Thread: Power Steering Rack Replacement — B6/B7 A4/S4

I replaced the steering rack on my B6 S4 for the second time and made this DIY on how to go about it.

TIME/DIFFICULTY
6-10hrs depending on your prep and pace
Medium difficulty range
No special equipment needed

PARTS
₪ ZF Steering Rack [new, rebuilt, or used]
₪ Synthetic Mineral Based PSF or M1 ATF – 2 Litres
₪ Rack Centering Bolt [M10-1.5 pitch]
₪ New Tie Rod Ends [optional]
₪ Banjo Bolt Crush Washers

TOOLS
[Key requirements]
- 10mm 12point socket
- 18mm Combination Wrench
- 19mm Combination Wrench
- 22mm or 7/8” Combination Wrench
- 6mm Allen Key and Socket
- 12mm Triple Square Socket
- 2ft of 3/8" Extensions
- Jack and Stands
[Basic necessities]
- a solid metric tool set
- Allen and Torx Key or Socket sets
- 3/8” Torque Wrench
- Screwdrivers
- Pick
- Pliers
- Hand Sledge
- Punches
[Misc.]
- Penetrating Spray
- Brake Cleaner
- Anti-Seize
- Petroleum Jelly
- Dielectric Grease
- RAGS!

SETUP/REMOVAL

— Apply E-brake, engage steering wheel lock at center position, loosen drivers side front wheel bolts, raise front of car on jack stands, and take off drivers side wheel.

— Remove Belly Pan, if applies.

— Siphon or drain any fluid left in reservoir.

— Disconnect battery, unbolt clamp, and remove battery; a 6mm 1/8” drive Allen socket, long extension, and ratchet works best.



— Remove driver side fuse access panel and lower dash panel. Dash panel is held on by 1 bolt behind the fuse panel and 2 bolts on the bottom. Disconnect OBDII port and light then place aside.



— Detach steering column from rack pinion. Use a 6mm Allen key or socket wrench to remove bolt then slide the column off the pinion.
............yes the pinion seal let loose and blew PSF all over the footwell




— Detach both tie rod ends from knuckles. Remove 13mm top bolt first then 16mm pinch bolt, use a punch or short extension and hand sledge to persuade tie rod ends out of the knuckle arms.




— Detach upper control arms from knuckle. Support knuckle with jack, remove 16mm nut, remove pinch bolt using a punch and hand sledge. Pop arms out of knuckle through the access holes using a punch and hand sledge. Penetrating spray and heat will be needed on this step most likely………

Alternative method if pinch bolt is seized: disconnect strut from lower control arm, pull strut aside, and jack knuckle up high into the wheel well. This will give you enough clearance to slide the rack out.



— Disconnect Servotronic electrical connector. A pick or precision flat head screwdriver to raise the connector clip is recommended.

— Remove access cover. Unscrew 10mm nut next to Servotronic connector and pull out the 2 plastic push pins located behind the strut then pull cover out. Don’t be afraid to contort it a little as it will catch on things coming out.

Order of disassembly reference



— Remove fluid lines. Lay rags under the lines and remove return line banjo bolt with a long 22mm or 7/8” combination wrench. Remove high pressure hard line completely; loosen hose fitting with 18mm and 19mm combination wrenches then remove banjo bolt with a long 19mm combination wrench, and place hard line aside.






— Ensure steering rack is completely disconnected from all associated components then unbolt rack from body. The rack is held on by 3 x 10mm 12 point bolts as outlined below.

Bolt 1: under battery



Bolt 2: next to brake booster



Bolt 3: underneath car; look up between the drivers side DP and trans and you will see it hiding in the shadows. A long, approx. 2ft single or series of extensions will get you there; a universal joint might be needed also.




— Remove rack. Lay some rags over the brake and ABS line and slide rack out through drivers side, you may need to get creative and conjure up some finesse…having a comrade assisting the rack out from the pass. side will make this step much easier. Disconnecting the strut from the lower control arm and pulling it aside will give added clearance if needed.



— New rack prep. Transfer Servotronic valve and tie rod ends to new rack then center the rack.

Swap or install new tie rod ends using 22mm and 18mm combination wrenches. Take note of the thread count on each side and match it when installing the tie rod ends on new rack. You'll avoid severe tire wearing issues if you can’t get an alignment right away. Anti-seize is your friend, so use it

Transfer Servotronic valve. Before installing, inspect the o-rings and replace if necessary. Regardless, apply petroleum jelly to the o-rings.

