Fitting Bilstein B4 front shocks - did I get it right?

[CalMarx]

Hi All,

So, started on my project by replacing the front springs and shock absorbers. Fairly straightforward to remove the first (broken spring and completely dead shocker) and put the new ones together with the strut mount ready to put back in. Then hit a slight bump due to my lack of knowledge.
I attached the top mount then located the bottom of the shock absorber in the knuckle joint but wasn't sure how far in it should go in before fully tightening. I guess I didn't put it in far enough because when I went to put the wheel back on the weight of it pulled the shocker out of the knuckle joint, twisting the shocker and damaging the swing bar (if that's what it's called) attached to the shocker. New swing bars now on order.

I started again and think I know where I went wrong. On the second attempt I noticed there are two small lugs at the bottom of the shocker, am I correct in thinking that they should be positioned on either side (above and below) the bolt that tightens the knuckle joint? That seems to make sense to me. And should tightening that bolt be really hard or am I making it more difficult for myself somehow?

Anyway, all advice gratefully received by this complete novice. I'd like to know I've done it right before putting the wheel on again
It still beats watching TV!

 

[SDJ]

Well done for getting that far. Everything is obvious.... Once you know how.
The 'drop link' is what attaches the shock strut to the anti roll bar (sometimes called sway bar).
Yes, the bolt goes in between the two pins. It doesn't need loads of torque so nothing special about tightening it.
Good luck

 

[enuff_zed]

Whenever I do them I put a scissor jack under the hub, make sure the pins are lined up in the slot, then wind up the jack until the hub stops going up and the whole car starts to lift.
The big knuckle joint bolt is something I always replace as the old ones are usually corroded and get really hot when you remove them. Not sure how much stress has gone through them, so for for a few quid why take the risk?
https://www.ebay.co.uk/itm/175141185140?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2648

 

[CalMarx]

Thanks guys,
I did jack it up from under the hub and replace the knuckle bolts so hopefully this time it's a more permanent fix.

 

[enuff_zed]

Thanks guys,
I did jack it up from under the hub and replace the knuckle bolts so hopefully this time it's a more permanent fix.

Good stuff.
The person who never makes a mistake never really learns anything.

 

[CalMarx]

Hmm, still not successful.
I've tightened the knuckle bolt as far as I possibly could (which felt tighter than it should) and the pins on the shocker sit above and below the bolt, but when I put downward pressure on the disc the whole hub assembly slips off the bottom of the shocker.
I had a chat with a friendly mechanic who suggested there may be two diameters of that particular shock absorber and maybe I'd bought the smaller one which isn't going to be held by the knuckle joint. It's possible but I thought I'd bought carefully from Autodoc.
According to BMW the OEM part number for my front left shocker is 31.31.6.785.989 (it has M-sport suspension) and the autodoc equivalent is 22-164568.
So, either I've ordered incorrectly or there's an issue with the tightening of the knuckle joint. What do you think?

Still beats watching TV.

 

[enuff_zed]

Not something I've heard of before. I thought the hubs were the same?
I've fitted the exact same shock on a 2.5si with Sport suspension and two other SEs. No problems with any of those.
Annoyingly I binned the old ones only a couple of days back or I'd measure them.
The knuckle bolt should protrude through about 2-3 threads. Is yours coming all the way through?
Also is it the same problem both sides?

 

[CalMarx]

Not something I've heard of before. I thought the hubs were the same?
I've fitted the exact same shock on a 2.5si with Sport suspension and two other SEs. No problems with any of those.
Annoyingly I binned the old ones only a couple of days back or I'd measure them.
The knuckle bolt should protrude through about 2-3 threads. Is yours coming all the way through?
Also is it the same problem both sides?

Space/jacks mean I'm limited to doing one side at a time. The bolt won't go any tighter and yes, it's through by a few threads on the far side. One thing I find odd is that although the bolt won't tighten any further the bolt head still isn't fully flush against the knuckle joint, there's enough play that the support arm holding the sensor cables remains slightly loose when the bolt head should be pressing against it. Getting that bolt out and then a new one in definitely seemed harder than I thought it should be.

 

[enuff_zed]

Not something I've heard of before. I thought the hubs were the same?
I've fitted the exact same shock on a 2.5si with Sport suspension and two other SEs. No problems with any of those.
Annoyingly I binned the old ones only a couple of days back or I'd measure them.
The knuckle bolt should protrude through about 2-3 threads. Is yours coming all the way through?
Also is it the same problem both sides?

Space/jacks mean I'm limited to doing one side at a time. The bolt won't go any tighter and yes, it's through by a few threads on the far side. One thing I find odd is that although the bolt won't tighten any further the bolt head still isn't fully flush against the knuckle joint, there's enough play that the support arm holding the sensor cables remains slightly loose when the bolt head should be pressing against it. Getting that bolt out and then a new one in definitely seemed harder than I thought it should be.

