If I'm not mistaken the M6 and M635CSI steering boxes have different ratios than the non M-cars. Can anyone confirm or deny this? I continue to have problems figuring out the culprit of my power steering issues and sourced a rebuilt steering box from a local parts supplier but it's for a 635CSI. The part numbers on it are different from the one in my car, which seems to confirm my suspicion but I'd love to know for sure. Does anyone have any experience with this?
-tj in los gatos
M635CSI steering box
Moderators: GRNSHRK, ron, bfons
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corsachili
So I've been looking through all of my BMW books searching for any concrete information regarding M6/M635CSI steering boxes. Jeremy Walton's 6-Series book mentions nothing about it, nor does My "Complete BMW" or the BMW Buyer's Guide. I do have a "M-Cars" book which mentions very briefly that the steering box in the M635CSI has "increased feedback" or something like that, but it doesn't say how.
I'm pretty certain that the ratios for the M cars are unique to them, but so far I can't find anything definitive.
I'll try emailing the Tech Advisor in Roundel and see what they might know.
-tj in los gatos
I'm pretty certain that the ratios for the M cars are unique to them, but so far I can't find anything definitive.
I'll try emailing the Tech Advisor in Roundel and see what they might know.
-tj in los gatos
IIRC Walton's book mentions that a quicker steering box ratio exists, but this might have been in relation to the racing E24s.
The standard steering box is 3-1/2 turns lock to lock.
It shouldn't be a big job to check the ETK numbers for the steering box?
Also IIRC the M635 is fitted with a different PAS pump with 120 bar rating(vs 110bar I think), which presumably alters the steering feel even if the steering box is the same thing.
cheers
The standard steering box is 3-1/2 turns lock to lock.
It shouldn't be a big job to check the ETK numbers for the steering box?
Also IIRC the M635 is fitted with a different PAS pump with 120 bar rating(vs 110bar I think), which presumably alters the steering feel even if the steering box is the same thing.
cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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corsachili
Just a silly question here but is the steering box in the BMW are around this time unique or pretty generic.
A quick search reveals there is a myriad of close ratio steering boxes in the marketplace. Would it be a massive custom job to install one or would it be reasonably simple.
A quick search reveals there is a myriad of close ratio steering boxes in the marketplace. Would it be a massive custom job to install one or would it be reasonably simple.
BMW’s
84 E24 M635csi
90 E34 M5 3.6
94 E34 540i/6 SC E85
97 E36 M3 euro SC U/C
97 Z3 2.8 widebody
OTHERS
11 Audi S5 3.0 SC
19 VW Amarok V6
84 E24 M635csi
90 E34 M5 3.6
94 E34 540i/6 SC E85
97 E36 M3 euro SC U/C
97 Z3 2.8 widebody
OTHERS
11 Audi S5 3.0 SC
19 VW Amarok V6
I've trawled through my books too, here's what I found
in original m series james taylor says about:-
the m635 and m6 - the steering ratio is 16.9:1 giving 3.2 turns ltl
the e28 m535i - has a different ratio in the steering box and shares this quicker steering with the with std 535i and the m5. It's ratio of 15.1:1 gives 3.2 turns ltl as compared to 16.2:1 ratio and 3.6 turns ltl of other e28
the e25 m5 - has the same 15.1:1 ratio as the 535i and m535i, it requires 3.2 turns ltl
in the 1987 BMW Source book it lists the steering ratio as 15.7:1 and 3.5 turns ltl for the m6, l6, m5, 535is and 528e.
so who knows what is correct?
My car has 3.5 turns ltl but it is not the original steering box can some m car owners please check and post their turns ltl.
in original m series james taylor says about:-
the m635 and m6 - the steering ratio is 16.9:1 giving 3.2 turns ltl
the e28 m535i - has a different ratio in the steering box and shares this quicker steering with the with std 535i and the m5. It's ratio of 15.1:1 gives 3.2 turns ltl as compared to 16.2:1 ratio and 3.6 turns ltl of other e28
the e25 m5 - has the same 15.1:1 ratio as the 535i and m535i, it requires 3.2 turns ltl
in the 1987 BMW Source book it lists the steering ratio as 15.7:1 and 3.5 turns ltl for the m6, l6, m5, 535is and 528e.
so who knows what is correct?
My car has 3.5 turns ltl but it is not the original steering box can some m car owners please check and post their turns ltl.
6/87 the steering box went to servotronic I think. Maybe they only made one ratio in that version. Again it would be easy enough to check on the ETK.
Prior to that there are two steering box part numbers listed for LHD and two for RHD in E24 82-87.
IIRC, according to the ETK, the M635 and M6 share the steering box with the M5, but no other E28 models.
The ratios quoted above may be all up the spout; on a stock steering box 3.5 turns gives (just under?) ~90 degrees of arc at the output arm, so 15:1 seems reasonable. But a quicker box (fewer turns lock to lock) should be a lower number, not a higher number, surely?
cheers
Prior to that there are two steering box part numbers listed for LHD and two for RHD in E24 82-87.
IIRC, according to the ETK, the M635 and M6 share the steering box with the M5, but no other E28 models.
The ratios quoted above may be all up the spout; on a stock steering box 3.5 turns gives (just under?) ~90 degrees of arc at the output arm, so 15:1 seems reasonable. But a quicker box (fewer turns lock to lock) should be a lower number, not a higher number, surely?
cheers
~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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mmulloy 123
- Posts: 78
- Joined: Mon Oct 06, 2014 9:21 pm
- Location: San Diego, CA /USA
Re: M635CSI steering box
I have 3 original M boxes 1-E28 Euro M5 1-M635CSI and 1- E28 us M5 they all have the same # on the red tag and are 3.5 turns lock to lock. For some reason my E 28 M5 euro feels quicker (turning) than my Euro 535i (which has a diiferent # on it but still has the 3.5 LTL. Is it possible that the M boxes are quicker but have a longer lock to lock which makes it seem thge same?