Cat To Y Pipe Blowing; Again.

[sir john]

I have botched this up with various types of "metal in a tube" things for the past 3 years now.

Im think about permanent salutions now.

Option 1; pay someone to weld the pipes; c£60.

Option 2; buy a MIG welder and have a go myself; c£150 and I will have a welder at the end on the job.

If I do it myself I will be doing it with the pipes still on the car.

[ManicMark]

May be obvious but if doing it on the car disconnect the Battery. Mark

[sir john]

May be obvious but if doing it on the car disconnect the battery. Mark

Good point. Thanks for that Mark. It is obvious but I would have forgotten to do it.

[ambermarine]

I have botched this up with various types of "metal in a tube" things for the past 3 years now.

Im think about permanent salutions now.

Option 1; pay someone to weld the pipes; c£60.

Option 2; buy a MIG welder and have a go myself; c£150 and I will have a welder at the end on the job.

If I do it myself I will be doing it with the pipes still on the car.

I did this on this on the Mark 1 just before I sold it in July the problem is according to the guy that did it, is getting the different metals to amalgamate without burning through the pipe .there are a minimum of three, cast steel, stainless steel and copper in the gasket if it is original .He ended up using thin wires to act as conduits for the weld to run round the joint and it needs a lot of skill and experience.The main problem is that even if the weld is successful the y pipe as become thin and fragile and the intense heat knackers it as happened with the Mark 1 as the guy who bought it found after he had driven it home for 250 miles it was blowing from the pipe not the joint. This problem on my car acted as the catalyst in its departure as I saw good money going after bad in the long run.

[black400]

on my old 7series bmw i had a leaking petrol thank and exhaust , had the thank rerapted at about 200 euros went again , it was under warrenty but so much hastle car of the road for two weeks ect . i got a fix called super steel about 8 pounds , its a two tube job and worked wonders , even the mechanic could not belive the results , never leaked in the two more years i had the car.

[Stevie 79]

I had the same problem I priced a new Y piece £340 from Lexus I ended up gping to a place in Leeds and the fitted a new stainless exhaust from the cat back for £349.

[ROYT]

I had this on my'94 model.

The cat flanges are not stainless and rust away to a thin mess.

I had to replace perfectly good cats because of this. [aftermarket half Lex price] and get a new Y pipe.[genuine Lex]

Again just bcause of rusty flanges .

A waterjet cutter could make new flanges easily, but from where and who can accurately weld them on.

A costly job, having said that they did last 15 years..

If you remove the cats take care not to break the upper fixing bolts, or it's likely the the exhaust manifold might have to come off.

Patience and WD 40 on these!

[sir john]

Thanks for the responses and ideas guys. Its not worth buying new cats and y pipes. The cars is 19 yrs old, on 191k miles and is not mint.

I have tried the super steel type stuff a coulpe of times and it does do the job, but it nly lasts a few months.

My other thought, and im sure i have seen these somewhere, is bolt on flanges. A flange in 2 halves that bolt together to form 1 flange. 1 of these for each cat and 1 for each end of the Y pipe.

Hope that makes sense. Problem is, i cannot remember where i saw them.

[ROYT]

Google 'split flanges', I thought of this but couldn't see any beefy enough for the job, when I looked.

My '94 has only done 70 odd thousand miles so I chanced the expense..

[ambermarine]

I looked at that flange idea and actually found some in the states were the correct diameter but on closer inspection found that there is'nt enough straight edge run to fit them on the existing pipes.