2007 S8 restoring to its former glory

So as an introduction I picked up my 2007 S8 last week, purchased it in PA and drove the 1,200 miles home to MN. It’s a good spec car with the premium pack and Adaptive cruise. Cosmetically it’s in really good shape for a 10 year old car with 95k miles.

Bought it form an Audi dealer who serviced it for the previous owner, it has a good history and has had the following already done:

  1. Replaced one of the rear struts, compressor, valve block and relay around 80k
  2. Replaced the IM around 74k

I got what I think was a decent price with some known faults, since getting it home I have found a few more, it has/needs:

  1. Front strut airbags slowly leaking, drops if left over 24 hrs
  2. Engine oil leak, dripping off the pan
  3. AC cruise needs adaption
  4. Upper Control arms need replacing
  5. RH front axle needs both CV boots replacing
  6. Front Parking sensors don’t work
  7. Rear trunk motor doesn’t lift
  8. Tranny and diff oil change

So I have some work cut out, but looking forward to working on the car and turning it into my idea daily driver.

So today the work started with looking into the oil leak, after doing some research it seemed the Oil filter housing O ring was the prime suspect. But then I looked at the previous service records and saw that the O ring was replaced at 55k (40k ago, 18 months ago) so I was concerned that it may be the upper pan leaking, which would be a major job.

So I took the front bumper off, removed the headlights that need refinishing anyway, and pulled the front, core out to give a little more room. Amazed that considering this car was serviced by Audi, was shocked by the # of missing and loose fasteners, and broken clips.
The removed the IM, it is pretty easy as long as you are methodical and there is already a DIY, only dropped 2 torx bits in attempting to remove the oil separator :frowning:

Well it looks like the O rings were either poorly fitted or leaking already

http://i1019.photobucket.com/albums/af319/d6lc/S8/87af4b11-be2b-4fa2-978f-cafa2a341d6e.jpg

Whilst the IM is off, I will also replace the valley pan cover gasket, oil sensor O rings, and put in a new oil separator.

The car was previously carbon cleaned and the valves looked good, so I am going to leave that for another year or 2.

One question I have, what is this bracket usually attached to?, it was just loose. its behind the intake at the firewall

http://i1019.photobucket.com/albums/af319/d6lc/S8/IMG_3851.jpg
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More to come tomorrow, probable attache the suspension whilst waiting for the engine parts

none of your pictures showed up. I recomend just loading the pictures you have right to this site. it makes it eaiser.

http://audirevolution.net/upload-media

Obviously I cant make out your picture so I cant really help you much there. I would suggest trying to get a car fax from the dealership if you can. You want to look for any other service work done in the cars history. Injectors are a big must

hopefully these pics work:

Here is the oil filter housing leak:

http://audirevolution.net/addons/albums/images/555365588.jpg

And here is the mysterious bracket:

http://audirevolution.net/addons/albums/images/589810956.jpg

So with the IM off, struts removed and axle off waiting for parts, I decided to have a go at refinishing the headlights.

They had the normal scratches, dings and one of the lights looked like some chemical had been spilt on it

http://audirevolution.net/addons/albums/images/858836183.jpg
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To start I wet sanded the light with 800, 1500, 3000 & 5000 pads, the super fine grain is easily available off Amazon. took about 20 minutes per light. Then polished the lights with a fine cut polish and orbital polisher.
Light on the left is polished, on the right is unfinished.

http://audirevolution.net/addons/albums/images/617434279.jpg

One they are polished they look good, but you really need to seal them, I use Helmspar UV protection clear, mixed 50/50 with Mineral Spirits. First wipe down the light a few time with denatured alcohol. Then apply the 50/50 mix with a folded shop towel, you just need to wet the lens, you don’t need to apply much. As it is thinned it will flatten instantly with no runs or smears.

This is the finished result

http://audirevolution.net/addons/albums/images/712922601.jpg

My shop lighting makes it look yellow, but its perfectly clear

All the pictures work you can see them just fine.

The headlights you can really see the difference when you put them side by side like that. I had normal ware and tear on my lights as well. I used the standard headlight repair kit that you can get from any auto store. I was very happy with the results but you can see you took your headlight job to another level. Looks fantastic. great work.

On the oil seal pictures you can see its got oil in the galley so replacing those seals would be a good idea. I don’t however see what your mention of the bracket is.

