Removing downpipe-How difficult?

[bvolks73]

We were replacing the exhaust on my brother's 90 Jetta today when we discovered 2 holes in the downpipe. I'm not sure which turbo it has but there are 6 bolts holding the downpipe on and they all look really bad. I could hardly tell there were nuts on some of them they were so corroded. Are there any tricks to get them off without breaking? This is the first time I've touched a TD so I'm completely in the dark as to the easiest way to do it or the best place to take it apart. By the way I searched and didn't find anything.

[TurboJ]

It's not too difficult. The nuts and bolts should have a rust-remover treatment first (CRC or similar). The only thing that can be tricky are the C-clamps that hold the cast elbow connected to the rest of the downpipe. They can be forced off using some leverage.

[Smokey Eddy]

They aren't tricky with a long enough bar  :mrgreen:  :mrgreen:  :mrgreen:  :mrgreen:
I broke a bolt off in the turbo =(
Be very careful. MAKE SURE you use something like a  breaker bar or better yet an inpact gun because you musnt put any lateral force on them or they will sheer off  :cry:

[bvolks73]

So the down pipe is definitely cast? Looks like welding up the holes in it is out of the question.

[Smokey Eddy]

oh yeah it's cast

try uhhh
high temp JB weld?
or making a new bigger downpipe
Your friend/bro would find less turbo lag if you did that.

[theman53]

I have welded cast...it's very pretty. Might take it to an exhaust shop and ask them if they could fab up something or make one from scratch.

[bvolks73]

We're going to try the JB Weld first. If it doesn't work I guess I'll have to try remove the downpipe and replace it. I have 3 of them on motors already out of cars so getting a replacement isn't a problem.

[arb]

Heat is the friend to rust - it accelerated it on the bolts. It is also your best friend for removing very rusty bolts without breaking anything. Ideally you'd use an oxyacetylene torch and get the bolt cherry red. It will unscrew like a new bolt if you do this. Next best thing is a propane torch, but you'll have to heat it for 10 minutes or so to get it HOT. This will cause expansion that will allow the bolts to come out without breaking.

The turbo gets much hotter than a plastic like JB weld can stand. You'll just be making the pre-welding job a bit harder. If you don't have high quality welder, high carbon welding rod (TIG or gas), and the skills, get someone to weld it for you that has experience with welding cast iron.  If not welding correctly, it will crack even more.

I had to weld some cast iron on my project http://www.vwdiesel.net/phpBB/viewtopic.php?t=15633&start=0

[mk2diesel]

welding cast iron ...
preheat!  then use "nickle rod"  for strength  or "splatter rod" to just fill in holes   with an Arc welder

Migs and Tigs can weld almost anything ... quite often while still on the vehicle.

[Vincent Waldon]

welding cast iron ...
preheat! .

2X... with a torch, or stick it in the oven. :wink:

[Smokey Eddy]

yeah sorry the JB was sort of a silly idea but those other options are rarely available to most people without a lot of money to spend on it (ie. pay someone to tig it for you).

could try the JB...? maybe you can get high temp JB weld?

if you guys REALLY don't care you can use hose clamps and soup/pop cans

i had pop cans and hose clamps sealing up my exhaust for ages.

[bvolks73]

We fixed it temporarily but plan on replacing the downpipe as soon as possible (on a weekend in a garage). Hopefully none of the studs will break off. The bottom ones are not a pretty sight. At least it's sealed and quiet for MVI.