Caliper change

[KarlS]

I need to install new calipers on my Cup car. It uses the same calipers as the 996 TT. I've removed calipers before but not swapped them. I'm guessing there is an ABS connection to remove and the brake line. Any tips on the brake line, esp. how to keep brake fluid from going everywhere?

Karl

[clord]

Karl.....You should not have to deal with the ABS connection. It is just a wired slug that plugs into the hub carrier, the end of which is close to the toothed ring inside the hub. The caliper change won't interfere with the ABS slug/plug. As for the brake fluid line connection it will leak all over the place unless you find some kind of plastic plug to stem the flow. I keep a collection of various plugs and caps for such purposes. You can even buy a set from tool suppliers such as SnapOn.

Note that the factory would have you replace the socket head (they call 'em cheesehead) bolts that hold the caliper to the hub each time you remove them. They come with a bit of goop on the threads to sort of lock them. I have never done so myself....but, have used a bit of blue locktite. Loren can quote you the torque settings.....important since you have steel bolts into aluminum hubs.

[Loren]

Karl,

This is from page 53 of the Cup Car Service Manual

Bleeding of the brake system

Procedure is as that of the 911 Carrera (996) production car.

Description in workshop manual.

Notice concerning four piston brake caliper

Mounting information

The brake caliper halves may not be separated from one another.

Piston seals, dust scraper rings and spring steel plates can be changed when the caliper is completely assembled.

Repair kit number: 996.351.919.91

Consists of:

1 piston per diameter with the corresponding seal.

Dust covers are not replaced.

The zircon oxide inserts are very brittle. Therefore, the brake pistons should not be pushed back into ‘new pad’ position using pliers, screwdrivers etc.

When mounting the brake caliper pistons the brake cylinder paste, 'Unisilikon' TK 44 N 2, must be used.

(This applies retroactively in the case of repair of other brake calipers).

The 'Unisilikon' paste is available as a spare part (ET-Nr. 000.043.117.00 / 50 g tube).

To remove the spring steel sheets, the mounting screws must be heated to approximately 150 degrees C with a hot air gun because the screws were fitted with an safety adhesive. When re-fitting new screws should be used and the threads thinly coated with Loctite 270.

[KarlS]

Note that the factory would have you replace the socket head (they call 'em cheesehead) bolts that hold the caliper to the hub each time you remove them.  They come with a bit of goop on the threads to sort of lock them.  I have never done so myself....but, have used a bit of blue locktite.  Loren can quote you the torque settings.....important since you have steel bolts into aluminum hubs.

Yeah, I never replaced the caliper bolts on my 996 either and I had them off many times. However, I didn't use Locktite, I always used a copper anti-seaze paste. My understanding is that with steel into aluminum, w/o the anti-seaze you run the risk of the steel bolts bonding to the aluminum under high heat.

Fortunately, my Cup car has studs in place of these bolts for fast caliper changes during endurance races. So all I have to do is loosen a couple of nuts to take them off.

Thanks for the Snap-on tip.

Karl

[KarlS]

Loren, I'm replacing not rebuilding the calipers, so I don't think any of this blurb applies. BTW, no one seems to stock these things. I called the 5 largest dealers I know of plus all the local guys and no one has a set of TT calipers in stock. FYI, Suncoast and Brumos gave me the best prices. Champion was the highest. Amazing how there can be so many different "list" prices for the same part.

Karl