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      03-13-2014, 12:37 PM   #1
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E90 lowered on coilovers, now snapped drop link!

Hi all, I managed to get a hold of some cheapo coilovers (Pro Sport) from an LCI 320D to fit into my non-LCI 320D.

All good I though, installed them fine, although the actual strut itself was shorter than the original SE strut. Went to move away and heard a massive ping. Thought that the strut had just seated itself and nothing to worry about.

Fast forward 4 days to today and MOT time, get a call saying that it has failed on 1 snapped drop link and 1 bent drop link!

It has obviously dropped a fair bit compared to the SE suspension, but I didn't think that much! What should I do, Do I need to get M-Sport drop links, or just the LCI ones?

Thanks,
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      03-13-2014, 12:44 PM   #2
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No difference in lci / pre lci drop links or m sport ones.

Lowered shouldn't make any difference either.

Often a problem with coil overs is they don't have proper mounting points for the drop links. You might have to get some brackets etc.

Did you get all the bits with the kit ?
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      03-13-2014, 12:50 PM   #3
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I got them exactly as they came off the donor car I believe. Came with strut top mounts installed.

When sat side by side with the originals, the eye for the drop link was about an inch lower, but I assumed that with the shorter length of the actual strut it would work out the same.

I just don't know what I need to do/buy to rectify it as I now only have 10 days to fix it or pay for another mot
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      03-13-2014, 01:00 PM   #4
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Most likely you've dropped too much and there was too much preload on the drop link. Shorter ones are needed.
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      03-13-2014, 02:39 PM   #5
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After chatting to the previous owner, he says he used the standard drop links.

The only thing I can think of that would affect it (hopefully someone can confirm) is with the strut in and the upper drop link sitting too high for the mounting hole, I raised the whole hub assembly up with a jack so that they would meet. Should I have wedged the ARB down instead with the hub assembly at normal height?

Also, another daft thing, if the method I used was correct, Could the rotation of the mounting hole also cause it to snap at the ball joint?
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      03-13-2014, 02:45 PM   #6
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PLEASE NOTE: If lowering your vehicle more than 40mm we would recommend that you fit drop links.
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      03-13-2014, 05:12 PM   #7
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Quote:
Originally Posted by Digitalize View Post
Most likely you've dropped too much and there was too much preload on the drop link. Shorter ones are needed.
What do you mean? the ARB moves freely up and down regardless of ride height. No such things as preload on a drop link.

As a car goes lower (either by lowering or during compression over a bump) the ARB moves up, so if anything you need longer drop links to maintain the standard ARB position, but its not needed anyway.
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      03-13-2014, 05:21 PM   #8
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Quote:
Originally Posted by HacKage View Post
After chatting to the previous owner, he says he used the standard drop links.

The only thing I can think of that would affect it (hopefully someone can confirm) is with the strut in and the upper drop link sitting too high for the mounting hole, I raised the whole hub assembly up with a jack so that they would meet. Should I have wedged the ARB down instead with the hub assembly at normal height?

Also, another daft thing, if the method I used was correct, Could the rotation of the mounting hole also cause it to snap at the ball joint?
On a ramp the Drop links should always meet the mounting hole with no effort.

Unless you have the car on a jack, then the wheel on the floor will be compressed so the drop links won't line up with the jacked side.

But this mis alignment is no different to the forces on drop links when cornering etc.

Maybe you have the struts in the wrong side (left / right) so the mounts are ate the wrong angle?
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      03-13-2014, 05:49 PM   #9
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No problem. I'm sure I had the car up one side at a time which may have explained it. Also the car has done 130k+ miles so it may be that the drop links were on the road out anyway?

I'll grab some new ones and make sure its up on stands with the wheels/hubs hanging freely. With regards to the sidings, I received the struts with the top mounts still on from the previous owner and the nipple lines up with the top 3 bolts so they are on the correct side.

What made me question the drop link length so much is the front of the car isn't all that low tbh. With 18s and 225/35 on the front, there is still say 20mm or so from tyre to arch. The back wheel is tucked in nicely, I'm just surprised that I'm not exactly lowrider and it has gave way at the ball joint.