The bracket is on the 2nd pic, unfortunately it is rotated 90 degrees ro the left. So that is the pic of the firewall. There is a steel bracket on the harness, mine wasn’t mounted to anything. I just wondered what it was supposed to screw onto.
Clearly the last garage never refitted it.

clearly. It sucks to have indy shops that just don’t put everything back together. You can tell how many times a car has been worked on by the amount of bolts and nuts that are missing.

If I’m seeing it right and I’m understanding what your talking about. Its the silver braket that goes to and then around the harness… That if I remember correctly goes to the intake. It helps keep the wire harness from falling down. I originally thought it went on the fire wall but I don’t see anywhere for it to mount. If you see a little black thread sticking out of the fire wall that would probably be where it goes.

So whilst waiting for a bunch of parts I decided to removed the plugs, not only as I am replacing them but also to make it easier to turn over the engine and to a carbon clean.

With all this engine work I had considered replacing the valve cover gaskets, but had no signed of leaks, so took the ‘if it aint brake’ attitude. that was until I removed the plugs

http://audirevolution.net/addons/albums/images/507859182.jpg

3 plugs on the RHS had some oil, 2 plugs on the LHS had about and inch of oil in the plug tower. not surprising the VC gasket had failed at 96k. Also i think the plugs were the originals, the gaps were huge!

I tried to remove the rear VC bolt but it is extremely tight, I know it is possible with a stub wrench, but as I had the inner wheel fenders and struts out, I took a simpler route

http://audirevolution.net/addons/albums/images/524461109.jpg

Sorry for the rotated image, anyone know how to change that?, I tried saving the image twice but it rotates it.

So finally got around to the carbon clean, it had been done around 40k ago, and didn’t look that bad. I’ll take some pics and pics tomorrow. I decided to do a 1/2 clean, ie remove 90% of the carbon with pics and not spray any solvents to do the final clean. I really dont want to take the risk of getting solvent in the combusion chamber and ending up wrecking an O2 sensor, I have no desire to remove the engine to replace those.
I know its not teh perfect job but i got most of it out and I figure I dont mind going back in in 30-40k to redo it.

So on sleeping on it I decided that I would do the full clean.

Here is the pic with the build up, not terrible after 40k miles. Not great pics

http://audirevolution.net/addons/albums/images/666781658.jpg

So my final process was:

  1. Close the valves, scrap off the major build up with a pick
  2. Test the port is closed by spraying in some starter fluid.
  3. Fill the port with brake fluid, and brush with a toothbrush
  4. Use shop towels to remove the fluid
  5. Use zip ties in a drill to remove the build up

http://audirevolution.net/addons/albums/images/76930422.jpg

6.Vac out again
7. fill with brake fluid again, and use the toothbrush, remove fluid
8. use pick again around the valve, you will see there is still build up, vac it out
9. repeat the above, you will be amazed how but is still there
10. blow out the port with an airline

I could have done a few more cleans, but I was happy with the finished result

http://audirevolution.net/addons/albums/images/131209871.jpg

You were smart to go back and finish off the CC clean. Any solvent you use will get burnt off in the cat as long as its working. Carbon on the other hand it won’t. So you see carbon chunks coming off those are one of the big cat killers.

You should have no issues getting everything out of the ports but if you did some how get solvents into the combustion chamber all you would have to do is pull the spark plugs out and dry fire the motor

So I did a little work on the car last night, got the idler roller replaced and new serp belt on.

Also replaced the valleypan gasket and refit the oil filter housing. Just out of interest for others my Filter housing O rings were replaced 18 months/40k miles ago by Audi with Audi parts, so I was suprised that it was leaking. I checked the old O ring vs new and it had flattened to 3.9mm vs the new one was 4.7mm.

The 2 O rings you replace are less than $20, I’d suggest to all to replace it regularly when you do a carbon clean as a preventive.

Most of the parts are here to finish the build other than the PCV, I already had the IM off so tackled the VC gaskets first

http://audirevolution.net/addons/albums/images/810254200.jpg

Once the covers were off you realize how aged the gaskets are, they were hard to the point of being brittle and breaking up as I removed them, after that I cleaned up the groove that the gasket sits in. I used shop towels and brake cleaner. it takes time but you really need to remove all traces of oil to get a good seal with the new rubber gasket.

