doruiacovescu

Hello! I found this brake calipers. 86.5-91 brembo -Part# 92835142203
The part number for the big blacks are 928 351 423 03 & 928 351 424 03
Anyone knows if they do fit properly on a 90 c4? Are they big blacks? THe PN is not actually the same as the big blacks's. What s the difference beetwen them?

TAI2

Please double check but I think they are the same except the hard piped brake line on the caliper is mounted on the opposite side of the caliper vs. the 964. This line can be moved and then you should be good to go. The 928 had the caliper on the opposite side of the rotor as the 964. Please check me on this as this info is second hand.

doruiacovescu

The first ones are using the same pads and pistons as the big blacks? What is the differnece between them? Thank you!

sleder

why not go with Big Reds?

Bill Verburg

It's unclear to me what you are asking about

there are several different calipers that you can use for a 964 bbk

there are 3 basic sizes, some black, some red come silver, color is not a good identifier

the largest caliper uses a 132x58mm pad and came in red leading mount or black trailing mount, the 964 needs leading mount so the trailing mounts need to have the bleeds and feeds swapped.

the big caliper uses a 132x48mm pad and for front mount came in black and silver, and black for trailing mount, again for use on a 964 the trailing mount calipers needs to have bleeds and feeds swapped. 928 351 423 03 & 928 351 424 03 are black trailing mount calipers in this size class, note that they are not the larger aka "Big Red or Big Black" other calipers in this size class are the 993 front and 965 3.3t front and 964RS front. All the 964 and 993 calipers are leading mount, the are all hydraulically equivalent and all use the same pads. The difference is in the rotors they will want. the 964RS and 965 3.3t will want 322x32mm rotors the others 304x32mm rotors, there are several different 322mm rotors some are 2 piece some one, some have 964 o/s some 993. There a re also several different 304mm rotors. All can be used but you need to be careful is selection to have matching components.

all of these above fronts will want 993 rear calipers and a bigger 23.8mm 993 m/c

doruiacovescu

Yes, forgive my lack of accurate description. Recap
1. These: 86.5-91 brembo -Part# 92835142203 are big blacks?
2. I understand thath these: 928 351 423 03 are exactly like big reds and they are big blacks. Clarify me on this.
3. What s the difference beetwen first caliper and second?

cobalt

The 86.5 -91 brembo brake is known as the medium S4 not the big blacks used on the 92-95 GTS's. The GTS was the first Porsche to receive the large black calipers later painted red known as big reds or big blacks. These as Bill stated used the larger 58 x 132mm pad vs the medium S4's, 993 N/A and early 91-92 turbos that used the smaller 48 x 132mm pad. The brakes from the 928 aka known as the medium S4's came in several different casting designs over the years but all used the smaller 304 x32 mm rotor and came with the same 44/36 pistons. The medium S4's that were used on the 91-92 turbos had the same pad and used same pistons but a larger 322 x 32mm rotor.

The only big blacks came on either the 94 turbos which could be special ordered in black instead of red and the 928GTS which all used the same 322x32mm rotor but the 928 had a non-crossdrilled version.

So what you are looking at ar not big blacks but medium S4's

Hope this helps.