Clunk from front suspension when stopping or going

[spoolinX1]

Over the course of the past week or so, I've noticed that my car has developed a single, dull clunk from the front suspension each I come to a moderate stop and also begin moving from a complete stop. It seems to be right in front of my foot when it is on the pedal, as I can feel it through the floor board. If I were to describe it, I would say it feel like as if the subframe or part of the suspension was shifting forward and backward just slightly as movement of the vehicle stops/starts. Strangely, it's only noticeable once things warm up. (After driving a few miles)

I have noticed that when turning a left turn the clunk becomes more rapid. It's not a click or a vibration and it's not a uniform sound. Also does not change based on the speed of the car. Just a sporatic dull clunk, clunk, clunk, most likely from the suspension adjusting as the vehicle jostles while moving. It is most apparent when turning to the left.

If it helps diagnose the issue - My car has been lowered for about a year on H&R springs with Bilstein B6 shocks and struts. I did trim the internal bump stops according to the advice given by members on the forum. I did not change any bushings or end links at the time of installation. Car has been aligned and wear pattern is perfect, although the pot holes and general road condition where I live are absolutely atrocious this time of year.

I took both front wheels off last night and everything seems properly torqued, including the nut on the top and bottom of the strut itself. Nothing seems to wiggle abnormally. There struts themselves look great with no leaking or anything like that.

Anyone have an idea what I should take a closer look at?

[X1Denver]

It’s possible the strut top mount bearings are shot. I have the same suspension setup and had to replace mine. Check if the nut is loose on the top of the strut tower also.

[spoolinX1]

Originally Posted by X1Denver

It’s possible the strut top mount bearings are shot. I have the same suspension setup and had to replace mine. Check if the nut is loose on the top of the strut tower also.

I have a feeling you could be right. Did your top mount get "Sloppy" when the bearings went bad? That's kind of what it feels like. Slopping back and forth when stopping and going and also jiggling on turns.

I see that ECS tuning sells a heavy duty version of the top mount.

[PrematureApex]

Check the hydrobearing (inboard side of the tension arm). They always fail.

Pics at the bottom of this thread on where it is.

http://e84.xbimmers.com/forums/showt...=tension+strut

[PrematureApex]

What led you to believe they had gone bad?

Could you see/feel it?

[spoolinX1]

Originally Posted by PrematureApex

Check the hydrobearing (inboard side of the tension arm). They always fail.

Pics at the bottom of this thread on where it is.

http://e84.xbimmers.com/forums/showt...=tension+strut

Under close inspection, my driver's side hydro bearing does have a tear in it. Are the factory bushings actually filled with fluid? If so, I'm wondering if mine has leaked out.

Is this the equivalent of the kit you have installed?

[X1Denver]

Originally Posted by PrematureApex

What led you to believe they had gone bad?

Could you see/feel it?

You could see the strut bearing had worn and was a bit jiggly.

[PrematureApex]

Originally Posted by spoolinX1

Under close inspection, my driver's side hydro bearing does have a tear in it. Are the factory bushings actually filled with fluid? If so, I'm wondering if mine has leaked out.

Yup, filled with fluid. Very common failure if that's what it is.

Originally Posted by spoolinX1

Is this the equivalent of the kit you have installed?

Damn! First I've seen those. It says for the curved control arm (which is what you want). For like 10+ years, NO ONE offered a poly for the xdrive tension/traction strut hydrobearing replacement besides Strongflex out of Poland. Those are one piece and must be pressed in.

If you can rig up a threaded rod, a press, or a hammer and some creative use of nails to get the OE bushing/race out, that would be an EASY replacement to pop right in. That would have saved me, and many, many others a lot of headache.

https://www.ecstuning.com/BMW-E84-X1...n/Control_Arm/

Besides a Strongflex poly (or apparently the new alternative you posted), people just replace the hydro with a modified M3 bushing, stock for stock, or just do the whole arm.

The hydro part number is:
31126768818

About $20-60 (generic vs. oem), but you have to press it in (involves getting creative).

But again, many people just replace the whole arm for a QUICK bolt-on solution with no pressing. $60-130.

