24Chromium

As you may have read in an earlier post, I found I was missing my left rear brake duct on Gisele. Here is how to replace it:

1 - Be sure to order all the bits. I had to make 3 trips to the dealer in order to get all the parts, not to mention the right parts (see prior post on this topic).

2 - Jack the car up and place it on 4 jack stands (you don't really need the front on jack stands, but then again, you don't want to damage your splitter now do you?

3 - Assuming you still have one duct in place, take a good look at how it's held on. It is a two piece affair, with a plastic clamp sandwiching one of the suspension arms, with the duct held by two screws on one side, and three tabs on the other, via the clamp.

Here is a photo of the clamp:



This is the duct:



Here is a close-up, so you can see the p/n:



This is how these two parts fit together:



Here is the existing brake duct (sorry for the lousy picture):



You can almost see the two screws, just to the right of the large bolt with the red marking on it.


The hardest part of this installation was getting the screws started. The screws use a T30 Torx bit. I wasn't able to get a screwdriver onto the screws, due to the very tight confines of the car. I purchased a T30 socket bit for my 3/8" drive socket wrench. Once I got the proper tool, it was dirt simple easy.

My parts guy ordered a small strip of foam with adhesive. However, I found that the duct already had the same size foam on it. I chose not to add the extra strip of foam, as the existing duct was a little floppy. I could easily jiggle it with my hands.

As I stated in my earlier post, be sure to get the right parts. The PET manual shows a completely different duct in addition to the correct one for the 2010 GT3. AFAIK the ducts are the same for the GT3, GT3 RS and GT2 RS.

Polarporsche

Thanks for the information, I lost one last week at Race City in Calgary due to the heavy rain and sitting water on the track, tore the brake duct off the passenger side. One of the other instructors picked up the duct from the track so I only needed to replace the mounting bracket/clamp.

It's on my to do list for this coming weekend.

Cheers

Russ

24Chromium

Yeah, it's interesting that I found one missing. Last time at the track (well, actually, the last two times) my brakes didn't feel good at all. The pedal was getting way too deep and I was having trouble slowing the car and blipping the throttle. My last track outing was a 3 day event and I was already overshooting the hairpin a couple of times on day one, so I put her up on jack stands to sort it out. I was shocked at how much air I found in the lines when I bleed the brakes. Way more than I've ever seen in my entire experience!

Now I'm thinking that maybe my missing duct was the culprit. Kinda hard to imagine, since it was the rear duct, but... ?

TRAKCAR

Lar, this maybe common knowledge, but it was news to me; When you blow out the rotor holes (I never did) it also feels like you bled the brakes..
Now I have slotted fronts, so the difference might not be as much with blowing out the rears only.

The air was there, air does not get into the line because of no ducts.

24Chromium

No... I'm thinking that because I went missing an air cooling duct (I may have lost it at Sears Point during an "off track excursion" - or even the event before that), I may have overheated that rotor and caliper. Then in turn, the brake fluid boiled and that's what caused there to be air in the lines.

24Chromium

I have to say, my brakes were pretty tip top this weekend at Thunderhill. I was overbraking on every corner! So, it seems to me that missing a rear brake duct is a big no-no if you track the car. I probably knocked it off quite some time ago (had a few off track excursions this season - gulp!) and that was causing my fluid to boil and I was always having to adjust my braking points as the track day progressed and the pedal kept going deeper.

Check 'em after every off-track and "bottom-out" on the public roads.

Larry Cable

The ducts were added to the .2 (and can be retrofitted to a .1 although you will have to cut or change the duct shields to obtain the full effect) to rectify the heating problems that the .1 cars experienced with the changes that they made to the initial brake bias on the 997 cars (vs 996).

Tracking a .1 or .2 without the ducts *and* with TC on will result in the rears overheating (esp on slower tracks where EBC may have more opportunity to be applied more often)

You should also ensure that the drill holes are not blocked while tracking as this effects the ability of the rotor to vent hot (pad) material and gas effectively also!

Larry Cable

that's wierd I am sure when I retrofitted these to the .1 that it was a std Mx bolt

Terry L

I am about to order my third left rear brake duct. They keep falling off at the track and someone runs over them. I don't think it's from hitting curbs but who knows. The last one fell off in the Lightbulb at NJMP, a long, smooth righthand carousel which puts a ton of pressure on the left rear but I don't know why that should displace the duct. The right one is safety wired and has stayed put.

Larry Cable

torn off ... or do you need to locite the bolts?

Terry L

Don't know since I have yet to see the carcass. Maybe this time I can recover it from the track.

Larry Cable

kinda weird that its the same side every time ... does it come off at the same place on the same track?

I can see how they could be "destructively" torn off ... if the car bottoms out and the leading edge of the duct makes contact with the ground ... only other way is for the nuts to come loose!

ir_fuel

I have to disagree. I drove more than 6 months without one of my rear brake ducts. Did a lot of trackdays and had no issues whatsoever. And no I don't have grannies in wheelchairs overtaking me on track

mateush

Sorry to bring this old thread back from the dead, but is anyone using the OEM GT2/GT3RS dust shield (backing plate) with the ducts?

I know that you can trim your existing one but maybe the OEM have some other benefits.
As far as I know the part numbers are: 99635280130 & 99635280230

Larry Cable

the big problem is that its a major task to remove the .1 dust shields and replace them with the .2 OEM shields that are already "cut"...