Safe use of a hydraulic floor jack?

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skate1968

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Is there a way in which i can 'lock' my hydraulic jack? Is there a way in which i can ensure that the 'release valve screw' will NOT turn counter clockwise while vehicle is raised?

I have a Pro-Lift 4,000 lbs hydraulic floor jack (not the bottle type).

By the way i already know not to entirely trust one single jack w/out jack stands. I'm asking this because i want to use the jack in addition to the jack stands as an added precaution. I'm aware that people die from having cars fall on them.

I'm already taking necessary precautions. I use jack stands, choke wheels, e brake, put car in gear, only use jack points, flat surface, don't use cinder blocks, don't exceed weight limits, etc.

Thanks for reading. And thanks to all of those who've already posted on this topic in other threads. I've already read several posts about safely raising a vehicle.
 
As i'm reading this i'm thinking that i could use a tool to tighten the release 'release valve screw.' That is make it extra tight.
 
The valve screw is usually not the failure you are guarding against by using jack stands, you are guarding against a seal failure that allows the jack to collapse regardless of release screw position. If you use a tool to tighten the screw and strip the threads out, it will become a failure point, when it shoots out of the jack followed by all the jack oil and a collapsing car. Probably the best thing you can do is not use cheap, old, or abused equipment. Ive seen cheap jack stands fail and put a rotor disc into asphalt. I usually use a jack stand and a jack adjusted so neither is taking 100% of the load. If your jack is leaking, replace it. If you can jack a car up and watch the car slowly drop, replace it. If you jack stands have one tack weld holding the two halves together, for heavens sakes, do not use them.
 
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Thanks Onmo!!!
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Sounds like you are doing things properly. I use 2 (3 ton) jack stands along with a 3 ton rolling floor jack whenever I jack up my vehicles.
 
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you sound as paranoid as I am--glad I'm not the only one...

I just use 2 sets of jack stands, the second set behind the other--not actually touching the car but less than 1/2" away, just to add redundancy in case the car falls on me. I realize this isn't necessary, but I'm incredibly afraid of having a >4000 lb vehicle fall on top of me.

Another thing you could do is stack 2 wheels on top of each other, and put then behind the jack stands...just in case....
 
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A while back I saw a hydraulic jack with a locking mechanism so you didn't even need jack stands. It seemed like a good idea considering some cars have small jackpoints
 
Originally Posted By: JOD
I just use 2 sets of jack stands, the second set behind the other--not actually touching the car but less than 1/2" away, just to add redundancy in case the car falls on me. I realize this isn't necessary, but I'm incredibly afraid of having a >4000 lb vehicle fall on top of me.


You need to go ahead & put the 2nd set of stands touching the car so it won't see the shock load. If you're going to do it, do it right.
 
Originally Posted By: George7941
I think the gap with the second set of jackstands arises from the fact that jackstands only adjust in about one inch intervals.


That's part of the issue. The other part is that I really don't have room on the frame for 2 jacking/support points, so the second jack stand hit in a part of the frame that would probably cause some damage to the vehicle.

It's strictly there as a catastrophic safeguard in case my jackstands somehow fail.

And, in a total thread hijack--I have a car ramp safety question: just how 'level' is level ground? The reason I ask: I'm getting ready to change my differential fluid, which uses a 'fill to the bottom of the fill hole' method of filling. I'd like the car to be level, as not to get a false reading. My parking pad in front of my garage at approximately a 1 degree-1.25 degree slope. Not much, but enough that if the back wheels are on some 8" ramps, the car is pretty much level. Is this safe?? I put it up there, let it sit for a couple of hours, tried to push the car around, but I was still afraid to get under the car. Am I just worrying too much?
 
Originally Posted By: skate1968
As i'm reading this i'm thinking that i could use a tool to tighten the release 'release valve screw.' That is make it extra tight.



That's not the only danger with a hydraulic jack. Any time its carrying the weight of a vehicle, you're one tiny O-ring blow-out away from it collapsing. Jackstands are MANDATORY. Even old hydraulic car hoists had mechanical locking failsafes so that a gasket blow-out wouldn't cause the lift to drop.
 
Originally Posted By: JOD


And, in a total thread hijack--I have a car ramp safety question: just how 'level' is level ground? The reason I ask: I'm getting ready to change my differential fluid, which uses a 'fill to the bottom of the fill hole' method of filling. I'd like the car to be level, as not to get a false reading. My parking pad in front of my garage at approximately a 1 degree-1.25 degree slope. Not much, but enough that if the back wheels are on some 8" ramps, the car is pretty much level. Is this safe?? I put it up there, let it sit for a couple of hours, tried to push the car around, but I was still afraid to get under the car. Am I just worrying too much?


I haven't done the math but it seems to me a car on 8in ramps would tilt about 5 degrees, so your 1.25 degree figure seems way off.
 
i don't know where to put the support stands. If i put it at the jack points the seam weld will be bent. help!
 
Try to use the points where the suspension is bolted on to the body, as these areas are reinforced, the lower control arm pivot point is usually good to support the front of the car, the rear can be tricky depending on what type of suspension you have.

My car has an independent rear suspension and there is a nice thick reinforcement bar going across, I can use a floor jack in the middle and lift two rear wheel at once, which gives me plenty of room for jack stands.
 
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Originally Posted By: George7941
Originally Posted By: JOD


And, in a total thread hijack--I have a car ramp safety question: just how 'level' is level ground? The reason I ask: I'm getting ready to change my differential fluid, which uses a 'fill to the bottom of the fill hole' method of filling. I'd like the car to be level, as not to get a false reading. My parking pad in front of my garage at approximately a 1 degree-1.25 degree slope. Not much, but enough that if the back wheels are on some 8" ramps, the car is pretty much level. Is this safe?? I put it up there, let it sit for a couple of hours, tried to push the car around, but I was still afraid to get under the car. Am I just worrying too much?


I haven't done the math but it seems to me a car on 8in ramps would tilt about 5 degrees, so your 1.25 degree figure seems way off.



well, say 5 feet between the front and rear wheels: rise/run, 8/60= 1.333. 5 degrees is steep! No way I'd trust that.

I'm going to take a picture over the next day or two and post a 'Is this going to kill me' thread. I really want to get the differential/bevel gear oil changed--but I'd like the car to be level when I do it so I can get in the correct amt.
 
Originally Posted By: JOD


well, say 5 feet between the front and rear wheels: rise/run, 8/60= 1.333. 5 degrees is steep! No way I'd trust that.

I'm going to take a picture over the next day or two and post a 'Is this going to kill me' thread. I really want to get the differential/bevel gear oil changed--but I'd like the car to be level when I do it so I can get in the correct amt.


You started your math on the right track, you need to take it a couple of steps further.
rise/run = 8/60 = .13333 = tangent of angle. Looking up tangent tables gives 7 1/2 degrees.

60in wheelbase makes the car a really small one, Yaris sized perhaps?
 
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