Setting a lift on its safety locks/catches?

[kartracer55]

Ok, So I have a question about setting up a car on a lift.

A shop teacher (ASE Master Tech, Master C.E.T, etc) Tells me that whenever you set up a car on a lift, you should lower the lift down onto its safety locks.

One of the Guys I work for (another ASE Master Tech, Master C.E.T, etc) Tells me not to worry about doing so, because they are safety CATCHES... the hydraulics hold up the car while it is on the lift.

So which is it? My teacher made a big deal about me not setting cars down on the locks, but I dont see the problem with it. The locks automatically catch, so if the hydraulics were to fail, the car would drop a few inches onto the nearest lock. On a saturday, The shop does mostly quick jobs like tires, brakes and oil changes. If I see 10-15 cars in my bay, that is alot of extra time getting the car off the locks. It can add up... is it really a safety issue?

The guys I work for think My teacher is an idiot, and my teacher thinks the guys I work for/with are idiots. Im stuck in the middle. I tend to listen more to my boss and the other guys because I have never seen my teacher mic out a rotor before/after cutting and he does brakes with white lithium grease... two bad practices. He also went to lincoln tech, and I have heard horror stories about tech's from there.

Whatcha guys think?

 

[tonyvlx]

Always rest car/weight on the safty locks.Dont leave the weight supported on the hydrolics.

 

[Charles (in GA)]

What if the locks don't catch? Where are you then? What if you stop it just below a latch catch point, so that when the hydraulics fail (hose burst or whatever) the lift drops six inches or however far to the next set of notches or catches, you would probably hurt yourself trying to get out of the way!

Common safety sense dictates that you engage the locks, that way, you know for absolute, positive, beyond any doubt, that they are engaged and will hold the car up. You don't bleed off all of the hydraulic pressure, just enough to set it lightly on the locks, should a lock fail, the hydraulics are still there to hold it.

If you worked in a shop I owned (and I don't own one) and didn't set the safety catches, you would not work there very long!

Charles

 

[Steve_S]

Two issues comes to mind. The first is that resting the weight of the lifting platform and vehicle on the hydraulics will wear them out faster. The other issue is as Charles noted above. If the lift is not resting on the catch, then you have no guarantee that the catch will grab if the lift should suddenly fall. Safety catches do stick sometimes. The extra few seconds it saves not using the catches is not worth human lives.

 

[wilbilt]

Common safety sense dictates that you engage the locks, that way, you know for absolute, positive, beyond any doubt, that they are engaged and will hold the car up. You don't bleed off all of the hydraulic pressure, just enough to set it lightly on the locks, should a lock fail, the hydraulics are still there to hold it.

Absolutely, 100% good information. I never get under anything heavy unless I know with certainty it isn't going to come down on me. "Safety Catches" are a backup, and are not intended to be the sole means of trust on a daily basis.

If you are working under a car using a jack and jack stands, would you leave it on the jack and put the stands under it "in case it falls"? The point is, you don't want it to fall - or move at all - in the first place.

2800 lbs, falling "just a few inches" can generate a lot of momentum.

 

[PxTx]

I think there are two perspectives here. The Teacher is cautioning you for saftey purposes. The tech's who operate outside the classroom are more concerned about time (especially if they are flat rate). I'm not condoning sacrificing safty for time, but you'll have to decide which is more important to you.

FWIW a car on a lift with a hydraulic line or seal failure will not drop much faster (if any) than you actuating the release valve. What other type of failure do you have in mind which would/could be saved by lowering on to the locks>

 

[wilbilt]

What other type of failure do you have in mind which would/could be saved by lowering on to the locks>

Cable or chain breakage? Fastener failure? Isn't any point of failure worth considering when the consequences could be deadly?

 

[wilbilt]

I worked under a lift similar to this one for a few years. The "lock" was the device attached to the lift cylinder that caught the "rack" under the lift beam as the vehicle was raised. The sole points of support were the rack notches. In use, the vehicle was hanging from the lift chains, and would move around and sway if any pressure was applied.

There were "slack safeties" in each column that were "supposed to" grab in case a chain broke. I never liked working under that lift.

 

[cc_rider]

The lifts I'm familiar with have catches that automatically come out as the car is raised; you can hear them 'click' as they go past each notch. We always raised it up to the height we wanted, raised it until we heard the next CLICK, then let the pressure off so the catches took the load. To release the catches you have to pull a cable on each side.

The lifts I really like are the screw type, which don't have catches per se, so have infinite height adjust. I think they're quite a bit more though.

Personally I wouldn't get underneath anything weighing enough to crush me without every possible safety feature engaged. But I'm a belt and suspenders kind of guy; YMMV.

c.

 

[katit]

I didn't rest car on locks and was leaving car on a lift like that for long periods of time. With home use (not even close to shop traffic) - I already have 1 cylinder and few fitting leaking. Good thing I'm still under warranty, but now I will now better.

 

[JohnZ]

Hydraulics are for lifting and lowering, not for "holding"; raise it up past the lock position you're going to use for working, lower it onto the locks, check for engagement at all locations, then go to work.

 

[bmwpower]

The only time I leave the car on the hydraulics is when it's not lifted high enough to catch the first lock...where you want to get the car off the ground, but not too high, depending on what you're doing. And that's usually only for a brief time (eg, draining coolant, etc.).

Depending how high off the lock the car was when the hydraulics went, the car might drop quickly/hard enough to break a catch..ie you're in trouble.

