B5 S4 Brake Conversion for the B5 & B5.5 Passat

Purpose

Install B5 S4 brakes and wheel bearing housings. The following OEM brakes will mount without custom brackets:

• B5 S4 HP-2 321x30mm rotors/calipers [VAG OEM]
• Touareg/Q7/Cayenne calipers and (modified Mercedes Benz C240 330mm or ML55 350mm rotors) [VAG/Daimler OEM, Shouldered bolts]
• B5 RS4 360x32mm rotors/calipers [VAG OEM]
• B7 RS4 365x34mm rotors/calipers [VAG OEM]

This installation will focus on installing B5 S4 brake rotors and calipers. If you prefer to source different calipers and corresponding rotors, you can still follow this guide for the wheel bearing housing portion. If you go bigger than 321mm, consider the effect on brake bias. Also, verify that your wheels will clear whatever upgrade you are doing. 16” wheels are too small for all of these brakes. It is possible to grind down the HP-2 caliper and/or install wheel spacers in order to make it fit if needed, but most 17” wheels should clear.

Audience

These instructions are for Passats with 82mm wheel bearings only:

• V6 & 1.8T B5.5
• V6 B5

If you have a B5 with 75mm bearings (engine code AEB/ATW/AUG), replace your axles first with B5.5 axles. That procedure is not covered. I did not research the brake conversion for the TDI.

Required Parts

(2) B5 S4 wheel bearing housings - (AKA upright/spindle/knuckle/WBH) with bearings* and hub** in tact (aluminum is preferred for weight savings, but has its own caveats). I paid $40/each. All of these WBH will work:

• 2000-2002 Audi S4 (aluminum or cast iron)
• 1999-2004 Audi A6 2.7T (aluminum)
• All VW W8 (aluminum and cast iron) - Swap out the wheel hubs for AWM/ATQ hubs [4A0407615G] if you want to run the above OEM BBK options in the future. Otherwise, you can use W8 front rotors with the HP2 calipers and keep the W8 hubs, but there is less rotor selection going that route.

Aluminum WBH part numbers: (Right) 4B3407254G; (Left) 4B3407253G
Cast iron WBH part numbers: (Right) 4B3407258E; (Left) 4B3407257E

The B5 S4 had aluminum WBH through mid-2000 VIN ending 080000. Aluminum WBH will probably be more expensive and harder to find in good condition. The part number is conspicuous making it easy for the salvage person to check. Do not stray from the above WBH part numbers.

If you try to source the aluminum WBH from an A6, make sure you verify the part numbers. The 2.7T A6 with factory 18” or 17” wheels should have the aluminum upright you need. Look for PR option code 1LX or T7G (which also indicate the HP 2 calipers, hint, hint). The easiest thing is to call the seller and verify the part numbers.

The B5 S4 with aluminum WBH uses the same lower control arm as the ATQ/AWM Passat starting in 2003 VIN 072001 and later. The B5 S4 with cast iron WBH uses the same lower control arm as the Passat up to 2003 VIN 072000. You might need new lower front control arms depending upon your selection of WBH material and the B5/B5.5 model year you own.

If you have a 2003 early VIN 072000 or earlier and want to fit aluminum S4 WBH, you will need (2) lower control arms part number 4B3407151C and (2) nuts N90848401.

If you have a 2003 late VIN 072001 or later and want to fit cast iron S4 WBH, you will need (2) control arms part number 4D0407151P.



*Check the hub for radial movement to determine if the bearings are good. If there is any radial movement, have the bearings replaced or follow recourse with the supplier. If you want/need to replace them, you will need two bearing kits and you might not need the drive axle shoulder bolts listed below (they might be included with the new bearing kit, but if they are not be sure to buy them). The aluminum WBH uses bearing kit 8E0498625B. The cast iron WBH uses bearing kit 4B0498625A.

**If you buy a WBH that does not include the hub, you can use the hub from your stock WBH. Stock hubs will not work if you are converting from engine code AEB/ATW/AUG (75mm bearings).

