Rear lifting beam

[Yum-yum]

For years I lifted at the rear frame using a piece of channel aluminum about 5.5 inches wide by 3 inches deep by 10 inches long to straddle around the exhaust. This worked fine but allowed the suspension to droop and I've been looking for a better means to lift the wheels at the same time. I recently put this lift beam together inspired by descriptions of wooden lifts from this site.
The main cross beam is rectangular box 3 x 1.5 x 40 inches. I've bolted on a couple angles to fit within the rear frame flanges. The outer suspension tubes are picked up by a couple acetal v-blocks which are allowed to pivot slightly to match the width across the tubes. There is a vertical pin which mates to the trolley jack and a horizontal cross pin which bears the weight and allows the main beam to rotate to accommodate the varying angle of the frame and suspension as it is lifted.
It works pretty well for the couple times I've used it, it's pretty solid. I still need to run the rear wheels up on blocks to get enough clearance to roll the trolley and lift under. Once lifted I can fit a jack stand under each end for better support. It won't allow too much suspension work but for all other under car work I think I'm going to like it. Even with the Rotoflexes the wheels turn nice and smooth.
Of course, any efforts inspired by this are at your own risk. Any suggestions, comments, warnings or questions are welcomed. Just thought I'd share.

[billwill]

One of the main requirements is that it mustn't twist sideways, dropping the car about 3 inches or so or more if it falls off the jack, you seem to have made sure of preventing this by having quite a long portion in contact with the centre of the car chassis. Well done that man...

[gherlt]

Hello Alex,
could you please give us more pictures of the lifting beam, to have a better view of it ?

Guillermo

[UAB807F]

That looks a good, I like the idea of supporting the wishbones as it lifts. It's certainly a more engineered solution than my wooden block arrangement. Are there two acetal supports at either end or just one ? A photo of just the beam itself in plan view would be helpful.
Brian

[Yum-yum]

Thanks for the comments.
The beam can not fall off the jack as the vertical pin sits (albeit a loose fit) in a receiver hole in the jack. I was thinking of using hardwood for the v-blocks (one at each end, about 6 inches long) but I found the acetal cheap at the local salvage lot. Total materials is about $50 USD.
Here's a top view:

And an underside view:

[prezoom]

Hi Alex,

What is the wall thickness of the main support tube? I have a long length of the same size tubing left over from a railing project around a deck that I am just completing. Was wondering what I was going to do with the excess. Never seems to fail, that left over material seems to find a use for itself.

Rob Walker
26-4889

[Yum-yum]

Hi Rob,

It is eighth inch (=.120") thick web. The same section is available thicker web, but I don't think it is necessary and it is already getting heavy. The beam does not noticeably deflect under load.

I had originally thought to use a flat steel bar, maybe 4" wide by 0.5" thick. This would keep the height profile down and maybe allow getting the trolley/lift under the frame without driving up on blocks. But this would mean having to weld on bearing supports for the v-blocks.

I would make sure the tube you want to use is structural and not decorative.

Alex