Proper use of floor jack and jack stands with a 123-chassis 240D: place where, how? - Page 4 - PeachParts Mercedes-Benz Forum

dmorrison · #46 01-22-2008, 01:34 AM

Quote:

Originally Posted by rino

Thanks for the explanation!

So in the case of the 240D you had the saddles (6-ton jacks) raised at about 18" (4 clicks) off the ground, with the front wheels on the floor... And that with the jacks saddles right under the frame box (near the MB jack holes), correct? Wow, that way the car is positioned at a pretty steep inclination...
Even if you place a set of good chocks under the front wheels, I don't know how safe I'd feel working under a car with the rear or front end raised that high. But then, again, I don't have much experience with this type of scenario, and I assume that once you start playing around with it then confidence follows.

I'll give my new 6-ton jacks a try in a week or so... I can't wait...

Rino

Rear wheels on the ground, with transmission pawl in place, parking brake on and wheel chocks. It's really not unsafe.

Dave

rino · #47 01-22-2008, 10:57 AM

Quote:

Originally Posted by dmorrison

Rear wheels on the ground, with transmission pawl in place, parking brake on and wheel chocks. It's really not unsafe.

Dave

Wait a minute... As far as I understand it, the only things holding the car steady
in the instance you described (while working on the speedometer cable with the
rear wheels off the ground) are the chocks, and the jacks' saddles gripping the
frame box at the points of contact.
Both the parking brake and the transmission act upon the rear wheels only, and
when the latter are off the ground... only the chocks and jack stands prevent the
car from moving forward.

Rino

dmorrison · #48 01-22-2008, 12:04 PM

Rear wheels are ON the ground, front wheels are off the ground

Dave

rino · #49 01-22-2008, 05:15 PM

Quote:

Originally Posted by dmorrison

Rear wheels are ON the ground, front wheels are off the ground

Dave

I read the whole thing again and, yes, YOU'RE RIGHT!

But suppose I go about changing the differential fluid and place
the 6-ton jacks, at the 2-click level (16-1/2" height), under the
frame box, with the back wheels up and the front wheels on the
ground, which should give me enough space under the rear end
to do the job...
Do you think it safe, in this case, to rely on just the chocks (and
and the jacks' saddles at points of contact) for stability?

Soon, I'll have to do that job too, and I'd definitely appreciate your
expert advice in that regard.

Thank you, Dave, you have been tremendously helpful.

Rino

TheDon · #50 01-22-2008, 05:19 PM

safe.. I was under it while doing the engine mounts.... do it all the time

buy a set of Mercedes wheel chocks

dmorrison · #51 01-23-2008, 01:34 AM

Rino

Your really putting way to much thought in to this. Be safe but you need to experiment with the setup you have. Jack the car up and place it on jack stands. Shake it and see if it seems stable. If it's stable, try jacking it up farther. I would not place the car on the highest position, it's like stepping on the top part of a ladder, just not advised. Take some time to learn your tool setup and work with it. Experiment without getting under the car and you will learn whats safe.
As shown in the picture above it is workable and safe.

Dave

carusle · #52 01-23-2008, 08:30 AM

Ramps

vstech · #53 01-23-2008, 10:28 AM

ON a level surface, chocks are not needed or recommended for lifting a vehicle with a floor jack. after it's settled on the jack stands, placing chocks behind the supporting tires is a good preventative measure, but not needed. if the surface you are supporting a vehicle is not level, be VERY CAREFUL. also, if the surface is out of level in more than one plane, avoid jacking the vehicle at all.

as long as you are on a solid level surface, don't worry about chocks or parking brake, it's not necessary. just use a good pair of jack stands, and go to work.
chocks ARE needed if your vehicle is up on ramps, cause the tires could allow the car to roll.
for HEAVENS sake, be SURE the vehicle is STABLE by shaking the car firmly BEFORE you move the jack.
(hey, lets use jack for the lifting device, and stand for the holding device in our wording...)
as for where I place my stands for supporting the front of the vehicle, I place them on the FRAME of the vehicle near the LCA mounting place. there is always angles of steel to keep the stands secure. I only use wood if I have to jack up something fragile. or if I need to REALLY lift up the vehicle, like say above 24" I jack up the car, put it on stands, lower the jack, put a 4x6 on the saddle of the jack, and lift the car further, then set the steel of the stand on the steel of the frame of the car, not the body, not the jack points, the FRAME.

rino · #54 01-23-2008, 01:12 PM

Quote:

Originally Posted by dmorrison

Rino

Your really putting way to much thought in to this. Be safe but you need to experiment with the setup you have. Jack the car up and place it on jack stands. Shake it and see if it seems stable. If it's stable, try jacking it up farther. I would not place the car on the highest position, it's like stepping on the top part of a ladder, just not advised. Take some time to learn your tool setup and work with it. Experiment without getting under the car and you will learn whats safe.
As shown in the picture above it is workable and safe.

