Audi A4 1.8t Repairs P.3
Repair #012 : Drivers front wheel bearing
The drivers front wheel had been making a horrible sound for quite a while. I thought it was the tires since they had some alignment wear on them. Eventually I figured out that it was a bad wheel bearing. This is lots of fun because you have to take the knuckle out of the car, press the old bearing out, and the new one in. Yay! (I don't have one of those on the car bearing remover things)
The axle bolt (either a 14mm hex key bolt or a 27mm hex bolt) should be loosened on the ground before you jack the car up.
The hardest part of the whole operation was getting the notorious pinch bolt out from the top of the knuckle. It pinches the knuckle around the ball joints on the two upper links. There are two gaps in the housing where the bolt goes through that are perfect for trapping water and salt slurry around the bolt. J____ and I hammered on that single bolt with the BFH for an hour before it came out, all the while bathing it in PB Blaster. When I put it back in, after cleaning the hole out, I covered the entire bolt with anti-seize and squirted some in the hole too. Torque for that bolt is 30ft lbs. I was very grateful that I'd done this when I replaced the upper control arms later.
The two lower ball joints came out with the help of my two jaw craftsman ball joint puller, although I was skeptical for a few minutes. I kept turning it and they kept not coming out whilst visions of the puller flying apart and killing me ran through my head. Eventually they both came out though. The axle has to be unbolted and move to the side to make room for the puller. The nut on the ball joint facing up was seriously on there. I had to keep the shaft stationary with a hex key wrench (omg such an awesome idea, thank you Audi!) and hit an end wrench with a hammer, over and over, until it was all of the way off of the threads. This would be a good time to replace your control arms if you have new ones. The hardest part is getting those ball joints loose.
The tie rod, the caliper, and the axle all came out without any trouble. The ABS sensor just pulls out of the knuckle, then you pull the grommet on the wire going into the body off of the car and undo the harness on the other side. Then you can pull the wire through the knuckle and get that out of the way. The brake rotor wouldn't come off so I hit it with the BFH and a piece of wood until it changed its mind.
I took the knuckle to a shop with the new bearing and let them do the press work. I would have done it with M's press but I didn't have a 75mm puck to use with it. If anyone knows where to get one without shelling out 200$ let me know.
Installation is reverse of removal except with a new axle bolt, a new pinch bolt that gets a bath in anti-seize, and precisely torquing all of the bolts with my newly calibrated torque wrench.
Repair #013 : Rear passenger side brakes
Pictured are Hawk HP+ rear pads, a new oem A4 rear caliper carrier and a new OEM rear caliper.
After some funny drivability for a while I noticed that the passenger rear wheel was locking up in cold weather. Upon further inspection it was obvious that the parking brake cable/caliper was seizing.
That tool they have to pinch the brake line is pretty neat! That lower picture is very important. You do not want to push your brake pedal all of the way down when bleeding your brake system or you may ruin your master cylinder. Save your master cylinder and buy a pressure bleeder from ECS or someplace with the Audi specific cap on it. Don't pump it up too much though or you'll blow the seals on the master cylinder (I don't know this from experience or anything >_<).
I wasn't positive what part of the system was causing the stuck brake. Most of the time the parking brake cable gets moisture in it somehow, which freezes when the temperature drops. Once a parking brake locks up it can cause the sliders to seize up. The subsequent heat and friction from the locked brake will ruin your rotors, pads, and possibly your wheel bearing. It's really best to replace everything if you can't absolutely pinpoint the issue. I would start with the parking brake cable, then the sliders on the caliper carrier, and lastly the caliper/parking brake assembly. My passenger side rotor looks like it went through a fusion powered cheese grater. Upon taking the assembly apart i think it was probably the caliper itself, but the cable was a little sticky.
This is about what most pad companies tell you to do with a little variance. This is a bit tougher for a rear pad because a. it's tougher to heat up and, b. you can't pull the parking brake after you stop. Best really to drive on a freeway or someplace you won't touch the brakes to cool them off.
Pictured is the new parking brake cable, the new OEM caliper and caliper carrier, the Zimmerman rotors. I put the new Hawk HP+ pads in after this shot. Don't bother with the HPS pads they aren't nearly as good as the +'s. I have a theory that zimmerman rotors are prone to squeaking, so if you don't like squeaking you may want to go with brembo rotors instead, especially on the fronts (which should be slotted on this car for better wet weather stopping).
The parking brake cable took the longest to install just because I wasn't quite sure how it came out. There is a plastic sleeve on the cable that goes through the lower control arm that you more or less have to break to get out.
Then I had to drop the differential mount by about 5-10mm to be able to slide the cable through that area. Beyond that the cable itself is held into a housing bolted to the bottom of the car close to the back of the parking brake lever in the interior. The end is held in with an axle style spring clip and a rubber o-ring. The cable comes loose from the handle inside the car pretty easily, i unbolted the handle to get some extra slack. What I ended up doing to get the cable out of the housing was to hammer the end out from inside the car with a 1/4" ratchet extension.
Repair #014 : Front lower control arms and links
That right there is why I have to replace 8 control arms and links on what is otherwise a brilliant suspension design. A non-serviceable ball joint. If the ball joint or the bushings go out you may as well buy all 8 of them because the rest are probably on their way also.
There is a lower control arm, a lower link, and two upper links, all aluminum, making for a very sophisticated suspension design. The geometry is such that it eliminates bump steer at stock ride height and creates a virtual steering axis.
