Proper use of floor jack and jack stands with a 123-chassis 240D: place where, how? - Page 3 - PeachParts Mercedes-Benz Forum

rino · #31 03-01-2007, 07:47 PM

Quote:

Originally Posted by vstech

just an extra bit of safety tip.
When lifting either end of a vehicle on rough or soft ground that will not allow the jack to roll, DO NOT CHOCK THE WHEELS or set the parking brake until AFTER the vehicle is raised!
Floor jacks need to move as much as 12" when raising, so either the jack needs to move, or the car.
I always try to have the jack on smooth level surface but it is not always possible.
also, I would not use the jack points to hold up the car, I would use the frame itself.
most floor jacks have 4 sharp points that will grip well into wood.
if jackstands are sitting at an angle, the car will slide and fall. try to get the stands so solid metal is in the saddle of the stand keeping anything from moving.
one time I was working at a used car place and in the corner of the shop was a twin post lift with a car 1/2 on the lift. the thing was saftey taped like a police scene waiting for the insurance inspector to come look. nobody went near that thing... rubber pads on metal arms mix in some tranny fluid, wait for disaster.

AH! AH! Guys, you should say these things right away! Now I understand a couple of things I experienced over the past couple of days with my brand new floor jack and stands, and also understand that I got pretty close to screwing up in a big way...
The floor jack I have is small (I wanted it that way) and it is a Craftsman (so I don't think it is a POS), BUT it did NOT roll as you say it should have, and it was instead the car to slide around on it during lift up and lift down... And I did put a nice piece of rubber between the car's metal and the jack's saddle, and yes, the rubber did get oily with diff fluid and engine oil (at differential and engine cross member lift points) and yes, I had the car in reverse gear and parking brake set and even chocks into place while using the floor jack... Yesterday in particular there was a moment the car shifted around while I was lowering it on the jack stands and the saddle contact point slided from center differential to left corner of differential, with part of the saddle protruding out. Had it fallen down, there would certainly had been some damage to the car. After that close call, I've been extremely careful with the procedure, lowering it all the way whenever I detect some shifting and then lifting it again....
I am glad you wrote this last post, which clarified a few important things. So no more rubber material between saddle and car for me from now on... Are you saying that wood is all right? For instance, is it all right to place a 1-foot length of 2x4 between the saddle and the diff or engine cross member?
What do you exactly mean by not using the jack points but the frame itself?
Where exactly do you place your floor jack when lifting rear and front?
When lifting the rear, I place the stands right under the metal thing with a bolt and springs in proximity of the rear jack holes, so the saddle of the stands is grasping the metal in that area, it fits perfectly by the way. But when lifting the front, there's no metal anywhere near the front jack holes, just that frame that looks like plastic... so I place the stands right there, underneath the jack holes, and buffer it by placing in between saddles and frame a 1-foot length of 2x4. Is this all right in your book or am I doing something risky there? I have done it that way a couple of times and it seems to work just fine...

Your post is much appreciated...

Rino

rino · #32 03-01-2007, 07:52 PM

Quote:

Originally Posted by 1983/300CD

Don't we all have the hydraulic jack on wheels?

I assume we all do... mine has them as well... but in spite of the wheels did not roll... at all. Rather the car on top of it did... And I am in Cali. All I needed was a nice, little quake at the time of my inspections nearby the car....

So, either I've been doing things wrong (and I assume I did), or the floor jack I got is a POS...

Rino

rino · #33 03-01-2007, 07:56 PM

By the way, vstech, another thing...
I don't seem to be able to use the floor jack longitudinally with the car (if I do, then there's not enough space to pump the handle)... so I've been using the jack (under the diff and ECM) at an angle... There's no other way to do it with this jack...

Rino

Panzermann · #34 04-18-2007, 10:25 PM

Quote:

Originally Posted by R Leo

Whenever I place a car on stands, I remove the jack from underneath then give the car a good, solid bump at each corner with my hip to detect and test for any instability.

Anal? Nope. I have still vivid, 6 year-old's memories of my dead neighbor's legs and feet sticking out from underneath his car after it fell on him one Saturday afternoon.

