Hi everyone. I just bought a very clean 2003 e39 540i MTech manual. Its wonderful.
Before the sale the previous owner did a suspension refresh,including shocks. Seems he used Bilstein B4s. The car handles soft at speed and while comfortable cruising not MTech level 2. The car is also sitting high, about 1/2 higher than my e39 525it. The previous owner says he retained the original springs.
To put this right I am considering replacing the shocks with Bilstein B6. I am also concerned that the springs may not be the originals as the springs dictate ride height not the shocks.
Any comments or suggestions would be very much appreciated.
Thanks !
Welcome to the forum patrm99.
Look at the springs, you should be able to tell if they are old or new.
I replaced my shocks with Bilstein B4 and I noticed an increase in ride height as well. I had hoped it would settle a bit over time but it really hasnt moved much since. I know conventional wisdom is the springs set the ride height, but I guess the pressure of the shocks is enough to raise the car slightly.
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The rear shocks for Mtech2 suspension have a lower spring perch, if you don't have Mtech2 shocks the rear will sit too high.
Were the strut bearings for the M5 the same as on a 540? Either that, or the M5 struts made a 540 sit too high. Check the part numbers to see what the PO might have installed.
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OP has a 2003 m-tech. Meaning he has m-tech II suspension ie M5 shocks/struts. I do have Bilstein B6 for my car. Got the fronts installed and it's higher than the old Koni shocks. The rears though due to longer springs, need to have another groove machined to lower the ride height back down because the m-tech II factory shocks have a lower spring perch. But that is for the M5. Being a 540i though I think the springs are shorter and believe you won't need to have another groove added. I could be wrong though. Bilstein says B6 are direct swap for 540i, though not sure if that includes 2003 m-sports. Probably not lol.
Some pics would help, but B4 I believe are designed for non sports suspension cars. B6 are for sport cars and are more firm. They have split opinions. Either you like them or not. Me I like them. But again my old Koni yellows were shot so can't really compare. Bilsteins usually take longer to settle compared to others because of their usual firmer damping.
All E39's use the same front strut mounts. However the rear shock mounts on the M5 and m-tech II 540i's are different than m-tech I and non sport cars. It's really confusing, but just go off the part numbers for your vin in realoem.com and you should be ok.
Last edited by Nfs021; 08-08-2022 at 04:22 PM.
Thanks for all the great responses. Much appreciated.
The springs look clean but probably not new. So figure the PO cleaned them before compressing them, hence I think the springs are likely originals. The fronts do have a green/yellow paint mark (see photo) and the rear an orange mark and thats the only identification I can see. Someone may recognize this. The strut bearing/top mount part # is original BMW, so they are likely originals too.
I do see that the front springs are possibly not seated correctly. The lower end of the springs are perhaps 90degrees rotated away from their correct seating position and this may account for some of the 'highness'. So its possible the combination of incorrectly mounted springs and the use of Bilstein B4's accounts for the problem.
Any more opinions on which shocks I should use to get close to the original ride of M-Tech II ?
Some photos attached.
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I don’t know man, I’m coming off of one of Paul’s posts, Blacknight530, he posted something about how an M5 specific strut sits taller on a 540. Maybe he’ll pipe in on this.
From my 2001 Canadian 540 Msport, the springs are the same as on M5’s, same with the sway bars, but the struts had a different part number.
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Man, that front end is skyhigh! I’m thinking the PO got struts for a regular grandpa 540, the Mtech2 springs being stiffer, are not as compressed as they should be when you lock it all down with the shorter Mtech2 struts, and this is why the front end is sitting so high. Another thing, replace the spring cushion seats, in the picture, you can see dry rot in the rubber. Make sure the bumpers are good too.
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I'm talking about just the m-tech ii or S705A shocks and struts like the OP has on his car. They are the same shocks and stuts as the M5. Even share the exact same part number. Though some think the fronts are valved different. M-tech 1 or S704A uses different part numbers and are considered more soft. No idea if the springs are the same? Long debated opinion if they are or not. Same with the sway bars. Though I think the rear one is slightly smaller than the M5, but still bigger than stock 540i.
I remember the springs being the same, but the struts are not.
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Nfs021 is correct, Mtech2/S705A shocks are the same between 540 and M5 both front and rear.
The front springs are different to account for the S62 being heavier, and the rear springs are the same.
Ok, so I went as far as checking realoem these knuckleheads are right, front struts for 2000 to 2003 M5, part number: 31312229612.
Front struts for 2000 to 2003 540’s with the S705A option, part number: 31312229612. I didn’t bother checking the rears.
Oddly, if you do a search on the option S705A, it is also the same option for Mtech2 suspension for 2001 to 2003 525, and 530 sports, but the part number is 31312229613 for the fronts.
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Alright so I went ahead checked whether the struts were properly seated in the wheel hubs. Seems they were both ~15mm high and the Bilstein L / R sticker had snagged on the hub and prevented the strut from going home. Actually sloppy on Bilstein's part as now the stickers indicating L & R are crunched, but perhaps these B4's were never intended for use in a 540. See before and after photos below plus I placed blue tape on the shock before forcing it all the way home. That gap is 17mm. Thanks for all the suggestions ! I plan to go ahead and replace these with Bilstein B6's anyhow.
The PO also did the timing chains and tensioners on this car before I bought and while it runs well the apparent lack of attention to detail has me a little concerned. Other than no rattle can be heard, is there test / check I can do to verify the chains and tensioners are working properly ?
Once again thanks to everyone.
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If the PO did the tension arms, I wonder if he knew about torquing down the bolts while the suspension was loaded? Depending on how many miles have been put since the swap, it may be way too late on those bushings are already stressed and cracking.
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