When I bought the A4 it had a creak coming from the front left someplace. I replaced the tie rods and that didn't fix it so it was obviously going to be the infamous Audi front arm replacement job. Almost all B5 A4's and S4's and C5 A6's have had to do this by now, some of them multiple times.
The ideal way to do this is to buy all new front lower arms from an online Audi dealer then buy a full set of front lower powerflex bushings (four of them). Then buy the upper links from CPP, which are solid adjustable racing units with hemi-joints and zero bushings/ball joints. If you plan to keep your car a long time i think you'll come out ahead this way.
That route is bloody expensive though so I bought a set of un-used front lower Febi brand arms from AW classifieds for next to nothing.
The front arm comes right out but the rear arm is freaking in there. The hard way to get it out is to drop the subframe enough to get the inner bolt out, which is how I did it. The easy way that I didn't think of until afterward was to pull that bolt out an inch or so and saw the head off. Now pull the bolt out through the subframe side. Install your new arm and feed the new bolt in with the head on the subframe side (towards the front of the car). Doing that saves a hell of a lot of time. Obviously if you can do the upper arms at the same time, I didn't have them when I did the lower arms.
The bushing on the lower link is non replaceable and huge and squishy. I'd love to fill this thing but it needs to articulate in just such a way and filling it would screw up the handling.
The quality of these pieces is very high. Comparing these to the links on my previous cars there is simply no comparison. Stamped steel and cast iron are only used for one reason= cheapness of manufacture. Most cars don't even have this kind of thing available in the aftermarket and that is a great deal of why I bought this car. The links are surprisingly light as well, as they should be.
The original (?) TRW arm below the new febi. The ball joint and the bushings both were shot on this drivers side arm. The arm on the passenger side was still good and I believe that it has been replaced. The handling in the A4 was much improved after I installed the four new lower arms, well worth the time and effort.
- Front lower track link (one that strut attaches to):
- Bushing bolt - Tightening torque: 80 Nm (59 ft lb) plus additional 1/4 -turn(90)
- ball joint nuts (lower guide and track control links) to 100 Nm (74 ft lb)
- Shock bolt: 90 Nm (66 ft lb)
- Stabilizer link bolts:
- upper nut: 40 Nm (30 ft lb) plus additional 1/4 -turn(90) lower nut: 100 Nm (74 ft lb)
- Rear lower link: 90 Nm (66 ft lb) plus additional 1/4 -turn (90)Tighten nut at ball joint to 100 Nm (74 ft lb).
Repair #017 : Upper front suspension links
One of the hardest items to remove from the car, the front upper suspension links. The upper pinch bolt seizes in the upright and it takes around an hour of hammering and filing to get it out. Lucky for me I did the drivers side previously when I did the wheel bearing so I only had to get one stuck one loose. It took about an hour and a half with the BFH, PB blaster, and a file. Once that, the tie rod, and the lower shock bolt are loose you just have to take the three nuts off of the top holding the shock/spring assembly in. Have someone step on the lower arm assembly and that makes enough room to just pull the whole thing out. Once the pinch bolts are out its quite simple. Now is a good time to replace your shocks and springs if you can, along with the inner bushing on the new links if you have the powerflex replacements.
The new arms should be installed and tightened at the correct angle. Snap-on ratchets have fantastic action.
A= 47mm BUT, that's only if you're at the stock ride height. If you're lowering your car you're going to have to figure out a way to set the car down and measure that spot, then jack up the arms and tighten them there. Good luck with that, i'm thinking a jack under the upright or some ramps or something. Be sure to use new bolts at all locations.
Upper front and rear links:
- inner bushing bolts: 50 Nm (37 ft lb) plus additional 1/4 -turn (90)
- upper ball joint pinch bolts: 40 Nm (30 ft lb)
Repair #016 : Down pipe flex joint
After leaking more or less since I bought the car my lack of new engine mounts tore the downpipe in half. A real exhaust was not an option at the time so I bought the cheapest downpipe I could find along with a new clamp and gaskets. New catalytic converter to turbo nuts should be acquired as well.
I had to saw that old clamp off (just through the two bands) and take the downpipe and cat out as an assembly. In order to do that you need to take the airbox and O2 sensors out as well. I took the top O2 sensor out and just unplugged the lower one as it was stuck fast. I cut the hanger off of the bottom of the old downpipe and rotated it kind of upside down and it came out from the top. There is also a small plastic wire channel that I moved from the body under the airbox area for room.
Once out of the car I undid the bolts from the cat to the downpipe, they basically broke off and I just tapped the ends out with a punch. With a new gasket and stainless hardware I put the new downpipe on with the cat out of the car. I had to saw the exhaust hanger off of the new downpipe also to get it to fit in. I left a little bit there and drilled a hole through it to fabricate a new hanger which was a bit of square tubing with two holes drilled through the ends- works great! After it all got back together it was very quiet and peaceful. Until I fixed the engine mounts with shore 80 034 units and it got really loud again :(
Tools needed:
- 17mm stubby end wrench
- misc screwdrivers and end wrenches
- jack stands, floor jack
- O2 sensor socket
- hacksaw and a good blade
- drill and bits
- new gasket (1H0 253 115), downpipe, and clamp
- turbo -> catalytic converter nuts (+N 903 690 01)
- turbo -> catalytic converter gasket (8D0 253 115)
- M8X35 stainless bolts, nuts, washers, and lock washers.
By all means, if you can, replace the cat with an ATP 3" test pipe(and relocate the cat under the car), or a high flow cat and the rest of the exhaust with an aftermarket unit. The stock stuff is pathetically small.