Strong vibration under braking
02-13-2002, 08:15 AM
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Strong vibration under braking
Just got my car back from the shop - it was in there to fix the creaky windshield. The good news is the windshield creak is completely eliminated BUT on the drive home on the motorway found that when I brake firmly from around 70mph there is a very strong vibration coming through the steering wheel which was not there before. It is not noticeable when braking very gently or at low speeds.
The rotors and pads were changed 1500 miles ago and the car has been driven gently since - all road use. Given no work should have been carried out anywhere near the vicinity of the front wheels or brakes does anyone have any idea what these guys could have done to my baby??
The rotors and pads were changed 1500 miles ago and the car has been driven gently since - all road use. Given no work should have been carried out anywhere near the vicinity of the front wheels or brakes does anyone have any idea what these guys could have done to my baby??
02-13-2002, 08:26 AM
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They took your car out for a hell ride! I remember some manufacturer had a special switch, that put the car into "owner away mode" so that the kids or valet would only be able move the car at up to 30mph. I wonder if an option is available for Porsche.
02-13-2002, 09:30 AM
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95%of the time the problem you describe is warped rotors. If the car has been sitting a bit(while the work was done) it could be tires out of round a bit. You might want to drive it a day or so to see if it gets better. If not, take it back and ask them the tough questions.
02-13-2002, 10:46 AM
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Hard to imagine anyone could warp Turbo rotors on the street with street pads. I believe they would also vibrate under braking at lower speeds, too.
I'd look elsewhere for the cause. Bent wheel?
(I always record the mileage when leaving my car for service!)
I'd look elsewhere for the cause. Bent wheel?
(I always record the mileage when leaving my car for service!)
02-13-2002, 10:51 AM
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Hmmm...perish the thought but it seems unlikely because they didn't have the car for very long, they are a large dealership so they see a lot of p-cars (one hopes they are bored of thrashing them by now), same amount of petrol, there was only a couple of extra miles on the clock (I expect they wanted to check the rattle had gone) and I imagine you'd have to try pretty hard to damage the brakes driving on normal roads with a 993 even if you were really trying?? From what I understand plenty of Rennlisters DE their cars on the track without adverse effect so difficult to imagine a 'thrash' on public roads would be a big problem?
Could a suspension component have been damaged or something like that?
Could a suspension component have been damaged or something like that?
02-13-2002, 11:02 AM
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Get the rotors hot, stop immediately without cooling them, and leave the handbrake on. Not good.....
As you say though, doubtful they could have done anything to it if they only put a couple of miles on the clock.
Eric
As you say though, doubtful they could have done anything to it if they only put a couple of miles on the clock.
Eric
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02-13-2002, 11:40 AM
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[quote]Originally posted by Chris C.:
<strong>
(I always record the mileage when leaving my car for service!)</strong><hr></blockquote>
How easy is it to disconnect the odometer in these cars? I had a Wrangler and one day the dials went dead though the digital odometer was still lit - only thing was it didn't register any mileage either. The problem was simply a loose plug but it was scary to see how easy it was to fiddle the mileage.
Eric - I see your point. If the handbrake acted on the front wheels I would say this is what happened - it does feel much more like the problem is in the front rather than in the back.
<strong>
(I always record the mileage when leaving my car for service!)</strong><hr></blockquote>
How easy is it to disconnect the odometer in these cars? I had a Wrangler and one day the dials went dead though the digital odometer was still lit - only thing was it didn't register any mileage either. The problem was simply a loose plug but it was scary to see how easy it was to fiddle the mileage.
Eric - I see your point. If the handbrake acted on the front wheels I would say this is what happened - it does feel much more like the problem is in the front rather than in the back.
02-13-2002, 12:17 PM
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[quote]Originally posted by tom97c4s:
<strong>It sounds like it may be ABS kicking in. Where the roads wet?</strong><hr></blockquote>
Not wet and definitely not braking hard enough for it to kick in but that is a very good description of what the vibration feels like only less violent.
<strong>It sounds like it may be ABS kicking in. Where the roads wet?</strong><hr></blockquote>
Not wet and definitely not braking hard enough for it to kick in but that is a very good description of what the vibration feels like only less violent.
02-13-2002, 12:40 PM
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Lug nuts torqued to 94 lb ft ?
02-13-2002, 09:53 PM
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The mechanic was a small fellow and climbed onto your wheel to get better access to your windshield seal, in the process of climbing onto your front wheel he kicked off a wheel weight.
02-14-2002, 05:39 AM
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Thanks for the responses. Will take the car back and this time not let it out of my sight while they put it right! When I find out what the problem is I will post it for the archives.
