silverbullet1

After having searched the web for help with changing the rusty/dangerous subframe on my 1996 A4 B5 2.6 V6, I have decided to leave a message to help others where I had none.

I was changing the oil/filter on my car and I happened to notice some rust around the lower rear suspension arm. I gave it a quick poke with my finger and hey presto my finger went through! There was no choice, if I wanted to keep the car I was gonna have to replace the front subframe. After some messing around I managed to locate a replacement second hand subframe from an Audi breakers yard. The replacement subframe was in great condition with a few scratches, the four huge rubber bushes seemed to be in great condition too. This happened only after I had been supplied with a 4 Cylinder subframe (from a so called Audi expert). The difference between the two is (6 Cylinder) has two symmetrical "half moon" style gearbox mounts. The 4 Cylinder version only has one "half moon" gearbox mount on one side and a "block mount" on the other side.

TO DO THE BUSINESS..

1. Jack up the front of the car.
2. Secure the car with GOOD axle stands (so that when shaken, the car does not move".
3. Chock securely the rear wheels (handbrake on, leave in gear).
4. Remove the flimsy un-Audi like tray from under the engine/gearbox area (big flat screwdriver).
5. Now remove the lower suspension arms from both sides of the car, this is no real challenge but the rear ones have a long bolt which does foul slightly on the body of the car, if you have real dramas removing the bolt, then you must gently release the large 18 mm subframe bolt and the two 13mm bolts which hold on the load spreading plate. When you have slightly released these bolts, you can get a pry bar and gently pry the subframe down in order to remove the bolt. To remove the lower ball joints you're gonna have to either use a ball joint separator fork or a ball joint compression tool.
6. BEFORE YOU GO ANY FURTHER... You must support the weight of the gearbox using a suitable block of wood on a trolley jack. Failure to do this will end in drama that you just don't need.
7. Now you can release the four x 13mm gearbox mounting nuts.
8. OK go to the front two 18mm subframe mounting bolts and release them all the way until they are removed.
9. Remove the rear two 18mm subframe mounting bolts and release them all the way until they are removed. (Also the two on each side 13 mm bolts from the load spreading plate).
If you now look at how the subframe sits (looking upwards at the front end of the car), you will notice that it is lined up with the alloy engine mount assembly, this is a very good datum for you to use when you put the new subframe in to make sure that its lined up absolutely exactly..
10. If you grab hold of the subframe, it should now move up and down a fraction, but, you are going to have to gently and slowly slightly release the engine mount 18 mm bolts which are located slightly forward of the subframe bolts (you will find that you do not have to do too much unscrewing to get enough room to remove the old subframe).
11. Now you can puff pant and wrestle out the old subframe, doesn't take too long, obviously, if its not coming you may have to release the alloy mount bolts a little bit more.
12. With the old subframe out you can now have a cup of tea and a cigarette bask in the new skills that you have. You can now transfer the plastic undertray mounting frame to your new subframe if needs be.
13. RE-ASSEMBLY is the exact opposite of what we've just done. Take your time, you MUST make sure that the new subframe is lined up exactly where the old one was. When you have bolted the new subframe up to the car, the 18mm subframe bolts should be torque tightened to 81 lbs/ft and then a further 90 degree bend (plenty tight). Almost all Audi dealers and good garages would urge you to change the subframe mounting bolts for new ones... I didn't, that's just the way I roll, If you really feel the need to do this, it's up to you.
14 Finally, I'm sorry I haven't any photos, the job was a big enough kerfuffle without messing around with a camera, I hope this thread is of use to somebody. Good luck.

silverbullet1

Sorry guys just reading through my post, should have mentioned that you should remove the front wheels once the car is jacked up on axle stands. Also when I replaced my subframe I also replace all the control arms, it's an ideal time to do it if yours are in any way tired or worn.