I've been using the Bendpak HD-9B for over 1 year now and had now problems with stability.... Chagned three to four transmissions over the year and have had a 5,115 # Eldorado on top of me. I have had car's on the lift that go for excess of $250k!
What are you doing that causes the lift to...
There are "washers" that are threaded through the ramp pins (two for each ramp) that keep the ramps from dropping down. Four should have been in the parts box. Took a while to find them - look at the detail page - not the instructions as they don't even mention them! They look like this...
Just put up mine HD-9B. Bought from RB-Wholesale http://www.rb-wholesale.com/ best price ~$2,475. Need to call and talk to Robert for the internet price! Rolling Jack 4500 was $1,125 and is really great! The RJ runs on air.
I moved the ramps to 44" so even though I ordered the drip pans...