High Speed Vibration From Rear End +70mph?
#16
Rennlist Member
I'd probably do the wheel bearings at the same time then you only have to defeat the 32mm nut once Well, unless this just started? I don't think you mentioned how long it has been like this or did I miss it.
How did the left side look?
How did the left side look?
#19
I've never seen a bent half shaft before. seen 2 break at the track but nothing bent.
can't even imagine how that happens.
after removing the shaft take it to a drive shaft shop and see what they say.
can't even imagine how that happens.
after removing the shaft take it to a drive shaft shop and see what they say.
#20
Rennlist Member
Johan, just noticed you mentioned you had a full alignment and corner balance done. Was the axle like this before the service? Did they have any comment?
Last edited by JB 911; 04-14-2014 at 05:09 PM.
#21
Rennlist Member
I had a vibration coming from the rear from the car at fairly high speeds (180km/h). Tried wheel balancing, new tires, full wheel alignment, etc. Nothing worked.
Popped by Porsche in Stuttgart on my way through Germany. The mechanic took it for a very fast spin on the Autobahn and came back with the diagnosis: dying flywheel.
He was spot on! Changing the clutch and flywheel fixed the problem.
Popped by Porsche in Stuttgart on my way through Germany. The mechanic took it for a very fast spin on the Autobahn and came back with the diagnosis: dying flywheel.
He was spot on! Changing the clutch and flywheel fixed the problem.
#22
Rennlist Member
I have two sets of wheels for my car- one set was balanced at the dealer when they did an alignment and the car is ROCK solid- no vibration at any speed. the other set I brought into Tires Plus to balance and there's a very slight vibration at 70 MPH through the steering wheel- nothing that you'd probably get worked up about unless you just had the other set on the car and felt the difference.
is there some sort of "magic" balancing machine I should be looking for? I'll get them redone and take get Tires Plus to pay me back the $ 40 bucks I paid them if so!
is there some sort of "magic" balancing machine I should be looking for? I'll get them redone and take get Tires Plus to pay me back the $ 40 bucks I paid them if so!
#23
Rennlist Member
Thread Starter
I always take my wheels/tires to get mounted and balanced here.
The equipment they use is on the bottom of their webpage. (Fast Forward Wheels is in the same shop as Wheel Dynamics)
When I had the corner balancing done, my alignment guy double-checked all the bushings/ball joints/bearings for excessive play. He confirmed that everything was fine, and suggested I did more troubleshooting of the entire driveline...
I should have taken this vibration more seriously, and done some troubleshooting beforehand. I must say that I was never too concerned about it, because I rarely drive on freeways. I only take the car out once a month for a leisure cruise in the mountains, and I honestly can't feel anything at slow speeds...
Up until a couple weeks ago, I was convinced it was just bad balancing/alignment, and aging rear tires. Now, I realize that it was the other way around. The vibration caused excessive and uneven wear on the right rear tire. Cord is showing only in a few spots, and at regular spaced intervals on the inside. The left tire is also worn on the inside, but evenly, and no cord is showing.
Here is a pic of what is left of the right rear on my 18s:
The equipment they use is on the bottom of their webpage. (Fast Forward Wheels is in the same shop as Wheel Dynamics)
When I had the corner balancing done, my alignment guy double-checked all the bushings/ball joints/bearings for excessive play. He confirmed that everything was fine, and suggested I did more troubleshooting of the entire driveline...
I should have taken this vibration more seriously, and done some troubleshooting beforehand. I must say that I was never too concerned about it, because I rarely drive on freeways. I only take the car out once a month for a leisure cruise in the mountains, and I honestly can't feel anything at slow speeds...
Up until a couple weeks ago, I was convinced it was just bad balancing/alignment, and aging rear tires. Now, I realize that it was the other way around. The vibration caused excessive and uneven wear on the right rear tire. Cord is showing only in a few spots, and at regular spaced intervals on the inside. The left tire is also worn on the inside, but evenly, and no cord is showing.
Here is a pic of what is left of the right rear on my 18s:
Last edited by CaptainGSR; 04-15-2014 at 09:13 PM.
#25
Rennlist Member
Thread Starter
Yeah, I have a bad feeling about this too. I am going to double-check and compare the lateral runouts of both rear hubs in a couple of days. I have the service manual...
#27
We've run into this issue before with some of our walk-in customers, they have done this and that and have had their wheels re-balanced etc.
Sometimes it's just not having the right machine but also having the right tooling for the Porsche and using it right when operating the machine that will make it work.
We've attached a pretty simple explanation which was well worth creating considering how many times we've had to send this information over the phone.
Right machine, Right accessories, right end-user = great balance!
Wheel Dynamics Inc.
Sometimes it's just not having the right machine but also having the right tooling for the Porsche and using it right when operating the machine that will make it work.
We've attached a pretty simple explanation which was well worth creating considering how many times we've had to send this information over the phone.
Right machine, Right accessories, right end-user = great balance!
Wheel Dynamics Inc.
#28
Rennlist Member
Thread Starter
These threads are useless without an update, so here we go:
I ended up getting medieval on the car, and spending $$$$ at Sunset...
The driveshaft was definitely shot at the outer joint. I ordered a new one from Sunset. In the Porsche box was a GKN15 axle (I will post a photo of the GKN tag on the shaft.) I honestly can't tell if it is the same GKN axle that Pelican sells for $200 cheaper. :-(
I also replaced the wheel bearing while I was in there (NTN was in the box.)
The lateral runout of the old hub was very hard to assess (rust messing up my readings,) so I decided to replace it also. (I had to remove it to change the bearing anyways)
The vibration is gone!
Final thoughts:
1- make sure your pss10 droplink mounts are very tight, otherwise you will destroy your passenger side driveaxle...
2- the harbor freight front wheel bearing tool works great for this application.
3- don't forget to reinstall the wheel bearing retaining brackets a before pressing the hub back in the inner race...
I ended up getting medieval on the car, and spending $$$$ at Sunset...
The driveshaft was definitely shot at the outer joint. I ordered a new one from Sunset. In the Porsche box was a GKN15 axle (I will post a photo of the GKN tag on the shaft.) I honestly can't tell if it is the same GKN axle that Pelican sells for $200 cheaper. :-(
I also replaced the wheel bearing while I was in there (NTN was in the box.)
The lateral runout of the old hub was very hard to assess (rust messing up my readings,) so I decided to replace it also. (I had to remove it to change the bearing anyways)
The vibration is gone!
Final thoughts:
1- make sure your pss10 droplink mounts are very tight, otherwise you will destroy your passenger side driveaxle...
2- the harbor freight front wheel bearing tool works great for this application.
3- don't forget to reinstall the wheel bearing retaining brackets a before pressing the hub back in the inner race...
#29
3- don't forget to reinstall the wheel bearing retaining brackets a before pressing the hub back in the inner race...
now that's funny.
so was the half shaft bent or just the outer cv joint toast?
what is the harbor freight front wheel bearing tool?
now that's funny.
so was the half shaft bent or just the outer cv joint toast?
what is the harbor freight front wheel bearing tool?