Shaking @ 80+MPH
#32
Burning Brakes
I have been experiencing the same issue with my '79. At 90mph plus a small vibration is evident. I can even feel the vibration in the shifter. At this point I suspect a flat spot in one of my rear wheels. Lots of interstate repair over here in the last couple of years and crappy asphalt patchs at 90 will do the trick.
#33
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Scott, wish mine was a small vibration. It's flat out shaking like crazy, drives you nuts because it's smooth as silk until 80, then there's a small vibration, then big-time shaking at 90.
I'll post what I find if I can get to it this weekend. My baby turns 19 so lots of things going on this weekend w/ the family, but I'm hoping to squeeze a few hours in.
I'll post what I find if I can get to it this weekend. My baby turns 19 so lots of things going on this weekend w/ the family, but I'm hoping to squeeze a few hours in.
#34
Drifting
I've never been able to resolve my vibration issues.
Balancing all four wheels at the same time makes a huge difference, but things get noticably worse within 1k to 2k miles. Leaving it more than 3k is just horrible.
I have spent big money (for me) trying to get all ride height and alignment issues resolved and this has helped a little, but not cured the problem.
Next I'm going to replace the engine mounts, as this probably makes a small contribution. Even so, this vibration is probably the most dissappointing aspect of owning the car. It can be felt in the seat, and back, and also as a vertical vibration of the steering column, there is rarely much turning effect in the steering wheel. It seems to have several "harmonics", 80mph is the first, it seems to come and go in 20 or 30mph increments.
As the car must be on original CV joints, is that where I need to look next?
Balancing all four wheels at the same time makes a huge difference, but things get noticably worse within 1k to 2k miles. Leaving it more than 3k is just horrible.
I have spent big money (for me) trying to get all ride height and alignment issues resolved and this has helped a little, but not cured the problem.
Next I'm going to replace the engine mounts, as this probably makes a small contribution. Even so, this vibration is probably the most dissappointing aspect of owning the car. It can be felt in the seat, and back, and also as a vertical vibration of the steering column, there is rarely much turning effect in the steering wheel. It seems to have several "harmonics", 80mph is the first, it seems to come and go in 20 or 30mph increments.
As the car must be on original CV joints, is that where I need to look next?
#35
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Paul-
If you can, without a doubt, rule out the wheels and tires, then I would say the next likely culprit would be bearings, suspension and possibly drive train (CV joints). Of course, it may not be in that order. And if you're as fussy as I am about vibrations and squeaks, it'll drive you MAD!
If you can, without a doubt, rule out the wheels and tires, then I would say the next likely culprit would be bearings, suspension and possibly drive train (CV joints). Of course, it may not be in that order. And if you're as fussy as I am about vibrations and squeaks, it'll drive you MAD!
#36
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did you guys check the "true-ness" of the tires on the rims. lots of times, they balance out, and at speed go NUTS with vibration.
check that. also, again, you can rule out engine and related components by just putting the car in neutral and pushing in the clutch. pretty hard time believing its goingto be a CV joint, heck, those things are only spinning sub 1200rpm. but, any thing is possible. more than likely its the tires out of round, (not flat spot, but out of round!)
MK
check that. also, again, you can rule out engine and related components by just putting the car in neutral and pushing in the clutch. pretty hard time believing its goingto be a CV joint, heck, those things are only spinning sub 1200rpm. but, any thing is possible. more than likely its the tires out of round, (not flat spot, but out of round!)
MK
Originally Posted by UKKid35
I've never been able to resolve my vibration issues.
Balancing all four wheels at the same time makes a huge difference, but things get noticably worse within 1k to 2k miles. Leaving it more than 3k is just horrible.
I have spent big money (for me) trying to get all ride height and alignment issues resolved and this has helped a little, but not cured the problem.
Next I'm going to replace the engine mounts, as this probably makes a small contribution. Even so, this vibration is probably the most dissappointing aspect of owning the car. It can be felt in the seat, and back, and also as a vertical vibration of the steering column, there is rarely much turning effect in the steering wheel. It seems to have several "harmonics", 80mph is the first, it seems to come and go in 20 or 30mph increments.
As the car must be on original CV joints, is that where I need to look next?
Balancing all four wheels at the same time makes a huge difference, but things get noticably worse within 1k to 2k miles. Leaving it more than 3k is just horrible.
I have spent big money (for me) trying to get all ride height and alignment issues resolved and this has helped a little, but not cured the problem.
Next I'm going to replace the engine mounts, as this probably makes a small contribution. Even so, this vibration is probably the most dissappointing aspect of owning the car. It can be felt in the seat, and back, and also as a vertical vibration of the steering column, there is rarely much turning effect in the steering wheel. It seems to have several "harmonics", 80mph is the first, it seems to come and go in 20 or 30mph increments.
As the car must be on original CV joints, is that where I need to look next?
