Rochester

iTrader: (9)

This was quite a read. Fantastic cautionary tale for anyone who's thinking of getting a QuickJack, or for anyone who has ever crawled under their car without jackstands, even for a moment.

chuckie311

iTrader: (3)

there is no way i would lift my car with those pinch blocks i could see how the car could slip out sideways they look worn out .. i bought the pinch weld frames blocks and have never had an issue

Selym

What if you placed the Quickjack pads inboard of the pinch welds, i.e. so they contact the car at the same points as the factory scissor jack.

canuckcoupe

iTrader: (1)

Update:

I measured the degree of misalignment on the lifting block:

It was toed out 6 degrees. Not much, but enough it seems.

Next, I measured the lateral force required to get one end of the Quickjack to slide across my tiled floor. I used a luggage scale:

With no weight on the Quickjack (the Quickjack weighs 78 lbs)., it took only 10 lbs of pull to start the jack moving.
Then I loaded the jack up with the weight toward the front.
Started with 200 lb:

(See what's written on them? Any guesses as to where they were made?)

I measured the force required to move the jack: 42 lbs

Added more weight:

200 lbs of blasting media for a total of 400 lbs

I measured the force required to move the jack: 73 lbs

Then I added rubber to the bottom of the jack. I cut the short lifting blocks on my table saw into strips about 1/2 inch high, 1 inch wide and 4 1/2 inches long. I got 9 strips out of each of the four blocks and epoxied 18 to each jack.



Then I remeasured the force required to move the jack with rubber feet and no added weight: 21 lbs (vs 11 lbs)
and with 200 lbs added: 88 lbs (vs 42 lbs)
I didn't measure again with 400 lbs, because the scale's limit is 100 lbs. I estimate it would have taken about 145 lbs.

Conclusion: with the addition rubber feet, the force required to slide the jack across my tiled floor approximately doubled.

Is that enough? Who knows? It's a bit disappointing. I was hoping for a factor of 4 or 5.

Summary:
1) plastic garage tiles are slippery
2) Quickjacks slide easily on plastic garage tiles
3) even a small misalignment (6 degrees) of the lifting blocks was enough to cause the jack to kick out from under the car
4) adding rubber feet increases the lateral force required to move the jack (by a factor of ~2 in my case)
Recommendations:
1) You probably should not use a Quickjack on plastic tiled floors. I would also wonder about epoxy floors.
2) Use blocks with grooves to accommodate the pinch weld, thereby eliminating the risk of misalignment.
3) As per the manufacturer's manual, always use supplementary jack stands! Don't ever go under your car without them!

PS: I have tried twice to order the pinch weld blocks online from Quickjack's Canadian site, but there's a glitch. The site offers no payment methods! I'll have to call them.

iCrap

iTrader: (8)

Rubber feet are a good idea, I'll add that to mine. I have epoxy floors and they don't slide nearly as easily as yours. Have not measured it but i know its more than 10lb to move it laterally.

DavidTB

Maybe you could make some type of crossbar that would go from one Jack to the other to lock them in a parallel position.

canuckcoupe

iTrader: (1)

I've thought about that. It would severely restrict the movement of a creeper though. So I'm reluctant.

I think my best bet is to buy a 3,000 square foot industrial warehouse with 15' ceilings and install a real lift... or two! (and a lathe and a paint booth and a blasting cabinet and a parts washer and a plasma cutter and... sigh) Maybe some day.

KEVON1

I cant ( from a physics stand point ) see this as being possible or even explained . The fact that the jack itself was still standing in the correct orientation and had not fallen on to it's side when spit out also can not be explained .

The markings on the lift pad that was misaligned should be mirrored by the other pad on the same lift , but it cant be . The angle of miss alignment on that one pad with the other pad being at minimum roughly 40 inches away would force the other pad to practically miss the other pinch weld entirely . Over that distance because the pads are not independent of one another while on a true horizontal surface (the frame of the lift itself and the pinch welds on the carl ) it would force the other side to be much more than 6 degrees off center over that distance .

I would spend the time to set up the 2 lifts PERFECTLY get the exact measurements with the car up and off the ground between the two lifts and get 3 square bars (like from a pop up tent ) and notch them to fit over the bottom rail in the front /middle and back so that the 2 lifts when the bars are placed on the rail can not misaligned when positioning the lifts ....when one side is perfect you know the other side is as well lift the the car then remove the 3 bars for purposes of the creeper.

I would also find out exactly what the slope of your garage floor is from front to back because the lift is not truly vertical as it as a radial shift by design , you also get horizontal movement because of the design . Any slope will cause one side of the lift to contact the one pinch weld before the other causing twisting of the other end if not perfectly square .

canuckcoupe

iTrader: (1)

Kevon1: Thanks for taking the time to think this through and offer suggestions. Unfortunately, there's an error in the information you started with: the lifting blocks are, in fact, completely independent of one another. They sit in trays on each end of the lift with plenty of room to move about.

Here you can see the front block toed out.

In the next pic, the rear block is toed in.


I'm still working on the Quickjacks. My first modification (adding rubber feet) caused them to be wobbly. I have subsequently modified that modification, and they are back to being stable again. I'll get back to it tomorrow, and I'll post pics when I get a set-up that I'm satisfied with.

SonicVQ

Have you told Quickjack your experience?

canuckcoupe

iTrader: (1)

No, I haven't.
Don't feel like it's worth my time, and as the days go by, I'm feeling less and less inclined to do so.
I just want to make the Quickjack as trustworthy as possible and get back under the car. My sway bars arrived a week ago. Cat back and test pipes arrived this morning. Springs will be here any day. I've got stuff to do!

On the other hand... I owe it to Quickjack's customers to warn them about plastic tile floors. It could save someone's life.
So, yeah, I'll compose a letter to Quickjack/Bendpak.

spoolin03

Great thread. I always put extra jack stands under the quickjacks just in case.

petemo94

iTrader: (1)

I definitely would tell QuikJack of your experience. They must have tested for this problem and have probably seen it in their tests. I think its worthy to call them.

I have the QuikJack-5000 on an epoxy floor and have not experienced this problem,

However i do know from time to time, one side will go up HIGHER than the other side when using this. This weight imbalance could be a possible cause. The side to side height indifference is NOT obvious if you are looking at the car from the side of it. However from the front or back, the height difference is VERY OBVIOUS.

Consider this as an option that could have happened. Good luck with it!

canuckcoupe

iTrader: (1)

Thanks for taking the time to comment, pete.
In this case, there was no lift imbalance. Both sides were locked at the first locking position.

petemo94

iTrader: (1)

I see

from what I recently experienced, my car didn’t start tilting to one side until it was “after” the first safety stop. When the lift was approaching the 2nd safety stop is when the difference in height was most noticeable.

whatever the case, please share any findings. I have the same lift and this is disconcerting. 👍