My car is an 07 which has the early LH (Drivers) side valve cover, Audi wanted close to $400 for the new cover and I wasnt going to spend that much. in the below pic you can see the difference

http://audirevolution.net/addons/albums/images/4777233.jpg

For some strange reason better know to the engineers at Audi they did a different design on the 2 VC’s, on the RHS the groove where the gasket sits is a consistent width for the gasket to sit in. On the LHS, for some reason they put 2 ribs in the groove as shown above. And the groove narrows, so the gasket doesn’t fit in it.

Its a pretty simple modification to the gasket, with a new box cutter blade just cut out the gasket locator to correspond with the ribs in the cover as below, just dont cut into the main sealing side of the gasket.

http://audirevolution.net/addons/albums/images/686430960.jpg

When fitting the modified gasket to the cover, just apply RTV to the areas you relieve the gasket just to ensure a seal.

Looks like many others have done this mod, so I hope it stays oil tight as paying $400 for a new valve cover feels excessive.

So with the VC’s done, I replaced the plugs with new items, fitted the IM and sorted all the wiring. Finally I refitted the core. Hopefully tomorrow I can fit the headlights, airboxes and bomber cover. Then onto fitted the new control arms, struts, tie rod ends and RH axles with new boots.

So still plenty to do.

good work that is what most people do. some go as far as cutting the wall down and putting the gasket inbetween the area where its blocked off.

Not sure why audi did that but they did that on almost all 06 - 09 cars.

WARNING, LONG WRITE UP. THIS ISNT MEANT TO BE A DIY, YOU WORK ON YOUR CAR AT YOUR OWN RISK.

Got to spend a solid 8 hrs working on the car yesterday, which was good as I pretty much got it all back together. Sorry but in my haste in working on it I didn’t take a lot of pics.

I got the core back in place on Saturday, so started Sunday putting the headlights and airboxes in. Headlights were not so bad, just took a little time adjusting them to get the gaps with the fender consistent.
The airboxes I must say were not that easy, I had the wheel inner fenders out for the suspension work, fitting them with the fenders in would have been really hard. Seemed to take for ages to get them in place and the intake snorkels fitted properly. The LH (Drivers side in US) was especially tight. Maybe there are some tips for easy fitment.
Glad I purchased some new air filter, these look like they have been in there for some time!!

http://audirevolution.net/addons/albums/images/494134361.jpg

I’m still waiting on the new PVC before I drive it any distance, but I put the old one back on so I could start the car and pump the suspension up once I had done that. One annoyance was I split the LH intake tube from the airbox to the throttle body. It was the connector that goes I think to the carbon canister pipework, clearly I was being a bit rough with age hardened plastic. Some duct tape sealed it up so I could at least start the car, that was an annoying $138 lesson to be a bit more gentle.

During all the work I have done on the engine, some of the thin/small hard plastic vacuum lines were broken, with time these get very brittle. Where they had broken I just cut them off square with a dremmel and replaced them with 3mm rubber hose. The car started with no warning lights so all seems well.

Finally, on the front of the car, connected the wiring and fitted the bumper cover. Considering this car has had nothing but repairs and servicing (no recorded accidents), it amazing the number of bodged/missing fasteners for the fender cover. I did my best to refit it properly with fasteners vs the zip ties that one of the garages felt was a good method.

One good piece of news was that on starting the car my front parking sensors now work, I had presumed I have a sensor out, but it looks like it was just a loose connection……that is a result in my book.

So with the engine work done, and the front end back on, it was time to sort out the suspension. I had already removed everything whilst I was waiting for parts. So it was refurbing/refitting new parts.

First up was to replace the RH front axle CV boots which were both split. I have never done this job myself before, but decided to tackle it and a good excuse for a new boot clamp fixing tool. Before you start this, invest in some disposable workshop gloves, as roll of shop towel and a can of brake cleaner. As its messy to say the least. Start with the outer joint first, obviously remove the old clamps and cut the old boot off. Then you can clean most of the excessive grease off. Then hold the axle in a vice and using a soft drift strike the joint off. Mine came off with one strike of a 4lb hammer.