Hopefully it is just down to how I installed it and not something that I need to mess about with for too long!
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      03-13-2014, 06:22 PM   #10
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The strut top mounts just spin round on bearings, that's how the car can steer!

Their random position is no guide to fitment....

Ride height won't affect drop links.
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      03-13-2014, 06:32 PM   #11
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Yes I know the top mounts spin, but next to one of the 3 bolts there is a small locating nipple that meets up up top and only allows the strut top to be installed one way on each side.

With the ride height you are correct, I'm just thinking about it the wrong way round!

From what I read and from what you've mentioned about when it is on ramps then the links should meet up no bother, does that mean that if I'm working with the car on axle stands that I should raise the hubs upto the same level as they would normally be using a jack, and then the drop links should insert into the strut no bother?
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      03-14-2014, 04:28 AM   #12
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None of the strut top parts are handed, i.e. the same parts go on nearside or offside, including the 3-stud top cup with dowel.

See here http://www.realoem.com/bmw/showparts...16&hg=31&fg=10



I wouldn't worry about forcing the ARB to get the drop link in with one side jacked up, this high level of stress on the links happens much worse when your are driving every day.

The force of the car on the links over potholes or round bends is 100x more than you could ever apply by hand.

For the links to bend or break it is not a normal operating force, either the geometry of the links is out or they are colliding with another component.
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      03-14-2014, 06:28 AM   #13
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I will be picking up new drop links today to install tonight. It could very well be that the struts are in the wrong side, I was under the impression that the struts were sided so that could be an issue whereby the link is having to sit awkward in the strut.

If I could get a final piece of advice from you (you've been a massive help so far!), I will be putting the car on axle stands with the hubs hanging freely, with both drop links removed and the ARB sitting free along with the hub strut assembly, do I need to raise the hubs to be at normal right height, or should they fit in with the hubs hanging as normal?

If I remember back to the install, with the original struts there was a small plate that sat roughly 90 degrees around from the slit in the hub that stopped the strut going in any further. On the coilover strut, there isn't this plate, but there is a protruding T piece almost that I thought sat in the split of the hub. Could it be that I have the strut on the wrong side, and the protruding T piece of metal is to sit on the side of the hub restricting further insertion rather than slotting in the split? If so, that would definitely account for the wrong positioning of the link mount on the strut, and mean I have to switch sides?

Thanks again for your help so far!
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      03-14-2014, 06:36 AM   #14
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The drop links can go in with the hubs at any height, it's all within the normal travel range of the suspension.

Having the car on stands with the wheels hanging is no different to cresting a humpback bridge where the car is at full suspension lift.

Both wheels at the same drop will make fitting the drop links easy, it's only hard work on a jack when one wheel is up and one is down.

People fret about lowering the car and say you need new this and that, but all your are doing is making the car sit further down in its normal suspension range, no different to fully loading the car with luggage and passengers. It won't break anything!

You should have a full 4 wheel alignment after changing struts as your steering toe etc will be out, as its a RWD car it has to be a 4 wheel alignment, a front only alignment is no good.
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      03-14-2014, 08:53 AM   #15
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It depends entirely on how far you're lowering it, but you'd never need longer drop links unless you were lifting it...

I know there essentially isn't any 'preload' in an ARB, but it will be sitting in a different place to standard, and could be somewhere where it will contact and not do the job correctly. Shortened drop links allow the ARB to sit closer to where it should as standard. Adjustable ones are the ideal as you can dial them in with your drop.

If you're going for a 'performance' based drop, you should be fine with standard drop links. If you're wanting to go really low, stancing etc, might be worth looking at shortened ones. Some cars need them, some are okay without.

Drop links are fairly generic too, with the fittings etc, so can usually get them off another car. I think Hyundai ones fit an E46 etc.
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      03-14-2014, 09:05 AM   #16
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I don't think you're getting how the front suspension works. The drop link attaches to the damper body up above the ARB, not the bottom wishbone like the rear.

When a car is lowered, the chassis, and ARB which is mounted to it, moves closer to the ground .

The strut, which is connected the wheel, doesnt move relative to the ground but it moves upwards relative to the chassis, I.e. up inside the wings

So the ARB and the strut (with drop link mount) move further apart as the car is lowered.

