Front Control Arms - Load Suspension?

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cory58
Posts: 155
Joined: Thu Aug 25, 2016 8:49 pm
Location: Charlotte, NC

Front Control Arms - Load Suspension?

Post by cory58 »

Good morning fellow E12 fans.

I plan to replace the front control arms on my 530i this weekend. Do I need to load the front suspension before tightening the inner bushing bolt? If so, has anyone using a 2-post lift loaded a front corner with a screw jack while also supporting the rear? I'm totally spoiled since having the lift for 4 years and getting too old to crawl up under cars on jack stands, but want to be safe.

Thanks!

Cory
1977 530i
1988 320i Touring (euro)
1992 325i Cabrio
2000 M5
2015 328i (wife's daily)
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Mike W.
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Re: Front Control Arms - Load Suspension?

Post by Mike W. »

cory58 wrote: Fri Jun 16, 2023 6:06 am Good morning fellow E12 fans.

I plan to replace the front control arms on my 530i this weekend. Do I need to load the front suspension before tightening the inner bushing bolt?
Thanks!

Cory
Yes.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
cory58
Posts: 155
Joined: Thu Aug 25, 2016 8:49 pm
Location: Charlotte, NC

Re: Front Control Arms - Load Suspension?

Post by cory58 »

Thank you.
1977 530i
1988 320i Touring (euro)
1992 325i Cabrio
2000 M5
2015 328i (wife's daily)
garyinwestoz
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Re: Front Control Arms - Load Suspension?

Post by garyinwestoz »

If you watch M539 Restorations, Streten often torques up the suspension bushes with a preload, and he does this by first measuring the wheel height - relative to the wheel arch with car on the ground, then once car is in the air, Jacks up the wheel to that measurement, then torques the bolts/nuts.

Quite a smart way of doing it - kinda better than using ramps and thus having limit torque arm movement which is how Ive had to do it!
74 525 auto
76 525 - 4 speed, LPG and holley carb- restoring
77 528i- 4 speed manual
77 528i -4 speed manual getting rusty
79 528i auto - a SA car?
80 528i auto - ready to relicense
81 528i +3.5ltr - auto - restoring
86 525e 5 speed manual- dd
cory58
Posts: 155
Joined: Thu Aug 25, 2016 8:49 pm
Location: Charlotte, NC

Re: Front Control Arms - Load Suspension?

Post by cory58 »

garyinwestoz wrote: Tue Jun 20, 2023 7:48 am If you watch M539 Restorations, Streten often torques up the suspension bushes with a preload, and he does this by first measuring the wheel height - relative to the wheel arch with car on the ground, then once car is in the air, Jacks up the wheel to that measurement, then torques the bolts/nuts.

Quite a smart way of doing it - kinda better than using ramps and thus having limit torque arm movement which is how Ive had to do it!
Love M539 Restorations! Quit your day job and make videos working on BMWs all day - heaven.

Doesn't Streten perform the procedure you described with the car on his 4-post lift? I have a 2-post lift and am scared that loading a single corner enough will dangerously change the balance of the car on the lift. I put a screw jack under the rear of the car earlier this week and tried to load the LF with another screw jack. Applied as much pressure as I was comfortable with and barely moved the LF suspension. Since that was a fail, I just let it down, put the front on ramps and crawled under it. Barely enough room to swing the torque wrench and couldn't get enough force on it to apply the required torque. Torqued it as much as I could and called it a day.

Cory
1977 530i
1988 320i Touring (euro)
1992 325i Cabrio
2000 M5
2015 328i (wife's daily)
User avatar
Mike W.
Posts: 2798
Joined: Wed Aug 30, 2006 12:12 am
Location: Sonoma County

Re: Front Control Arms - Load Suspension?

Post by Mike W. »

cory58 wrote: Thu Jun 22, 2023 12:01 pm Barely enough room to swing the torque wrench and couldn't get enough force on it to apply the required torque. Torqued it as much as I could and called it a day.

Cory
As long as you can get it tight enough not to slip once in the air, you can fully torque it in the air as you locked it in position already.
Mike W.



1980 528i, 3.5 euro, 5 speed conversion
1981 528i, 3.6, Recaros and more. Project
1998 328is, quick and efficient, but not satisfying
2000 528iit, Vacation mobile/wife's grocery getter
cory58
Posts: 155
Joined: Thu Aug 25, 2016 8:49 pm
Location: Charlotte, NC

Re: Front Control Arms - Load Suspension?

Post by cory58 »

Mike W. wrote: Thu Jun 22, 2023 12:26 pm
As long as you can get it tight enough not to slip once in the air, you can fully torque it in the air as you locked it in position already.
Excellent. Thank you.
1977 530i
1988 320i Touring (euro)
1992 325i Cabrio
2000 M5
2015 328i (wife's daily)
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