Volkswagen Passat Forum banner

1 - 18 of 18 Posts

·
Registered
Joined
·
257 Posts
Discussion Starter #1 (Edited)
I have a 2003 Passat Wagon 1.8T and the exhaust connection has rusted away near the flex pipe. The flex pipe itself does not appear to be broken but it's hard to tell because of the braiding. The downpipe (which the flexpipe is part of) was cut after the mount point and every few years meineke has welded on a new flex pipe. The transition from old to new (red arrow in pics) is where it rusted away and now it's making noise again.





Temporarily I've stuffed some versachem exahust crack sealer all around the crack to hopefully help with the noise. I'll find out tomorrow if that works but even if it does I doubt it will last because there's a lot of vibration there. The weld is completely gone so it's just one pipe in another.

I was thinking about repairing it myself this time. Though the flex pipe is not leaking yet obviously I would replace it. That old pipe is so rusty at the end that I'm not sure if I can weld on to it. I am not opposed to buying a new pipe except that it looks so difficult to disconnect the old one from the catalytic converter. The flange nuts look rusted away (unfortunately no pic of that). Also reviews for Bosal and Walker replacement pipes (they call them intermediate pipes) for this car say that the mounting tab is in the wrong position and needs to be welded. Which makes me wonder if it's worth it if they can't even get the pipe right.

Here are some pics of the pipe measurements and the pipe clamp further down (also with rusted away nuts).





Given how it looks what would you guys do? Has anyone here had to deal with a similar cut that was going bad? Any suggestions for brand or size of flex/intermediate replacement? Do you think it is possible to fix this without welding? I hesitate to weld under the car given how tight the area is.
 

·
Administrator
Joined
·
23,301 Posts
I have a bosal one and it fit just fine. No modifications. Amazon Prime was pretty cheap. Less than $100 iirc.
You just need to remove the DP and cat as a single unit, then separate them, bolt up the new one to the cat, and bolt the cat back onto the turbo. You will need new bolts and copper nuts for the cat to DP, new nuts for the cat to turbo, and a gasket for the cat/turbo and cat/DP..
 

·
Registered
Joined
·
257 Posts
Discussion Starter #3
Thanks for the info I am thinking about doing that. First I have to price all the parts. Do you remember how long it took? Did you use anti-seize?

The versachem cement seems to have helped a little but I have a feeling it recracked because I could hear it at odd times on the highway. But it was like completely random, like I'd slow down and rev back up a little and hear it sometimes but not other times. So it did something.
 

·
Registered
Joined
·
1,333 Posts
I second the "bosal" brand, I got mine at Advance Auto,90 bucks 3 years ago, they use an internal "string of pearls" internal mandrel so there is nice smooth transitions unlike a lot of manufacturers with "pleats" at the curves, fit was perfect,and as suggested by some seasoned forum veterans, since I am in rust belt , cleaned and painted with hi-temp paint
 

·
Registered
Joined
·
136 Posts
Part link?

Just got a quote of 600 for two new intermediate pipes and flex pipes....i told them no thanks.
2002 2.8 ATQ 4mo GLX wagon.

Did they mean down pipes? I am not so familiar with the whole layout of this exhaust (unlike my titan's....still up in the air, I got passenger's side done, but I broke a stud on the drivers side exhaust manifold....and I don't have a hot enough torch.
 

·
Registered
Joined
·
257 Posts
Discussion Starter #6
Part link?

Just got a quote of 600 for two new intermediate pipes and flex pipes....i told them no thanks.
2002 2.8 ATQ 4mo GLX wagon.
There are different part numbers for different engines, for manual and automatic transmission, and for 4motion and non-4motion. Yours is two runs of similar pipe and mine is just one. I've uploaded the relevant pages from ETKA to my dropbox, hopefully that helps. As you can see in illustration 253-75 Page 1 it looks like there's two catalysts for yours and I'm not sure whether that's a flex pipe next to them. The connecting pipes (or I guess you'd call them intermediate pipe) each have a flex pipe. You'd have to get under there yourself to see what's broken unless they were nice enough to point out exactly what is.

