Pulls to the left
 

Through the summer I've been doing a bunch of suspension work. I did a home corner balance, replaced a bunch of bushings, etc. I also had the alignment done and bled all the brakes. Now, the car seems to handle well but pulls to the left under hard braking. Under normal driving conditions it's just fine, but when laying on the binders at 80mph I definitely pull hard to one side.

What would you look to first? Would it be a sticky caliper? Or might you suspect that the corner balance is off and the uneven weight distribution is causing the car to dart around?

I'm planning to go out in the rain or dirt and see if one whell is locking before the others. Would this be a good next test?

Unless you know it was done recently, I would rebuild all 4 calipers, and replace all 4 soft oil lines. Total bill for all that is ~$100 with parts from our host.

Tom

What are key symptoms of a sticky caliper? Do they typically drag and over heat, or does one not actuate as powerfullyas the other, causing the opposite wheel to lock or pull?

I don't believe this has been done and it would probably be a fun off-season project to rebuild them all and replace the lines.

Hey Echrisconnor:
How 'bout posting the 4 corner weight values? Maybe there is some "jacking" still in-play, because many don't fully understand proper corner balance techique ....
--Wil Ferch

The corner balance I did was followed some of the directions in the PP archives for getting things sorted out relative to one another. It involved jacking the car up in varous ways and comparing heights. I never got it on a scale.

The reason I mention that I suspect the corner balance is because I don't fully trust what I did. One of the rear wheels concerns me. It's dead even with the other side when you measure from the torsion bar tube to the ground. The fender and the bumper are low on that side though. This is the right rear of the car and the car now pulls to the left under these braking conditions. I want to test to see if that rear wheel locks before the other, but haven't gotten the car on something slippery and don't want to make any flat spots on my tires from skidding on dry pavement.

I still don't know what the classic symptoms of sticking calipers are, and whether they can cause the car to pull one way or another. Can anyone tell me?

Hi:
If you never got it on a scale ...frankly...you didn't corner balance, or, at least...you don't know what you have.
I'd go this way...
1.) Take off wheels and try to manually retract the pistons into the calipers...like when replacing pads. You should easily determine if anything is sticking or feels like it's binding.
2.) Back to corner balance. If I understand you correctly, the right-rear ( RR) is low...let's now "presume" that becomes a heavy corner. If so, the diagonal-opposite is also heavy. That means the LF is heavy. If the LF is heavy, then the RF ( in relative terms) is light.
Hmmm...LF heavy...RF light..which way would it pull if braking hard under these conditions ??

I vote it pulls left.

Once you check caliper action, and if it's found to be OK...my money is that you're weight-jacked.
--- Wil Ferch

Wil,

I agree that what I did wasn't a true corner balance. That's part of why I suspect it. I'll do the caliper test and see what happens.

As for the low right rear. If one wheel is low does that mean that it is heavier or lighter? You say heavier, which makes sense if you look at it from the perspective of more weight makes it lower. If I throw a large weight in one corner of my car, that corner will drop due to the added pressure.

If you look at it from the perspective that the torsion bar has less preload than the others, then it's light. When a torsion bar breaks that side drops. It is supporting less weight than the other 3 right? If one corner is low, you raise it by applying more pressure to that corner.

Diagonals play in for fine tuning and typically what you do to one corner will affect the diagonal opposite. If I want to raise that low right rear corner I wouldn't drop my diagonally opposite front would I?

My car also pulled to the left BADLY, both when lifting off the throttle sharply & braking. As my tyres were quite worn my local Porsche specialist recommended fitting new tyres before doing the wheel alignment. To my amazement this solved all my handling problems and it no longer pulled to one side! May be worth a look if the tyres are worn or even old as they can distort over time.

The tires are brand new. I just got them a couple months ago. It was shortly after I got the tires that I did the suspension work and had it aligned.

You need a cornerbalance

echrisconnor:
You make a compelling counter-point...
Correct...I didn't say you *absolutely* had a heavy RR...read again, please..I said "presume" it is ( which it indeed "may"be). From that ...I postulated the rest. Yep...you're point is valid too, we won't know for sure which way it'll go until you check the two possibilities of CB problem or brake caliper problem.
Best,
--Wil Ferch;)