new De Dion tube installation

[peter clarke]

Seems to have been several sessions on De Dion tubes again so I thought I would post a note on my replacement (did it yesterday), as some advice in tech talk was to take off callipers and break pipes and drive shafts etc, which I felt was unnecessary, but made me a little concerned as to how long it would take, to say the least. There is a lot of good advice on here but also some is questionable. Car is a 1997 S3, damage to tube was the normal cracking/splitting around the bottom damper fixing.

 

So:

Jack rear up, put on stands, wheels off.

Remove dampers completely. You need to undo the bottom anyway and removal makes access much easier.

Loosen the 4 rear bolts to De Dion ears.

Loosen bolts to link arms, detach ARB links first if you have them.

Loosen bolt to A frame.

Remove nut holding rear brake line to tube and cut off nylon ties holding brake pipe to tube. Push off the brake T piece

Now you know that everything that needs to be undone is undone (sigh of relief), take bolts off, support ends of the drive shafts as they move out and drop (I used axle stands) and then rotate and slide the tube out.

 

Take some well earned refreshment and then pop the new tube in and reverse the above procedure.

 

If you want to replace the diff oil it is a good time to do it as access is easy. I also put rust protector in the tube before assembly.

 

So how long did it take? Less that 4 hours and that includes cleaning all tools and putting them back plus cleaning the floor etc.

 

Hope this is of help.

 

Peter

 

 

[charlie_pank]

Peter, I found that with the diff in there, there wasn't enough room to rotate the DD tube because of the big triangle shape that the A-frame bolts to - maybe you have more clearance than me between diff and DD tube? Which is why I took the caliper off the ear and then pulled the driveshaft and ear right out of the car and put to one side. Also, I found that I didn't need to remove the dampers completely, but could just leave them hanging.

 

With your method and the standard copper lines all the way to the calipers, you need to be VERY careful as when the 'ends of the drive shafts ... move out and drop', the hub, driveshaft, caliper and de-dion ear is hanging on that copper brake tube! I fitted flexi-lines from the T-piece to the caliper a while ago, so I didn't need to disconnect the brake lines to take the calipers off - it's only 2 bolts on each caliper after all, and once that's done there's nothing else to undo before pulling the whole hub and shaft out of the diff and out of your working area. The diff oil level should be such that it doesn't come out through the driveshaft hole when you pull out the shaft.

[peter clarke]

Charlie, thanks for the additional information, it makes it more clear. I know all Sevens are a bit different but surprised you had problem taking the tube out, with mine it just need pushing up, a small twist and slide it out. Even if I had left the dampers in would not have been a problem.

Second point noted, that is why I said that it is necessary to support the ends of the drive shafts, which is easily done. I can see your reasons if you have flexible brake pipes, but to remove the rigid ones and then have to bleed the brakes is a pain, so no point in doing it unless you have to!

 

Peter