Trolly Jack Safety

Doesn't sound good to me. What happens when you jack up a car with it - how quickly does it go down?

It goes without saying that you shouldn't work under a car supported

*only* on a trolley jack, of course - even if it's in perfect condition.

pretty much normal, you only need a tiny mark on a valve surface to allow slight leakage, there is a large spring that is always pulling the jack closed, not just the weight of the arm. Mine does it too.

Al was thinking very hard :

Mine is a bit more up market, a small commercial garage jack, but no it is not normal for mine. I could leave it up for weeks/ months without movement.

Its not a good idea to leave the piston/ram exposed for long periods, they can rust, which will then wreck the seal. I always park mine fully down, which it has to be fully down anyway, to enable it roll under the bench where I keep it.

Absolutely!! I use two tripods as well as the trolley jack; this goes back many years to my first car. I once had a trolley jack from Halfords collapsing, went back to the shop and got a free replacement. I asked how this could possibly happen? The assistent hinted that the DIY ones were not of same quality as those used by the trade.

A long time ago when I was a medical student I was shown a skull x-ray that resembled a partially crushed hard boiled egg.

Apparently a leaky trolley jack had trapped the poor unfortunate under a car and it had slowly crushed his skull in the limited space. Luckily for him the space was big enough to prevent a fatal crushing but he never passed out and heard all the cracking noises!

Tim

Even with a full compliment of axle stands and left-in-place jacks, it's still fairly testing of the nerves being under 1.5 - 2t of vehicle!

Does anyone else admit to just using a trolley jack for, say, brake pads or something else where you're not going underneath?

Changing a wheel is about the limit for unprotected lifting.

even with axle stands in place I take the old approach of a large solid lump of something thick enough to keep the car off me.

even a disk/pad change needs something extra, just in case. A crushed hand would be devastating.

Scott M explained :

I don't mind doing wheel changes and brake pads on my proper garage jack, but I will not risk going under it. I have several scissor jacks,

4x stands, an unused DIY trolley jack, a commercial trolley jack and my latest purchase a powered hydraulic side lift.

The later plugs into a 13amp socket and is like a fork lift. It can lift by a wheel, or under the sill, the entire rear or the front end up to a 1 metre height. Once up, you can insert a steel pin, so even if the hydraulics fail it cannot drop down on you. It makes it easy to sit under the car to work on it.

Harry Bloomfield formulated on Saturday :

I also collected various bits of timber, including a few short sections of railway sleepers.

Years ago I used doubled up bits of sleeper with a bit of 2x2 on each end, 4 of those, one under each wheel and the car was high enough and safe enough to slide under on a creeper, oxy acetylene welding was the most exciting activity under a car, a spark goes in to the nozzle and it pops, spraying you with molten steel droplets, ah happy days.

I have a concrete drive, but with the usual imperfections. Once had a tripod axle stand tilting over ever so slowly, you could hardly see the movement, but spotted it just in time. So always make sure that the stand is still on good fotting.

Do you use the jack on the jacking point, then put the axle stand/whatever next to that, or the other way round? Or isn't the actual point of jacking/support all that critical?

It all depends on the vehicle, some are a nightmare to jack and block, such as mercedes.

Ramsman used his keyboard to write :

The manual will give the location of suitable places where a car can be jacked up by, but it will likely not be a full list. Mine just indicates 4x reinforced points under the sills, plus front sub-frame and a location under the wheel well. There are several other places mentioned in the manufacturers full workshop manual.

Having been under 2t of Discovery on four axle stands on less than even ground, I'm all for that!

I've only come adrift once and that was with the BMW jack on my old E36 which slotted into holes in the sill. Had been working my way round the car and must have had the suspension/drivetrain wound up a bit as, on the last wheel (think it was just swapping rims) I leant on the wing and the car shoved off backwards in slow motion, the jack twisting and fighting it down to the ground until it was sat on the disc.

I usually throw the wheel under the sill. Gets it out of the way if nothing else.

I'm very wary of getting any part of me under the hub for that reason!

I'm not sure how the valve on a trolley jack operates, but might it not be the case that it needs weight to make a good seal, in the locked position?

Terry.

After about 20 years my trolley jack had a problem with descending slowly (when it shouldn't) The pump pushes the oil past a spring-loaded ball on a seat, that will seal better with weight, but the problem on mine was actually the release valve and overload valve (which is a spring loaded needle valve) letting some oil by, which is made worse with higher loading. So the light end of a car would stay up on the jack overnight, but the heavy end would go down in a half hour or so. I cleaned out every part and then adjusted up the relief valve till the heavy end of the car would stay up ok for an hour or more. I would not expect a trolley jack to hold up indefinitely, and they should always be supplemented by some sort of secondary support, just as a vehicle lift is.