Loud groan in brakes or suspension? halp!

[papa_g]

I bought an automatic '05 coupe in September. 87k miles. I noticed immediately there is this loud, abrupt groaning sound right before the car comes to a complete halt, and when changing from drive to reverse & vis-versa. Per PPI, the brake pads were at 85%, the control arms/bushings and rear shocks needed to be replaced. Also the brakes desperately needed a flush as there was still super blue fluid in there. I took care of all the above, thinking this would solve my issues. Nothing has changed in regards to this groaning sound.
Imagine this. You are stopped in the garage. Your foot is on the break and you put the car in reverse. There is a slight lurch backward, with a short groan as well. You back out of the garage while applying the break, and there is no squeal or whine from the brakes. Right before you stop reversing, another groan. You put the gear in drive; a small lurch forward with an associated groan. I think this is an easy diagnosis to those versed in the brakes and suspension of these cars. Sadly, I know very little.

Any help would be appreciated. I hope it is something as simple as tightening a suspension or frame component.

[SaltyNC]

Since it is easy to do, it might be worth loosening the sway bar brackets and greasing the inner rubber that contacts the sway bar.

Does it sound like this?
https://www.youtube.com/watch?v=4ODcxWm4Icg

Salty

[papa_g]

I have a feeling it is associated with the sway bars, i just can't believe the shop that did my PPI didn't pin point the noise. It does kind of sound like that vid, but it's much louder, much more pronounced and often has a high pitched squeal associated with it. I asked my brother to stand by the car while I moved and stopped, as well as shifted between park, drive and reverse. He says when I put it into reverse and drive, he noticed the back end rise and fall a little, respectively, and heard the sound coming from the rear when that happened. When just braking, he couldn't really pinpoint the sound. I wish i knew someone with a lift so i could just walk under the car and look at everything from a good vantage point.

[SaltyNC]

I know what you mean about the lift. I always get a little jealous when I read about our European friends that have rent-a-garages. Man, that would be so handy, and they seem to be common in some European countries.

Salty

[papa_g]

There's a self service garage where I live that rents for $40/hour, including lift and 450+ tools. But knowing me, I am very meticulous and take a long time doing anything with the car. I would end up paying a lot more than I feel comfortable with. If I knew I could diagnose and fix the job in an hour, I would do it. Hopefully someone on the forum knows exactly what I am talking about and can tell me how to fix it.

[papa_g]

Just started doing more research. I am not sure if the "lurch" i feel when shifting to drive or reverse is normal. Also, the back end moving up and down when shifting also seems suspect. Read some stuff about rear diff bushing or transfer case bushings going bad. Any other insights?

[Newjack]

Just started doing more research. I am not sure if the "lurch" i feel when shifting to drive or reverse is normal. Also, the back end moving up and down when shifting also seems suspect. Read some stuff about rear diff bushing or transfer case bushings going bad. Any other insights?

I don't have an automatic, but a slight lurch when switching from drive to reverse sounds pretty normal to me. Instead of a clutch, you have a torque converter which sends power to the wheels. It keeps spinning even when the brakes are pressed and it wants to keep moving, that's why the lurch is there.

I think SaltyNC called it with the sway bar bushings. It would explain your sound issue. Start with those bushings and see if the noise persists. Cars are just one of those things that you sometimes have to guess what the issue is and just start replacing things until you find the issue. Ask me about my cooling system...

Someone with an auto might chime in about the drive to reverse issue

[papa_g]

I am getting an alignment tomorrow at Firestone, I will have them inspect my brakes and suspension in detail while they have the car on the lift. Hopefully they find the issue.

[Newjack]

Post back and let us know what they find

[papa_g]

Got my alignment. I asked them to check brakes and suspension, and they told me the car was "pad slapped", which basically means new pads were put on without putting on new rotors which were needed as well. I know very little about brakes, but and Indy BMW shop in San Francisco said the brakes were fine. Also, my friends and I don't see anything wrong with the rotors. Long story short, they tried to quote me $1,600 to do all the brakes, and rear control arms and nothing was solved.

[Newjack]

Got my alignment. I asked them to check brakes and suspension, and they told me the car was "pad slapped", which basically means new pads were put on without putting on new rotors which were needed as well. I know very little about brakes, but and Indy BMW shop in San Francisco said the brakes were fine. Also, my friends and I don't see anything wrong with the rotors. Long story short, they tried to quote me $1,600 to do all the brakes, and rear control arms and nothing was solved.

