johnsopa

Earlier this year, I had to replace the lower half of my passenger side rear brake duct due to driving in the grass at NJMP.

While detailing my GT4 over the weekend, I just realized that my drivers side rear brake duct is completely gone -- including the "support" piece that attaches to the brake duct from the top side of the lower control arm (or "wishbone" as Porsche calls it).

So, I get the spare parts that I ordered from Suncoast out of the box. Bummer, no screws are included (you'll need two M6x10 screws per side).

Just out of curiosity, I checked the two screws on the passenger side. They were loose and about to back out completely, which means I would have lost the entire passenger side rear brake duct assembly.

I went down to the local True Value hardware store (they happen to have a LOT of metric fasteners, unlike Home Depot or Lowes) and picked up up the following for each side:

• 2x M6x12mm socket head screw (longer than the stock 10mm due to using the washer
• 2x M6 lock washer
• Loctite (Blue 242)

I suggest checking your brake duct screws and possibly using a drop of Loctite and a lock washer on each before retightening them.

Also, below are the part diagram and list for the rear ducts.

The duct is #30. The upper support (which goes on top of the LCA) is #31. The screws are #32.

gmaki

My passenger side duct is also completely missing, so I must have fallen victim to the same issue. I zip tied the driver side but did not check the screws. Thanks for the info, now I know I need to check the driver side as well!

blackmist27

its really strange that on a car that costs this much we still have to worry about these types of things. not a huge deal i suppose however its not easy to get under this thing unless you have a lift.

DrPhil Gandini

An access question: can these screws be checked while the part is on the car, up on a lift? Is there easy access to confirm the screws are secure?
Thanks for the heads up!

Mech33

Thanks for the heads up. I am going to loctite these suckers.

Knolow

Thanks for the head up. I'm going belt and suspenders... Loctite for the screws/bolts and zip tie for the the bottom half.

johnsopa

Access is pretty easy. I have a lift but decided just to put the rear up on jack stands.

I also decided to conduct a test. Left duct gets duct tape only. Yellow because I have PCCBs. Lol. Right side gets duct tape and the preciously mentioned zip ties.

Both sides got the lock washers (probably not needed) and loctite.

I think the problem is two fold. Number one, these things are dealer installed before delivery. Loctite should be spec'd. Secondly, this is a so-so design. If the bottom half of the duct is supposed to be sacrificial then offer it as a separate part.

All of the pics below were taken from under the car tonight.

johnsopa

Hmm. No pics. Here you go...

Joegnsx

You sure these are not getting knocked off...then the screws get loose...?
These are very low.

Voyager6

I have 997 GT3 versions on my 981 S. I have lost one from each side at different times. I used lock washers, but no loctite as it won't help. If you notice the part that goes over the control arm, the side opposite to the screw holes has three fingers that slip into the lower duct to hold that side in place. A good whack on the duct will cause the fingers to slip out of the retaining holes and away goes the duct regardless of how permanently tight the screws are.

After losing the first, I used two zip ties criss crossed over the LCA and under the ducts. Still didn't save it.

WonderWagon

Was the theory that these were designed to breakaway easily disproven? Thought I read something about that here.

paradocs98

I was just wondering that based on Voyager6's post. If the ducts get so firmly attached to the LCAs that an off-track excursion or hard curb whack can't knock the ducts loose, will the force of impact get transferred to the LCAs?

paradocs98

I've also noticed something interesting about the front air ducts for the brakes. There are two pieces--a lower scoop to direct air, and a separate, larger upper scoop that appears to direct airflow within the wheel well. This upper scoop is securely fastened by two screws at its bottom portion and a single screw at its top portion. This single top screw fastens to a small metal bracket that allows the scoop to jut out into the airflow. What's interesting is how the screw fastens to the metal bracket--it is secure, but the receiving end on the bracket appears to be designed to allow some play so that the top portion of the duct can move a bit. I confirmed that the screw is tight, and this is the same arrangement on both sides. Not sure why the duct should have play in its attachment, but there must be a purpose...

Should have taken a picture to show...

Bill Lehman

I checked my brake duct screws today while doing a trial wheel/tire fit. There actually was evidence of a purple thread locker at the very top of the threads however, once the screw broke loose, there was no resistance on the way out. I cleaned the threads and used Blue thread locker. Thanks for the tip John.

MVEED3

I observed and did the same as Bill along with the added zip ties.