the jack just under the shock absorber and lift it there. If it's going to be up in the air any length of time. I position jack stands under the side jack sockets on the car. My jack stands have fairly deep recesses on top, and the crease from the fender meeting the floor pan just fits, without distorting any metal.

The front and rear subframe are both just connected with a couple of bolts and rubber. I wouldn't want to twist and torque either of them.
 

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But surely position 3 has to be ok. What your saying with position 1 is that the metal itself will twist, and if that's the case I would have to agree.


As Scott said, the subframe, #s 1 and 3 in your pic, is attached to the unibody with four bolts. The service manual shows complete lifting of the front done at the sump. Not without reason, I would imagine.

When only lifting one front wheel I would agree with Scott about the use of the lower control arm at the shock mount. Far less overall lifted height needed to clear the ground.
 

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1986 560 SL
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I don't like the idea of jacking the oilpan, despite what the manual says.
Lots of stress in odd places.
 

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1973 450 SL
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Discussion Starter · #13 ·
Thanks, All

So in conclusion, when lifting the front end use the sump (oil pan), and place the jacks as per the positions shown in photo 1 (on the frame).

For the rear lifting point, use the differential, and for jack stand points use a point below the jack tubes with wood blocking, I would assume. My jacks would be similar to yours, Scott, with a very deep depression recess on the top.

I just don't want to screw anything up, and as has been pointed out, there most certainly is that possibility.

BTW, the CD service manual doesn't talk about this, or perhaps I just haven't been able to find it. One would think the front and rear lifting and jack stand points would be described.

What (paper manual) section is this in?

Loren
 

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lfedje said:
BTW, the CD service manual doesn't talk about this, or perhaps I just haven't been able to find it. One would think the front and rear lifting and jack stand points would be described.

What (paper manual) section is this in?
I don't have service materials any more, but I thought it was on the CD.....
 

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1984 380SL
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The CD does cover this topic in the Chassis part section 40-013. It calls out for the use of qty 4 "jacking up shoes" This very custom looking device stabs into the jack tube holes and then has a pad that wraps under the rocker panel. They also show some very nice jack stands with a circular pad that go under these jacking up shoes. The jacking up shoe part number is given as 123 589 11 63 00. I am certain they should be readily availeable at your local Pep Boys
 

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1973 450 SL
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Discussion Starter · #17 ·
Thanks, obanos

I did actually see that section of the manual. It looks like a good alternative to concerning yourself with undercarriage damage. Will have to check into the cost and availability. My next question is how these will work with my existing stands.

Loren
 

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Outstanding Contributor , Bob's Your Uncle!
83 280 SL- 5 speed-The PIG
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I do things differently....might not be the best, though.
I put my floor jack under the "subframe" rail under the floor pan.
Positioned in the middle, the floor jack picks up the whole side of the car. I then put the jack stands on the rocker panel near the jack points.
 

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1977 Mercedes 280SL, 2002 Mercedes CLK 320 Sport, 2009 Mercedes ML350
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Interesting discussion. I prefer lifting the front end / rear end up completely. (as opposed to the sides). I've been using position 1 - which is easy to reach with my jack. I didn't notice any bending of the metal. I don't like lifting by the engine, thinking that the engine mounts are designed to hold the engine up, not the other way around. If Mercedes has this as the recommended procedure than I guess it's fine - but I'm still not going to do it. The sub-frame is under the body - so it's designed and does carry the weight of the car every day. I may fabricate some sort of adapter to widen the load point, but I'm still planning to lift at point 1 moving forward.

Now for jack stand points. I used the same points as the arrow (after having lifted the car at point 1). However, when lowering the jack I was shocked by the amount the whole body flexed! The entire weight of the engine is ahead of those jack stand points, and the whole thing flexed - what seemed like a whole inch. This is a heavy convertible, so maybe this is normal? I was afraid to leave the car just on the stands, and kept the jack under the front as well. Of course is shops they'll just lift the whole thing and let the front dangle. Anyone notice this as well? Or maybe I have a weakened frame?
 

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R/C107 Moderator
1986 560SL: '84 500SL: '84 280SL 5 speed: other 107s
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I made these so I could still move the car around while the engine was out. I added a pipe under the car to bolt them together because they tended to flex apart. Worked OK. Would have rolled better with bigger casters and shorter pipe. But I could push the whole car around myself with a little effort.
 

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