Weekend project: re...
 

[Closed] Weekend project: replace car exhaust.

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What fun!

So, I have a new full exhaust. Well, not the downpipe/cat etc. But the mid and back-box. A kit with the two parts and all new clamps and rubber hangers.

Here's my plan.

Go out in a minute, squirt WD40 on the clamp nuts connecting the old mid section to the cat. Maybe later, possibly tomorrow: car up on stands, remove entire old rotten exhaust (hopefully without too much lost knuckle-skin and without using the angle grinder)

Assemble new exhaust on the ground using old as a guide. Do I definitely need to use paste on the joins? And if so, will [url= http://www.autosessive.com/products/61262/pro-seal-red-hi-temp-rtv-silicone-instant-gasket-85g?fo_c=1195&fo_k=b3a1f149910d537ca50e1c9c870f5557&fo_s=gplauk&gclid=CjwKCAjww9_MBRAWEiwAlaMJZgTT3AfewWNSsI2gK_G5rGexwD0H-n_n-NQA2rOfs73aUkDNuduZ5BoCDF0QAvD_BwE ]this[/url] do? I've got some left over from another job in the spring. Can always nip to Halfords though so not a problem if not.

Anything I've forgotten? Any tips?


 
Posted : 19/08/2017 10:33 am
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I see you said not using an angle grinder but that would be my first port of call. plus fit on car as you can tuck into recesses as required, do not try to match on ground and get fairy liquid for the rubbers to slip on. I would use paste as it gives a proper seal (if it leaks its MOT fail and will be harder to sort after several months use.Think that stuff you are looking at is more for engine casings see link below. try starting car and taking for run to see if exhaust is hitting body and adjust as required.

http://www.halfords.com/workshop-tools/garage-equipment/head-gasket-exhaust-repairs/holts-firegum-150g?cm_mmc=Google+PLA-_-Garage+Equipment-_-Head+Gasket+&+Exhaust+Repairs-_-741520&istCompanyId=b8708c57-7a02-4cf6-b2c0-dc36b54a327e&istItemId=litwwq&istBid=tztx&_$ja=tsid:94971|cid:865695754|agid:42483194623|tid:aud-297219197929:pla-394228274317|crid:203186037810|nw:g|rnd:5845529013286538250|dvc:c|adp:1o2|loc:1007132&gclid=EAIaIQobChMIlp-y-JPj1QIVYbHtCh3JdgsMEAQYAiABEgL73PD_BwE


 
Posted : 19/08/2017 12:05 pm
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Might as well piss on the bolts than use wd40.

Get a proper penetrant spray...

How ever as above I'd probably just go straight to rotary spanner for an old exhaust.


 
Posted : 19/08/2017 12:08 pm
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Thanks chaps,

Sacked it off till tomorrow as it was a bit rainy.

I'll get some paste, I just had some left over instant gasket from fitting a thermostat housing in the spring so thought I could use it up. But you're right, only want to do this once. Good call about fitting on car and fairy liquid.

When I say WD40, I mean my own special blend of olive oil and the ex's nail-varnish remover 😀


 
Posted : 19/08/2017 8:45 pm
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Usually quicker to split your nuts so to speak.
Or belt an old socket on and snap them off (not if the 'bolt' is a stud mind you...)


 
Posted : 19/08/2017 9:12 pm
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Any tips?

Get it done by an exhaust place.

Based on my experience of replacing an exhaust on a Renault 18 years ago, I would say that no amount of money would persuade me to do it again.

If you do insist:

Get some Plus Gas on the nuts (unless you have oxy-acetylene gear);

Assemble the new bits in-situ, starting from the front;

Prepare to be massively frustrated.

Enjoy the toughest neck/shoulder workout you've ever had.


 
Posted : 20/08/2017 12:03 am
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It's fiddly to get everything lined up. And you're going to get rust in your eyes. But other than that it's simple.

Assemble it without paste then do it again with paste, don't try and do it all at once. Getting old exhaust rubbers off can be a pain, I've ended up cutting them off the last couple of times.


 
Posted : 20/08/2017 1:16 am
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You may be pleasantly surprised- I recently changed the original never been removed full system (cat, mid, and tail pipe) on my 13 year old Volvo and like yourself was dreading it.
I went to Volvo and bought every single fastener and gasket involved in the job (~£50) and was fully armed with grinder/dremmel/blow torch/massive amounts of Wurth rustoff and it turned out to be the easiest car tinkering job I've ever done, every single fastener came undone without swearing once.

However if it's not the worlds best engineered and manufactured car (Volvo) and you don't have the luxury of your own 2post hydraulic ramp/lift then you are truly ****ed my friend! Expect hours of swearing, bloody knuckles, a job that runs way overtime, crap quality parts made by someone who has no idea what the car is the parts are supposed to fit, rust filled eyes, mithering mobile phone calls at critical points, rain water dripping on you, the dog wanting to play whilst your underneath, days following of neck pain and the required spanner always being just out of reach!
Good luck!


 
Posted : 20/08/2017 6:44 am
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🙂

Today could be the day. You're all putting me off now! The old one's practically hanging off, and emissions were an advisory on the last MOT, hence the job. But it's not due until December and the blowing exhaust sounds great 😀

I did one years ago on a vauxhall and seem to remember it being really easy.

We'll see...


 
Posted : 20/08/2017 8:28 am
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Remember exhausts are hung on the car not bolted up. Take a bit of time to make sure it's sitting nicely and don't just waz it on.


 
Posted : 20/08/2017 8:35 am
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Don't use paste. It doesn't allow for the slightest bit of movement. There's a bloody good reason OEMs don't use it. Use proper gaskets.

PlusGas is infinitely preferable to WD-40, a blowtorch on standby is always handy.

If the nuts are buggered, Irwin bolt grips are an absolute godsend. Especially when grinder access is limited. Far less chance of collateral damage as well.

6 sided sockets should be the initial port of call.

Axle stands everywhere, getting the front up often makes it so much easier to access.

Old carpet to lie on to reduce neck ache and scalp scuffs!

Eye protection!


 
Posted : 20/08/2017 8:36 am
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use paste.

don't use paste.

😐


 
Posted : 20/08/2017 8:56 am
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Use genuine gaskets.
Don't do it today - the weather forecast is nice for the day, you'll spoil it with guaranteed rain.


 
Posted : 20/08/2017 9:07 am
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Don't do what I did..... Buy exhaust from eurocarparts, reg and car details checked, back box, mid section and gubbins purchased, old back box, mid section and rubbers removed.... offer up new pieces, find that new pieces are wrong and holes and metal prongy things are in wrong places... noisy drive back to eurocar parts, that was only exhaust on system for my car, refund, drove to Kwik Fit where they took pity on me and fitted exhaust for £20 more than I paid for all the bits

So, my advice is, drop car off at garage and go for a bike ride


 
Posted : 20/08/2017 9:10 am
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use paste.
don't use paste.

Just to balance it up, maybe use paste.


 
Posted : 20/08/2017 9:12 am
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To be clear when I suggested using paste it was meant for u-bolt sleeved joint, as submarined says I wouldn't use it on joints with gaskets (I should have been clearer on that).


 
Posted : 20/08/2017 9:43 am
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Just to balance it up, maybe use paste.

And just to unbalance it (slightly), don't use paste upstream of the cat - unless the paste is 'cat' safe.


 
Posted : 20/08/2017 9:57 am
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Cat safe paste? Not sudacrem then..


 
Posted : 20/08/2017 10:03 am
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And just to unbalance it (slightly), don't use paste upstream of the cat - unless the paste is 'cat' safe.

I'm feline that logic.


 
Posted : 20/08/2017 10:03 am
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50/50, one of my cars was easy, the other I gave up and drove it (noisily) to the garage as the bolts on the back of the cat were on top (i.e. the cat did a U shape with the exhaust exiting upwards) and no amount of driveway contortion could get to them. None of the bolts were stuck though.