ATQ and AWM mufflers - 4MOTION - 253-90 Page 1
ATQ and AWM mufflers - NON-4MOTION - 253-85 Page 1
ATQ front muffler pipe - 253-75 Page 1
ATQ front muffler pipe - 253-75 Page 2
AWM front muffler pipe - 253-55 Page 1
AWM front muffler pipe - 253-55 Page 2

I haven't ordered yet but I'm probably going to go with the aftermarket Bosal intermediate due to the recommendations here.
 

·
Registered
Joined
·
136 Posts
There are different part numbers for different engines, for manual and automatic transmission, and for 4motion and non-4motion. Yours is two runs of similar pipe and mine is just one. I've uploaded the relevant pages from ETKA to my dropbox, hopefully that helps. As you can see in illustration 253-75 Page 1 it looks like there's two catalysts for yours and I'm not sure whether that's a flex pipe next to them. The connecting pipes (or I guess you'd call them intermediate pipe) each have a flex pipe. You'd have to get under there yourself to see what's broken unless they were nice enough to point out exactly what is.
Thanks! 4Mo 2.8L ATQ Auto Wagon. Yeah I know I need to get under it, just lack of time - plus I need to get my truck back together. and get my lawnmower up and running as pretty soon you aren't going to be able to see anything shorter than 3 feet at my house.

I haven't ordered yet but I'm probably going to go with the aftermarket Bosal intermediate due to the recommendations here.
I have ordered some Bosal and Eastern Catalytic stuff for my Titan. I haven't had a chance to put it all back together and use it, but seems solid and well built.

Also where in Westchester? I grew up in Irvington. I was supposed to be there this weekend but that is not happening.

I didn't take these pics, but pics of the bottom of passat in question....from the shop.
2019-05-29 (1).jpg
you can see some of the braiding on the flex pipe failing.
2019-05-29.jpg
 

·
Registered
Joined
·
257 Posts
Discussion Starter #8 (Edited)
Also where in Westchester? I grew up in Irvington.
New Rochelle (Southern Westchester NY)

you can see some of the braiding on the flex pipe failing.
I can't tell but I'll take your word for it. Let us know what happens, I am going to do the same... and speaking of that:

I received the Bosal intermediate pipe 860-975 from Amazon today. The flange holes are very big. They are oval holes 13.5mm x 12.5mm. The nut's flange is about 17mm so it may work but I don't like the idea that it can just move around with an 8mm bolt in those big holes. Interestingly the gasket for that flange Bosal 256-339 I also have and its holes are normal 8mm size. Did those of you that used Bosal have any problem with the large holes on the flange?

 

·
Registered
Joined
·
1,333 Posts
yes , they are (from Bosal) way "large" , see if 10mm bolts fit in your cat, I will check when I get home, I 'm pretty sure I got 10 mm bolts (stainless) and nuts (stainless)from Ace Hardware and then "double" nutted to keep them secure.
 

·
Registered
Joined
·
136 Posts
yes , they are (from Bosal) way "large" , see if 10mm bolts fit in your cat, I will check when I get home, I 'm pretty sure I got 10 mm bolts (stainless) and nuts (stainless)from Ace Hardware and then "double" nutted to keep them secure.
Fastenal if you have one local
Zoro.com as well ( I think they also list on ebay and amazon)
 

·
Registered
Joined
·
257 Posts
Discussion Starter #11 (Edited)
I still haven't done this yet, I've been delayed by bad weather. Probably for the best though since I almost was hurt by a scissor jack that went bad as I was jacking up each side more and more to get a good height, and it gave me time to think, you know, that I don't want to die. Fortunately the car collapsed in the other direction and just missed my neighbor's fence. I've since bought a floor jack and some jack stands to get the car up high enough.

I also found some torque specs in an Audi B5 AWM manual series (Audi_A4_B5_97-2000) from searching.

