Help Please - Brakes or IMS?

[tonycarreon]

so i think i have a brake issue, but let's see.

first a picture



yes, i had to get a tow. i changed the oil today and decided to go for a drive - 70 miles round trip. i went to gettysburg. exiting the highway i pressed the brake pedal and heard a fwap-fwap-fwap noise coming from the rear driver's side but it was only momentary and i thought it was the road. on my way back home i pressed the brake again doing about 70 and when i got down to around 60 it was back - fwapfwapfwapfwap... until i hit 50 and then it stopped. i pulled over to a rest stop and looked under the car - nothing unusual no leaks, etc.

i get back on the highway and no noise. then i thought - what the hell - and pressed the brake again, nothing. i was doing about 50 at the time. so i sped back up and when i got to 70 i pressed the brake again. noise was back - fwapfwapfwafwapfwap. i stopped, looked at the tires because it really sounded like a chunk of tire was hitting the wheel well. they were fine. get back on the road go maybe 10-15 miles, have to brake because of a slower car and the noise comes back. but this time when i let off the brake it doesn't stop. fwapfwapfwapfwap.

i again pull to a stop - the whole time fwapfwapfwap..fwap....fwap....fwapping away. look - nothing i can see. as i was pulling away i pulled up on the emergency brake and about half-way up i heard a very loud pop. i noticed i could "feel" the fwapping in the emergency brake handle.

i pulled out the video camera and recorded the noise.

something to note - it definitely seems get faster the faster the tires rotate. standing still no noise, if i rev the engine no noise, only when i'm in motion.

first video is no noise, then i press the brake for a few seconds @ about 50 seconds in...
http://www.youtube.com/watch?v=3vh7P3E0_lw

next 2 videos are constant noise (no noise when stopped, only when in motion)...
http://www.youtube.com/watch?v=14iWPvomj9g (in motion)
http://www.youtube.com/watch?v=BA_vjx5cl5o (driving home from shop)

any thoughts? there are no lights on the dash - brake, CEL, or otherwise.

[extanker]

pull the rear wheels and have a look and feel

[tonycarreon]

Originally Posted by extanker

pull the rear wheels and have a look and feel

i plan to, once it cools down.

[ChrisZang]

well if the noise only happens when braking it's not the IMS
The loud pop (or bang) when pulling the e-brake while driving is normal (at least mine does that too).

Take the wheels off and look at your rotors and brake pads

It "might" be that the e-brake shoes got stuck but then you would see (and smell) a lot of brake dust

[al83s]

embarased to say, but same thing happened to my accord, it was as simple as lug nuts on the front driver wheel were loose and one missing (i had wheels balanced at costco the night before). Lesson learned, hope yours is something just as simple...

[crios]

I had a similar noice...clunk...cluck....cluck sound, real loud, did not sound good at all. Took it to the dealer, they said the brakes were sticking, cleaned then up, went away for a couple of months, then it came back.

I didn't want to take it back to the dealer, $400 for nothing, so I took it to an Indy should, they opened it up and found the below damaged, which was causing the issues.

If after you jack up the car, the noice goes away, could be this, this is what would happen to me. If could also be the trannmission as well? I'm getting a rebuilt not, broke 2nd gear, and that sounded like a bunch of rock in an tin can...all other gears worked fine.

Before:


After wacking it back to shape:

[tonycarreon]

ok got it jacked up, put it in gear and it took about 3 seconds to figure out what it was.

i'm not sure but i think that's the e-brake cable line. if someone could confirm for me.

looks like a zip tie broke off that was holding it away from the wheel. when the wheel goes around, the weight on the inside hits it (you can see how it's worn away the weight, which might explain my recent rougher ride).

[jjanari]

I believe that is your e-brake cable.

btw, I've never known wheel weights to be placed in that location as seen in your picture. they're usually inside the rim. are you sure the weight didn't move?

[extanker]

Originally Posted by crios

I had a similar noice...clunk...cluck....cluck sound, real loud, did not sound good at all. Took it to the dealer, they said the brakes were sticking, cleaned then up, went away for a couple of months, then it came back.

I didn't want to take it back to the dealer, $400 for nothing, so I took it to an Indy should, they opened it up and found the below damaged, which was causing the issues.

If after you jack up the car, the noice goes away, could be this, this is what would happen to me. If could also be the trannmission as well? I'm getting a rebuilt not, broke 2nd gear, and that sounded like a bunch of rock in an tin can...all other gears worked fine.

Before:


After wacking it back to shape:

those darn self-tightening bolts again

[tonycarreon]

thanks guys, that's all it was. i zip-tied the line back down and the noise is gone. all is well again.

i feel like jeremy clarkson when he taped pennies to the wheel on the 944. "i mended something!"

Originally Posted by jjanari

I believe that is your e-brake cable.

btw, I've never known wheel weights to be placed in that location as seen in your picture. they're usually inside the rim. are you sure the weight didn't move?

yeah they didn't move. they're the kind that are clipped on to the rim. don't know where the previous owner had the tires installed. i do have the weights that are glued to the rim itself - those are still there as well. i need rear tires soon anyway, i'll make sure they're done right.

as an aside, after my car was towed, the tow truck driver asked me if it was the first time i'd ever had the car towed. when i said "yes," he noted "yeah, you looked pretty nervous."

[landrovered]

Originally Posted by extanker

those darn self-tightening bolts again

Wanker Yanker,

You are a stooge but hey if you want to keep bringing it up then fine.

This is a quote from a British engineering firm that specializes in bolts, bolt tightening and bolt failures.

In the UK, loss of the wheels from the left hand (nearside) rear drive axle seems to be most common and this is thought to be due to the effects of road camber and the fact that these wheels are subject to both braking and driving torque. However, as almost all wheel studs have right hand threads, which are tightened in clockwise direction, there have been several suggestions that the use of left hand threads for the left hand side wheels would overcome the problem. Again whilst this may prevent full unscrewing and loss of the nut it does not address the main cause of loss of tension in the fixing following initial tightening and the wheel would eventually be lost because of fixing and /or wheel wear and fracture.

http://www.boltscience.com/pages/failure4.htm

Rotation direction and centripetal forces do have an effect on bolt loosening. This is what I was referencing in my orginal statement. If instantaneous acceleration of the part is high enough then it will tighten the bolt (example: crankshaft bolt on diesel motor) or conversely loosen it. If you read this excellent website that I have provided the link to, you will find that multiple forces are acting on the bolts in the Boxster axle. I would also conclude quite readily that loctite would be a good tool to reduce failure of this joint for those other nay-sayers. If you don't believe me watch the video of the Junkers machine.

If you want to bring this up every time a halfshaft is mentioned on this board then I will be happy to oblige you and prove my point even further.

EDIT: PS, the photo of the 986 halfshaft is the left side....Golly gosh gee whiz

[Boxtaboy]

The zip ties always come loose. Here's a better solution...
http://www.ppbb.com/phorum/read.php?6,1454979,1454979#msg-1454979

[ekam]

Wheel weights should not go there at all... it should always be along in the inside of the wheel.

[Perfectlap]

I guess you have IMS on the mind!!

[dallison]

glad it wasn't anything major.