Front shock absorber question

[6670charger]

Need to replace the front shocks. Looking in a couple of sources, I've found a reference to an M12-D14 mounting stud. I have a Euro spec 1995 520i touring. Anybody know what those codes mean? Found a set on ebay that shows the same part number reference that realoem.com gives for the car, but also talks about the M12-D14 stud.

[ahlem]

Which stud are you referring to? The front struts are fairly straightforward and somewhat typical of an installation. M12 is a fairly large diameter.

[6670charger]

That's the thing. I'm not sure. I was looking for shocks on ebay and found a reference to M12 - D14 mounting stud. Unless I misunderstood the reference as it was a German translation. This is my first shock absorber project and essentially my first BMW so I'm a little unfamiliar with some aspects of this.

[Bill R.]

They are talking about the diameter of the shaft where the nut goes onto the strut up on the fenderwell. Within the same model years some e34s have one size nut and shaft and others have a different size . You determine which strut you need by the shaft and nut size and by the size of the plastic/rubber cap that goes over the opening up top in the engine compartment.
After looking it up in the etk I don't think it applies to your car, they only show a 14mm nut m14 on the older cars like mine they had the possibility of either 12mm or 14mm nuts

[6670charger]

OK. I thought that might be what they were refering to, but wasn't entirely sure.

[Tiger]

I got one Boge front strut if you are interested...brand new.

[whiskychaser]

M12 will be the size of the thread on top of the strut. The nut size will be bigger eg 19mm. D14 is the diameter of the pin where it comes through the top mount. I'd make sure you have the following info before buying. This is for mine but you will get the drift:
Shock:
14mm pin. Distance from shoulder to start of taper to thread: 37mm
Distance from shoulder to start of thread: 45mm
Distance from shoulder to end of thread: 65mm
Thread size:12mm
Nut: 19mm
Top mount (one piece) Marked Boge '91
Centre bush thickness: 45mm
Hole in centre bush: 14mm
Pretty easy to see they match but I've seen shocks on ebay.de with shoulder to start of taper to thread at only 29mm. Mine are factory spec for MY car but may well be wrong even for your Euro '92 525i. And you never know if somebody did a swap already:D

[6670charger]

OK. Very good info to go with, but, how do I know what is factory spec for my car, considering that specs seem to be different from car to car? That's what confuses me. I want to make sure I get the right part the first time because once I try to install something, I won't be able to take/send it back for a refund if it's wrong. I mainly need to change the springs, but, figured I'd change the shocks at the same time since I'll have it all apart anyway. I'm attracted to ebay at the moment because they're substantially cheaper than anything from either BMW or the local parts stores. $350 seems like an awful lot of money for standard shock absorbers.

Also, does the factory bump stop (I assume that's the part that slides onto the upper shaft of the shock) fit on any shock absorber, or only the factory ones?

Sorry. Might seem like a bunch of stupid questions, but, like I said, I've never changed my own shocks before. Trying to learn as much about this process ahead of time as I can.

Thanks.

[whiskychaser]

Factory spec for your car will be on realoem. But if you put the struts off your '92 525i onto the '95 520 an owner down the line wouldnt have a clue. I know somebody on a UK site who found different front shocks and top mounts on the same car! So IMHO you are best taking apart what you have, measuring it and ordering the same again. If it has bump stops now, it makes sense you will need them in future.
By the way, if you havent changed springs before, then get the best spring compressors you can afford. Or get a garage to pop them on for you. Springs are mean and can bite. You will need 24" stilsons to undo the collar that holds the shock in the strut too.

[6670charger]

The front struts are staying. The only things I'm changing are the shocks and springs. I actually found a pair of good front springs from a 750. Gonna use the back springs from my 92 though. Ordered new bump stops for the back from BMW today. Found the fronts at a local auto parts store yesterday. What a difference in price, though. 31 Euro for the front ones and 70 Euro for the back ones.

I'm working in a Military Auto Skills workshop so I have plenty of tools and even some advice when I need it. Thanks for the info on the shocks. Sounds like most any shock with the correct OEM part number application for that particular car should work.