(2) 4A0407643A* - Drive axle shoulder bolts, 190 nm plus ½ turn
*Be sure you order the Audi part number and not the VW part number. The VW part number was superceded by a new part number that will not work. If you search the part number and it is not superceded, then you will receive the correct part.

(2) B5 S4 front calipers (Lucas HP-2) - Also found on the same models listed above. I paid $25 each. Part numbers 4B0615108B and 4B0615107B. Rebuild the caliper if the condition calls for it. The unspecified triple square driver size in the write-up is 12mm. I did not have the proper 11mm flare/line wrench when I disassembled my caliper and rounded the nut on the hard line. I bought new lines for less than $15/ea from www.genuineaudiparts.com. If you have to order HP-2 caliper parts, check here for the part number. Be careful with the carrier pins and bolts, you will have to buy another caliper if you damage them (not sold separately as far as I can tell).

(2) B5 S4 321x30mm front rotors

(1) B5 S4 front pad axle set

(2) N0347908 and (2) N10286102 – Upper control arm pinch bolt and nut for cast iron WBH, 40 nm
-OR-
(2) N10468201, (2) N10406105 and (2) N10286102 – Upper control arm pinch bolt, washer and nut for aluminum WBH, 40 nm

(4) N90876802 – Caliper carrier to WHB bolts, 200 nm

(1) Liter brake fluid

Optional Parts

(2) B5 Passat front brake hose – If the nut connecting the hose to the caliper hard line in seized, you will need this.

(2) B5 S4 ABS wheel speed sensor - See if your source for the WBH will include these. Otherwise, the part number is 4B0927803B. E-bay is a cheap source. You can use the stock ABS sensors, but they will leave some sensor metal exposed. I chose to keep the stock sensors and have no issues to date.

(2) S4 tie rod end or tie rod assembly - While you have everything apart, you could replace these if you have high miles on your current tie rods or want to install solid tie rods. You will need an alignment if you change your tie rods.

(2) S4 control arms and track guide - While you have everything apart you could replace these if you have high miles on your current arms.

The Bentley manual specifies replacement of various nuts, bolts and washers once removed. Some people choose to re-use some nuts/bolt, others replace per manual instructions. Here are the rest of the bolts/nuts used to install (2) cast iron WBH:
(2) 4D0407192C – Tie rod pinch bolt
(2) N10286102 – Tie rod nut, 50 nm
(2) N90628902 – Tie rod end bolt, 7 nm
(4) 4D0407644A – Control arm and guide link nut, 100 nm

For (2) aluminum WBH:
(2) 4D0407192C – Tie rod pinch bolt
(2) N90892301 – Tie rod nut, 50 nm
(2) N90628902 – Tie rod end bolt, 7 nm
(4) N90848401 – Control arm and guide link nut w/ washer, 125 nm

Required Tools

¼” Ratchet
½” Breaker bar
½” Ratchet
½” Ratchet extension
7mm hex driver
10mm hex wrench or driver
10mm socket
11mm flare (line) wrench
16mm socket
17mm hex driver
17mm socket
18mm socket
18mm combination wrench
21mm socket
Anti-seize compound
Ball joint separator or awl/punch
Coat hanger or similar wire/hooks for hanging calipers
Flat blade screwdriver
Floor jack
Hammer
(2) Jack stands
Torque wrench (at least 200 nm, preferably 250 nm for accuracy)
Torque wrench (up to 10 nm for tie rod end bolt)

Optional Tools

Corded drill and brass wire wheel - to clean parts
Dremel tool and cutting discs – needed for super extreme pinch bolt removal technique
PB Blaster

Preparation

If you recently had your pinch bolt out, you could probably skip this part. If the bolt shows signs of corrosion, remove it with a wire brush before applying the PB Blaster. This will allow the PB Blaster to penetrate easier. While you are waiting for your parts to arrive, apply PB Blaster every other day to pinch bolts where the two upper control arms connect to the wheel bearing housing. Tap the bolts with a hammer to help get the point across. In extreme cases, you will have to do this. It is better to start with the PB Blaster now instead of delaying the project later.