Center the rack. Remove the access bolt using a 12mm triple square socket. Align centering notch on gear with access port by turning the pinion then use a M10 – 1.5 pitch bolt to secure gear in place.



REASSEMBLY
Point of advice; if it has a shank or threads, apply anti-seize and if it has electrical contacts, apply dielectric grease.

— Install rack. Position steering rack back in the plenum chamber in reverse order of removal and loosely bolt rack in place then torque bolts, starting with the top then bottom, to approx. 50 ft-lbs…I say “approx.” because the use of long extensions makes it near impossible to achieve proper torque accuracy. You just want the rack to be evenly tightened.

— Reattach steering column and reinstall dash panel.
— Remove rack centering bolt and reinstall access bolt.
— Reconnect fluid lines starting with return then high pressure line and tighten firmly, use new banjo crush washers.
Applying petroleum jelly on the upper washers before placing them on the lines will help hold them in place while you battle getting the banjo bolts threaded in. Be patient on this…

— Reinstall access cover
— Reconnect Servotronic electrical connector
— As necessary, reattach upper control arms to knuckle and strut to lower control arm. Before tightening strut, lift knuckle to curb weight position to avoid damaging the bushing.
— Reattach tie rod ends to knuckle arms. Tighten pinch bolt first then top bolt.
— Reinstall battery

FLUSH/BLEED

Flush the system free of any old fluid and leftover debris prior to bleeding.

Koolade did an excellent write up on this which can be found HERE

FINAL DETAILS

— Start car, check system for leaks and abnormal noises.
— Reinstall belly pan
— Reinstall wheel
— Lower off jack stands
— Take a test drive
— Schedule an alignment

If you’ve made it this far, wipe the grin off your face

Great write-up!

Awesome write up!!

Thanks everyone! and Jakehobbs thats really great to hear!

Update:
While I had the dash panel off I did the 'Servotronic Mod' as outlined by member Eddie Man. It was extremely easy to do and cost me only $4, after a months worth of Sunday blasts on mountain roads I can say this is a must for spirited driving. The feedback is incredible and now my steering is spot on due to the added resistance. When city driving I can just flip the switch and have all the convenience of power assist back. Really simple yet effective mod.

Great write-up, thanks! I'm about to tackle this job.

just passing through looking at ways on how people take off there bottom half of the dash. Just wanted to say awesome DIY by the way.

Does anyone know if you can swap the B6 or B7 S4 steering rack into a B6 A4 1.8T without having to modify the pressure lines etc.? I have done multiple searches without any luck. Appreciate any help in this matter.

If it's quattro you're in with a pretty good chance, the part number 8E1422054CX is listed for:

on the 3.0 the inlet in on top and the outlet is the one on bottom.

Used this write up to replace mine, thank you SO Much, quick question. Anyone know what the torque spec is for the banjo bolts? Recently as in 3 months later my 3, 10mm bolts came loose and the 19 mm banjo bolt started leaking, I retightened the 3 10mm, and was able to get about an 1/8 to 1/4 more on the 19mm, before I felt I might strip it. Thoughts? TIA Also, do you think I am in the clear with that banjo bolt?

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Great write-up on replacing a steering rack on a B7 S4. Looks doable. However when i read my bentley manual, it says that the heat shield has to be removed and to remove the heat shield one has to remove the front exhaust pipe. The procedure for that looks very difficult. Were you able to accomplish this without removing the heat shield?

Will this work diy work for an 02 1.8 Quattro Auto A4? I believe it will, I just would like some clarification because where Aussiedan listed the part numbers I see it starts from 03. I'm trying to do this in a couple weeks and save money, since my local shop quoted me a about $1500 to do it. Thanks in advance for the responses!!

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edit:
My 19 mm banjo bolt for hardline at rack was loose. No longer need help there but would still like cobfirnation in where the crush washers are meant to go.

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Thanks very much OP!

I've had a bunch of issues with this repair. Working on trying to rectify now. Please give me some feedback if u have a minute and know any answers. Meanwhile I'll be troubleshooting here.

1. I replaced rack completely but did not yet remove centering bolt, adjst, nor replace with new bolt. My steering wheel is perfectly aligned to straight wheel as-is. Do I still need to do those steps?