"26-1 Exhaust system components remove and install" says:

Cat-To-Turbo: 30 Nm / 22.1 ft-lbs
Cat O2 sensors: 55 Nm / 40.6 ft-lbs
Cat-To-Pipe: 25 Nm / 18.4 ft-lbs
Pipe Mount Bolts: 25 Nm / 18.4 ft-lbs (the tab welded to the pipe with the hole and then there are two bolts that suspend it somehow)
Pipe Clamp: 40 Nm / 29.5 ft-lbs
Heat shield to transmission: 23 Nm / 17 ft-lbs (Audi recommends this for removal to remove the pipe, it looks like the tire will need to come off but it doesn't say that explicitly)

There's some cool procedures like for alignment in the PDF but I hesitate to post verbatim since I am unsure of the source and copyright.

I've since found in a Mitchell data document for engine overhaul for 2000 Volkswagen Passat GLX that lists 2002 Passat AWM specifically, and in torque specifications it says:

Cat-To-Turbo: 30 Nm / 22 ft-lbs
Cat O2 sensors: 50 Nm / 36 ft-lbs
Cat-To-Pipe: 40 Nm / 30 ft-lbs (50% more than the Audi spec, pretty big difference. past accepted max torque limit for an 8mm bolt)
Pipe Mount Bolts: not listed
Pipe Clamp: not listed
Heat shield to transmission: not listed

Does anyone have VW B5.5 AWM torque specs, are they the same as the Audi B5 AWM specs or VW Mitchell specs?
 

·
Administrator
Joined
·
23,301 Posts
If it's online without a password needed or pay to download, I can't see why not. Maybe a link?
 

·
Registered
Joined
·
257 Posts
Discussion Starter #13
If it's online without a password needed or pay to download, I can't see why not. Maybe a link?
https://www.dropbox.com/sh/ywwnbr7atw1wdxo/AACR38aCZ2KotYh_PahK5K6Fa?dl=0
Credit to mp3driver at audizine (post).

https://drive.google.com/folderview?id=1FYExZQHMsWCZ4uVlLIUx6fWRKkQjRyRn
Credit to Breppinq at audizine (post).

Engine Mechanical\1.8T%205V%20(%20AWM%20)\Exhaust%20&%20Emission\26-1 Exhaust system components remove and install.pdf

In the dropbox one if you try to access that over the web it will say "There was a problem completing this request." The workaround is just download the whole thing from dropbox (click the Download button in the upper right hand corner in the Audi_A4_B5_97-2000 directory) or use the google drive link (which appears to be a copy).

And the Mitchell AWM engine document is at http://passat.pavsweb.com/docs/aug_awm_engines.pdf
 

·
Registered
Joined
·
257 Posts
Discussion Starter #14 (Edited)
I'm about halfway through the job, it's already taken me 12 hours over 2 days. I'm not sure where the time went. I did take notes and pics and I will post everything when I'm done but right now I have one question.

The spring mount is crooked and has no flex, like the rubber bushing on the transmission is already loaded. Is that ok? It's supposed to hang directly down and flex a little but it's all the way over and there's no flex. I haven't even tightened it yet. Did anyone else with the Bosal have this problem? I checked the exploded view from the Audi manual and it is assembled correctly, with the pipe's mounting tab leftmost capped by the nut. So my guess is the mounting tab isn't an exact match. Here's a pic:

 

·
Registered
Joined
·
257 Posts
Discussion Starter #15
I didn't follow up on this thread right away because I knew it was going to be a long post and take some time to write. Long story short though I finished the job successfully 2 months ago. I used the directions in the Audi manual 26-1 that I referenced in an earlier post. I used the sections "Front Exhaust Pipe, removing and installing", "Catalytic converter, removing and installing" and "Stress-free alignment of the exhaust system - Vehicles with front wheel drive".