I met one guy that survived the fall of the car, but he was a quad.

bellyboy · #35 04-18-2007, 11:01 PM

keep cell phone or other alerting device attached to body

vstech · #36 04-18-2007, 11:08 PM

oops, I hate it when a thread I gave info on, had followup questions and I miss them..
sorry rino.
anyway, the jack should be solid on the diff in the rear. if your jack will not reach the dif, you need a longer jack. if you are just changing a tire, using the jack points with wood as a buffer should be fine. but it is inadequate to support the vehicle to do major repairs.
on the front, I jack up with the crossmember solid on the floor jack. and use the lower arm mount to support the jackstands.
to get the jack to slide, you need SMOOTH surface under the jack, or solid wood gripped into the jack surface and wedged solid into frame, if the jack face will not grip solid onto the crossmember/diff, and the vehicle must be free to move as the jack lifts.
John

chetwesley · #37 04-18-2007, 11:46 PM

Quote:

x2. I had those same jack stand and have got to say, they are no good. The narrow base combined with the pin-through-hole design made me very nervous when using them.

The pin part is actually very safe... the amount of weight it would take to shear off one of those steel pins is incredible. As for the rest of the design... well, you may have a point.

rino · #38 01-18-2008, 10:45 AM

Quote:

Originally Posted by dmorrison

Don't make this to complicated. It's not rocket science.

For the front I use the engine cross member just behind the oil pan to jack the car.
I place the jack stands under the frame box just inside of the jack hole provided by Mercedes. Been doing it this way since I have owned Mercedes, 27 years with no problems.
Look at this post, second page. Those are the 6 ton jacks at Harbor Freight.

617 engine, replacing the oil separator check valve in the upper oil pan.

For the rear I use either the subframe mount area or the differential. I usually place the jacks under the subframe mount area.

Dave

Hi Dave, I have no idea if you get to read this, but I sure hope so.
It was time that I got a new pair of jacks, so I followed your advice and
yesterday bought the 6-ton jacks from Harbor Freight.
What now puzzles me is that these jacks' minimum height is 15-1/8" and
the subframe mount area on my 240D is only about 10" from the ground.
Using the 6-ton stands would therefore position the car at a pretty steep
incline... and it appears the load placed on the jack stands should be as
vertical as possible to the jacks for safety reasons, as prescribed by the
manual that came with them.

Can you give me some feedback on this one? From your picture from
that post http://www.peachparts.com/shopforum/attachments/diesel-discussion/25842d1114794674-617-engine-replacing-oil-separator-check-valve-upper-oil-pan-oil-seperator-fix-6.jpg
it looks like you used an even greater height than 15-1/8", assuming that,
as you said, those are the same 6-ton jacks from Harbor Freight that I have...

(With the 2-1/4 ton Craftsman jacks from Sears that I've been using
so far, I've always placed solid wood under the tires on the opposite
end, so as to lift the car about 3-4" from the ground, and then the jacks
under the subframe, with the car's subframe evenly lifted that
way (back and front ends of the car evenly lifted) at about 13.5" from
the ground. That ensured that the load was completely perpendicular to
the jacks, as I understand that to be an important requirement.)

Also, from your picture I can see you did not place anything between
the vehicle subframe and the posts saddles (I was told to always use
something soft in between, such as a short length of 2x4, so as to
avoid possible slippage). What's the right way to do it, metal to metal
or with something soft in between? A clarification here would be
appreciated.

The big question for me however is, is it safe to work under a car
positioned at such an incline?? (I'll be placing the jack stands under
the subframe box, near the jack holes provided by Mercedes.)
Or should I return the 6-ton jacks and get smaller 3-ton ones with
a lower minimum height?

TIA,
Rino

dmorrison · #39 01-18-2008, 02:13 PM

Rino

A couple of opinions. I have always placed the jack under the frame box on the W123 and W107. I have not used a 2X4 or any other "pad" between the jack and frame, the wood can split and cause the car to shift. A hard rubber pad would be better. Harbor freight makes them for the 6 ton jack. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95952
I have not bought them because I am comfortable with what I am doing, And I will spend money at Harbor Freight ( can't get out of that store without dropping $100 ) Make sure the frame box is centered over the jacks stand pad. I make contact on both sides of the pad at the 2 edges of the boxframe. I jack the car up raise the jack to just below the boxframe and slide it towards the rear allowing it to make contact with the boxframe at the two pad spots. Do the same think on the other side but make sure the 2nd jackstand is raised the same amount of clicks as the other one. This way your car should be level ( left to right ). Lower the car on the jackstands and give it a shake so you can see it's stability on the stands. If it does not seem stable , move the jackstands to get it more stable.

