Brakes and exhaust system problems

I have a 2007 Passat turbo wagon and my cat converter got a hole in it the other day. I drove in morning and it was just noisy otherwise fine. My wife took it in afternoon and almost didn’t make it home. Could hardly make it up a hill and brakes had to be applied to floor. Anti lock would vibrate but not very responsive to stopping. Was towed to local mechanic next day and he thinks problems are related. Could the computer cause a breakdown of the brakes due to bad exhaust system? He says he can’t find ant leaks in brake system. He is waiting for the cat converter to come in to replace and hopes brakes will work again.
Anybody hear of anything like this?

Usually fed emissions warranties are pretty long on cats?

The two (three) problems may be related. I’m unfamiliar with your setup, but of the upstream oxygen sensor is at the forward flange of the converter and the hole is adjacent to it, it could easily cause air turbulance inside the system that would throw the reading off and cause the engine to run funky. Or, the computer could be causing it to run funky. Either way, if the engine is barely running and vacuum is low, you’ll be applying your brakes without assistance from the brake booster, which is vacuum operated. Without the booster, the brakes will seem ineffective and (in some cars) you’ll strain your brain.

Besides, it’s generally wise to fix what definitely needs fixing and then see how it affects a secondray problem. I support what he’s doing.

Thanks for the comments.
The emmisions warranty is 8yrs 80k miles. I’m at 84k. The mechanic checked on that first.
Fixing the cat seemed to fix the brake problem. Oxygen sensor was salvagable one cat mount hole stripped had to be retapped. Expensive!!!

But not as expensive as it could have been!

Happy motoring. And thanks for the followup post.

Final outcome:
Cat was completely cut at flange near engine. Not sure how could have happened like that. When pipe dropped down hot exhaust blew on brake booster vacuum hose and melted it- so no brakes! Mechanic said if any kind of oil leak car would have ignighted. Just glad happened when and where it did. I hope there is nothing causing pipe to be cut and it was just wear and tear.
Thank you for previous advice- was very helpful

I wonder if there was a “crew” in your area cutting off cat converters. Criminals have been known to do this to sell the converters on the black market or return them for recycling. They’re worth enough cash to stimulate such activity.

I’ll ask around and mention it to my mechanic. It certainly looked like a clean cut.
Thanks again!

" Comprehensive Insurance ? "
Save Old Parts, Just In Case.


Someone heisting the converter is a very real and common possibility.

Not too many years ago someone’s car broke down on the Interstate in OK City and they left it on the shoulder. When they returned a few hours later with a tow truck, the tow driver noticed as he was winching it up on the flatbed that the converter was gone and only fresh cuts remaining where the converter used to be.

Someone had stopped and sawed the converter off in broad daylight with thousands of cars passing by so it illustrates just how far some will go to get them.

Well I continue to learn alot from this experience.
My mechanic said that he does see alot of converter theft. He said one dealer in the area had 12 stolen one night!
He thought that if mine were cut the edges would have been more jagged and they would have started at the back end. He thought it was possible but didn’t think so in my case.
The one he put on has a 5yr 50k warranty so hopefully that will last me till its time for another car.
Thanks for all the posts!