[spoolinX1]

Originally Posted by PrematureApex

Yup, filled with fluid. Very common failure if that's what it is.



Damn! First I've seen those. It says for the curved control arm (which is what you want). For like 10+ years, NO ONE offered a poly for the xdrive tension/traction strut hydrobearing replacement besides Strongflex out of Poland. Those are one piece and must be pressed in.

If you can rig up a threaded rod, a press, or a hammer and some creative use of nails to get the OE bushing/race out, that would be an EASY replacement to pop right in. That would have saved me, and many, many others a lot of headache.

https://www.ecstuning.com/BMW-E84-X1...n/Control_Arm/

Besides a Strongflex poly (or apparently the new alternative you posted), people just replace the hydro with a modified M3 bushing, stock for stock, or just do the whole arm.

The hydro part number is:
31126768818

About $20-60 (generic vs. oem), but you have to press it in (involves getting creative).

But again, many people just replace the whole arm for a QUICK bolt-on solution with no pressing. $60-130.

Awesome. Thank you so much for your input. Going to see if I can limp through to Memorial Day weekend, as I've got no time before then to dedicate to the project. I will perform the swap with the new split type bushing from ECS and follow up with the results. The asymmetrical metal insert has me a little nervous. I'm not quite sure what orientation I should be shooting for when I install it. I'd imagine the positioning will affect tire angle to some +/- degree.

If I'm looking at your other post correctly, you drop and swing the control arm out without removing any other components? You don't have to remove the strut assembly or anything? Did you have to loosen the nut on the ball joint or is there enough rotation with it tight to allow you to swing the arm to the rear side of the wheel by simply removing the 18mm bolt/nut by itself?

[PrematureApex]

Originally Posted by spoolinX1

Awesome. Thank you so much for your input. Going to see if I can limp through to Memorial Day weekend, as I've got no time before then to dedicate to the project. I will perform the swap with the new split type bushing from ECS and follow up with the results. The asymmetrical metal insert has me a little nervous. I'm not quite sure what orientation I should be shooting for when I install it. I'd imagine the positioning will affect tire angle to some +/- degree.

If I'm looking at your other post correctly, you drop and swing the control arm out without removing any other components? You don't have to remove the strut assembly or anything? Did you have to loosen the nut on the ball joint or is there enough rotation with it tight to allow you to swing the arm to the rear side of the wheel by simply removing the 18mm bolt/nut by itself?

Correct (may have had to drop the undertray a bit, but I think I might have wrestled it out without. If you have a good impact gun to use as a puller/pusher (using like a Harbor Freight pressing kit and ball-joint clamp, or similar) to drive out the factory bushing, you can leave the ball joint on, and just rotate the inboard arm out a bit.

Unless you're doing it that way, any other bushing removal methods are going to require popping off the ball joint.

I take it you can still see those pics? The one below shows the bushing half-way out, the threaded rod of the clamp is pressing on a bearing press adapter which just fits inside the opening in the arm. Sorry if I'm stating the obvious.

Just keep in mind, you need to WAIL on a good electric impact to press it out.

[spoolinX1]

Originally Posted by PrematureApex

Correct (may have had to drop the undertray a bit, but I think I might have wrestled it out without. If you have a good impact gun to use as a puller/pusher (using like a Harbor Freight pressing kit and ball-joint clamp, or similar) to drive out the factory bushing, you can leave the ball joint on, and just rotate the inboard arm out a bit.

Unless you're doing it that way, any other bushing removal methods are going to require popping off the ball joint.

I take it you can still see those pics? The one below shows the bushing half-way out, the threaded rod of the clamp is pressing on a ball joint adapter which just fits inside the opening in the arm. Sorry if I'm stating the obvious.

Just keep in mind, you need to WAIL on a good electric impact to press it out.

Awesome info. Thanks again. I do have a great electric impact with a great amount of torque. I'll make sure that I pick up or rent the proper tools in order to press the bushing out. Your photo is great.

[spoolinX1]

OK, so I was able to isolate the sound yesterday. It is definitely coming from the uppermost portion of the strut area on the drivers side. The passenger side does not make this sound at all. I thought that maybe my strut nut was loose, so I backed it off a little, then re-tightened it to proper torque. There was no difference in sound whatsoever.

