SevenCostanza

My '06 C2S cab has a hiccup of some sort. Here goes the description:

From a stop, if the wheel is turned all the way right or left and I begin to slowly back up or pull forward, there is a THUNK-THUNK-THUNK. The steering column almost "pops" with each THUNK. Only does it if the steering wheel is turned to near lock.

CV boot or something worse? There is some vibration at speed, but I was contributing that to the wheels needing a balance. Car handles fine and has no other symptoms.

Thanks for the assistance.

Macster

With no other symptoms of steering or suspension problems and with power fluid level ok the symptom is normal.

Briefly, due to the car's steering geometry at full lock the inside front wheel/tire is not perpendicular to the road surface.

When you back up -- or even drive forward at low low speed -- this inside wheel's partial contact causes it to skip. The outside wheel's tire is in full contact with the road surface so it won't/can't skip. The noise you are hearing, the vibration you are feeling is this skipping.

In a parking lot with room pull in and pick a spot and stop the car with the steering wheel turned to full lock. Shut off the engine. It is hard on the power steering system to leave the wheel at full lock with the engine running, even at idle.

Get out of the car and look at the front wheels/tires. You'll see the inside tire is making roughly 50% contact with the pavement.

A car's proclivity -- at least in the case of Porsches -- to generate this noise/behavior is if the weather is cool or cold, if the tire's old (heat cycles cause the tire's rubber to become harder, less grippy) and how much tread the tire has left.

Sincerely,

Macster.

kyrocks

^^ totally agree. My '09 C4S cab does same thing. Handles great, no vibration at speed, no issues. It is also more pronounced when cool/cold, but I rarely try to turn the steering wheel fully to the left/right.

ajayabb

I wonder if its the affect of cold temperatures on summer performance tires during start up. Where do you live and how cold has it been?

SevenCostanza

Great to know! Yes, it has been quite cold here and I DO hear the noise more frequently the colder it is. The tires are nearing replacement time, too.

I'll have to get out and check the tire position relative to the pavement. Seems like a perfectly reasonable explanation.

TooSixy

I think it's the cold weather.

cbzzoom

Yup, Macster is right on, this is probably just the tire crabbing.

BTW since I got a "performance alignment" this is way diminished.

stevepow

Same thing here if my car sits in a parking lot when the mercury drops to 30F or lower. Last year was a milder winter.

TerpsRED

Most certainly the cold weather. Here in Maryland the weather has been cold for some time. My front end hops like a little bunny when backing up and turning hard. Does not do it at more reasonable temps in the 60s (F) or higher.

Fahrer

My does the same thing. It can be quite alarming when first experienced.

shyamvenky

Wow! Thanks a lot Macster. I found the answer to my question without even having to ask.
Seriously, this forum is a treasure.. I have found answers to tonnes of questions across all my Porsches.
Kudos to all the contributors! Long live Rennlist

floatingkiwi

Mine did that too, it seemed to diminish with changing my front brake cooling ducts to GT3 versions. The originals had been rubbing on the strut for some reason and I could hear this thwacking noise on hard lock.

yashagrawal

Macster, u da man !

Cloudspin

+1. That he is.