Using an 11mm flare/line wrench, you should try to slightly tighten, and then loosen the flare nut connecting the brake hose to the brake caliper hard line to see if the nut is seized. If the nut is seized, buy two front brake hoses. If the nut is not seized, retighten. Do the same for the other side. I had replace my brake hoses after I rounded the flare nut using the proper flare wrench, brake cleaner, PB Blaster and tightening then trying to loosen.

Removal Overview

Remove wheel, caliper, caliper bracket, rotor, dust shield, ABS/pad sensor and wheel-bearing housing.

Removal Procedure

Step 1: Loosen axle bolts & remove wheels
Measure the distance from center of the center cap to the top of the wheel well above the center cap. Write down this measurement, as you might need it later if you discover that you have to replace control arms. You will definitely need this measure if you plan to replace your control arms. Remove front wheel center caps. Loosen, but do not remove both front drive axle bolts using the 17mm hex driver, 2” extension, breaker bar and jack handle. Tap the hex driver with a hammer into the axle bolt until seated. Attach extension and breaker bar. Slip jack handle over breaker bar handle. The bolt should loosen with little effort. Be careful around the passenger side mirror. Loosen, but do not remove, lugs on both front wheels using 17mm socket. Jack up car and place jack stands under front left and right jack points. Remove front wheels. Store wheels in a safe place; you will need them later.

Step 2: Remove brakes
Disconnect pad wear sensors from calipers. Remove your brake fluid reservoir cap and bleed most of the fluid out of the line through the bleeder screw. As you can see, I am telling you how to do this in an order better than how I did it. Live and learn.


Were you able to loosen the flare nut connecting the caliper hard line to the brake hose in the Preparation section above?


Yes and I plan to keep my stock brake hoses: With an 11mm flare/line wrench, loosen the flare nut where the brake hose connects to the hard line on the caliper.
No: Trace the brake hose into the wheel well where it meets the hard line. Disconnect the hose from the hard line using an 11mm flare/line wrench.



Place a sandwich bag over the exposed hose or hard line and wrap a rubber band around it to catch dripping brake fluid. Remove brakes as described in steps 2-9 in this wonderful write-up.

Step 3: Remove ABS wheel speed and brake pad wear sensors
Using a 10mm socket, remove the three bolts retaining the splash shield.



Remove ABS wheel speed sensor from the WBH.










Now push the ABS pad sensor into the top of the wheel bearing housing and gently pull on the sensor to remove it. The last part through the WBH will be the red and black connectors in the above picture. Do not try to push the cylindrical metal part of the ABS sensor into the WBH. That is the wrong direction. It may damage the sensor and lodge into the WBH.



Step 3: Remove wheel bearing housing
Remove 18mm control arm hex nut and track guide hex nut from bottom of WBH.




Remove 13mm tie rod bolt and 16mm tie rod hex nut and bolt from upper WBH.







Pull the tie rod down to disconnect from WBH.




Use ball joint separator to partly separate the track guide pin and completely separate the control arm pin from WBH. Keep the track guide pin partly inserted, as this will hold the WBH in place later on.




Next is the infamous upper control arms pinch bolt. Use a 16mm socket to loosen upper control arm nut a few turns. Hammer the nut until flush with the WBH. Loosen the nut a few more turns. Hammer… Repeat until the nut comes off and bolt is flush with the wheel bearing housing.


Punch out bolt with a punch, awl, screwdriver, etc. If you cannot and all else fails, follow this procedure or do whatever you are comfortable with. Once the bolt is free, pull the upper control arms up and out of the WBH.




At this point, the loosened axle bolt and pin from the track guide are holding the WBH. Be sure that you removed the nut from the track guide pin before proceeding. Begin to remove the axle bolt while pulling the WBH out and toward the front of the car and remove the WBH.




Step 4: Clean up reusable parts
A wire wheel is quick and effective, followed with some degreaser.

