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[RichB]

Driving to work this morning I thought my car sounded a bit louder than normal, I turned the stereo down and thought the exhaust was leaking.  I checked it later and the exhaust has snapped where the right pipe joins the backbox, it is really rusty and doesnt look repairable.  Its been fairly loud since I bought it over a year ago.  Looking at the left pipe that looks almost as bad so think I will need a whole cat back system  I was going to go down Vauxhall tomorrow to buy it all, I have got the part numbers from the yellow book but I was wondering if I will need to buy any u bolts or rubbers etc or just reuse the old ones?  Also do I need exhaust paste?

I have never done any exhaust work before I have always taken it in to a garage.  Are there any tips for changing it over or should I buy the system from Vauxhall then get a garage to fit it?

Sorry for all the questions, cheers,

Richard

[unlucky alf]

i done my partners astra backbox today & it was a git to get off as the pipe wasnt rusty & when fitted before  the system pipe was right into the backbox, had to angle grind it off!, but as yours is rotten it may be best to take off the clamps then jiggle the box & see what happens, if the box comes away itll be easier to get to the connecting pipes so you can cut them off or maybe open them up with a hammer & chisel, when refitting use new u clamps as the chances are the old ones will be distorted or they may snap anyway getting them undone, just hope that the one you are taking off wasnt put on with shed loads of fire gum your rubbers should be ok to re-use.

[RichB]

I guess I will have to give it a go then and see what happens, I will ask them at the parts desk for gaskets and u bolts then but reuse the hangers.  So do I need exhaust paste?  Shall I get that from Halfords?


Cheers,

Richard

[unlucky alf]

im not a lover of fire gum but sometimes it has to be done, the main thing is when you put the new clamps in make sure they are only on the outer pipe & not overlapping onto the one you are joining to, but as near to the edge as you can, i also find that doing the nuts up evenly a bit at a time so you have the same amount of thread showing on each helps as it doesnt distort the clamp, if i were you by all means use the fire gum if you are unsure but dont go mad with it, its only an aid to sealing & not reliant on it. i dont know how your backbox is fitted but would imagine its straight pipes & not flanges so shouldnt be any gaskets or fire rings, cant really advise you where to get the box from but others on here are adamant on vx parts but if budget is a problem then an after market one would probably be cheaper, somebody else may come on here & advise you where to get it & how much to expect to pay.,,,,good luck

[Lazydocker]

If you want to go down the budget route... PM Jamesv6cdx... He's just got a really good pattern system by the sounds of it

[Andy B]

If you were going to try to reuse your middle boxes I think you'd REALLY struggle to get the remnants of the back box off the middle sections. I also struggled to undo the two bolts on each down pipe. Either shear them off like I ended up doing & re-tap, or drill out the sheared off studs with a clearance drill & use a nut & bolt or .... ask very nicely (and cheekily ) at an exhaust place to heat up & release them for you before you start.

[Big_Roger]

Hi,
Its a fairly easy system to fit yourself, but a bit heavy. Lot easier if you can get a hand from someone.

You will very likely have a problem undoing the flange bolts where the centre sections are joined to the cats. Lots of Plus Gas may help, as will heat, but may well snap a couple at least. Trouble is the bolts are screwed into tapped holes in the flanges on the cat side of the system.

Original bolts are HT steel, so if you have to drill out, tip is to drill about a 3 mm hole in broken bolt first, then open up with larger drill.

Even if you get all bolts out, if I were you I would open up holes to 8mm and use 50mm x 8mm bolts and nuts (preferably stainless steel ones) to put back on. Use two nuts on each bolt to lock them.

If the centre flange joints are not too pitted then should be OK without Firegum, but I think it makes for a more secure joint with it, only needs a smear. If you don't use Firegum on the rear pipe slip joints, then give a smear of grease, this helps to get the pipes into the correct place.

I don't expect you will need new support rubbers but as you have to take them off the chassis hangers to fit the system then you may well need the little clips that hold them in place 90323550 I broke several trying to get them off. (There are seven supports)
You can get the universally used "U" bolt clamps for the slip joints, but the best clips for the job are the Vx ones, a single bolt clamp type 90234827

HTH

Roger

[feeutfo]

did mine about 3 weeks ago, cat back with a twin pipe box £312 on trade club by the time i had bought 4 cat bolts and u clamp bolts. But you can fit 2.5 litre box with a single pipe for less. I did not need any rubber hangers or clips and re used my u clamps, but my car is 02 so you need to take age into account. Obviously your box clamps will be buggerd so new ones there.
The main issue with removal is the cat bolts. Chances are they will shear in the cat section and youll have to drill them out, dont drill all the way through first off, you may well find the bolt will come loose when drilled half way leaving enough good thread left to avoid retapping or as i had planned to put a nut on the end of the original bolt, stud pullers wont do it as the lip is in the way. Its better to get the bolt out in one peace obviously so try and undo it like your tapping a thread but in reverse, ie undo a little and do up a fraction then undo a little more
, do up a fraction and so on, it just gives the back of the thread a chance to clear. If its too far gone theyll just snap but its worth a try. Plus gas is highly thought of on here for penetrating rusty bolts.
Oh and youll need titanium coated drills, or what ever they are, as anything else might as well be made of chocolate.

Having read all that you may well think better of diy and i have to say when the first bolt snapped off, so did i... i guess it comes down to how able bodied and rich you are. But it is doable. Hth

[markey mark]

or i have a second hand pattern system you can have for £60 !

[JueV6]

I got a few spare miggies ......... i'm sure 1 will do the same job

[feeutfo]

can anyone tell me why on earth they put the thread in the cat section and not in the bit your throwing away? Hmm? Ffs!

[markey mark]

can anyone tell me why on earth they put the thread in the cat section and not in the bit your throwing away? Hmm? Ffs!

cause the rrp on a v6 cat is over £300  

[feeutfo]

can anyone tell me why on earth they put the thread in the cat section and not in the bit your throwing away? Hmm? Ffs!

cause the rrp on a v6 cat is over £300  

Oh i see, and the next join up the thread is on the manifold,and the thread is on the engine and the thread is on the chassie and before you know it you gota buy a new car koz the exhaust fell off at the only point where its not bolted together. Makes perfect sense.  

[MutantCav]

As your not far away could well be worth taking up Markey's offer...especially if your car is able to get to him and especially if the exhaust is all in one piece rather than seperated into the 3 parts...as you can just stick the exhaust straight on in one piece no need for gum and its much easier that way...

[tmx]

my backbox done this and theres no point fixing it as the backbox will problably be naffed inside i welded 2x 2 1/4 pipes to the exhaust system before backbox as a tempoary messure and got a brandnew genuine GM box for £100 of the local stealer btw non chrome ends