Elusive vibration starting 55 and continuing to highway speeds

[spyro235]

Originally Posted by ard

Bet you an e-beer its the tension strut bushing.

Cali has got some good beer! I love me some Sour Wrench, and there isn't a much better place to have one than their brewery in Long Beach.
Just doing bushings is honestly a pain in the butt compares to grabbing a new arm. Looks like it's $81 a side. I need to do the front springs, shocks, and all the mounting bits anyway, it's a bit overdue. The question is, do I go HAM and swap other things too?

[spyro235]

Well, It looks like some front end work is due. Dealer agrees that the "thrust arm" bushings are completely shredded- I had looked under the car yesterday and found a few bushings in the front end that were looking pretty rough at 220k.

I'm seriosuly considering taking a weekend and doing all the front arms. I need to check the bushings in the upper wishbone, but if I'm there.... maybe I'll just do all 3 arms on both sides. I have broken springs (well, rusty at minimum, along with blown spring perches) too, and don't know when the last time the struts were done. So... Maybe I'll just refresh the entire front end. I'm going to price it out, if it'll cost me less than $800, I'll probably do it sometime soon.

[SPL15]

lol! If a bushing is looking "rough" at all, even a smidgen, it's completely shot, without a doubt... Broken springs? Come on, this was an easy one to diagnose if you stated this stuff originally...

Fortunately, the front suspension on the E70 is pretty dang easy to completely overhaul yourself; so long as you have the tools, space, & basic competency to do it properly.

Even though it's a more complex system than is typical in BMW's past, the E70 front suspension is FAR easier to work on than swapping lower front control arms on an E36 or E46, which can be a bit tedious / annoying depending on whether the ball joint threads are rusted, but still not all that difficult to do.

The front thrust arms are about as easy-peasy to replace as anything on any suspension ever created, period (an hour or so, tops, if you're going very slow & methodical, with breaks to sip on a beer). If you're strapped on free-time, might replace these 1st to resolve the immediate issue, then gather parts over the next month or so to do a complete rebuild whenever it's convenient, as you'll need to schedule time for an alignment at a shop immediately after. Doing the torsion arms only, you could likely get away without doing an alignment (although, would be recommended to get an alignment), as these don't / shouldn't change your alignment appreciably / if at all, so long as the last alignment was performed w/ torsion arms that weren't all that worn out & you replace w/ the same part from the same manufacturer...

[spyro235]

Well, I'm fairly certain the springs are just rusty now, looking at pictures of factory ones. No sections missing. The struts seem ok, but if I'm there, I might as well do them too. The vibrations I'm getting aren't spring related, because they would change with turns.


Long story short- I know that when a bushing looks even a bit rough, it's totally shot. I've replaced every single part of the driveline and suspension on my drift car, and that is one rusty 18 year old vehicle. The E70 doesn't look like it'll be that bad, it's just forking out the $1300 to do everything. All the bump stops, cushions, spring perches, all 3 arms, shocks and springs... they add up. I hate doing things twice, and I know the car will likely feel great after doing all of that.. but money might just not allow it right now. The shocks alone are $346 Thank you for your help!

[SPL15]

I've got an 01 E46 as well... If you did all that on your E46, the 35d should be far less frustrating & far less rusty .

No kidding on the constant "Pay to Play" game w/ out of warranty BMW's... Just spent $1K replacing the entire vacuum system on my 35d w/ all OE or OEM parts (and this was just part cost, with me doing all the labor); however, it's still better than a car payment in my book.

I'm the same way: If I'm in there, I'm replacing everything I can reach so I don't have to tear things apart later on to do it again when I don't want to; however, the front torsion arms are easy enough to swap out very quickly without any fuss, to where I didn't feel guilty at all only replacing these until funds are available to go balls deep on the rest of the suspension.

Something I've been eyeballing to re-replace the mushy OEM torsion arms are a set of monoball torsion arms from Synchro Design Works...

https://syncrodesignworks.com/produc...nt-thrust-arms

[spyro235]

Originally Posted by spyro235

I'll definitely jack it up and check the axles, but I'd be very surprised if it was them. The only thing that DOESN'T vibrate is the steering wheel!

I swapped the tension struts. Car feels more stable under braking which is nice but didn’t effect the problem at all.

[spyro235]

Originally Posted by ard

Bet you an e-beer its the tension strut bushing. AT 220k I would do the whole arm, not just the bushing.


I'll bet the silicone filling on yours ruptured 100k ago...

I’m glad I replaced them, but it hasn’t effected the vibration. You, sir, owe me an e-beer!

[spyro235]

Originally Posted by SlickGT1

It’s your axle CV joints. Time get new/rebuilt front axles. You can double check by grabbing the shaft between the two boots, and wiggling it in every direction. Especially side to side. Any movement or even a clanking noise, yup axles. Just hunted same problem a few months back.

Wait, axles shouldn’t move linearly to their direction? I haven’t checked the fronts, my bad, but both rears slide back and forth about an inch in the hub-diff direction.

[SlickGT1]

Front axles. Grab the shaft and yank on it in every direction. They should not make noise, or move much. If yours do, they are shot.

[spyro235]

Originally Posted by SlickGT1

Front axles. Grab the shaft and yank on it in every direction. They should not make noise, or move much. If yours do, they are shot.

Why specifically the fronts? Pretty sure my vibration is in the rear- it bobs the seats, and you feel it in your butt and back. Wheel doesn’t shake. Should I not worry about the rear axles that can slide back and forth?