Now that we know that the upper strut nut is tight and the three bolts holding the upper strut mount to the car are also tight, does this sound like I have a failed upper strut mount?

Here's a video of the exact sound with the dust cap removed and the strut tower brace pulled to the side. This is me pushing downward on the car in the front driver's side corner: https://streamable.com/09gj0.

It's driving me crazy, as I get this sound everytime I travel over a small bump and also any time I come to a complete stop or begin traveling from a stop. I can feel it in my brake pedal too. It does not make any abnormal sound when turning the steering wheel.

[spoolinX1]

Just to follow up, BMW was able to pin-point the sound and repair it. I had a failed Sway Bar Link. They replaced both of them and the sound has gone away.

Edit: Scratch that. Sound came back on my drive home. Popping has returned, even with brand new sway bar links. Pulling a strut this weekend to get a good look at the upper mount. I've got a brand new one to install.

[spoolinX1]

For those interested, I seem to have figured out what the "Pop" is over the weekend. The upper strut mount on my driver's side had compressed which allowed excessive play (Wobble) in the top of the strut assembly. I was able to isolate and could reproduce the "Pop" sound with the assembly out of the car. Definitely coming from the excessive sloppiness of the bearing and additional room for the spring to wiggle around since the compressed upper mount wasn't holding down on the strut as tight as it should have been.

The taller strut mount in these photos is the new one.

Edit 8-9-19: This guess was incorrect. The popping returned shortly after installing the new upper strut mount.

The correct fix was to install a 1/2" Grade 8 Lock Washer under each of the front top strut nuts. Photo is below in this thread. There was too much slack in the strut assembly, since the H&R springs are shorter than stock. The nut was bottoming out on the shaft and the assembly wasn't quite tight enough, allowing it to wobble up and down about 1/8".






Looking at this photo, you can see that the bearing itself sits in a much higher location on the new, uncompressed mount:

[themishmosh]

wow. thanks for the follow up! you think that's from bottoming out? aftermarket suspension or stock?

[spoolinX1]

Originally Posted by themishmosh

wow. thanks for the follow up! you think that's from bottoming out? aftermarket suspension or stock?

I truthfully don't know. I stumbled upon a thread from the e90 forums where some people were experiencing the exact same issue and it was driving them nuts. One of them figured it out and shared a photo similar to mine. We apparently have the exact same upper strut mounts as the E90s.

Original post here: http://www.e90post.com/forums/showthread.php?t=675968

I'm lowered on H&R springs and Bilstein B6's. Something to keep in mind if anyone encounters this sound.

[spoolinX1]

I FINALLY FIXED IT!

Turns out it was not the upper strut mounts.

The actual fix took another year to diagnose and correct. In that time I changed my thrust bushings to poly type thinking that might fix it. Nope. Kept digging and retightening everything Nothing made a difference.

Eventually stumbled upon a great thread on a 5 series forum which perfectly mirrored my issue. I noticed that they were encouraging others to install a Grade 8 lock washer under the top most nut on the strut. Theres was a 9/16", ours is a 1/2". Thread here.

Basically, when Bilstein designed the B6 front struts for the X1, they must have designed them to be used with stock height springs. The reason I say this is because there is an unthreaded portion of rod at the top of the strut that does not allow the top nut to be tightened down enough when a shorter spring is used. You think you have torqued the top nut down properly, when in actuality, you are just bottoming it out on the portion where the strut threads end and the unthreaded portion of the rod starts. By installing this 1/2" grade 8 lock washer, you are filling in that extra gap between the top of the upper strut mount and the end of those threads. Heck. It might even be smart to use two washers instead of just one. There is still a TON of thread remaining above the nut when just one washer is used.

I can say that the addition of this 1/2" lock washer has completely fixed my issue. I'd recommend it to anyone who is experiencing a pop from the upper portion of their strut tower over small, quick bumps or when stopping or going. A quick diagnosis would be to have someone push down on the front of your car while you listen at the front. You'll hear the popping as the strut moves up and down.