http://audirevolution.net/addons/albums/images/686117470.jpg

Now clean up the outer joint to remove all the grease, just be careful as it’s easy to manipulate and the balls fall out. Once you have most of the grease removed with shop towels, blast ½ can of brake cleaner on it to remove all the old grease.
Then cut off the boot for the inner joint. You can remove the inner joint but I left it fitted and just cleaned it out with towels and brake cleaner. A blast with an airline dried it out and it was good to rebuild.
Apply a little grease to the inner boot and slide it onto the axle, then pack the joint with the grease that comes with the boot, I packed it with grease and moved the joint around to ensure coverage. Once that is done you slide the boot in place and fit the clamps.
For the outer joint, grease the new boot and slide it on first with the clamp. I packed the joint with grease before driving it onto the axle, for me it is easy to do this with the joint separated. Then you need to drive the joint onto the axle, first make sure the locating clip is in the axle groove (sorry I didn’t take pics, didn’t want to cover my phone in CV grease). Then line up the joint onto the axle splines and drive it on with a heavy hammer, I used the soft drift to take the impact as you don’t want to damage the end of the joint splines. Considering how easy the joint came off, driving it back on took some pretty hard wacks with a 4lb hammer. Once it is in palace slide the boot over it and fit the clamps.
Overall it was a pretty easy, and dare I say satisfying job, took just over an hour all in.

http://audirevolution.net/addons/albums/images/184468056.jpg

I will be interested to see how the boots hold up. I got them from Pelican parts, the inner boot was a GKN part and the outer was a Meryle part, the GKN felt more rubber like and the Meryle felt more plastic/rubber. After doing it if they fail again it’s a pretty easy fix. So let’s see which one holds up best.

Refitting the axle is straight forward, only item to note is that if the car is lifted (both front wheels off the ground) its not easy to tighten the CV to diff bolts (6). First tighten all the bolts up as best you can, then us I found the easiest way to do torque them was to place 2 wheel lug bolts in the hub and wedge a pry bar through the bolts to the ground. You then just tighten the 2 bolts you can get access to, rotate the axle, move the lug bolts and tighten all 6.

I also had to replace a tie rod end on the RHS, the ball joint was fine, but the circlip holding the rubber boot was missing so only a matter of time before it wears. Easy replacement, loosen the lock nut, then count the number of rotations to remove it. Fit the new one with the same # of rotations and your steering alignment should be close (as long as the length of the new and old tie rod is the same). As I am fitting new upper control arms so my car needs a full alignment and ACC calibration once all the work is done.

Next task was to fit the new upper control arms, I know that some people pre torque them in position. I didn’t do that as I would rather torque that with the car sitting in the right position on its wheels, and its easier to fit them if they are loose enough to move around. I had to replace my struts, so I have the complete assemble out of the car, one thing to check is the 3 suspension mount threads. The mounts aluminum and very easy to damage/cross the threads. One strut had already been replaced on my car but on refitting they had stripped one of the treads, probably driving the bolt straight in with an airline driver. I replaced mine with a used one for $50. I’d suggest either running the bolt or even better a tap through the treads first to ensure they are clean.
Then refit the strut assy, place the top of the strut in place first, then lift the bottom of the strut over the lower control arm and slide the lower bolt on place to hold it. Once in place insert the upper 3 bolts by hand to ensure you thread them correctly as noted above. Tighten them sequentially to pull the mount into place. Then lightly tighten the lower bolt, but don’t fully torque it up yet. Attach the airline connection and electrical connector.

Then slide the upper control arm ball joints in the hub/suspension casting, I gave them a very light smear of anti seaze, and a light smear on the pinch bolt shaft (but none on the thread), just to make removal in the future easier.

Refit the sway bar with new links.

Once both side were done I fitted the wheels, and lowered the car. Don’t lower it to the ground yet, but enough that it senses when you start it that it needs to pump up. Start the car and let it pump the suspension up, once it is up and stable remove the jack and let the car sit on its wheels.

I then torqued the axle bolt up, the easiest was I found to do this is us a 6 inch extension on the socket, then put an axle stand under the extension, so when you lever the breaker bar to tighten, you keep the socket square to the bolt.

I then started the car, set the suspension to auto and drove the car at 5mph to the bottom of my drive and back. DON’T DRIVE IT ON THE STREET AS YOU HAVENT TORQUED THE SUSPENSION UP.