 

[Ed and Sandra]

This has been a very interesting and informative discussion which we've enjoyed following. We agree with the concept of allowing the lift to rest on the safety latches; however, that's not always possible. In our case our BendPak PL-7 has solenoid operated latches that are interconnected with the control for raising and lowering the unit. In the "up" mode the spring loaded latches go into slots every few inches and then are pushed aside until the next slot arrives. In the "down" mode the latches are simply retracted out of the way by the solenoids and held there until at any point the operator button is released. There is no way in the design to release the hydraulic pressure while leaving the latches engaged. One could listen carefully to the clicking of the latches as they engage in the slots when the lift is being raised and stop the lift very close to resting on them without it actually doing so.

Best regards,
Ed and Sandra

 

[Aahz]

The only thing I would add to this discussion is that if your head is 1" away from the vehicle and your locks are 3" apart, that vehicle will fall at least far enough to smack you a good one. (Personally, I wouldn't want 3-4000 lbs smacking me in the head....but I'm not really brave my wife tells me)....

In most cases that I've heard of (and seen)...the hydraulics slow the descent down long enough to allow the tech to get out from under the vehicle. Cases that have involved lifts failing DO HAPPEN...for various reasons..(vehicles not racked properly, hydraulics failing, improper installation, poor lift design, etc.) I ALWAYS recommend using whatever safety is available...(and techs that tie off their safety release to "save time" have a deathwish...)

 

[heavytlc]

I guess lifts vary from mfg to mfg. I have an Ammco 2post. It has air locks. It may take 10seconds total to set the car at the locks. I always stop at one of the locks, and I make sure that both side are on the locks. That is how I do it, you can do whatever you want as long as I am not under the car.

 

[ron in sc]

On one of the lifts I've looked at there are safety catches every 2 or 3 inches that go the length of the columns. Are thoses the safest? They engage as the lift is raised. The lift was a Mohawk.

 

[HoosierBuddy]

I guess I'm the "belt and suspenders" type. I lift mine up, let it down on the catches, and then hit the lift button for just a half second or so (not enough to allow the car to raise) to preload the hydraulics, in case the catches bust.

I did a ton of work on Jackstands before I got my lift last year. What ever you are doing with your lift HAS to be safer than working on jackstands...especially if you are doing something like taking the rear axle assembly out, where you can't have the jackstands under the frame.

I'm a pretty big guy, and I always feared I'd get over rambunctious, and pull the car off the stands while laying under it, pulling on a wrench...or a wrench with a big cheater, if required.

Bad way to die. Alone, pinned, and running out of air.

Yeah...use the safeties.

Phil

 

[SuperKid]

To put vehicle on lift:
1. Position vehicle between posts
2. Put transmission into neutral (do not set parking brake)
3. Put arms under manufacturer's reccomended lift points
4. Be sure all other people are clear from lift area
5. Lift vehicle until tires are off of the ground
6. Shake vehicle side to side, front to back, and on an angle
7. If vehicle is safely positioned, lift until desired height has been reached
8. Lower vehicle onto safety catches

To remove vehicle from lift:
1. Be sure nothing is underneath the vehicle
2. Be sure all people are clear from lift area
3. Lift vehicle off of safety catches
4. Release safety catches
5. Lower vehicle too ground
6. Put transmission into park (or set parking brake if it's a manual transmission)
7. Remove arms from under vehicle

The reason you'd lower the vehicle onto the catches is because if the hydraulics were to fail, the falling then abrupt stop of hitting the safetys could cause the vehicle to fall from the lift.

 

[PxTx]

If the hydraulics fail, the car will lower at the same rate as it normally would when releasing the pressure. I guess for added saftey- like some of the concerns listed above (other than hydraulic failure) like hardware failure, improper loading and such you could use 4 heavy duty pole jacks to support the underside of a car.

I'm okay with standing under a car, being supported by the hydraulics on a well maintained lift. Maybe someone else can chime in, but I beleive the saftey factor for a lift to be rated for 10k lbs is 3x- meaning the hydraulics are tested to be able to lift 30k lbs.

 

[ron in sc]

but I beleive the saftey factor for a lift to be rated for 10k lbs is 3x-

I'm shopping for a lift and I've been told by at least one company that the current standard is 1 1/2 times the rated load, but the testing now is not for a lift to just hold that weight but to be able to raise and lower 1 1/2 times the capacity. They called it a dynamic test. I have not idea whether I was being total the truth or not.

 

[brownbagg]

my lift automaticly lowers onto the safety locks, after you raise it bleeds down to the lock. It the way it was designed.

 

[wilbilt]

If the hydraulics fail, the car will lower at the same rate as it normally would when releasing the pressure.

I think that depends on what fails, and how. Here in CA, the maximum allowable descent rate for an automotive lift is 20 feet per minute. I assume that is governed by a flow-restricting device in the hydraulic system, probably in the control valve.

If a hose or seal blows, it is very possible the lift will descend at a much faster rate.

 

[Rrumbler]

Would you consider working on a car on a floor jack, without setting it down on jackstands? Would you trust the jackstands to catch a car coming down due to a failure of the floor jack? In my mind, the safety catches on a lift are the equivalent to the jackstands. Use you own sense of logic and self preservation, and don't let someone bully you into taking foolish chances.

 

[PxTx]

It has been my experience that the rate of decent has little do whit the actual power unit and release valve than it does with the size of the hydraulic fittings intergated into the hydraulic ram. If somehow the ram were to be quickly sheered in half, the rate of decent would be quick. Otherwise the line failure, internal seal, structural crack or other hydraulic failure, would not nesisarily be the limiting factor.

Be safe!

I think that depends on what fails, and how. Here in CA, the maximum allowable descent rate for an automotive lift is 20 feet per minute. I assume that is governed by a flow-restricting device in the hydraulic system, probably in the control valve.

If a hose or seal blows, it is very possible the lift will descend at a much faster rate.