Also here's two good passatworld threads worth reading, though I didn't use them:

Question on replacing flexpipe section on 03 1.8t
How to replace the downpipe and/or catalytic converter on a 1.8T (DIY)


The rest of this post is my notes, is going to be kind of long, is for general interest in case you are in the same situation and is not a DIY. If you need instructions use the Audi manual and/or the DIY above.

The torque settings I used were all from Audi 26-1 except:
  • Cat O2 sensors I used Mitchell's 35 ft-lbs instead of 40 ft-lbs. The O2 sensors were a PITA to get off. I used a propane torch and destroyed one in the process. I put them back on with fresh anti-seize and didn't want to overdo tightening so I went with the lesser value.

  • Cat-To-Pipe I used 25 ft-lbs. There was such a big discrepancy between Mitchell and Audi that I decided to split the difference.

  • Cat-To-Turbo I used 30 ft-lbs instead of 22 ft-lbs because the 10mm lock nuts were harder than 22 ft-lbs to turn so I couldn't tell when it was actually torqued without a higher setting.

  • Safety crosspiece I used 55 ft-lbs. The safety crosspiece sits below the front pipe right before the clamp between the front pipe and the pipe to the muffler. I couldn't find torque settings for it so what I did was I made a mark on each bolt between the 16mm head and the mating surface and made it so I could tell which bolt was which and where they were tightened to. I used an impact driver to remove them because it required more force than I could apply without worrying about rocking the car off the jack stands. To reinstall both bolts to their marks took about 55 ft-lbs.

  • Note also Audi torque settings are in Nm not ft-lbs, I converted them because I use ft-lbs.
Pics and notes

I jacked up the front of the car pretty high, about 22". You can read the details in the related thread Jacking the front of the car up high but basically it looked like this:



I used an extra jackstand to hold up the muffler pipe. The front pipe (the pipe with the flex pipe I've been calling "exhaust downpipe" but which audi calls "front pipe") is clamped to the muffler (or is it resonator?) pipe. I did not load it up I just let the saddle contact the pipe at the normal height. I wanted to be sure that once the muffler pipe was separated from the front pipe that its weight couldn't possibly cause something in the back to break off. Here's a pic of that:



I removed the safety crosspiece (seen in above pic) and then the clamp. The clamp bolts were rusted on and I used a grinder with a cutting wheel to cut the straps off the clamp around the bolted area. I had tried to use a dremel to cut the straps but it was taking forever, the straps are very hard steel. Once I did that I was able to slide the clamp down the pipe to separate them.

At that point I was able to take out the broken off piece of the front pipe.

In the manual it says remove the passenger drive shaft heatshield after taking the wheel off. That is supposed to be so that the front pipe can be disconnected from the catalytic converter. Even with the shaft heatshield removed not all the flange bolts were accessible, so I decided to take out the cat as well. Later I would discover that the downpipe mating surface was rust welded to the cat, was hard to separate even when the bolts were removed and was not smooth. Here's a pic of the joint before I removed it:



I removed the airbox which was mostly easy except for two things. First I could not for the life of me disconnect that MAF sensor. I pivoted the flathead tip away from the sensor (what I thought I was supposed to do) but I just couldn't get it to come up. It did come up eventually but the connector lasp looks damaged like the plastic is too soft. Second thing is one of the rigid plastic hoses that runs above the cat was bonded together and took some time to break the bond with a hose puller. Here's a pic of that:



You can also see in the above pic that I used a cheater on my ratchet to remove the top cat nuts. I think I might have needed to use a wrench on one as well, due to clearance. To remove the lower one it looks like at one point I also used a wobble extension, and here's a pic of that:



I removed the cat (and the partial piece of front pipe connected to it) by twisting clockwise as I brought it up and out. My O2 sensors were seized on and not being able to remove them from the cat made things harder. I did disconnect the wires as it says in the manual so they were free to come out with the cat. Here's a pic of that:



The cat flange was destroyed on removal. It was rust welded on the cat and took some persuasion with a wood chisel to pry it off without damaging the surface of the flange. Even then I couldn't get it all off so I lightly used a wire cup brush on my grinder to finish up, and that took some time. If you've never used a wire cup brush before the individual wires can and will come off as you are using it and embed in clothes or possibly skin. I suggest wear a plastic face shield and make sure no pets or kids are around. Here's a few pics of the flange, before and after:





I also cleaned the other cat flange surface with the wire cup brush. The turbo flange surface felt smooth and appeared to be in good condition but I did a quick once over.

