Front Control Arm Bushes

[fka]

I've been chasing a rattle (yes I know it could be anything) which seems to be coming from the front strut area on both sides of the car. Only evident on fairly poor roads and usually when I go over fair sized ridges running 90deg to the direction of travel. It's a metallic sound and can range from an annoying rattle to a clunk. Although I think the clunk may be when the strut has just been allowed to fully extend when dropping off a ridge or into a pothole.
Subframe bushes have recently been replaced with poly, recent B12 suspension, new droplinks and poly arb bushes.
I took a look at my control arm bushes again today. There's little up/down movement on either of them but a lot of fore/aft movement.
I've actually just booked it in for it's MOT in August and will have new arms fitted then (along with a new cat back) anyway as they seem a bit tired. But would the movement shown in the video linked below cause any concern?

I went for my second COVID test so far, last night in one of the drive through centres and when I drove over one of the cable trays a little too quickly, it sounded like the ar5e had dropped out of the car.
Good poke around today and I can't see anything else upfront that's obvious. And what I'm hearing may well just be a function of the B12 and poly subframe bushes??


https://www.dropbox.com/s/zl9r81mtg5m0rz9/2020-07-17%2011.24.43.mp4?dl=0

[sgould]

Did you replace the top mounts when you changed the front struts?  If so, what mounts did you use?

I changed my front struts four years ago and they came with "free" unbranded top mounts.  These only lasted 500 miles before the rubber came unbonded from the body of the mount.  The noise was only apparent on bumps.  It might have got worse, but I got them changed after a nervous 2000miles drive around Germany and home.

If the car is firmly sat on the ground, the strut should be held in place and you can take off the top plate and have a look.  Are the strut tops in the middle of the hole?  One of mine wasn't.

I split the mount and the source of the noise was apparent, along with the cause...

[fka]

I bought a pair of Meyle top mounts. I checked them a month or so ago just to be sure and they were dead centre.
Will have another look but I'd be very surprised if Meyle parts had failed that quickly..

[fka]

still sitting dead centre..

[sgould]

When you find it, it shouldn't be too expensive then! 

[fka]

Hopefully not 
I've decided to go with and ordered front control arms with powerflex bushes pre-fitted. I know it will make it harsher.
I'm not at all convinced the noise is from the control arms but it's the only part of the front suspension I've not refreshed.

I tidied some bits up under the bonnet, like the loose battery cover and actually the valve I posted a pic of on Carreras thread, which was bashing on the inner arch and used to be wrapped in spongy stuff..

[Audax]

Hard to say from the description but I've known of cars with poly bushes that make lots of noise, especially over undulating bumps.

[carrera]

Hmm, lots of new bits.

Is it possible that the springs are going free when the strut is in full droop ?

Small little helper springs are available that will take up the slack

[fka]

Hmm, lots of new bits.

Is it possible that the springs are going free when the strut is in full droop ?

Small little helper springs are available that will take up the slack

Yes I'm terrible for replacing stuff that might be warn but probably isn't, in the hunt of a 'tighter' feel (so to speak  ).. However I'm kind of with your thinking, especially with the shorter stroke b8, I think the strut is going to it's full extension over the bigger lumps, although I'm not sure the spring is going free - it certainly shouldn't be, it's matched to the damper!
I've been chucking it round quite a bit recently and apart from a fair amount of torque steer (the thinking behind the poly bushed control arms) the handling is spot on - esp on or off. For a big estate, it's a lot of fun..

As you say Audax - I guess it's part of the payoff and I need to accept that!

[carrera]

Here's a helper spring in case the main spring is going free



The low tech alternative is to tie wrap the spring to the top or bottom plate.

If you want a tighter feel, stop playing around with Bilstein and get some proper gear.... you can just see the helper spring on the top of the Evo3 strut.  Deeeeep pockets required though

http://www.proflexuk.com/products.html

[fka]

I've given the spring a good wiggle with the wheel off the ground and it's in no way free.
I the EVO3 might be a bit of a step to far for a road car 

[carrera]

I have often wondered how the high speed bump adjustment would cope with road humps on those struts. Admirably I think

So, that's that theory out of the window then, there isn't much left. Steering rack, ARB all properly secured,  track rod ends in good condition, droplinks fine, even though they are new, bobbins for oil cooler intact

[sgould]

I've never investigated this for myself, but there have been some issues with engine sub-frame bushes where the big washers have been put on the wrong end.

[fka]

Bit more potholed driving today and it is very noticeable.
I keep thinking it's maybe the poly ARB bushes squeaking (which they do a little and more so when wet.) but it's definitely more of a rattle - which I would have said was drop links but they're new genuine Saab jobs.
I'm convinced it's coming from the strut and have just come across a lot of post about Bilstein knock - which appears to be a fault with the strut in some cases. Never had a problem with them on the 9-3. I'll ask Joe to check the top nut is torqued up properly at least and get his opinion when he has it in August.

I do keep coming back to the control arms. My video doesn't show it too well but that fore/aft movement is a good half inch and without much effort.
Anyway I'm off to Devon tomorrow at 6am with the caravan so I'm going to have to live with it for the time being.. Wont be an issue on the motorway mind!

[fka]

I've never investigated this for myself, but there have been some issues with engine sub-frame bushes where the big washers have been put on the wrong end.

engine subframe bushes? You mean the front two on the subframe?
I'm 99% sure mine were fit with the washers on top between the bush and the body..