Hi,

just curious if anyone had something like this ever before, when car is cold and before I step on brakes hard for a first time - sometimes, but not all/every time when I braking on regular way car jumps to the left. Looks like left front brake engages fully and right does not. if after that I hit brakes reasonably hard it cures and never happens again for a whole day, or sometimes even on a next day. But it has repeated often enough to be noticed. Steering wheel while this happens turns with enough force - if I keep my hand too loose it can actually jump off my grip. Brakes were flushed 2 weeks ago.

When it happens and I notice that - if I brake mildly several times it shows in same way - steering wheel is trying to jump to the left when I`m 'knocking' at brake pedal. And then I give it more solid press and right side brake engages fully.

So after it is gone there are no side effects left at all - braking is equal on both sides, there is no difference in caliper temperatures, brake pads are worn on exact same progression, there is nothing that could show any issue. No vibration while riding, acceleration is ok, alignment was done too, car behaves as perfect and as normal as it can be. So it does not seem as a total classic caliper malfunction or stuck slave cylinder. Not sure.

As it happened this morning I let it stay for an hour then tried it again - no, does not repeat. It only seems to happen when car was idle for some reasonably long time.

I called dealer today - they naturally never 'heard' if caliper may act like this (porsche calipers never fail?!) so they cannot say, naturally, if any work on such an issue will be covered by warranty by default or not (naturally) and my gut feeling is that if I give them my car with current half way worn pads and rotors they will fix actual problems then replace pads and rotors, bill me for a whole thing and blame it on pads or braking fluid, or similar.

So, what would be best approach for this? Just to wait it out until time will come to replace rotors and brake pads and if after that it will happen again - go to the dealer? Is there anything at all I could diagnose myself by taking caliper apart? Or is reason for such a problem would not be a caliper at all but may be some sort dirt particle somewhere inside of hydraulic lines?

Or is there anything on a right car side that may drip or condense on right brake disk and not a left one? I am not sure what to guess, it is quite weird.

Any ideas?

PS. car is 06 997.1 C2.

 

And if it may be something related to hydraulics - how can I check it? Garage floor is perfectly dry, there are no leaks I could see, brake fluid level does not seem to reduce at all.

 

take it in and let them figure it out. Since it was recently flushed, I would suspect air in the caliper or near it in the line - but it is also possible that they didn't flush the clutch or ABS properly. New pads and rotors will reduce pedal travel and make it all feel firmer, but they will not correct a side-to-side problem unless your right side pads are covered in fluid (did they spill it all over them?) or grease or are otherwise badly damaged. Pads should not have been removed for the flush, btw, so it is unlikely that anything changed that impacted the pads or calipers directly other than air in the lines. I'm certainly no expert on this - just my thoughts.

 

Well, issue was there before flush - I forgot to articulate that, my fault. It started happening some time mid-summer.

Flush was done not by a dealer - I have independent Porsche shop nearby. I would assume it was done properly, fluid was replaced, clutch also flushed. As of ABS - not sure, I think there are only 5 lines there, 4 lines for brakes and one for a clutch. Not sure how can I suspect air in the system if it was properly flushed.

I am generally trying to figure out what is it I can do myself and what can be left for dealership to investigate. I spoke to them preliminary and my feeling is there are definitely plenty of chance that they will find a way not to put it under warranty. I definitely do not want to pay more than $500 for solving this non-sense as it is not something that affects car badly.

Just went to suncoast - got this stuff to try to fix caliper, if it is a caliper. Brake pads were due anyway, they had 2-3mm left before sensors would touch rotors.

99635108801 Front Brake Pad Damper 2 $18.68 $37.36
997C2C4FRPD Carrera Front Brake Pads 1 $130.33 $130.33
PadSet: 99735193903
987ScFrontKit Front Caliper Repair Kit 1 $23.25 $23.25
style: 95535296000
99907340201 Caliper Bolt 2

 

The fact that it happens intermittently will make it hard to replicate and isolate the problem. Could be a pad issue. Could be a sticking caliper. Could be tire pressure is way off on the left front. Could be a crowning on the road. Could be ...

 

I know, it may be a lot of different stuff. That is why I want at least to try to do something myself prior to surrendering it to a dealer.

Tire pressure is fine, road is not the issue. It happened 5-7 times already on different roads.

Pads I`ll replace. But, well, what can I do to a caliper other than to use that caliper repair kit I ordered already? Clean its pistons holes with MAF cleaner aerosol?

 

Dealer sounds like best approach if still in warranty. But, if you want to do it yourself I would suggest:
1) double check those tire pressures - often overlooked cause of this issue
2) change front pads - since you plan to anyway and clean the rotors with brake cleaner in aerosol can
2) rebleed the brakes - could have air on one side (away from the pull) that gets compressed and less impact after you have pumped the brakes a few times. In fact, you could test this by stepping on the brake firmly several times before you start to drive - does the peddle get noticably firmer? When you then go for a short test drive do you get the pulling as badly as usual? If not suspect air in the system.
3) If these steps don't help suspect a caliper problem and head to the dealer - would recommend against servicing caliper/pistons yourself if not experienced.

 

I didn't notice your mileage. You're ready for new front pads?

 

Mileage is 44K miles. Pads should be ready, again, as I said - 2mm or so is left from sensors plastic caps to a disk.

BTW I drove car today - not a sigh of a problem, everything was perfect. Lazy piston most likely, or dirt accumulation in piston shaft. I do not want to think it may be something with hydraulics. Will see how it will go with new pads and clean caliper.

 

Wish I could offer something, but it seems like all the usual ideas are there already. Assuming all wiring is intact that could affect the ABS system.