#37
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Y'know, this is probably stupid, but since the vibration occurs at increasing speed, and you have to get up to a pretty decent speed for it to appear, I'd even check to make sure the rear wing is securely attached. Also, maybe put it up on a lift and make sure the front spoiler is firmly attached along with any various pans under the engine. Makes me wonder if it's just wind turbulence acting against something loose.
#38
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Originally Posted by bigs
Y'know, this is probably stupid, but since the vibration occurs at increasing speed, and you have to get up to a pretty decent speed for it to appear, I'd even check to make sure the rear wing is securely attached.
Last edited by deliriousga; 03-18-2005 at 12:28 AM.
#39
Drifting
Originally Posted by mark kibort
did you guys check the "true-ness" of the tires on the rims. lots of times, they balance out, and at speed go NUTS with vibration.
check that. also, again, you can rule out engine and related components by just putting the car in neutral and pushing in the clutch. pretty hard time believing its goingto be a CV joint, heck, those things are only spinning sub 1200rpm. but, any thing is possible. more than likely its the tires out of round, (not flat spot, but out of round!)
MK
check that. also, again, you can rule out engine and related components by just putting the car in neutral and pushing in the clutch. pretty hard time believing its goingto be a CV joint, heck, those things are only spinning sub 1200rpm. but, any thing is possible. more than likely its the tires out of round, (not flat spot, but out of round!)
MK
I also make sure that the wheels are mounted with the valve, looking wheelnut and red stud all aligned. I am still getting uneven tyre wear despite my all my efforts, so I'm going to get another alignment check soon, I will post the results when I get them.
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Any follow-up?
#41
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Originally Posted by bigs
Any follow-up?
It will probably be another weekend as I had to do the 60K maintenance on the Boxster today (still have to find the darn spark plugs) and my daughter's 19th b-day is Sunday and the whole family will be here all day I'm sure. I will post my findings as soon as I get the TB taken care of.
#42
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My first investigation was the belly pans and spoiler. I checked them and there were several screws missing. I think the PO replaced several of them as there are different types, some are hex head and some phillips head and different sizes. It looks like they are all the same except for two 10mm head bolts that go in the middle of the front pan. Please let me know if this is wrong.
I got replacement screws that match the majority (hex head w/ 8mm heads) of the screws and replaced three with larger bolts. The holes were larger than the others on those (two went into the car, not speed nuts) so the old screws would not fit.
After getting it completely in place and tightened down, I checked the front spoiler again and all of the speed nuts I had replaced were still in and firm. Took her up to 80 and shaking began. Still the same all the way through.
I'm working on a retreat this weekend where I'm "guarding" the folks on the retreat at night (the retreat center is in a remote, rural area and we're basically the alarm system with cell phones) so I'll have all day Saturday and Sunday to do a few things and take her out for a few tests. I think I'm going to remove the bouncing flippable spoiler first and go from there.
I got replacement screws that match the majority (hex head w/ 8mm heads) of the screws and replaced three with larger bolts. The holes were larger than the others on those (two went into the car, not speed nuts) so the old screws would not fit.
After getting it completely in place and tightened down, I checked the front spoiler again and all of the speed nuts I had replaced were still in and firm. Took her up to 80 and shaking began. Still the same all the way through.
I'm working on a retreat this weekend where I'm "guarding" the folks on the retreat at night (the retreat center is in a remote, rural area and we're basically the alarm system with cell phones) so I'll have all day Saturday and Sunday to do a few things and take her out for a few tests. I think I'm going to remove the bouncing flippable spoiler first and go from there.
#43
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John-
I think you're best off to look at tires. I'll put 2 beers (at SITM) on tires. Swap 2 at a time with the boxter. Again, if the shaking is in the steering wheel, then it's most likely the fronts, otherwise start at the rears. Let us know what you find out.
I think you're best off to look at tires. I'll put 2 beers (at SITM) on tires. Swap 2 at a time with the boxter. Again, if the shaking is in the steering wheel, then it's most likely the fronts, otherwise start at the rears. Let us know what you find out.
#44
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Originally Posted by Andrew Olson
John-
I think you're best off to look at tires. I'll put 2 beers (at SITM) on tires. Swap 2 at a time with the boxter. Again, if the shaking is in the steering wheel, then it's most likely the fronts, otherwise start at the rears. Let us know what you find out.
I think you're best off to look at tires. I'll put 2 beers (at SITM) on tires. Swap 2 at a time with the boxter. Again, if the shaking is in the steering wheel, then it's most likely the fronts, otherwise start at the rears. Let us know what you find out.
#45
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Originally Posted by deliriousga
so I'll pick those 2 brews up this fall at SITM if I can get there.
by accepting my offer, you do realize that I meant, if it is the tires you'll owe me 2 beers. If not, I owe you. Either way... LOL!