You don't always need to replace your rotors when you replace brake pads. Honestly it's good practice to replace both pads and rotors at the same time but it is absolutely not necessary. If your rotors still have enough thickness and don't look warped when you spin them, they are fine.

Also don't listen to Firestone, they are probably trying to sell you a bunch of shit you don't need. If your car was inspected by a BMW tech I would trust them before Firestone.

Doesn't sound like they checked your sway bar bushings, so I'm not surprised the issue is still there.

[papa_g]

Yeah it's a real shame. Almost disrespectful I would say. I went through the hassle of describing my issue to them, telling them my opinions, my findings, and hoped they could at least check some of the obvious culprits. And they throw some completely unrelated shit at me. My brakes don't squeel, rumble, shudder or anything under any kind of braking, and I explained this to them. It's only the last inch of movement before complete halt that you hear a sound, and if you listen closely, it sounds like it's coming from the suspension.

[Newjack]

Yeah it's a real shame. Almost disrespectful I would say. I went through the hassle of describing my issue to them, telling them my opinions, my findings, and hoped they could at least check some of the obvious culprits. And they throw some completely unrelated shit at me. My brakes don't squeel, rumble, shudder or anything under any kind of braking, and I explained this to them. It's only the last inch of movement before complete halt that you hear a sound, and if you listen closely, it sounds like it's coming from the suspension.

Find a good shop around your area. Look up reviews or speak to someone on the forums here or E46f who can give you a good recommendation. Take your car there, explain the situation and see what they find. I've done most jobs on the car myself (with help from the forums here and from forum members) but sometimes I either don't have the tools or the time to get a job done and I take it to my mechanic.

[papa_g]

Find a good shop around your area. Look up reviews or speak to someone on the forums here or E46f who can give you a good recommendation. Take your car there, explain the situation and see what they find. I've done most jobs on the car myself (with help from the forums here and from forum members) but sometimes I either don't have the tools or the time to get a job done and I take it to my mechanic.

Agreed. I want to do this on my own if I am going to be honest. It seems too simple to hand off to someone else. I'll just find the time to get underneath the car one day and inspect every bushing. Could be something as simple as greasing up an old bushing and putting it back on.
I do think I will do the full brake job in the near future though. Do you have a preference when it comes to rotor/pad combination? I've done a but of reading and it seems with reduced dusting you get less initial bite.

[Newjack]

Agreed. I want to do this on my own if I am going to be honest. It seems too simple to hand off to someone else. I'll just find the time to get underneath the car one day and inspect every bushing. Could be something as simple as greasing up an old bushing and putting it back on.
I do think I will do the full brake job in the near future though. Do you have a preference when it comes to rotor/pad combination? I've done a but of reading and it seems with reduced dusting you get less initial bite.I like performance. When I press the brake pedal I want to feel my car stop immediately, so I kept the BMW stock pads. They dust like a bastard but it's worth it for me. Ceramic are a thousand times cleaner and less dusty, but they don't bite as hard or stop as quick. It all depends on what you want out of your brakes and the driving you do. Only get track pads if you actually track the car, otherwise they will be loud as shit and won't work well until they get nice and hot.

I'm running centric slotted rotors and stop tech stainless steel brake lines. Overall very happy with my setup.

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[danewilson77]

You don't always need to replace your rotors when you replace brake pads. Honestly it's good practice to replace both pads and rotors at the same time but it is absolutely not necessary. If your rotors still have enough thickness and don't look warped when you spin them, they are fine.

Also don't listen to Firestone, they are probably trying to sell you a bunch of shit you don't need. If your car was inspected by a BMW tech I would trust them before Firestone.

Doesn't sound like they checked your sway bar bushings, so I'm not surprised the issue is still there.I went through 2 sets of pads on the BMW Performance Rotors.

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[Newjack]

I went through 2 sets of pads on the BMW Performance Rotors.

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OP just remember that not everyone here can be as cool as Dane Wilson - He is truly one of a kind (http://www.zhpmafia.com/forums/showthread.php?6002-ZHP-Mafia-SIGFest-2012-Williamsburg-VA-May-18th-19th-amp-20th&p=179523#post179523)

[ZHPizza]

I like performance. When I press the brake pedal I want to feel my car stop immediately, so I kept the BMW stock pads. They dust like a bastard but it's worth it for me. Ceramic are a thousand times cleaner and less dusty, but they don't bite as hard or stop as quick. It all depends on what you want out of your brakes and the driving you do. Only get track pads if you actually track the car, otherwise they will be loud as shit and won't work well until they get nice and hot.