Well I can't work out exactly what the issue is, but you've definitely found it. If the head of the bolt isn't tight then it's not clamping the joint tight. Start by pulling it back out and checking the thread, both of the bolt and the hole it goes into. Something is stopping it going any further. Only thing I can think of is there's a shoulder on the bolt (IE. the thread doesn't go fully up to the head) and it's bottoming out before it can fully tighten. Did you say you used new bolts? How do they compare with the originals?

 

[CalMarx]

The new bolt was straight from BMW so there should be no issue there.
I've compared the new and old bolts side by side (for some reason can't attach an image), what's interesting is that last cm or so of both look like they have been squeezed tighter and there's a little damage on the thread of the new bolt, suggesting there's something in the shape or thread of the far knuckle joint causing extra stress. Could this have been caused when the spring broke?

A simple solution might be to add an extra washer to the new bolt to create that extra squeeze and just get on with it.

 

[enuff_zed]

The new bolt was straight from BMW so there should be no issue there.
I've compared the new and old bolts side by side (for some reason can't attach an image), what's interesting is that last cm or so of both look like they have been squeezed tighter and there's a little damage on the thread of the new bolt, suggesting there's something in the shape or thread of the far knuckle joint causing extra stress. Could this have been caused when the spring broke?

A simple solution might be to add an extra washer to the new bolt to create that extra squeeze and just get on with it.

Whoa!
A little light bulb moment!
Does your bolt look like this?

You should already have a washer on the bolt?

 

[CalMarx]

I've tried to insert an image of the new and old bolts by "adding file", the "insert image" icon doesn't do anything.

My new bolt did look just like that, it came with a washer, except the end cm or so now looks a little squeezed like it's having to be forced into the second part of the knuckle joint.

 

[enuff_zed]

OK, well that definitely looks the correct bolt, and the new one looks like there's damage to the thread.
I suspect some issue with the thread in the second part of the knuckle joint. Ideally you should run it through with a tap to clean it up.
Or see if you have another really good bolt with the same thread. If you don't have one, cut the old bolt back a bit to get rid of the manky thread at the end.
Try screwing it in from the other end.
Use loads of WD40 or similar. Go in half a turn, then back out and clean it. Then another turn in and repeat. Hopefully you'll clean up the thread enough.
Which side is it?
I know it'll be a PITA, but bigwinn did have one spare hub, not sure which side though.

 

[bigwinn]

OK, well that definitely looks the correct bolt, and the new one looks like there's damage to the thread.
I suspect some issue with the thread in the second part of the knuckle joint. Ideally you should run it through with a tap to clean it up.
Or see if you have another really good bolt with the same thread. If you don't have one, cut the old bolt back a bit to get rid of the manky thread at the end.
Try screwing it in from the other end.
Use loads of WD40 or similar. Go in half a turn, then back out and clean it. Then another turn in and repeat. Hopefully you'll clean up the thread enough.
Which side is it?
I know it'll be a PITA, but bigwinn did have one spare hub, not sure which side though.

Near side one spare here

I seem to break these for fun!!!

 

[enuff_zed]

OK, well that definitely looks the correct bolt, and the new one looks like there's damage to the thread.
I suspect some issue with the thread in the second part of the knuckle joint. Ideally you should run it through with a tap to clean it up.
Or see if you have another really good bolt with the same thread. If you don't have one, cut the old bolt back a bit to get rid of the manky thread at the end.
Try screwing it in from the other end.
Use loads of WD40 or similar. Go in half a turn, then back out and clean it. Then another turn in and repeat. Hopefully you'll clean up the thread enough.
Which side is it?
I know it'll be a PITA, but bigwinn did have one spare hub, not sure which side though.

Near side one spare here

I seem to break these for fun!!!

Well just to tempt fate, I've been lucky so far. I guess if they shear on the way out you're stuffed, but I have considered getting a thread cleaner to use before putting new ones in.

 

[CalMarx]

Thanks guys.
I have another new bolt so I'll try cleaning from the other side as you suggest

 

[enuff_zed]

Thanks guys.
I have another new bolt so I'll try cleaning from the other side as you suggest

Take it slow and easy. I'm hoping you'll find a restriction to prove it's the thread in the hub.

 

[CalMarx]

Gents, the tip to slowly clean out the thread by putting the bolt in from the other end worked a treat and that's the corner finished and back on the ground. Now to start the other side.

Thanks for the advice all the way through this, much appreciated from a complete novice.

 

[enuff_zed]

Gents, the tip to slowly clean out the thread by putting the bolt in from the other end worked a treat and that's the corner finished and back on the ground. Now to start the other side.

Thanks for the advice all the way through this, much appreciated from a complete novice.

Excellent news!
Well you learned something anyway so that's a good result.
Do the same on the other side now, just in case.

 

[CalMarx]

I thought I had replied with an update but it doesn't seem to have appeared.
The tip to clean up by screwing the bolt in from the other side worked a treat and I finally got that corner sorted. I also did the other front shocker/spring with no issues at all.
Thanks everyone for the advice and support, much appreciated.