Play in wheel. Wheel bearing or top mount?

[EddieJT]

My 316ti is due an MOT, and I'm getting the occasional clunk from front left when hitting bumps. So I jacked the wheel up and am getting play and a clunk at 3,9, and still slightly at 6,12. When looking I can't see any obvious play in joints, so I'm suspecting wheel bearing, although there is no rumbling sound from it when driving and it spins well.

I read that a wheel bearing will stop showing play if you press the brake and try, so got the wife to press the brake but it made no difference; still had play despite the brakes on.

What do you reckon? Maybe top mount?

[mrtwisty]

Doesn't sound like a wheel bearing to me. If you're getting play in a bearing that you can feel by hand, it'll invariably be making a horrible noise at anything above 10mph.

I'd be having a thorough check of all the bushes and top mount.

[EddieJT]

Glad to have that confirmed.

Any particular tests for top mounts?

[mrtwisty]

Not sure of the set-up on a 316, but there's usually a covering plate over the top mount, accessible under the bonnet (bolted down, adhesive or both). Get that off then get your missus to give it a good waggle (fnnaarrr) while you listen.

[EddieJT]

She'll enjoy that!

[naturalaspiration]

You can't easily see play in ball joints - you can only feel it by gripping both the end of the suspension arm and the joints whilst moving the wheel - ideally with a helper.

[EddieJT]

Thanks.

I'd better start training the assistant.

[mrtwisty]

Another good check for bushes/balljoints is to get a decent sized pry bar and slot it between various bits of the suspension arms/sub-frames/chassis at different angles and apply force, looking/feeling/listening for untoward metal-on-metal contact.

[E-bmw]

Sounds at least as likely to be a bush/ball joint.

My next task would be get the corner jacked up, get the wheel off & look closer using feel particularly when trying to wobble the hub etc.

[EddieJT]

Thanks for your help guys.

With the wife rocking the wheel, I was able to get my hand on all the joints, and although not obvious by sight, I could feel the knock coming from the bottom ball joint (between control arm and hub). So I'm glad to have diagnosed it.

Next question, is this best done as a new lower arm?

[E-bmw]

It depends on if they split into arm/joint or only available as one piece.

Also, the norm with suspension joints is to do both sides at the same time (saves doing it again next year on the other side) and get the tracking checked afterwards.

[BFleming]

The wishbone is all one piece. There are 2 types, normal & M Tech (so if you have a Sport).

RealOEM is handy for stuff like this...
https://www.realoem.com/bmw/enUS/showparts?id=AT52...

[EddieJT]

Great website