Is it OK to jack under the differential?

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Bumpa
Joined: Fri 23 Jun, 2017 20:31
Posts: 70

  Z3 roadster 2.2i

Is it OK to jack under the differential?

Post by Bumpa »

That's the question. Is it OK to jack under the differential?
Mike

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Gazza
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Joined: Tue 04 Oct, 2005 20:58
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  M roadster S54
Location: Romford Essex

Re: Is it OK to jack under the differential?

Post by Gazza »

I have in the past
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

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mrscalex
Joined: Fri 13 Mar, 2015 09:14
Posts: 901

  Z3 roadster 1.9

Re: Is it OK to jack under the differential?

Post by mrscalex »

If you mean the rear beam under the vicinity of the diff yes. If you mean the diff itself - not so sure I would do that.

I've always used the rear beam centrally in the diff area.
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2001 Z3 2.2 Topaz Blue (Trudy) - Keeper rebuilt from a write-off
2002 Z3 2.2 Titan Silver (Cookies) - Keeper rebuilt having been bought with a seized engine
2002 Z3 3.0 Sapphire Black (Peanut) - Keeper awaiting rebuilding having been bought as an abandoned project
Plus Willy, Kodak & Maycee - All 2.2 Sport projects. Yes, 6 is a lot of Z3s :)
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Bertie
Joined: Sun 06 Oct, 2019 03:46
Posts: 44

  Z3 roadster 3.0i
Location: Montreal Canada

Re: Is it OK to jack under the differential?

Post by Bertie »

The Pelican parts Child's Guide I wrote about recently jacks the Z3 under the differential before lowering the car onto jack stands .
Bertie

LaRy
Joined: Mon 12 Nov, 2018 17:47
Posts: 74

  Z3 roadster 2.8

Re: Is it OK to jack under the differential?

Post by LaRy »

I was reading the post "Z3 illustrated Child's Guide to DIY maintenance" from 17th of June, where it you can find links to https://www.pelicanparts.com/BMW/techar ... ain_Z3.htm . I was just reading the section jacking up your car. It clearly shows in picture 10 that you can place the jack under the differential.

Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2054

  Z3 roadster 2.8
Location: Daglan, France

Re: Is it OK to jack under the differential?

Post by Mike Fishwick »

Yes - you CAN place the jack under the diff, but it is pretty poor practice! Just because some nameless person has placed something on the internet does not mean that it is automatically the best option - it is just like believing all the garbage written about the Z3 which you can read in the media . . . If it was really such an evil-handling car we would probably all be dead by now!

A far better method is to buy two trolley jacks (they are cheap enough these days) and lift the car via the jacking points, with a piece of hardwood between the trolley jack platforms and the plastic jacking point. When you get the car high enough, support the cross-member with several pieces of wood, and lower the car to remove the trolley jacks. The car will be in a far safer condition than relying ona single trolley jack under the diff (or under the cross member), and the two jacks can now be used to lift the front end in the same way, locking the jacks with a suitable piece of rectanguar steel tube between the jack frame and the platform.

If you want the car higher still, place the jacks on wooden blocks and lift the car higher still.
A Z3 is not just for Christmas - it's for life!

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Gazza
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  M roadster S54
Location: Romford Essex

Re: Is it OK to jack under the differential?

Post by Gazza »

I don’t think anyone was suggesting leaving the trolley jack under the diff unsupported :wink:
Gazza

"Understeer is when you hit the wall with the front of the car, oversteer is when you hit the wall with the rear of the car. Horsepower is how fast you hit the wall and torque is how far you take the wall with you"

Z3 S54 M roadster Image, BMW Z1, BMW M3 CSL, Z4M Coupe
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Bertie
Joined: Sun 06 Oct, 2019 03:46
Posts: 44

  Z3 roadster 3.0i
Location: Montreal Canada

Re: Is it OK to jack under the differential?

Post by Bertie »

My post said very clearly that you lowered the car onto jack stands ,after raising it by jacking under the differential .; before working under the car.
The jack stands would be placed under the rear jacking points.Being Canadian I would use hockey pucks between the jack stands and the jacking points
Bertie

Bumpa
Joined: Fri 23 Jun, 2017 20:31
Posts: 70

  Z3 roadster 2.2i

Re: Is it OK to jack under the differential?

Post by Bumpa »

Mike Fishwick wrote:
Thu 25 Jun, 2020 13:56
Yes - you CAN place the jack under the diff, but it is pretty poor practice! Just because some nameless person has placed something on the internet does not mean that it is automatically the best option - it is just like believing all the garbage written about the Z3 which you can read in the media . . . If it was really such an evil-handling car we would probably all be dead by now!

A far better method is to buy two trolley jacks (they are cheap enough these days) and lift the car via the jacking points, with a piece of hardwood between the trolley jack platforms and the plastic jacking point. When you get the car high enough, support the cross-member with several pieces of wood, and lower the car to remove the trolley jacks. The car will be in a far safer condition than relying ona single trolley jack under the diff (or under the cross member), and the two jacks can now be used to lift the front end in the same way, locking the jacks with a suitable piece of rectanguar steel tube between the jack frame and the platform.

If you want the car higher still, place the jacks on wooden blocks and lift the car higher still.
Yes, I would use the jacking points normally, of course I would. But what if you are removing the sills for rust clean up as I was? I just wondered if jacking centrally under the diff and then using axle stands on strong points would be simpler.

As for the comment about trolley jacks being cheap enough. I bought a fairly pricey Sealey trolley jack and found it almost impossible to lower it in a controlled fashion. So I took it back and was referred to a Sealey repair centre where the guy there said that they all did that because the design of the valve was so poor. He did what he could and it is slightly better but not great and can come crashing down if you are unlucky. Then I bought a cheap one from Halfords which worked well for 13 months and then leaked so badly that it became completely useless. It seems that nobody knows how to make decent things any more.

Flight
Joined: Mon 16 Sep, 2013 20:43
Posts: 97

  blank

Re: Is it OK to jack under the differential?

Post by Flight »

They were probably made in China. Have a look around for a British made jack and leave the Chinese rubbish on the shelf

Mike Fishwick
Joined: Fri 19 Jun, 2009 10:27
Posts: 2054

  Z3 roadster 2.8
Location: Daglan, France

Re: Is it OK to jack under the differential?

Post by Mike Fishwick »

For a reliable and safe means of supporting the car, why not use the ends of the cross-member, below its rubber mounts?
A Z3 is not just for Christmas - it's for life!

mikeh7@tiscali.co.uk
Joined: Wed 08 Jul, 2020 15:06
Posts: 2

  Z3 roadster 2.8

Re: Is it OK to jack under the differential?

Post by mikeh7@tiscali.co.uk »

Hi As a newby, for what it's worth, I too have been wondering about this, the problem is if you want to jack up the car and put on axel stands placed on the proper jacking points, if you use trolly jacks the trolly jacks are in the way of putting the axel stands!
Personally I would not recommend jacking up under the diff it self as the way the diff is mounted leaves a lot to be desired ie only just adequate. I was interested in the idea of using the cross beam though.

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