[mathewst]

Hello,
I have e91, 09/2005
Recently problem with vibrations under braking growed so I visited dealer, he said its front rotors, after replacing them problem seemed to be gone.
After 5000km, its with new rotors, pads and aligned tires its growing again, its very sad cos i really dont know what could cause these problems. Vibrations occurs under almost any speed, from light pedal press, seems to be not as significant if i rotate steer wheel while braking or do very hard braking. Both front tires seems firm, no slackness.
Are new rotors screwed again? Hope not, they with pads together costed me 500EUR, gee..

Any advice would be way more than helpful

[Nalod]

Tire tread?

Balance would happen at differnt speeds so I don't think its that.

Check the tires first.

[mathewst]

Originally Posted by Bargamon

Tire tread?

Balance would happen at differnt speeds so I don't think its that.

Check the tires first.

Tires and Discs are perfectly fine, aligned reweighted and most important, IT DOES NOT happen unless i brake, any speed 10-200KMh

It happens only if i brake
Tires are Gooed Year Excellence 7000km on them

[canucklion]

maybe it's your braking habit? Do you do a lot of hard braking?

Sounds like the problem was fixed when you got new rotors and pads, and now it's coming back again.

[Healey3000]

Hi,

Vibration under braking is often related to worn thrust arm bushings. These are also called lower control arms. Odd to see this at 5000 km, however.

Check those for wear/damage.

Regards

[Edward]

yea, check the front suspension linkage. The fcabs are probably cracked and have some play. The braking force moves from pad on metal to the lower arm joint where the metal sticks into the bushing. It it's not snug, the arm will vibrate a lot in there, giving your entire car a lot of shake.

[mathewst]

Originally Posted by Healey3000

Hi,

Vibration under braking is often related to worn thrust arm bushings. These are also called lower control arms. Odd to see this at 5000 km, however.

Check those for wear/damage.

Regards

nop car has 270k km, i said 5k after replaced rotors/pads problems starting to occuring again

[mathewst]

Originally Posted by canucklion

maybe it's your braking habit? Do you do a lot of hard braking?

Sounds like the problem was fixed when you got new rotors and pads, and now it's coming back again.

nothing significant original parts for 500eur shouldnt withstand for 5000km, pretty standard highway kms, with not single ABSenabler encounter..

[mathewst]

Originally Posted by Edward

yea, check the front suspension linkage. The fcabs are probably cracked and have some play. The braking force moves from pad on metal to the lower arm joint where the metal sticks into the bushing. It it's not snug, the arm will vibrate a lot in there, giving your entire car a lot of shake.

what is FCAB, any part no or image i could see it? any price estimation?
is FCAB linked with control arms bushings other post, or FCAB mean "front control arm bushing" me idiot hehe...
Shouldnt FCAB show some looseness on tire when on lever? We checked that and seemed to be firm.
Btw dealers here in Slovakia are pretty much clueless

[JuppiOne]

if there was no vibration right after you replace the rotor pads etc... and it reoccurred after 5000KM, maybe your caliper is bad, it got sticky and ruined your new rotor? it may be possible to have the dealer check your caliper to see if it's bad, could be a stick cylinder? you may be able to savage the rotor just by turning it.

[yakev724]

look into the hub bearings as well...no experience with how long the last on BMWs, but I've replaced them on at around 150k miles on 2 previous cars. Symptoms are pretty much exactly as you describe. Usually with braking, vibrations increase in amplitude as you brake harder, bearings do not share this effect.

[mathewst]

thanks for replies guys, i understand all but "hub bearings" sorry my tech english isnt good enough, could you please explain? part number or some else hint?
i ll check these all with dealer in monday

[mathewst]

got even hub bearning thanks so far, so priority for me:
1.) fcabs
2.) calipers, cylinders
3.) hub bearings

lets hope its not all of them, btw both rear wheels has some looseness in vertical axis but that shouldnt cause problem i guess

[yakev724]

#5 Below. This is the whole wheel hub with the bearing inside. It's a pretty expensive part so yours should be tested before just replacing it. Sometimes it's possible to replace the bearing only (and re-use the hub assembly), but I do not know if it is possible on our cars. Good luck

[mathewst]

i guess it wont be hub bearing hopefully, cos it would vibrate more likely not only during braking and would maybe make some huuu sound?, just picking up every possible thing

[Bcube]

You have 270K km (168K miles) on your car?

It is your control arm bushings. Generally, bushings have degraded and are leaking fluid by 145k km.

I had the exact same problem as you. I thought it was the new brakes I had recently installed. Brakes/rotors were absolutely fine. So, took the opportunity to replace the controls arms with E9X M3 units. Car steers better than when new and no front end vibrations with or without brakes.

I recently replaced the OEM struts/shocks with Koni FSDs. At 240K km, the hub and hub bearings were fine. An area where BMW didn't skimp on quality/engineering.

It's your control arms. #9 (BMW calls them tension struts), with your mileage, you should also change #14 (wishbones) if you can.

[Healey3000]

Originally Posted by mathewst

nop car has 270k km, i said 5k after replaced rotors/pads problems starting to occuring again

Hi,

If you have 270k on your car, I'm almost certain it's your thrust arm bushings. They have lasted longer than average and the symptoms you describe are classic.

Regards

[mathewst]

Originally Posted by Bcube

You have 270K km (168K miles) on your car?

yep thats correct milleage, i have car for 2 year made last 100k km myself
car is great otherwise, just had some problems with passenger foot module blowed circuits after oxidated contact in 5th door light (had to be replaced), otherwise no problem at all

[mathewst]

Originally Posted by Healey3000

thrust arm bushings

is it the same as "control arms bushings?"
problem never really dissapeared totally, just gone marginally after rotors/pads replacement, now its growing serious again 5k km after rotors/pads replacement

[Healey3000]

Originally Posted by mathewst

is it the same as "control arms bushings?"
problem never really dissapeared totally, just gone marginally after rotors/pads replacement, now its growing serious again 5k km after rotors/pads replacement

Yes.

[driverman]

Originally Posted by mathewst

problem never really disappeared totally, just gone marginally after rotors/pads replacement, now its growing serious again 5k km after rotors/pads replacement

Can you explain the vibration? Do you feel it in the steering wheel and/or front end and/or body?

Given the miles (KM's) and the recurrence of the problem, it sounds like you need to have the suspension checked out soon by a suspension expert. It would be best to find a BWM suspension expert, but any suspension expert should be able to find the problem.

[mathewst]

Originally Posted by driverman

Can you explain the vibration? Do you feel it in the steering wheel and/or front end and/or body?

Given the miles (KM's) and the recurrence of the problem, it sounds like you need to have the suspension checked out soon by a suspension expert. It would be best to find a BWM suspension expert, but any suspension expert should be able to find the problem.

steer wheel but in lower speed its also like it slow down more for a while then less, dont know if you understand its like 1 half of braking time its braking little stronger than second, these intervals shortens with speed gone completely by like 100KmH