How long can car be left on a lift?

[BMWDavid]

Hi All,

Might be a silly question but...I'm finally going to take the plunge and buy a Bend Pak MD-6XP mid rise lift.

Anyway I'll be using it so I can remove the wheels to replace tires and all sorts of other related things that one can do with car up in the air.

I have a habit of starting projects and not finishing them until some time has passed due to work related interruptions. That being said if I have the wheels off I can't lower car back down so I was wondering how long I could leave car suspended on the lift?

I'm assuming I would be lifting car at the jacking points behind front wheels and in front of rear wheels. Car is totally rust/corrosion free so no issues with weak metal.

Thanks!

David

[Peter Zimmermann]

At my shop we always took care to never close the doors on Targas/Cabs when they were in the air. Those cars would "bend" just enough that damage to the door latch/striker plate assembly could occur.

For extended lifts, if your car is a Targa/cab, measure from the windshield frame to the roll bar or some other convenient place, then lift the car to see how much the measurement changes. If a change exists you might want to consider putting the wheels back on with a couple nuts each, and put the car on the floor. (If you do this always tag the steering wheel that wheel/tire installation isn't complete!)

My 914 has been in the air for about three months, but it doesn't flex/sag when lifted. If you have a coupe, don't worry about time, a month or more is no big deal as long as you're using recommended lift points.

[BMWDavid]

Pete,

Thanks for the reply! Now I feel comfortable if I have to leave the car up for an extended time.

David

[RarlyL8]

Pete, my SC non-sunroof coupe pops the doors funny when on my 2-post lift. I've always noticed this about the car. If I open the doors when it is on the lift they will "pop" open which does not happen in the same manner when on the ground. They also are more difficult to shut. I use the recommended lift points and the car has no rust that I am aware of.
Why is this?
Another thing I notice is that if the car is on the lift for extended periods it will look like a 4x4 for a day or so until the suspension settles.
Is this harmful the the suspension?

[911pcars]

How long will it stay? If you do it correctly, minimum 57 sec.:



Sherwood

[UrQuattro]

Oops..

[JJ 911SC]

QUOTE=Peter Zimmermann;5733214]At my shop we always took care to never close the doors on Targas/Cabs when they were in the air. Those cars would "bend" just enough that damage to the door latch/striker plate assembly could occur.

For extended lifts, if your car is a Targa/cab, measure from the windshield frame to the roll bar or some other convenient place, then lift the car to see how much the measurement changes. If a change exists you might want to consider putting the wheels back on with a couple nuts each, and put the car on the floor. (If you do this always tag the steering wheel that wheel/tire installation isn't complete!)

[/QUOTE]

Peter

I guess I should not apply for a job at your garage...

I though closing the doors would be better

Will do the measurement today and post.

Merci

JJ

[kach22i]

Originally Posted by JJ 911SC

I though closing the doors would be better

I thought this as well with my Targa. My reasons are that if I leave the them closed while on jack stands (under torsion bars) the doors open and close fine afterwords.

The one time I left them open it took about 20 minutes of sit time and driving my car from one driveway to another to get it to settle back into place so the doors closed in a normal and familiar fashion.

What stress there is on the latch/strike plates I would have assumed Porsche designed for. Guess I was wrong.

[whalebird]

One word of caution. ALWAYS lock the lift and release hydrolic pressure from the lift cylinder. Over time, some lifts may bleed pressure and slowly lower...anything under the car will come through the floorboard.

[911pcars]

QUOTE=Peter Zimmermann;5733214]At my shop we always took care to never close the doors on Targas/Cabs when they were in the air. Those cars would "bend" just enough that damage to the door latch/striker plate assembly could occur.

For extended lifts, if your car is a Targa/cab, measure from the windshield frame to the roll bar or some other convenient place, then lift the car to see how much the measurement changes. If a change exists you might want to consider putting the wheels back on with a couple nuts each, and put the car on the floor. (If you do this always tag the steering wheel that wheel/tire installation isn't complete!)[/QUOTE]

At first, I'm thinking there should be little/no difference between supporting the chassis from a lift or supporting the chassis via 4 wheels on the ground. Think about it.

However, a lift may not distribute the weight equally from all four lift pads which might/will stress the chassis enough to create door opening/closing interference issues while in the air.

My '69 is a coupe and I've always noticed window frame & upper door opening (next to roof gutter) rubbing when parked at my parent's uphill, banked driveway entrance. From earlier discussions, early 911s aren't so swell in the chassis rigidity dept. compared with later computer-designed unibody vehicles.

Sherwood

[UrQuattro]

THANK YOU! someone finally admitted it. The coupes flex a fair amount as well. Yeah!

You may go about your business now.

Michael