I love my QuickJack for working on my SC. You've seen me use it for suspension rebuild. However, I ran into an unsafe state that I had not even suspected possible. It can be in a "false lock" state wherein its otherwise exceedingly secure locking mechanism fails to actually engage. Basically, the QJ locks securely by jamming the end of a bar against stops in a lower rail. Weight of the car makes it near impossible for that lock to release. It's super secure when it locks into position. In fact, the normal operation is to fully depressurize the hydraulics once the QJ locks.

Normal operation is to raise the QJ until the locking bar passes a stop. Then go back down and the bar jams solidly into the stop. However, if you go just a little bit further up and the pivoting cam also goes past the stop, you're set up for trouble. Going back down jams the pivotable cam against the stop. It WILL hold weight, but because the cam can flip positions, the "false lock" can suddenly let go. Thankfully, mine was only partially depressurized when such a fals lock broke free. Not much of a drop and just a loud bang as the end of the locking bar happened to catch the stop after the cam broke free of being jammed against the stop. YIKES! If that happened minutes later with full depressurization and me under the car.

Absolutely verify that the end of lock bar itself is creating the lock. If you raise the QJ up a little too far before letting it settle back down to lock, you can create an unsafe, false lock with the cam jamming agains the stop. That will support weight, but be prone to sudden lock release. BAM, the entire side may fall all the way down if the lock bar doesn't happen to catch against the stop as the cam pops out of "false lock." Always halt going up as soon as the lock bars just clear the stop. Don't let the cam get between the end of the lock bar and stop. If you do that, you will create a potentially catastrophic "false lock" against just the cam.

 

thank you for letting us know.
what are your future plans with the QJ?
will you start adding Jack stands under the car for extra safety?

I know when I use ramps or a Jack with Jack stands, I always have an aux safety measure by using two of the previous three, in any combination.

 

I plan to continue using the QuickJack. When it locks properly it really is very securely up. I do place jack stands as additional measure, but my jackstands are only 18 inches tall, while the QJ is 21-22 inches up. They are only to catch things in the unlikely event of catastrophic failure. When correctly locked into position, my QJ is much more stable than ever had with jack stands.

Important warning is that there is a non-obvious "false lock" condition that can occur with just a very minor variation in lifting procedure. One need only go up a little bit more before going back down to induce a false lock. The cam should never be able to jam between the lock bar and stop point. It needs to be reshaped or spring loaded to be impossible to catch on the stop. As it is currently shaped, it is just the correct shape to be jammable. Bendpack should at least alter its lower side curve so it will always pop up instead of jamming. Then, a false lock state should be very difficult to induce.

My process now includes always stopping upward motion as soon as the lock bars pass over the stop. Never let the cam also pass over the stop. Also, look carefully once locked to verify that the cam is not the part being jammed against the stop. The end of the lock bar must be the jammed part. Once properly jammed in lock position, it simply won't go down without lifting the car (unless you also get a mechanical shearing off of a part, but that should not occur until 3 x rated load).

 

Went ahead and filed a report with CPSC. It's a hidden and serious hazard condition that looks a lot like the intended, safe state.
A simple reshape of the cam could make the unsafe false lock impossible to occur. I think a redesigned cam replacement should be supplied to existing owners to prevent a tragedy.

CPSC report is number 20201128-2FEEE-2147367840

 

Here is a diagram better showing what happens during a 'false lock"

 

Interestingly, CPSC says this is not in their jurisdiction and I should file report with NHTSA instead.

 

Might save a life!! Posting with NHTSA is a good idea, in my opinion!! Can't hurt

 

BendPak has been unresponsive. I've also written the Automotive Lift Institute, but I see one of BendPak's execs is on their board. We'll see how far that goes.

I'm doing what I can to keep someone from discovering this hazard the hard way.

I was lucky, but the next guy might not be. Thus far, nobody really cares.