Installation Overview

Install S4 WBH, ABS/pad sensor (stock or S4), S4 dust shield, S4 rotor, S4 caliper, S4 pads and wheel.

Installation Procedure

Step A: Install new wheel bearing housing
Apply anti-seize compound onto guide link and control arm pins. Place S4 WBH guide link pin sleeve onto guide link pin and insert control arm into sleeve. Finger-tighten nuts.


Insert drive shaft and finger-tighten new axle bolt.




Apply anti-seize compound to upper control arm (AKA upper links) pins and insert into S4 WBH.


Apply anti-seize compound to unthreaded part of new upper control arm pinch bolt. Install new bolt and nut (and washer if you have the aluminum WBH).


Apply anti-seize compound onto tie rod pin. Insert tie rod into WBH. Align notch on tie rod pin with hole in WBH using a 10mm hex driver/key. Apply anti-seize compound to unthreaded part of tie rod pinch bolt. Insert tie rod pinch bolt and nut - finger-tighten. Insert tie rod end bolt - finger-tighten.


Torque all of the nuts/bolts to spec:
Control arm and track guide nuts – 100 nm (125 nm for aluminum WBH)
Upper control arm nut – 40 nm
Tie rod pinch bolt nut – 50 nm
Tie rod end bolt – 7 nm


Step B: Install ABS sensor and dust shield


Installation is opposite of removal. You can feed a wire down through the WBH, then tie it to the black and red wires and pull them through. I did this on one side, but was able to do the other side without resorting to such violence. If you are having a tough time then do it, otherwise do not risk damaging the wires.


Connect the ABS/pad sensor wires and use a screwdriver to tuck the lip on the rubber seal into the wheel well. Make sure you get all the way around it so water cannot get through. Apply anti-seize compound to the copper sleeve from the old wheel bearing housing and insert into the new WBH.


Apply anti-seize compound to the ABS wheel speed sensor. Twist and push the sensor into the copper sleeve until it stops. How do you know if it in far enough? Your ABS light will come on until you push it in far enough. Push it in too far and it will hit drive shaft and probably destroy the sensor once you start driving.

Install the S4 dust shield.


Step C: Install brakes


Apply anti-seize to hub and install rotor. Hold in place using lug bolts or wheel hanger.


Install caliper using 21mm bolts. Torque to 200 nm


Attach brake hose to brake line. The connection looks the same as the stock caliper. The hose fitting inserts into the bracket. On the other side of the bracket, place the tensioner (I have no idea what that thing is called) and then the flare fitting for the hard line. Tighten using an 11mm flare/line wrench. I didn’t have a way to torque this nut, so I tightened until snug and went another ¼ - ½ turn.


The new pads are a little more involved than the stock pads. You have two different pads to deal with. Inner = closer to center of car; outer = farther from center of car.


Install brake pads. See this article. Start about 2/3 down the page at the line “Install new inner pads” and stop after connecting the pad wear sensors. If your pads do not have pad wear sensors, you can short the sensor to disable the brake wear alert. See steps 13 & 14 here.


Bleed all four brakes with new brake fluid. A Motive Power Bleeder really helps here, but you can also do it the old-fashioned way. Here is a write-up for a brake fluid change and bleeding.

Remove the lugs from the rotor and install the wheel. Hand-tighten lug bolts and jack the car down.


Torque the lug nuts to 120 nm in a star pattern. Torque axle bolts to 190 nm. Switch to a breaker bar and tighten axle bolts an additional ½ turn. Replace front center caps. Start up car and pump brakes a few times. The brake pedal should firm up. If it goes to the floor, bleed your brakes again. Go for a slow drive to make sure your brakes are working. Once you are comfortable that everything is OK, bed your brakes and enjoy.





DISCLAIMER: Do this at your own risk. I have done my best to describe in detail the steps involved in this procedure. I have used the Bentley manual and ETKA diagrams to develop this document. To my knowledge, the information in this document is accurate. Mistakes can occur and I cannot be held liable for any mistakes in this document. Understand the risks involved in working on your brakes, suspension and drive train before starting this task.:wrench: