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[grifter]

Going to be changing rear centre sections and back box, just wondering what surprises i'm likely to experience when removing. Obviously not caring about join between back box and centre sections just when it gets to join to front of exhaust. Is the next part of exhaust the cats and studs likey to break?

Cheers

Andrew

[BazaJT]

When I did mine recently one of the centre pipes had rotted through just before the back box so when that was out of the way I hacksawed through the other one.The cat bolts needed lots of heat but even then one still sheared off and needed drilling out I  replaced them all with nuts/bolts.

[Nick W]

The issue is whether the centre section to cat bolts undo. If you have to drill them out, that can take some time. If they've been replaced before then you can just cut them off.
Then it's a quick slice through the rubbers and gravity drops everything to the floor.
5 minutes maximum if it goes well.

[grifter]

Cool thanks for advice, will check cat to centre section bolts for rot and give some penetrating fluid. Got a loan of a ramp to do job so want to make sure i dont end up with a problem while doing it.

[ajsphead]

Getting the exhaust apart is one thing. the rust on the floor pan above the back box that you'll discover may be something else.

[steve6367]

Ir you have GM rubbers on there, don't slice them - remove and reuse - much better than those that come with the cheap replacement exhausts (which are otherwise excellent) and crack in short order.

[DrAndyB]

Make sure you have a couple of drill bits ready 

I was going to do mine, but local garage offers £15 to fit my new one    Glad I snatched their arm off took them up on their offer as one out the two on each pipe by cat was seized.

If you have a ramp, then all should be OK, but yes as already mentioned try to use the existing rubbers if GM originals.

I got an ETS 3.0 V6 system and love it. 

[mantaray]

As said above, bolts can be a pain, but not a hard job, just give yourself plenty of time.

[TheBoy]

Make sure you have a couple of drill bits ready 

Chrisgixer and I got through 23 drill bits changing the exhaust on TBE last year.

[terry paget]

Make sure you have a couple of drill bits ready 

Chrisgixer and I got through 23 drill bits changing the exhaust on TBE last year.

I have similarly made hard work of drilling out the old bolts. There clearly is a good way of doing it, garages do it with confidence, forum threads say' just drill them out'. Please advise.

[Nick W]

Make sure you have a couple of drill bits ready 

Chrisgixer and I got through 23 drill bits changing the exhaust on TBE last year.

I have similarly made hard work of drilling out the old bolts. There clearly is a good way of doing it, garages do it with confidence, forum threads say' just drill them out'. Please advise.

Use good quality drill bits.
If the surface you're starting with isn't flat, make it so.
Make a heavy centre punch mark in the middle of the bolt.
Start with a 4mm bit, at the correct speed, with plenty of cutting fluid. Use oil if that's all you have.
Drill straight!
You should then be able to use an 8.5mm bit to remove what's left of the bolt.


Cheap bits, overheated or broken are the usual problem. Sometimes exhaust bolts can be really hard, which leads to trying to cut corners.

[terry paget]

Make sure you have a couple of drill bits ready 

Chrisgixer and I got through 23 drill bits changing the exhaust on TBE last year.

I have similarly made hard work of drilling out the old bolts. There clearly is a good way of doing it, garages do it with confidence, forum threads say' just drill them out'. Please advise.

Use good quality drill bits.
If the surface you're starting with isn't flat, make it so.
Make a heavy centre punch mark in the middle of the bolt.
Start with a 4mm bit, at the correct speed, with plenty of cutting fluid. Use oil if that's all you have.
Drill straight!
You should then be able to use an 8.5mm bit to remove what's left of the bolt.


Cheap bits, overheated or broken are the usual problem. Sometimes exhaust bolts can be really hard, which leads to trying to cut corners.

Thanks. I used smaller starting bits, which used to break. I presume the correct speed is quite slow. I shall try it next time the need arises.

[Andy B]

Make sure you have a couple of drill bits ready 

Chrisgixer and I got through 23 drill bits changing the exhaust on TBE last year.

Did they come from Poundland? 

[Nick W]

Thanks. I used smaller starting bits, which used to break. I presume the correct speed is quite slow. I shall try it next time the need arises.

Not really; a quick look at the required speeds suggests over 2000rpm for a 4mm bit, and about 1000 for the 8. Those are about what a 2 speed cordless drill manage. Which is handy

[Doctor Gollum]

Alternatively, tighten the nut until it shears off, then hammer the bolt out...

Failing this, notch the flange, then knock the bolt out...

Just be mindful that using an angle grinder in a confined space under the car might result in impromptu face removal surgery