I do make sure that the transmission parking pawl has engaged when I stop the car, engage the parking brake and I park on a flat, hard surface.
the car will sit at a angle on the jackstands. The amount shown in the picture allows me to work under the car easily but I am not uncomfortable with the angle the car is sitting at. I am just working on the engine. If I have to work under the complete car I use 6 ton jacks ( I edited this to change the size to 6 ton jacks )and jack the car up pretty high in 2 stages. I also have the HF long body jack that can raise the car 33 inches. As I said I do this in 2 stages.

If your uncomfortable with just the 2 jacks. I sometimes leave the raising jack under the engine crossframe instead of removing it after jacking. Drop the car down on the jack stands and allow the raising jack to just kiss the frame. Now your supporting the car in 3 places. Or place another 2 jacks near the 2 installed but just barely touching the frame, a sort of backup.

Always make sure you chock your front wheels when jacking just the rear of the car. Good chocks, not 2X4's.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96479
It will roll on you when jacking and be unstable when on the jack stands.

Good luck and be careful.

Dave

rino · #40 01-18-2008, 08:06 PM

Well, if you say you've always done that and that the inclination thus achieved is no big deal as far as stability goes, provided that good chocks are used, I'll go ahead and give it a try the way you do it. I was also a bit concerned the direct contact of the jacks's saddles with the frame box might damage the latter, but if you've been doing it all along with no ill effects... then I'll do the same thing myself. I won't even have to raise the jack's posts at all, since 15-1/8" (the height of the 6-ton jacks with the posts all the way down) is more height than I have ever used and all that I need. 12-ton jacks as you say are definitely very safe, but their minimum height is 19-1/2" and I don't see how you can raise an end of the car that high without also raising the opposite end (right?), and that quite complicates things a lot, IMHO.

Yep, the same thing happens to me too each and every time when shopping at Harbor Freight. I went up there yesterday with the intention of getting just the 6-ton jack stands (they are currently on sale at $19.95) and perhaps a couple of additional low-cost items. I ended up buying a whole bunch of different things that I have no immediate need for for a total of slightly over $120. There's something *hypnotic* about HF that causes you to buy, buy, buy. The only good thing about it, is that I'd been HF-free for over 6 months...

Thanks a lot for all your tips and advice. I'll keep the 6-ton ones and give the things a try when my oil change becomes due at the beginning of February. These jack stands are H-U-G-E compared to the Craftsman 2-1/4 ton ones, and look at least 10 times as sturdy. I am glad you suggested 'em and that I finally got 'em.

Just please confirm this once more for me: on the w123, when, for instance, you raise the front end, you place the HF 6-ton jacks (which have a minimum height of 15-1/8") under the frame box right where the MB jack holes are with the rear wheels of the car on the floor. Is this correct?

Thanks again,

Rino

Quote:

Originally Posted by dmorrison

Rino

A couple of opinions. I have always placed the jack under the frame box on the W123 and W107. I have not used a 2X4 or any other "pad" between the jack and frame, the wood can split and cause the car to shift. A hard rubber pad would be better. Harbor freight makes them for the 6 ton jack. http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95952
I have not bought them because I am comfortable with what I am doing, And I will spend money at Harbor Freight ( can't get out of that store without dropping $100 ) Make sure the frame box is centered over the jacks stand pad. I make contact on both sides of the pad at the 2 edges of the boxframe. I jack the car up raise the jack to just below the boxframe and slide it towards the rear allowing it to make contact with the boxframe at the two pad spots. Do the same think on the other side but make sure the 2nd jackstand is raised the same amount of clicks as the other one. This way your car should be level ( left to right ). Lower the car on the jackstands and give it a shake so you can see it's stability on the stands. If it does not seem stable , move the jackstands to get it more stable.

I do make sure that the transmission parking pawl has engaged when I stop the car, engage the parking brake and I park on a flat, hard surface.
the car will sit at a angle on the jackstands. The amount shown in the picture allows me to work under the car easily but I am not uncomfortable with the angle the car is sitting at. I am just working on the engine. If I have to work under the complete car I use 12 ton jacks and jack the car up pretty high in 2 stages. I also have the HF long body jack that can raise the car 33 inches. As I said I do this in 2 stages.