Dave

OK. My asking so many questions... it's just that I've heard stories of
people not doing it right and getting crushed under their vehicles
as a result... I never got to raise the vehicle this high with the old stands,
so I wanted to make sure I understood enough about it to be on the safe
side. Excellent advice, yours, by the way. Thanks.

Rino

rino · #55 01-23-2008, 01:25 PM

Quote:

Originally Posted by vstech

ON a level surface, chocks are not needed or recommended for lifting a vehicle with a floor jack. after it's settled on the jack stands, placing chocks behind the supporting tires is a good preventative measure, but not needed. if the surface you are supporting a vehicle is not level, be VERY CAREFUL. also, if the surface is out of level in more than one plane, avoid jacking the vehicle at all.

It's a perfectly solid level surface, in my garage.

Quote:

Originally Posted by vstech

as long as you are on a solid level surface, don't worry about chocks or parking brake, it's not necessary. just use a good pair of jack stands, and go to work.
chocks ARE needed if your vehicle is up on ramps, cause the tires could allow the car to roll.
for HEAVENS sake, be SURE the vehicle is STABLE by shaking the car firmly BEFORE you move the jack.
(hey, lets use jack for the lifting device, and stand for the holding device in our wording...)

I've always made sure to test it that way first thing after putting it on stands.

Quote:

Originally Posted by vstech

as for where I place my stands for supporting the front of the vehicle, I place them on the FRAME of the vehicle near the LCA mounting place. there is always angles of steel to keep the stands secure. I only use wood if I have to jack up something fragile. or if I need to REALLY lift up the vehicle, like say above 24" I jack up the car, put it on stands, lower the jack, put a 4x6 on the saddle of the jack, and lift the car further, then set the steel of the stand on the steel of the frame of the car, not the body, not the jack points, the FRAME.

Now, this is new to me. I've always placed the stands under the frame
box, near the jack points. Why would that not be advisable? Where do you
you place the stands for supporting the rear of the vehicle?
Please keep in mind I have a 240D... I have been told in several instances
that with this model it is best to place the stands under the frame box close
to the jack points...

Rino

dmorrison · #56 01-23-2008, 01:35 PM

Quote:

Originally Posted by rino

OK. My asking so many questions... it's just that I've heard stories of
people not doing it right and getting crushed under their vehicles
as a result... I never got to raise the vehicle this high with the old stands,
so I wanted to make sure I understood enough about it to be on the safe
side. Excellent advice, yours, by the way. Thanks.

Rino

Good approach, Always be safe. But it's time for the little birdie to get out of the nest and go experiment. If your unsure about your stability of the stands, might I suggest multiple stands. Go to Harbor Freight buy an extra set of stands, I own 4 sets of stands. 3-6 ton, 1-3 ton. At times I have used 2 sets of stands on one end of the car. My normal points and some other points "just in case". I do this when there will be a lot of shaking and movement. The second set is there for my safety. If the car falls the safety stands will probably damage the car but save me. I'll place them under the floor section or somewhere out of my way, for the job, but will support the car just in case.
Go give it a try, don't get under the car until your satisfied that the car is safe. Spend an hour or so experimenting with the stand placement.

Dave

vstech · #57 01-23-2008, 02:16 PM

I have not had the rear of my D sedan up in the air... so I can't be specific as to where to put the stands. on my wagon, I set the stands where the lower control arm attaches to the frame. Just get it up in the air, and look for some solid steel locations that will keep the saddle of the stand from sliding. I positively never place stands on body panels. even with a 2x4, I don't like to do it. STEEL IS BEST! if you can not find a good place, you may want to build a pressure treated chunk of lumber with a steel sleeve around it to spread the load more evenly. the control arms usually have a pocket to place a stand saddle in. near a spring pocket or shock connection. not helpfull if you are wanting to work on the LCA though... look for a spot of steel. good luck. If I ever work on the rear of a sedan 123, I will take some nice pictures of where to properly support the vehicle.

rino · #58 01-24-2008, 05:34 AM

Thanks guys. The little birdie is now out of the nest and on an experimenting trek...

Rino