Power steering up grade from steering box to rack & pinion.

[Mercinstein]

G'day thanks for having me. I'm wanting to convert my w124 230e from steering box & linkages to a steering rack & pinion . As I'm also doing a Buick V6 5 speed manual conversion. I need the room that is taken up by the steering box & linkages. So could someone please advise on steering rack may be from another MB model Or any other suitable make and model.


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Upper Lockyer Queensland 4352

[merc-304]

Does the steering box foul on the motor ? Has been done in a w201 and the steering box was retained just some mods to the drag link or idler/ pitman arms i think.
omerhanx w201 3.8 ecotec in the Modified section

[kimrh]

W210-E class "rear mount rack" (see pics below) should be a good start
or from a Ford Falcon which i have heard will also work in W126 so should also work in W124

[Mercinstein]

W210-E class "rear mount rack" (see pics below) should be a good start
or from a Ford Falcon which i have heard will also work in W126 so should also work in W124

Thank you very much kimrh.


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Upper Lockyer Queensland 4352

[Mercinstein]

G'day kimrh thank you would you know what the length of the w210 steering rack is from centre of the tie rod ends please. I have a Vn Commodore power steering rack it's 1265mm long . I am about 75mm over length as the w124 is 1190mm from steering arm to arm off the wheel.


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Upper Lockyer Queensland 4352

[merc-304]

Ok ...will keep everthing over here on this thread...do you have a manual pedal box and the rest of bits and pieces to go manual ?
Worth having a read up on W124 e500 ...and what steering they used to maximise room when they squeezed those big v8 lumps in the engine bay.

[Mercinstein]

Ok ...will keep everthing over here on this thread...do you have a manual pedal box and the rest of bits and pieces to go manual ?
Worth having a read up on W124 e500 ...and what steering they used to maximise room when they squeezed those big v8 lumps in the engine bay.

Hello yes I picked up a clutch assembly from Mercbits in Melbourne they are very good there.
I have had a look at the layout of the w124 500e it is all a matter of the Mercedes built it to fit in there built vehicles. But I'm wanting to fit a engine an gearbox from a different maker so I have to change things too suit my engine. So I'm asking what other people know works or may possibly work for a conversion such as this.


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Upper Lockyer Queensland 4352

[kimrh]

All the W210 E-Class steering rack dimensions are in my last pic i attached written on the cardboard the rack is sitting on
1350mm tie rod end to end but that is an easy fix with shorter tie rod ends swapped in
The W126 measured 1250mm so it meant getting shorter ties ends by 50mm shorter each side (= 100mm total reduction required)
The more important equation is bump steer
https://www.google.com.au/search?q=meas ... o1tpoBM%3A

You want the rack length where it pivots each side to be close to an imaginary line drawn between the upper and lower control arm pivot points
They refer to it as the "Instant Centre" or "Intersection Point" to achieve negligeable or no bump steer.
There is a bit more to it than that - but that is the basics needed when measuring a steering rack pivot point length required to make it all work - plus the steering rack throw on how far it will travel lock to lock for good turning circle as the original steering box set up has a good throw
Some guys have shortened the connecting arm on the wheel hub to compensate (replaced it) so the steering rack does not have to travel so far to swing the wheels lock to lock.

The actual adjustable tie rods ends that screw off are the easy part as they can be purchased in varying lengths to suit or custom made to exact length required to achieve the desired whole length of the rack to match your car

[merc-304]

Plenty of room in those engine bays when fitting a v6 have you tried a test fit with the original steering box in place but with the motor forward a few inches ?
Probably wise to tack in some temporary bracing into to the crossmember....being as you have removed a lot of its strength

And remembering back to reading about a V6 holden motor swap into a BMW E30...the GM computer was piggy backed off the BMW one making the wiring reas simple ?


A wise man on this forum 'Mercmad' once said...tis better to make up custom headers to suit than mess with steering geometry/german eng.....or something along those lines.

[Mercinstein]

Plenty of room in those engine bays when fitting a v6 have you tried a test fit with the original steering box in place but with the motor forward a few inches ?
Probably wise to tack in some temporary bracing into to the crossmember....being as you have removed a lot of its strength

And remembering back to reading about a V6 holden motor swap into a BMW E30...the GM computer was piggy backed off the BMW one making the wiring reas simple ?


A wise man on this forum 'Mercmad' once said...tis better to make up custom headers to suit than mess with steering geometry/german eng.....or something along those lines.

G'day Merc-304 thanks for all your help. I've done a fair bit of giggling about an got everything to work with keeping the steering box original. The rack & pinion steering would've been a good conversion for direct precise steering. But I'll come back to that one latter. I'll get this conversion V6 5speed finished first.
Yeah I've had all the bracing of the crossmember done sense those pics.


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Upper Lockyer Queensland 4352

[Mercinstein]

All the W210 E-Class steering rack dimensions are in my last pic i attached written on the cardboard the rack is sitting on
1350mm tie rod end to end but that is an easy fix with shorter tie rod ends swapped in
The W126 measured 1250mm so it meant getting shorter ties ends by 50mm shorter each side (= 100mm total reduction required)
The more important equation is bump steer
https://www.google.com.au/search?q=meas ... o1tpoBM%3A

You want the rack length where it pivots each side to be close to an imaginary line drawn between the upper and lower control arm pivot points
They refer to it as the "Instant Centre" or "Intersection Point" to achieve negligeable or no bump steer.
There is a bit more to it than that - but that is the basics needed when measuring a steering rack pivot point length required to make it all work - plus the steering rack throw on how far it will travel lock to lock for good turning circle as the original steering box set up has a good throw
Some guys have shortened the connecting arm on the wheel hub to compensate (replaced it) so the steering rack does not have to travel so far to swing the wheels lock to lock.

The actual adjustable tie rods ends that screw off are the easy part as they can be purchased in varying lengths to suit or custom made to exact length required to achieve the desired whole length of the rack to match your car

kimrh thank you very much for all your help this conversion I will come back too . I will complete the V6 conversion first now I've got everything where it needs too be.


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Upper Lockyer Queensland 4352

[merc-304]

Mercinstein did you get it to fit by bringing the mtr forward a tad ?

To gain some more room for the exhaust manifolds can you you use a left manifold on the right side giving you a front exit or will you have too make custom headers ?

[Mercinstein]

Merc-304 no I've lifted the engine up an back as far back as possible the throttle body is 10mm off the firewall.
The custom headers will be needed to get around the steering box.


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Upper Lockyer Queensland 4352

[merc-304]

Post some pics if you could.

[Mercinstein]

Post some pics if you could.

Yeah no problem. Would anybody happen to have access to the w124 wiring digram in pdf file ?


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Upper Lockyer Queensland 4352

[merc-304]

How you going with this swap ? a guy out Toowoomba way has one for sale on Gumtree..also a 5sd manual Modplated and full rego...could be worth a call if you need some wiring info .

[Mercinstein]

Yeah mate completed an on the road . Cheers


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Upper Lockyer Queensland 4352

[Mercinstein]

Whereabouts out toowoomba way


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Upper Lockyer Queensland 4352

[merc-304]

On Gumtree : Toowoomba city price is $8k
Are you happy with your conversion ?

[Mercinstein]

Yeah she's a Beaty an goes very well thank you better then she was with the 4 cylinder.


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Upper Lockyer Queensland 4352

[merc-304]

Did you have to go with custom headers..can you post some pics of engine bay etc
Thanks.