gota911

I need some advice or help about a brake issue.

My right front wheel collects about twice as much brake dust as the left front wheel. I have had this issue since I got the car. My local Porsche dealer has already replaced the right front caliper, but that did not resolve the issue.

I installed Hawk low dust pads on all four corners about 10 months ago, and while the brake dust has diminished by 65%, the right front wheel still accumulates twice the dust that is on the left front wheel, an obviously much more than is on the rear wheels.

A couple of months ago, I removed and rechecked the right front pads and found an extra pad backing plate on the inside pad, which I removed. This seemed to be causing the right front drag ever so slightly. The right front no longer drags, but I still get an excessive amount of brake dust on the right front.

Both front brake ducts are in place, so it probably is not an air cooling issue.

I am at a loss of what to do next. What could be causing this?

Your thoughts about the cause and potential solutions would be greatly appreciated.

Thanks,
Tim

997_Toronto

Wheel Alignment? Do you see any excessive wear on the right front tire?

ltcjmramos

Did you measure the pad thickness to see if there's a corresponding more pad wear? Might just be airflow is greater on one side compared to the other.

gota911

Wheel alignment was completed about 9 months ago and I did not notice any excessive wear on the right front tire.

I did install A/S (all season) tires in November to get me through the winter. However, with the previous tires, which were Michelin Pilot Super Sports, I did not notice a different wear pattern on the right front compared to the left front. Both of the front tires had about 31K miles on them when they went to the tire grave yard.

gota911

No, I have not done that. I still have the OEM pads I removed when I installed the Hawk pads. I recall that the OEM front pads had about 75% life remaining on the pads and the rears still had about 95% of the original pad thickness.

I will measure all four OEM front pads when I get home tonight.

stronbl

Three things generally contribute to brake dust - pads, brake discs, and caliper piston force. Speed and heat are also factors, but we can probably rule them out for this exercise. The use of a differential analysis can be helpful in determining the cause(s) and then the remedy. Unfortunately it is also trial and error. Here's how I would approach the problem ...

How old/new are your discs? Use a micrometer and measure disc thickness for inside/outside surfaces on both right and left sides and compare them. Thoroughly inspect the discs for signs of abnormal wear (ridges or diagonal undulations) or cupping. When you inspect the pads, also check for signs of an uneven wear pattern on the right inside/outside and compare it to the left inside/outside wear pattern. Although the differences may be very small, like millimeters, that can be enough to cause excessive wear on a side. You may also want to consider replacing both front brake discs and pads, in other words, start fresh and see if you still have the same issue. If so you probably have a piston problem with your caliper.

I would also have suggested a thorough cleaning of the caliper pistons, get out dirt, grease, etc. but since you have had a new right caliper installed, and saw no difference (i.e. you have attributed the less brake dust to a pad change) perhaps there is not a caliper piston issue. But if you do replace the discs, and while the calipers are off, retract the pistons into the calipers, right and left sides. then re-attach both front calipers without any pads to the wheel (you need to bolt each caliper back to the wheel housing otherwise when you press the brake pedal, you may get some torque on the caliper and mess up your brake line). Press the brake pedal one cycle - should be very soft - and check your calipers now. You should see how far the pistons have extended. Visually note any differences as it may be difficult to measure accurately. I have a small flexible metal tape measure that I can insert into the caliper housing and measure the pistons, but even so, getting an accurate reading takes a lot of patience. Again, this is a check to determine if you have a caliper/piston issue.

All the above is pretty easy and straightforward if you are a DIYer. If not, you may find it rather expensive to have a shop do it for you. Good luck.

Wayne Smith

Just a thought to the side. When I lived in snow country, the right side of my car was always dirtier in the winter. Just the way the dirt came up from the shoulder. This affected the front more than the rear. I didn't see details on you usage. This may not apply.

