[Scuba]

So the PPI on the new to me track car ('83 SC w/ "993 front brakes") included that it would need new front pads before going to the track.

Since I intended on taking it to Dominion tomorrow, I did a quick check of the pads this weekend. Driver's side looked great, so I was about to let enthusiasm take over and just go ahead with it, but decided to check the passenger side for piece of mind. Outside pad looked just like the driver's side, with plenty left, but the inside pad was worn all the way down - strange...

I peeked behind the rotor and found the outside 1" of the circumference was scored down with a noticeable lip. So, I pulled the rotor and made a quick trip to get it turned down.

I found the cause of the ground lip on the rotor:




Here's the condition of the pads in the caliper - it almost looks like the rotor may have been rubbing against the caliper as well:




I didn't remove the bearings from the hub before running the rotor/hub out to a shop to get it turned. The bearings fell out while on the lathe, and the shop balled them up in a rag to send them home with me.

After cleaning out the hub and bearing to repack it, I checked the '83 parts diagrams to look at proper reassembly, and I appear to be missing some parts - all I have is the bearing seal (below - which appears to be crushed), and the inner bearing.




I'm not sure if they were ever in there, and that's how the rubbing against the lower A-arm occurred, or if the shop didn't return them - regardless, I've got new parts on the way.

The things I'm unsure of are:

- Is this a 993 caliper?

- On a 911SC rotor and hub?




- I'm thinking improper assembly of the hub (probably a missing spacer) is what allowed the rotor to rub the lower A-arm - or, is there some failure of the caliper that may have allowed this?

[Scuba]

Should be tearing down the other side tomorrow night for comparison purposes, but curious if anyone can ID the rotor, and tell whether the caliper may be malfunctioning.

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[Fumes]

take to intersport. done!

[Trak Ratt]

Pic of Caliper please. Also, what size rotor (diameter and width). Most BIG brake mods on SC/Carrera spindles require adapters for mounting caliper to spindle and spacers for using the appropriate larger calipers. Google big brakes for SCs to see what I mean.

I did mod a set pf 944/964 calipers to work on the front of my '82 SC w/o adapters. But had to run stock '84 to '89 Carrera (24mm vs, 20mm) calipers. But anything bigger would require adapters and spacers.

[Lupin..the..3rd]

Those are not SC rotors, they're some kind of aftermarket kit. Stock SC rotors are a single cast piece, but these are two piece, hat + rotor. Since you just had them turned, they probably don't have a lot of life left. Did the seller provide a source for replacements? The uneven pad wear likely means a caliper rebuild is in your future too. Good news is that it's all bolt-on stuff, so you could easily put it back to stock if need be.

[BlackTalon]

Ah, nothing like a used track car...

For some of the brake kit 'upgrades' a spacer is needed behind the pads as the backing plates are not thick enough for much of the actual pad to project beyond the caliper. not sure if that is the case here or not.

[Dr K]

The hub looks a lot like my old Carrera (and prior to that SC) hubs. But I haven't seen a 993 hub so I have no idea if that looks like a 993 hub, too. I can't see where George was noting a 2-piece rotor. It's possible those screws around the outside of the hub are for a backing plate which is part of a brake cooling kit that blows are inside the center of the rotor, with the backing plate to keep the air from going out the other side so it's forced out between the 2 sides of the rotor. I had something similar on my '86 race car.

I'm big on DIY, but with the possible missing parts, certainly FUBAR'd present parts, and non-standard setup on a new-to-you car, getting Charlie, Artie, or others in the gang to weigh in with the car in front of them could save some expensive parts (struts) and lives (yours). Hate to have to agree with JD but perhaps just this once...

[Vicegrip]

Balls? Front wheel bearings are caged taper roller bearings. You have something unsafe going on here. Take the other side apart and compare. Considering lack of inspection and service shown here I would be inclined to do a full sort of the brakes and go over the susp with care.

[smdubovsky]

Take a pic of the back of the hub/rotor too along w/ the others requested above. Agreed those are some sort of aftermarket rotor/hat. 993 brakes can use a 930 turbo rotor setup so I wonder if thats the 'specs' its using. There are lots of common parts swap combinations possible on 911s. For example, I have 993 'little reds' on the front of my 911SC using 930 hubs and rotors. Two pc OEM 930 rotors are pricey buggars so many use an aftermarket hat to utilize commonly available less expensive rotors from coleman/wilwood/etc. The combination is chosen to mimic the factory rotor size and spacing.

Ask the PO what brake rotors are on it for when its time to replace them. He will surely give you the source if he remembers. Will save you a ton of sleuthing.

[Chopper Dropper]

Also rare to see rotors turned on Porsches usually when badly scored or developing a lip it is time to get new. Seeing your brake unknowns there, I would minimally do a complete tear down or take it to a good shop.
Dirk