Front subframe mount on a lift

[wwheeler]

I had a discussion with a friend and he said that you should NOT lift a W113/W111 up on a two post lift with the front subframe unsupported. I told him I thought there was some mechanical stop to prevent unlimited stretch of the mount. He showed me a cutaway drawing of an installed mount and I certainly could not find any such stop.

If that is the case, then it is up to the rubber to metal bond and then the shear resistance of the rubber to hold the subframe up when unsupported. I do notice that on my W111 and when on a two post lift, the P/S pulley hub contacts the radiator shroud.

So if it must be on a two post lift, then what should be done to relieve the stress on the rubber mount?

[ja17]

The front shock absorbers, are one of the final stops for front subframe travel downward. Old dried out and deteriorated sub frame mounts may not survive the two post lift. When in good condition, the sub frame mounts should handle the "stretch".

[wwheeler]

Thanks Joe. I had forgotten about the shocks as being a mechanical stop. Same as for the rear I suppose.

Would you recommend using a bar wedged between the floor and subframe if using a two post lift as added insurance?

[stickandrudderman]

A two post lift is the perfect way to establish if the sub frame mounts are failed or not as the rubber will separate from the top half of the mount when failed and you'll see rust staining where the rubber should be bonded.
What you should NOT do is run the engine with the car elevated on a two post ramp as the fan may foul the shroud.