noob question on E34 front inserts

[welshpug]

Hi All from sunny Wales!

I have a late 93 525 TDS Touring, currently an Auto soon to be manual

I recently picked up a set of Bilstein B8 front inserts with Alpina springs, and rear dampers with Alpina springs as well, I believe they came from a 535i.

my question is was it around 1990 that the front strut inserts changed to a larger diameter body and larger diameter top spindle thread?

I tried the inserts in some spare 525 front leg assemblies I have, the locking ring is the same thread but there is a fair difference in the O.D of the insert, the Bilstein is about 45.8mm (its a 40mm inverted insert)

the Boge unit that came out was a 26mm rod and roughly a 50mm o.d.

also different is the top spindle thread, my B8's are a 19mm nut, so I guess M12, and the car is a 22mm nut so M14.

[632 Regal]

As far as I know all the inserts should be inter changeable except the nuts and diameter of the top that goes through the mount. Boges come with a small shaft and a collar so it fits both varieties here in the US. Difference in body diameter should only effect the volume of oil added to the housing. I always add too much and the extra oozes out upon tightening the collar nut.

I have not heard of an insert not fitting the housing.

[genphreak]

I can confirm that, I've swapped newer into older struts before, just by changing the top.

[welshpug]

Ok thanks guys, so I guess the top lockring locates the insert rather than just holding it in, so if i add a sleeve to the top spindle or get some early top mounts ill be fine.

[whiskychaser]

If you are talking 535i, the changeover date was 7/90. My 2/92 525i had pre 7/90 inserts matched to the proper top mounts from the factory. But it wasn't Euro spec. All you should need to do is match the diameter and height of the pin with the hole in the top mount. BUT I am not sure this applies to the diesel or 520i. I think they had odd ball strut housings

[welshpug]

I believe the tds shares most of its underpinnings with the 520 and 525, the 30 and 40 being v8's I believe just had different springs and inserts

[whiskychaser]

I believe the tds shares most of its underpinnings with the 520 and 525, the 30 and 40 being v8's I believe just had different springs and inserts
N America didn't get the diesel or the 520 so you may not get a definitive answer here. I am sure there is a thread somewhere on forumbmw5.co.uk which confirms they differ from the 525i +. Maybe you know the site?:D I had Bilsteins on the rear of my E34 but they were not B8s. IIRC they were B6s.

[genphreak]

Total guesses, but this is what I'd expect, based on engine and body type:

Small nut
All M10 518i
All M20 520i/525i
Early M50 525i
Early M30 530i/535i
S36 M5

Large nut
Late M50 520i/525i
Late M30 535i
All S38 M5
All M40 518i
All V8 (M60) 530i/540i

As the Tourings came later, they MAY all be Large nut.

Of course it may well depends more on the factory and production run rather than the model/engine code.

[genphreak]

Sorry, M10 518i should read M40, and M40 518i should read M43.

For all those running the e34 best suited to becoming a hybrid powerhouse (http://www.metricmind.com/data/bmw.pdf)...

[welshpug]

Finally Figured last week what the differences were from early to late E32/34 top mounts, basically make a 1mm sleeve to take the spindle from 14 to 16mm! Also figured that the inverted B8 bilstein front insert is located by the locking ring so the 5mm gap around it doesn't matter (the Boge o.e insert was a snug slide in fit)



https://farm3.staticflickr.com/2904/14696144801_4cf1aae72a_z.jpg (https://flic.kr/p/ooDzQV)

20140720_122247 (https://flic.kr/p/ooDzQV) by WELSHPUG (https://www.flickr.com/people//), on Flickr



Today I got round to fitting them with the Alpina springs, sorted the reverse rake right out, looks superb now :D





front bump stops essentially non-existant



https://farm3.staticflickr.com/2906/14699018182_6b46282d36_z.jpg (https://flic.kr/p/ooUiZY)

20140720_120415 (https://flic.kr/p/ooUiZY) by WELSHPUG (https://www.flickr.com/people//), on Flickr



Rear dampers a total doddle!



https://farm3.staticflickr.com/2907/14513843448_b3689f831c_c.jpg (https://flic.kr/p/o7xf19)

20140720_171044 (https://flic.kr/p/o7xf19) by WELSHPUG (https://www.flickr.com/people//), on Flickr



looks spot on.



https://farm4.staticflickr.com/3919/14700497365_e24be97d39_c.jpg (https://flic.kr/p/op2TH8)

20140720_171902 (https://flic.kr/p/op2TH8) by WELSHPUG (https://www.flickr.com/people//), on Flickr

[genphreak]

Nice pics, thanks for posting back.

I hazard a guess to say that, with narrower shocks, you need to fill the strut housing with more oil to ensure heat is still sinked to the housing promptly.

IIRC, a snug fitting strut needs at least 30ml (maybe iuts 50ml?) of engine oil in the bottom, so a narrower strut should probably have 100mL? The thing to achieve is the same oil level in the strut as with the factory one.

[welshpug]

not the b8's, theyre inverted inserts :)

[genphreak]

@welshplug; I don't get what you mean- they might be inverted internally and have the bump-stop built-in, but they will still need a bit of oil in there. Some have a 40mm metal band around the shock tube to ensure they locate correctly in the strut (around the lower section), others locate without it.

I would have thought all need a little oil but be very careful- it must not go beyond that band- else it may not sit all the way down.

The amount is probably not critical unless you are racing/putting them through hell and need to avoid thermal failure.

But having said that, the heat is probably more generated at the top- perhaps that is why you say it is unimportant.

[welshpug]

Bilstein state these don't need Oil in there.

the piston rod you see on a standard strut, which has a nut on the top, is secured to the bottom of the insert so its the body of the damper which goes up and down.