So you would need longer links with extreme lowering ...

On the rear however, yes shorter links would be needed.

Last edited by doughboy; 03-14-2014 at 09:11 AM.
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      03-15-2014, 11:26 AM   #17
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Quote:
Originally Posted by HacKage View Post
If I remember back to the install, with the original struts there was a small plate that sat roughly 90 degrees around from the slit in the hub that stopped the strut going in any further. On the coilover strut, there isn't this plate, but there is a protruding T piece almost that I thought sat in the split of the hub. Could it be that I have the strut on the wrong side, and the protruding T piece of metal is to sit on the side of the hub restricting further insertion rather than slotting in the split? If so, that would definitely account for the wrong positioning of the link mount on the strut, and mean I have to switch sides?

Thanks again for your help so far!
Reading the topic, this is where I'd be looking... double checking, correct strut position and rotation. The ARB brackets have to be in the correct position to allow freedom of movement.

I assume you have simply checked the steering "lock to lock", ensuring the drop links have total clearance and not touching any other component.

Same applies for brake hoses, ensure there isn't tension on the hoses on lock.

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      03-15-2014, 12:22 PM   #18
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Quote:
Originally Posted by doughboy View Post
I don't think you're getting how the front suspension works. The drop link attaches to the damper body up above the ARB, not the bottom wishbone like the rear.

When a car is lowered, the chassis, and ARB which is mounted to it, moves closer to the ground .

The strut, which is connected the wheel, doesnt move relative to the ground but it moves upwards relative to the chassis, I.e. up inside the wings

So the ARB and the strut (with drop link mount) move further apart as the car is lowered.

So you would need longer links with extreme lowering ...

On the rear however, yes shorter links would be needed.
I still can't picture this. Admittedly I don't have experience with the E90. But on other cars I've worked on, lowering brings the ARB and drop link mounting point on the bottom of the damper, the part that is fixed in the hub, closer together.

I'd need to see it in person, but okay, I must only have experience with the rear type suspension.
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      03-15-2014, 01:03 PM   #19
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Quote:
Originally Posted by Digitalize View Post
I still can't picture this. Admittedly I don't have experience with the E90. But on other cars I've worked on, lowering brings the ARB and drop link mounting point on the bottom of the damper, the part that is fixed in the hub, closer together.

I'd need to see it in person, but okay, I must only have experience with the rear type suspension.
You would be right if the bmw was fwd!

Your thinking of a linkage system on fwd where the arb is attached to wishbone that will move up when lowered thus meaning shorter links!

On an e90 the drop link attaches to the shock body, which, although it moves up and down, never physically gets closer to the arb!
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      03-15-2014, 01:08 PM   #20
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I installed 2 lemförder drop links and all went well. Rotating the struts definitely helped although I still have some concerns.

When it was up on the stands with the suspension fully extended and the drop links in the struts, the bottom of the drop link rests on the track rod I think it is. With the hubs raised using a jack to normal ride height, it is about an inch away from the track rod but I'm not sure if it should rest like that with no load?

Also on the way to the mot station this morning I noticed a knocking when going over bumps and small potholes etc. I'm hoping that it's something I haven't tightened and not something else.

Finally I have noticed that while the tracking is obviously out, the car seems to wander on the motorway, especially when hitting small defects in the road. Any ideas?

Here are the old drop links....
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      03-19-2014, 02:32 PM   #21
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I have pro sport coilovers on mine and they use a shorter drop link compared to standard bmw ones. You can get correct sized ones from pro sport dealers (let me know if you want a name/number if who can post out to you) or you can check out Hyundai coupe ones, lemforder (sp?) ones that are better quality.
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      03-20-2014, 09:15 AM   #22
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Often coilovers have the DL mounts in a different place to the OE strut. If they are lower down, as JAT says his are on Prosport, then yes you will need shorter links for sure to avoide clashes.

You don't want any moving parts like that within a inch of each other, can you take a picture with one wheel on lock to get the camera in there?

Re the tracking, it's bound to be out if you've change the struts, it should always be re-tracked (4 wheel alignment) after strut changes, but sort your links first then get it tracked when its finished.
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