I removed the O2 sensors from the cat with help from a propane torch, which turned out to be a big mistake since the high heat likely killed one of the O2 sensors. I don't really have a good suggestion to remove the O2 sensors. If you use too much heat you could kill the O2 sensor but if you just hammer away with a sledge you could cause the brittle honeycomb material in the cat to break up and you might need a new cat. Just low heat I guess, use an infrared thermometer and point the heat towards the cat and not on the O2 sensor.

I tried reinstalling the cat and front pipe as one by threading the pipe down from the top and turning counterclockwise but I just couldn't make it work. I was worried about damaging the flex portion of the front pipe by bending and twisting it too much. Instead I reinstalled the cat from above and then installed the front pipe from below.

It took some time to jockey the front pipe in and get its flange to line up exact. As I mentioned in an earlier post I am using a Bosal aftermarket front pipe which has larger than normal flange bolt holes, possibly to account for that. I was able to get it exact though after I played with it for a while. I used some spacers I got from Lowes and cut to fit in the bosal flange bolt holes, to make those holes a little bit smaller so that it would stay centered. It was probably not necessary to do that but here's a pic of what i mean:



Tightening the front-pipe-to-cat flange nuts was going to be difficult no matter how I did it so I went with inserting the bolts through the top so that the nuts went on from the bottom (that is opposite how it's done OEM). That way I could tighten the nuts from below and I had a somewhat ridiculous setup to do it. I needed like 16" with the final being to a wobble to a universal joint since I needed a lot of play. That also made it hard to connect to each nut. From above I needed to stop the head from turning so I used a combination wrench which I held on with a block of wood. I think for another bolt head I may have used a tiny stubby ratchet but i'm not sure. There's surely a better way to do this if you have a helper or an S wrench but anyway I had neither. Here's a pic of the wobble to universal joint and of the wood holding down the wrench on a cat flange bolt head:




The mounting tab that extends from the front pipe to connect to the transmission mount bracket was not an exact fit so I used propane to heat it up and a linemans pliers to bend it about 1/2". Below is before and after pics. (Note in the after pic part of the mount bracket is missing, that was only temporary while I was working.)




The front pipe to muffler pipe connection I made using a new OEM clamp. I went OEM because I read of reports of aftermarket clamps leaking. I used some fine grit sandpaper on the outside of the muffler pipe in the area where the clamp would sit to get it smooth. Also I at some point I must have used a spare jackstand to hold up the new front pipe to properly align both pipes together before I put the clamp on. Here's a pic of that:



Before the pipe can be clamped together the muffler has to be preloaded which is described in the manual as "stress free alignment". Basically what you do is use something to push the muffler (and its pipe) forward like 10mm before clamping. I used an Irwin quick grip clamp and for the spacer I used a 10mm bolt. The manual says take the measurement from the back muffler hanger so that's what I did but I don't know if that's necessary.






That's it for pics if I remember anything else I'll add it when I can.
 

·
Administrator
Joined
·
23,301 Posts
Great instructions! I was able to remount the downpipe to cat and reinsert the assembly through the top which made it much easier overall. You just have to picture the pipe-to-cat orientation correctly. Then all I had to do was bolt the cat to the turbo.
 

·
Registered
Joined
·
1,333 Posts
kudos for the write up,excellant job and pics for the 1.8 owners ! I love the Bosals but as mentioned holes in flange way to big,ah but love the spacer you made so simple so effective! THANK YOU for the effort!
 

·
Registered
Joined
·
26,077 Posts
Good work, glad I don't have to worry about rust :p
 
1 - 18 of 18 Posts
Top