I'm running centric slotted rotors and stop tech stainless steel brake lines. Overall very happy with my setup.

Sent from my Nexus 5X using Tapatalk

+1 @slater and I were just talking about this last week. You really cannot beat the initial bite that the OE pads have. You pay for it in dust, but that bite is part of the package that makes the BMW driving dynamics stand out.

[slater]

+1 @slater and I were just talking about this last week. You really cannot beat the initial bite that the OE pads have. You pay for it in dust, but that bite is part of the package that makes the BMW driving dynamics stand out.

amen, brother!

[papa_g]

I went through 2 sets of pads on the BMW Performance Rotors.

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OP just remember that not everyone here can be as cool as Dane Wilson - He is truly one of a kind (http://www.zhpmafia.com/forums/showthread.php?6002-ZHP-Mafia-SIGFest-2012-Williamsburg-VA-May-18th-19th-amp-20th&p=179523#post179523)

Isn't it normal to go through 2 sets of pads on one rotor? Or do the BMW performance rotors wear a lot faster than normal?

[danewilson77]

Isn't it normal to go through sets of pads on one rotor? Or do the BMW performance rotors wear a lot faster than normal?I had 1 set of rotors. Several sets of pads.

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[papa_g]

Sorry Dane, I meant 2 sets of pads. I edited my last post. What I will do is measure my rotors one of these days to see if they are above minimum thickness. If not, I'll just order a whole new set, front and back, of pads, rotors and sensors. Steel brake lines i will leave for another day, as I literally just flushed my brakes, unless you guys think its ok to pump out the fluid I just put in and pour it back in once i put on new steel lines?? (I am assuming not, but hey, worth a shot)

[SaltyNC]

I definitely would avoid that, Papa_G. It's just not worth the risk of contamination over $7 to $16 worth of brake fluid. I would just chalk it up to a little waste and not try to re-use it. It wouldn't take much fluid to replace what is lost from the line swap and then just bleed off your brakes and top up your master cylinder. I actually just got in some stainless lines, and I ran to O'Reilly and picked up a combo pack of rubber vacuum caps for less than $4. I was using the tips from a rubber glove and a small o-ring, but it gets slick and hard to manage. The rubber vacuum caps can be quickly placed on the line for minimal loss during the swap. Also, if you use a stick or something to hold down the brake pedal, you won't get much leakage anyway.

I went with ECS tuning steel lines. They look good.

Salty

[papa_g]

I definitely would avoid that, Papa_G. It's just not worth the risk of contamination over $7 to $16 worth of brake fluid. I would just chalk it up to a little waste and not try to re-use it. It wouldn't take much fluid to replace what is lost from the line swap and then just bleed off your brakes and top up your master cylinder. I actually just got in some stainless lines, and I ran to O'Reilly and picked up a combo pack of rubber vacuum caps for less than $4. I was using the tips from a rubber glove and a small o-ring, but it gets slick and hard to manage. The rubber vacuum caps can be quickly placed on the line for minimal loss during the swap. Also, if you use a stick or something to hold down the brake pedal, you won't get much leakage anyway.

I went with ECS tuning steel lines. They look good.

Salty

Salty to the rescue! That is actually some very valuable information. If I am going to lose minimal fluid, then I am all for changing the lines right now. I actually still have a good amount of ATE gold left over from my flush, so I would be set! Did you get the dorman caps? I bought a 4 pack and used one to replace the old worn out bigger vacuum cap on the back of the intake manifold.

[SaltyNC]

Salty to the rescue! That is actually some very valuable information. If I am going to lose minimal fluid, then I am all for changing the lines right now. I actually still have a good amount of ATE gold left over from my flush, so I would be set! Did you get the dorman caps? I bought a 4 pack and used one to replace the old worn out bigger vacuum cap on the back of the intake manifold.

Yep, 8 count Dorman rubber caps for $3.69. The hard line connection is small so you need one of the smaller caps. When I replaced my calipers yesterday, it dripped about one drop per second without the brake pedal being pressed. I would guess I lost no more than half a shot glass of brake fluid even futzing around with the rubber glove fingertip and o-ring tourniquet I made. :) Very minimal loss. And it won't take much to bleed the new lines. They hold practically nothing because the inside diameter is so small. My new ECS steel lines are 3.2mm ID, so we're talking about a teaspoon of brake fluid to fill that line. Of course, bleeding will burn through a little bit of fluid, but not much.

Salty