Scissor Jack

[Rubyred]

Hi all, just taken delivery of space saver wheel and jack for my now ordinary tyre shod C Class AMG Line.
The scissor jack that came with the wheel is a 1 ton jack and after trying it out it seemed to struggle a bit.
Question is, should I go for a 2 ton jack or is the 1 ton sufficient do you think. It’s just that it looks a bit precarious.
Ive adapted the drive on the jack to use a socket and racket rather than the two piece handle, which is pretty useless.
I may have answered my own question really, but any other thoughts guys.
Keith

 

[renault12ts]

1 tonne is insufficient.

 

[whitenemesis]

Wouldn't a 2 tonne bottle jack be more robust? Perhaps less easily stowed but safer?

 

[190]

In my limited experience scissor jacks have a weakness. look at your jack and there should be interlocking teeth at the bottom end of the lower arms that ensure the jack rises vertically. These teeth can wear and eventually bend out of engagement when the jack is overloaded. I've seen it happen and as a result would not trust my car on a scissor jack. I never did raise the car with this old scissor jack and only used it as an additional support as well as jack stands when getting under the car. I wouldn't trust it for even that now. Even if you have no intention of getting under the car, if the jack fails while the wheel is off you are left with a real problem getting it up again.

 

[chic0821]

1 tonne is insufficient.

Why, C class weighs 3855lbs, your not lifting the whole car into the air only one corner
Prefer a bottle jack myself, easier to use in an emergency.

 

[renault12ts]

Why, C class weighs 3855lbs, your not lifting the whole car into the air only one corner
Prefer a bottle jack myself, easier to use in an emergency.

3855lbs is 1.7485 tonnes.
When you lift a car at a corner you need a jack that will be capable of lifting 0.75 of the total weight...so, in your case a jack capable of lifting 1.312 tonnes.
So...a 1 tonne jack is insufficient.

 

[chic0821]

Why are you lifting 0.75 of the weight, one corner is 0.25

 

[Martin 1]

I've been using scissor jacks for decades and I've always hated them ! Cheap and unstable, emergency use ONLY !

 

[merc estate]

Get a used mercedes jack of ebay or a breakers, when it falls off the scissor jack you will wish you did

 

[markjay]

Why are you lifting 0.75 of the weight, one corner is 0.25

The official spec car jacks is that the jack should be rated at 3/4 of the car's overall weight. This obviously includes a safety margin. A 1 ton jack will work, on a practical level, but it will be below spec.

 

[markjay]

I've been using scissor jacks for decades and I've always hated them ! Cheap and unstable, emergency use ONLY !

They are lighter and fold flat so easier to store in the boot, than a hydraulic bottle jack. Also, a bottle jack with sufficient reach to lift the car when resting on a flat tyre will be tricky, you'll typically need two bottle jacks, a small one for the initial lifting and a larger one for fitting the spare tyre.

I don't like scissor jack either... but as said they are small, lightweight, maintenance free, and do the job (in an emergency).

 

[Rubyred]

Really appreciate all of your responses. I think I will go for a more robust scissor jack, a bottle jack would be better but they are heavy to carry in the car and as markjay says tricky to use with a flat tyre.
Its obviously only going to be used in a puncture situation, so hopefully never.
The stupid thing is I had a really good quality scissor jack tucked away in the garage and I must of got rid of as I can’t find it. Doh!!

 

[Deleted member 126251]

......... These teeth can wear and eventually bend out of engagement when the jack is overloaded.

How often do you get punctures? ;-)

 

[190]

How often do you get punctures? ;-)

Never had a puncture in 50 years of driving that involved using a jack out on the road. Perhaps my scissor jack had a hard life before it came to me. It did fail though so I believe my comments are still valid for anyone thinking of buying a cheap scissor jack - look at how it works and how robustly it's constructed.

 

[markjay]

Scissor jacks aren't the safest thing around... they should be used with great care. But then again I wouldn't trust a bottle jack either - no parts of the body under the car, and where possible also place a wheel under the car. Unfortunately using an axle stand at the roadside is impractical as you wouldn't carry one with you.

 

[markjay]

I actually used to carry two hydraulic bottle jacks in the boot a small one and a big one - for roadside repairs - but that was quite a long time ago when I used to drive DIY modified cars where reliability was a secondary consideration to performance (OK, call it Barryed-up )

 

[Bellow]

Really appreciate all of your responses. I think I will go for a more robust scissor jack, a bottle jack would be better but they are heavy to carry in the car and as markjay says tricky to use with a flat tyre.
Its obviously only going to be used in a puncture situation, so hopefully never.The stupid thing is I had a really good quality scissor jack tucked away in the garage and I must of got rid of as I can’t find it. Doh!!

Then the jack you have will be fine.
Nothing short of a trolley jack is properly stable and a bottle jack is no better than a scissors - arguably worse.
What you need to do is minimise the time available for the car dropping to the ground. Do this by placing the wheel you are using as the replacement under the car until ready to fit it to the hub. As soon as the wheel coming off is removed, slide it under the car. The time the car can fall is reduced to mere seconds.
It can only ever be asked to lift half the weight of the car so 1 tonne is adequate. Even if it lifted three wheels clear of the ground, the one remaining on the ground will be supporting half the weight of the car, the jack the other half. The chances of lifting three wheels clear is between nothing and zero.

 

[BTB 500]

The rating of any jack will already include a significant safety margin, so a 1 tonne jack should be absolutely fine lifting one corner of a 1750 kg car.

 

[chic0821]

A 1 tonne jack will have a minimum Factor of Safety of at least 2,
Have a read of this FOS is around 4

 

[E55BOF]

OP, do you have an OE mercedes scissor jack with a nylon moulding on the lifting point to engage positively with the recess on the car, or a cheapo-cheapo aftermarket universal item?