Originally Posted By: Panzerman
I had a 1978 Cadillac Eldorado. They were the huge front wheel drive boats. I pulled it up on steel ramps to change the oil and it sat there for about 5 minutes and then just collapsed and buckled the ramps-flat. I ended up getting new ramps and welding all this reinforcement steel on them. It still spooked me, since I was just getting ready to go under there. I place wood blocks under the steel part of the ramps now, I feel that would give you some time and room to escape. Even though I don't own any big Caddies now. The weight of that car was over 6500 lbs. My biggest vehicle is the Dodge and it sits high enough to service without ramps.
I had an excursion break rhino ramps, like you it sat there a little while then bulged on the sides and collapsed.
These ramps were older, about 5 years old, it seems the plastic deteriorates over the years and gets brittle.