E90 325D brake issue - vibration under braking and sometimes when off brakes

DuckSlice

I have an issue with my brakes, which i think is stemming from the front right of the car. I had a slight vibration under braking for year, didnt take any notice of it as assumed it was just a warped disc. (i changed the discs when i got the car, one of them was warped and i changed them for another set, there was still a slight vibration in the brakes but i lived with it)

I needed new pads on the front as they had worn on the inside a lot more than the outside, in my head backing up the idea there is a slight warp in the disc and it had been rubbing on one side more than the other.

Changed the pads and when the brakes got up to temp there would be a vibration in the car and a lot worse when braking. 60mph and up it got really noticeable, so bad i thought there was a stone stuck in my threads or something. it comes and goes.

Then changed the discs, everything ok for a while then its back so obviously not the discs. Discs are brembo so not cheap. Also it would be extremely unluckly to get 3 sets of discs all with a warp in the one i fit on the front right.

Next job i took the caliper off, checked to see if the piston was moving in and out correctly. removed the piston cleaned it all up put it back in. Was using air to move the piston and i could see the piston backing off when i stopped the air so was happy enough that its functioning properly.

Cleaned the caliper slider pins, they had built up dirt over the years and weren't smooth at all so thought this is the issue. put it all back together and its still there. not as bad though. i drove to work 50ish miles this morning and only had the slight vibration under braking, nothing when off the brakes.

The only thing i can think of is rubber guides for the pins are knackered. Could this be causing the issue?

The wheel isn't hot after a run so i don't think the caliper is sticking on, usually the wheel would be hot if this is the case. the only other thing i can think of is I'm actually looking at the wrong wheel but that's where it feels like its coming from. there is no feedback through the steering wheel so maybe I'm looking in the wrong place?

tcawley29

Did you change the pads and discs at the same time?

DuckSlice

tcawley29 wrote: »

Did you change the pads and discs at the same time?

Changed them within a couple of weeks of each other, pads first. I did consider changing them when changing the discs but figured they would be fine, asked my usual mechanic and he thought the same.

ongarite

Have you checked the front suspension for worn control arm bushes?
Seems to be a common cause of steering wheel vibration when braking on E90.

DuckSlice

ongarite wrote: »

Have you checked the front suspension for worn control arm bushes?
Seems to be a common cause of steering wheel vibration when braking on E90.

I haven’t but I don’t have steering wheel vibration, passed Nct in January with no issues also. I’ll have a look at them but I think if it’s them then they would have been caught in the test as this vibration was there then, but not as bad. Thanks I’ll have a look.

wandererz

You say this happens even when not braking.
Have you checked the wheel bearing?

DuckSlice

When i had the disc off i had a check on the bearing and there was no play in it.

challengemaster

DuckSlice wrote: »

Changed them within a couple of weeks of each other, pads first. I did consider changing them when changing the discs but figured they would be fine, asked my usual mechanic and he thought the same.

Not ideal at all really. You've basically bedded in new pads to old discs and then swapped the discs

DuckSlice

challengemaster wrote: »

Not ideal at all really. You've basically bedded in new pads to old discs and then swapped the discs

Should i change them again? i would have thought the pads would wear flat regardless of what state the disc is in, and they would sit flat on the new disc.
They are a cheap enough item to change so maybe i will just change them again.

Checked again last night for a hot wheel after a journey and they were all the same temp. the calipers were even cool to touch.

DuckSlice

Something i remembered from the last time i had tyres put on. The tyre man said that the front drivers wheels had a slight buckle in it.
Think ill swap the wheels the weekend to see if this is an issue, but id be surprised if i could feel it under braking, but you never know.

Dale Parish

In these cars, shimmy between 80-120kph is time for a front suspension overhaul

wandererz

DuckSlice wrote: »

Something i remembered from the last time i had tyres put on. The tyre man said that the front drivers wheels had a slight buckle in it.
Think ill swap the wheels the weekend to see if this is an issue, but id be surprised if i could feel it under braking, but you never know.

That's an important bit.
The wheels on the e90 have a tendency to crack etc.
In fact, wheels can disintegrate while driving.

Remove the wheels while you're at the rest and check for cracks. Although, the best option is to remove the tire and check the entire wheel.

Bruthal.

DuckSlice wrote: »

I needed new pads on the front as they had worn on the inside a lot more than the outside, in my head backing up the idea there is a slight warp in the disc and it had been rubbing on one side more than the other.

Wear seen a lot more on one pad than the other could be sticking slider pins on the caliper. Which could cause heating of the disks while not actual braking, as the pad might be in contact with the disk after braking and releasing. Then when you do brake, vibration from overheated disk.

You would notice the wheel heated up after driving though, if you put a hand on it.

DuckSlice

Dale Parish wrote: »

In these cars, shimmy between 80-120kph is time for a front suspension overhaul

It’s had a full inspection, and the top guide on the front shocks changed. Shocks were in good working order so I think everything is ok in that department.

DuckSlice

Bruthal. wrote: »

Wear seen a lot more on one pad than the other could be sticking slider pins on the caliper. Which could cause heating of the disks while not actual braking, as the pad might be in contact with the disk after braking and releasing. Then when you do brake, vibration from overheated disk.

You would notice the wheel heated up after driving though, if you put a hand on it.

Yea the wheel doesn’t get hot at all! I think I’m just going to order the rebuild kit for the caliper and rule it out. They are only cheap online and enjoy doing that kind of thing anyway.

challengemaster

The inside pads generally wear more than the outer ones, it's fairly common. It depends what you're defining as "a lot more", which we can't really tell without any visual comparisons. It should only be a few mm though, not a massive difference.

You'd get a new caliper for €50-60 and new slide pins for an extra €5. I'm not sure I'd bother pissing around with a rebuild kit for the sake of €25 quid.

DuckSlice

challengemaster wrote: »

The inside pads generally wear more than the outer ones, it's fairly common. It depends what you're defining as "a lot more", which we can't really tell without any visual comparisons. It should only be a few mm though, not a massive difference.

You'd get a new caliper for €50-60 and new slide pins for an extra €5. I'm not sure I'd bother pissing around with a rebuild kit for the sake of €25 quid.

The outside pad probably had 4-5mm left on it the inside had about 2mm on it.

Calipers are about about 100 euro unfortunately, rebuild kits are 20 euro, its 15/20 minutes extra work to replace the seals once you have caliper off so makes sense to me.

DuckSlice

I swapped the wheel the weekend, gave both of them an inspection and couldn't see any craics. The one on the drivers side did look like it has taken a small hit on the inside but nothing major.

When i had the wheel off i took out the slider pins of the passenger side and gave them a good clean, they were dirty but not as bad as the drviers side was. Car seems to be better today but the vibration is still there but i don't feel it in the pedals as much. Im thinking it is the wheel and it feels like it was in the brake pedal because they are close to the drivers side wheel.

I wont know properly until the drive home from work on the motorway, which it seems to be at its worst. Starting to think that surface isnt the best on the motorway as you leave Galway.