Parked the car back on the lift and left it to idle for a few minutes to settle the suspension. Then switch the car off and you can just get your hand in between the wheel and fender, now mark a line with a sharpie across the upper control arm and mount as a reference. Jack the car up and remove the wheels for better access. I then place a floor jack under the brake disc (with a piece of wood so you don’t damage the disc), then jack the suspension up until the sharpie line you put on the control arm and mount are aligned (essentially mimicking the cars ride height). Then torque up the upper control arm mounting bolts and lower strut bolt. Do the same for the other side. Refit the wheels and you’re done.

I haven’t driven the car yet as mentioned I want to replace the PCV first. But started it again and left it to idle and settle the suspension. I’m pleased that I don’t have any warning lights after the engine work and nothing seems to be leaking.

I also want to let the car stand to make sure I have addressed the dropping front end, in an earlier post I commented that I thought both front struts were original and leaking. But once removed I realized the LH was original and the RH was an Arnott replacement with a 11/15 build date. Previously the car would drop at the front within 24 hrs. I left it overnight and the old Arnott on the front and one of the back corners seem to have dropped about 5mm after 12 hrs, I’m going to measure it over 48 hrs and see how it goes…

Sorry for the long write up, it was a busy weekend and I have a running car, sort of , cant wait to start driving it.

Coming up to 48hrs after working on the front suspension and replacing the front LH strut and all its not well.

Quick recap, the front end of the car was dropping (both sides pretty equally) when I purchased the car. When I stripped the suspension out I found that the LHS was the original and the RHS was an Arnott replacement build 11/15. I have no record from the PO of, if or when he replaced the RHS, but guess it was around 35-40k ago based on the dates on the Carfax.

So the car is dropping as follow at arpund 48 hrs standing:

LHF (New remanufactured Arnott) 7-10mm
RHF (35-40k old Arnott) 20-25mm
LHR (OEM 20k old) 0-3mm (I think it just settled slightly after my initial measurement)
RHR (Original) 5mm

I sprayed the RHF with soapwater and cant see any leaks, to be honest I think the LHF dropping is the sway bar pulling it down when the RHF is losing air.

I have ordered a remanufactured Arnott for the RHF, should be here by the weekend.

In the meantime, I will start the car again and pump up the suspension and disengage the front sway bar and disconnect the battery and measure again over the next day or so.

So there is a leak in the air system. but your not sure if its the air shocks or not.

Great posts by the way. lots of good work.

Thanks Justin, working on these cars is a pleasure.

I think the RHF strut is leaking and with the sways attached it was pulling down the LHF. Last night I disconnected the sways and the battery. This should give me a more accurate guide as to whether that assumption is true.

I also think I have a very slow leak on the RHR, which is the original Audi strut so at 95k and 10 yrs it is probably on borrowed time!

As mentioned I disconnected the front sways and the results after 48hrs are as follows:

LHF (New remanufactured Arnott) 10mm drop
RHF (2yr old/35k Arnott) 33mm drop
LHR (OEM ) 10mm raise
RHR (Original 95k) 14mm drop

Interesting that with the sway disconnected the rear left raised, I guess it is basically like a table with a short leg, you press down on that corner and the opposing corner lifts. The RHR original shock is showing some signs of age and I think I will keep an eye on it.
The interesting one is the LHF which I just replaced with a remanufactured Arnott. This weekend I will check the valve block and the airline connection to the shock to be sure that id good. Maybe that level of drop is to be expected. I’m not totally comfortable by it, but at the same time I don’t see the value in replacing struts on these aging cars with OEM at a cost of $1,800 a go. Trying to be pragmatic, if it means my compressor works a bit harder and every few years I have to replace that then so be it. My wife has a 1yr old Grand Cherokee, and that automatically lowers itself around 25mm every time you get out of it and the pumps it back up every drive, so I guess my 5mm a day shouldn’t be an issue.

I trust Arnott on the replacement warranty if the problem worsens, I called them about the bad shock and if I could have proved purchase they would have replaced it under their warranty, which is pretty good service considering I wasn’t the original buyer. Unfortunately, I don’t have any record of purchase and attempts to contact the PO has failed. I also had Arnott’s on my wifes previous GL450 with no issues.

As its only an hr or so’s work to replace them, maybe that is the price to pay to keep a a 10yr old top of the range Audi that’s worth 15% of its original list price on the road without breaking the bank. I guess time will