View Full Version : Passat B5 4motion rear brakes to A4 B5 quattro

05-07-2012, 11:40 AM
Hi everyone,

I have an A4 B5 1.9 TDI quattro with some engine modifications And I feel like I need better brakes. I already upgraded the front brakes to A8 312mm rotors and I want to upgrade the rear to 269mm A8 rotors. I know that for this I need S4 b5 calipers to keep parking brake function without modifications A8 carriers and rotors.
I searched a little in ETKA and I found that Passat w8 has 269x22mm brakes on the rear and I found a one on the local market. The problem is that W8 calipers are different PN from S4.
S4 are (LEFT) 8D0615423C, Passat W8 4B0615423 (same as A6 4.2L). Carriers are common for all 4D0615425B. The brake system is Lucas for S4, PW8 and A6
and from pictures, the passat and s4 looks the same, regarding parking brake system.
If the carriers are the same for all of them, even for A8 (2000y) which has 269mm rotor, the offset should be ok. A seller from ebay, who sell W8 brake kit says that is suitable.
What can you say?
the picture is with passat caliper http://i1061.photobucket.com/albums/t471/arazvan2002/Masini/passatw8rear1.jpg

05-07-2012, 01:03 PM
They should work just fine. Like you said, they use the same carrier and that is really what matters, and they use the same rotor. The W8 also uses HP2 front calipers (same as B5 S4).

Your other option is to go with our 300mm rear kit, which uses B7 S4 rear brake rotors and B5 S4 calipers, but you would want at least a 330mm front rotor BBK to maintain braking balance.

05-07-2012, 01:18 PM
Thanks for your answer. I'm very glad to hear this because I found already a complete kit from a Passat.
330 front and 300 rear would be nice, but the cost would be much bigger and as a daily driver I can't run on 17". Bad roads :D 312mm front with 269mm rear would be great from what I heard.
I think I will buy the complete kit and after that, a metalic brake line kit and Motul RBF600 brake fuild, or maybe Castrol SRF. What you recommend?
Now I have Ferodo dot 5.1 brake fluid and after few agressive brakes it boiled :D

I found that the offset of the Passat disc ~54mm is bigger than the Audi a8 or s4 ~46,4mm. That means I don't need the washers included in the following receipe:

269mm x 20mm rear A8 upgrade kit will work on the following cars:
A4/S4: AWD, 1.8T + 2.8 + 2.7T (No calipers required for the S4)
A6: AWD, 2.8 + 2.7T
allroad: AWD, 2.7T
Passat B5: AWD, 2.8

Parts required:
Two Audi A8 269mm x 20mm vented rotors: Audi Part# 4D0-615-601-B
Two Audi A8 caliper brackets: Audi Part# 4D0-615-425-B
Audi S4 left caliper: Audi Part# 8D0-615-423-C
Audi S4 right caliper: Audi Part# 8D0-615-424-C
Four 2mm washers: (~$0.05 at a hardware store)

I think Audi is using another hub than VW for these applications.

05-08-2012, 05:32 AM
As we discussed through PM...here's a post I made in a previous thread......

I don't know the exact formula to figure out bias and stuff because there's way too much involved in figuring it out. Due to piston size, number of pistons, the Hydrualic Pump setup...all those things matter.

All I did for mine, was figured out how much the increase was from stock front rotor size to the upgrade and applied that factor to the rears. I actually ended up with full A8 brakes. 312 up front and 269 out back. The 269mm rotors fit under the S4 rear calipers with A8 carrier brackets. From what I can tell it is a very balanced stopping method. You can go bigger if you want, but you have to remember that if you go huge you really should look into changing the master cylinder and maybe even the hydraulic pump.

Incedentally, if you ETKA the parts, the only thing that's different between the A8 and the A4 is the master cylinder. All other system parts are the same....everything bolts up with the right carriers!

05-13-2012, 05:42 AM
I bought the Passat w8 kit second hand. Everything is fine but the Passat rotors have a bigger offset 56mm. I need to buy A8 rotors with 46mm offset and it will be fine. I need also Passat brake lines, the last rubber line to fit caliper. I has other model than original line. They are just fine with 16" wheels.
Thanks for support :)