Raising and supporting light vehicles (ie. cars) - some thoughts and observations.

On the last page we were using the car's own jack to raise it. There's a problem with using these jacks which come with the car. There are many slightly different designs but they all have one inherent problem which is they are not very stable. Here's some typical ones:



The black one is the Pandas original and intended for the car. The red one is a generic one bought off the internet. Notice the saddle which contacts the car will not work how it's meant to as the weight will be taken on the sill seam and the "claws" are likely to scratch the paint off. The last one, at the bottom of the picture is from the Ibiza and you can see it has quite a nice nylon insert to minimize paint damage to the sill. All have one big problem though. they have just one "foot" so have no inherent stability. If the car moves it'll fall off the jack. Then, especially if you've got the wheel off, you've got a very real problem because how do you lift it back up when it's flush with the ground and you can't get the jack back under it? Better for this situation not to arise at all so, Always chock the wheels. Of course you've got the handbrake on tightly haven't you? If you're just changing a puncture then chock the wheel diagonally opposite the one you're working on - so if you're working on the O/S front then chock the N/S rear, and chock it both in front and behind. with a bit of luck that will stop it rolling forward or backwards but it won't do anything to stabilize it sideways. Be aware that as you jack up one wheel the other one on that end of the vehicle will also be experiencing weight removed from it. So if you're jacking up the O/S front then the N/S will also rise as you jack and this reduces the load on the N/S wheel and the ability of the tyre on that side to grip the road/ground. Jack it high enough and the car will move sideways and fall off the jack so only ever jack up high enough to get the new wheel on. A "nasty" aspect of this is that if we consider the above scenario, ie. O/S/F being jacked up, and the N/S/F is on an unstable surface like gravel, mud, even a slimy, perhaps mossy, surface, then the N/S/F tyre will loose it's grip and the car will fall sideways off the jack. So, only jack up on a sound surface. Keep in mind also that a flat tyre will have a flat bottom - if you see what I mean - so if you just jack up far enough to remove the punctured wheel you won't be able to get the spare on without winding the jack up a bit further. It's better to get all the jacking done in one as operating the jack is when it's most likely to fall over.

A lot of this problem can be alleviated by using a trolley jack which is much more stable. I'll come back to trolley jacks in a while. Bottle jacks or similar aren't really a "goer" for this sort of thing and are also pretty unstable.

Here's a couple of trolley jacks with home made sill protecting pads on their "business" ends. You can buy commercially made protective "pucks" which are made from hard rubber with a slot in the middle to protect the sill seam.



The smaller jack is in use here and you can see it's managing to lift the car just far enough to get the stand underneath on pretty much it's lowest position. This is quite enough to be doing brake work though - as you can see the wheel is well clear of the ground. Sometimes, like working on exhausts etc, you need more height when something, like the red jack, will be needed. Here's three representative examples:



The one nearest to us is my friend's with a total lift of 390 mm which gets the axle stands up to a bit above the first hole but not high enough to get the pin in the second hole. Next is my very old friend, first trolley jack I ever bought and now sporting a new pumping element (the red bit) as the original wore out and started leaking. He has a lift of 415 mm and can get the car up high enough to get the pin in the second hole on the axle stand. The big red one is another old friend which I've had for so long they don't make that model any more and he can get the axle stands up to full height with a lift of 500 mm. I find working with my friend's jack a little limiting due to it's lift restriction. Also you may notice it gets that lift at the cost of it's closed height - look at the saddle and you'll see it's higher from the arm compared to both of mine. It's not quite so good for going under low vehicles for this reason. It's lifting arm is 220 mm long compared with my wee one's 270 mm. So mine starts off lower but still achieves a higher lift ultimately. For years I worked at home with just this jack and found it worked well for most jobs.