2. i started car and flyid dumped out from somewhere near the hardlines. My rack had come with 2 of each sized crush washer. Upon reattaching hardlines , I put one washer on each side of the hardline's "end fitting." (Banjo bolt?) Can't Google now as this phone I'm typing on us on my last nerve. Was that right or do both washers go between hardline end fitting and rack? Hopefully I will find that the leak is only due to one of these bolts being loose. Couldn't crank to spec because my damn torque wrench is seized or something.

3. On passenger side, I reattached tie rod end by first doing top bolt, then pinch bolt. Then I re-read these instructions which specify the opposite. So I loosened pinch bolt and began to tighten top bolt more when the head snapped off it. Then I attempted to remove pinch bolt so I could hopefully extract broken top bolt and found that the pinch bolt and but are twisting indefinitely. Neither tightening or loosening as I twist but and bolt stays still. Was unable to hammer tie rod end out and no surprise since the bolt is still in. I'm kind of baffled. Do you agree with this: I ordered new top and pinch bolts to replace. Must drill out punch bolt, hammer it out, try to extract broken top bolt from tie rod end using multispline extraction bits, reassemble. Finally, I don't think the specified order of reassemble here by OP seems correct. Is it? Pinch bolt, then top bolt? I think that would strip the top bolt as it went it.

Thanks again OP and all AZers. Gotta go take it all apart again now. Will be back to check for replies.

I just did this job for the second time last week, fortunately everything went super smooth and was able to remove the old rack in an hour and install the new one in an hour and a half with no helper. Yes the stars aligned for me.

I am going to try and help you out duk3.

1. My suggestion is grab some vice grips and turn the rack either right to left and count the turns or left to right, do your best to find the middle. Remember the rack should have a key and really can only line up one way.

2. I am sure you are using new crush washers either copper or aluminum is fine. To keep it simple, bolt, then one crush washer, then feed thru line then crush washer then screw into rack. Basically crank the crap out of these, you don't want them to leak on you. (Most of the time they leak because they were not tight enough or there was movement in the rack and it wasn't tight enough, special note here to use Blue Loctight on the 3 bolts to hold the rack in and crank these to. Use your judgement here)

3. Dude good luck with getting that top bolt out, never see one snap. I always just tighten the top one snug then tighten the pinch bolt. You are probably going to have to remove the pinch bolt and take the tie rod end off the drill that bolt out or buy another.

Just some great tips to share that will save you some time and headaches, in no specific order....

-use Loctight on the 3 bolts holding the rack in.
-tighten the crush washers really tight, I started from the wheel well, then went in from the bay, a box set wrench works really well here, start with the 19 mm first, then the 22mm. I also has the rack in and bolted before I connected the banjo bolts, done it both ways and easier to bolt the rack first then banjo bolts.
-jack the knuckle up to easily have room to slide the rack in, you might have to adjust the height by 1" to get it to twist and finally get in there, it will go, don't force it.
-be careful feeding the rack in not to knock off the shifter linkage.
-when everything is in and wheels on, put the tires on a piece of cardboard, this way you can easily turn the wheel and get most of the bubbles out. I turned mine back and forth 10 times. Normal driving will take care of the rest.
-probably pretty obvious but never hold the wheel at full turn, the amount of pressure built in the lines is huge.
-carry an extra bottle of fluid in your trunk just in case a banjo bolt works it's way out, you don't want to starve your pump.

Hope this helps... good luck.


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IMO, I didn't see a purpose to the centering bolt, or even see one on my rack. If there was one I overlooked it. Try referring to 1. in my prior post. That is how I centered the rack. You truly can't mess it up. Good luck.

If you need to replace the servotronic fasteners, the dimensions are M4x0.7x40mm.

I bought some stainless 316L bolts. They happily get rid of the torx interface for a less strip-risky internal hex (1/8") and are more corrosion resistant than the coated fastnerss. I had to buy in bulk qty (of 10) and only used 4. If anybody wants the remainder, I'd be happy to donate where there is need.

http://rackdoctor.net/

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Just did this yesterday, and idk why you psychos are doing it with the strut and spring in the way. I removed my strut and first of all, you’re looking at only the 3 top bolts, knuckle pinch bolt, and lower strut bolt and it all comes out.

secondly, you have an insaaaaane amount of room to work with. enough to where I was able to pull the rack out a little and access the fluid line banjos from the wheel well, and then properly torque them from under the car with how much room you have to move the rack around.

IMG_9450.jpg


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