If your uncomfortable with just the 2 jacks. I sometimes leave the raising jack under the engine crossframe instead of removing it after jacking. Drop the car down on the jack stands and allow the raising jack to just kiss the frame. Now your supporting the car in 3 places. Or place another 2 jacks near the 2 installed but just barely touching the frame, a sort of backup.

Always make sure you chock your front wheels when jacking just the rear of the car. Good chocks, not 2X4's.
http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=96479
It will roll on you when jacking and be unstable when on the jack stands.

Good luck and be careful.

Dave

dmorrison · #41 01-18-2008, 08:19 PM

I edited my post to correct the size jacks I have.
The picture your looking at on the post showing my car jacked up are 3 ton jacks.

When I really want the car high I use the 6 ton jacks. After reading your dimensions on you last post I measured mine and checked them. I have the 6 ton jacks not the 12 ton.
I do jack the car up and place them on the 6 ton jacks and allow it to sit at the low position angle without any problems. If I want the 6 ton jacks higher I do the lifting in a 2 stage lift. Front up to the lowest jack stand position. Then the rear to the height I want and then do the front to the same height as the rear. Check for stability and then get to work.

Sorry for the confusion. Had 3 real long days of flying so I was pretty tired.

Dave

rino · #42 01-20-2008, 11:36 PM

Thanks for clarifying, Dave. Those could not have been 6-ton jacks with the posts raised as shown in the picture and with the other end of the car resting on its wheels...
One important thing to keep in mind (and which I did not fully realize last year after getting my first jack stands) is that the max. capacity given by the manufacturers always refers to that weight evenly distributed PER PAIR of jack stands - therefore, each "3-ton" jack has a max. capacity of only 1.5 tons; and 6-ton ones, are really good for only 3 tons each, and so on.

I'm curious, when you do the two-stage lift and have the front end of the car sitting on a pair of 6-ton jacks at the lowest post position, how much do you feel the other end of the car can be safely raised above that level (with the car eventually sitting on four jack stand at an incline, though only temporarily)?

Rino

dmorrison · #43 01-21-2008, 01:22 AM

When I do the two stage lift I usually raise the 6 ton jacks about 2 clicks and then jack the car up to settle on that height, for the first stage. for the second stage I jack the rear on the differential about 25 inches. Install the rear jacks allowing the car to settle down to the closest jack stand height that will accommodate the height of the car on the lifting jack. Then I raise the front, adjust the jack stands to the exact height of the rear jacks stands and settle the car onto all 4 jack stands. I notice how the car is sitting on the jack stand pad and if I'm not happy with it I will reposition the car on the jack stand. Actually I jack up the car and move the stand so that it will allow the car to better sit on the jack.

Now be advised I own the Harbor Freight long body jack. A standard jack will not fit under the rear of the car all the way to the differential.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=42820

I was just under my daughters 240D replacing the speedometer cable ( it was broken) and had the 6 ton jacks on click #2. To tight working under the rear of the tranny so I jacked it up some more raised the jack stands another 2 clicks and was able to finish the job. It sat at that angel without any problems.

Dave

Dave

bustedbenz · #44 01-21-2008, 03:24 AM

When I'm rotating the tires (every oil change) - admittedly, I'm not UNDER the car for a particularly long time except for the drain plug - I jack up one side or the other at the front, with a floor jack and a loose wood block (2x4) right under the factory jacking hole - where the rubber jack pads would be if they hadn't fallen off or crumbled. Then, I put a jack stand under the front... well idk what it is, just inside from the wheel, maybe the spring perch? Something stable in that general area. Nice flat surface in the same place on both sides. Then I go around, put the other side of the front up the same way. Then, I jack the back by the differential (NO block of wood here, it fits perfectly on the little jack plate anyway) and generally leave it up just like that while I rotate the tires since i'm not actually under the car during that process anyway.

It's never even tried to let go that way.

**EDIT: It probably isn't the spring perch. But it's whatever that nice flat surface that fits the metal jack stands so nicely is - the jack stand probably sits three or four inches towards the center of the car from the wheel's inside rim.

rino · #45 01-21-2008, 08:13 PM

Thanks for the explanation!

Quote:

Originally Posted by dmorrison

I was just under my daughters 240D replacing the speedometer cable ( it was broken) and had the 6 ton jacks on click #2. To tight working under the rear of the tranny so I jacked it up some more raised the jack stands another 2 clicks and was able to finish the job. It sat at that angel without any problems.

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