ADias

That's what I observe. All my cars have dirtier right side wheels.

gota911

The original front OEM pads were on the car for 49,xxx miles. I did not mark them so I don't know which were on the right or left side, inside or outside. The thickness of the pads are:

1. 13.6 mm
2. 14.1 mm
3. 13.9 mm
4. 14.1 mm

While pad #1 is is 0.3 mm thinner than pad #3, I am not sure if that is enough of a difference to be indicative of the problem, since all pads have 49K miles on them. If that tells a different story than I am inferring, please let me know.

I understand and agree with the "right side is dirtier" situation. While this may be some of the cause, it is probably only about 10% of the difference between the right and left side.

My car is my daily driver and now has 60,300 miles on it. Weather permitting, I wash my car each week. In cold or unusually rainy periods, it may not get washed for two, and on rare occasions, even three weeks. During the extended "no wash" periods, the difference in appearance between the right front and the other three wheels becomes extremely pronounced.

gota911

Thanks for taking the time to write the above. I really do appreciate this and all of the comments and questions from other Rennlisters..

The disks have 60,300 miles on them. I have noticed that the right front is a little more scored than the left front disk.

I should be able to do the inspection of the pads and disks, as outlined above, this weekend.

Able1

I have had a brake hose cause the symptoms you are describing. Since you already replaced the caliper I would check the hose next. How I check for this is when you return from a trip ( so the brakes are warm) jack up the wheel you are having an issue with and have someone apply the brake and release while you are trying to spin the wheel, as soon as the brakes are released the wheel should immediately turn, if it does not you have something hanging up the pads, since you already replaced the caliper the hose would be next, as long as the caliper was replaced properly to begin with. Hope this helps.

gota911

Able1,

Thanks for the hose idea.

Was the hose kinked?

Did it have a pin hole sized leak?

Petza914

Just replace your hoses with braided stainless lines and you'll elimnate the hose as a potential issue, while also getting better brake feel and a firmer pedal. Your original rubber brake hoses are now about 9 years old and the problem with brake hoses is that the rubber swells over time. Most people think if theire aren't visible cracks in the exterior rubber that the hoses are still OK, but when the swell up internally, they can restrict the flow of brake fluid both to and from the caliper pistons and that can manifest itself as a pull when first applying the brakes since one side may flow better than the other or as a stuck caliper since the pistons can't quickly force the fluid back when you release the pedal pressure.

Obviously, opening up the system to change the hoses will mean a full brake system bleed is necessary, but the good stainless lines have teflon linings, which don't swell like rubber so it's an upgrade that should last the life of the car. Get staiinless lines that have a coating over the stainless braid which makes them much less abrasive on anything they might come in contact with - most have this, but some don't.

I have Speigler kits on both my 997s (from Essex Parts Services for $142/set) and the lengths were perfect and end-fittings completely compatible so a straightforward swap without any problems.

gota911

Pete,

My car is a 2010 so my hoses are about 5 years old, not 9. However, I get your point. Since I have never changed out brake fluid, I am not sure I want to use my Porsche to learn how to do it, especially since it is my DD. If I screw it up (hey, **** happens), I will have no mode of transportation.

Macster

Based on the scoring I would attribute the extra brake dust on the right side arises from differences in the two front rotors. The right rotor is probably softer than the left rotor. Add in the fact the right side is going to be the dirtier side...

With my Boxster I have over the years noticed some brake rotor/pad combinations generate more dust than others. (The current brake hardware is a really dusty combo. The front wheels are almost perpetually black from brake dust.) Also, brake hardware life varies, too. I attribute this to differences in rotor material hardness with possibly pad hardness or composition differences contributing. Not every set of rotors and pads are from the same OEM even though I buy the brake hardware from the Porsche dealer (but not always the same dealer).

In the case of your car it could be it somehow ended up with two dissimilar rotors.

Assuming they were both replaced at the same time, one explanation is whoever pulled rotors off the parts shelf just happened to get two rotors from two different OEMs. Rare but it can happen.

If you are that bothered by the dust difference you could I guess elect to replace the rotors and pads this time making sure the rotors are the same as are the pads.