Holts fire gum is essential, you won't get a seal without it, go crazy with it, no point holding back.


 
Posted : 20/08/2017 10:26 am
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Recently replaced exhaust from cat back.
Even with the aid of a 2post lift and transmission jack to help we spent the most time on the front joint where the studs that were part of the system had nuts that were so corroded that nothing would grip them - even if heated . The answer was an air saw which
Was thin and compact enough to cut the studs. We had oxy on hand but it would have made more of a mess. So best thing is to carefully asses the state of all fasteners to check if you can handle the job.


 
Posted : 20/08/2017 10:37 am
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No updates for a while. Let's hope the axle stands haven't toppled over and squished the OP.


 
Posted : 20/08/2017 3:47 pm
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Well he's either cogitating over the great paste debate or, more likely (?) gone for a bike ride.


 
Posted : 20/08/2017 3:53 pm
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6hrs since OP last posted.

Can only assume it's all going swimmingly.


 
Posted : 20/08/2017 3:54 pm
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Or still in A&E getting rust picked out of his eye with a needle - "dont blink and look straight ahead" 😯


 
Posted : 20/08/2017 4:51 pm
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Posted : 20/08/2017 5:02 pm
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If it's the section from the cat back, it's pretty ****ing likely that the bolts will have corroded to bits at the cat at least as the cat will almost certainly be stainless, and the bolts carbon steel.

So take an angle grinder to them, and knock/drill out any studs that are press fitted as necessary, replace with bolts and nuts, job's a good 'un.

I replaced a cat a while back and the nuts were so rusty that there was nothing to get the socket onto (on the other hand, I replaced a similarly aged back box with a huge hole in it with absolutely no problems). Obviously go careful with the angle grinder, you don't want to cut other things off (including body parts) and it's a limited space under there. Wear safety goggles to keep rust and sparks out of your eyes.

I do wonder how much replacing these parts will help if your emissions are borderline - I'd be tempted to chuck some injector cleaner through to solve that issue.


 
Posted : 20/08/2017 5:09 pm
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OPs currently still under the car, long out of swear words, looking the darkening Sky and wondering aloud to himself if he should can cycle into work tomorrow and sleep on it.

I've only done it once on a golf, downpipe back, it not bad if a) you cut off everything you need to remove if you can b) don't try to reuse anything.


 
Posted : 20/08/2017 5:40 pm
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Sweepstake on how many knuckles skinned, anyone?

I'd go for three on the right hand and two on the left. Probably a gashed forearm, too.


 
Posted : 20/08/2017 6:55 pm
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Last time I did an exhaust swap was on an old banger winter car, an Audi 80. When checking the old exhaust for leaks I managed to give myself a dose of carbon monoxide poisoning! Took 4 days to swap that thing over - 1 hour to check and remove the knackered exhaust, 2 days in hospital on pure oxygen then under observation and a day to fit the new one without it rattling against something. I t was a stupidly tight fit between the suspension and other bits under there.

Strangely it was the original exhaust on there and even though the car was 18 years old at that point every bolt undid with little resistance. The previous one I'd done was on my Corsa and that just point blank refused to come off, angle grinder got a lot of use that day.


 
Posted : 20/08/2017 7:09 pm
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Done a fair number of exhausts on mine and friends cars and never had anything seriously obtuse.

Perhaps the worst was an early Citroen c1 cat which is between the radiator and the front of the Blok mounted vertically. Had to do the pre and post cat lambdas as well , they were always a bollocks until the day I splashed out on lambda sockets. What a difference. Like most things if you attack with correct tools you at least give your self a chance of it going smooth 🙂


 
Posted : 20/08/2017 7:13 pm
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10hrs.

#pray4OP


 
Posted : 20/08/2017 7:17 pm
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[img] [/img]


 
Posted : 20/08/2017 7:30 pm
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😆

I'm back.

Sorry to disappoint, but I couldn't be arsed with it today. Too much other stuff needs doing at the moment which requires a car, and well... it's Sunday innit. I've bought the exhaust; that's the main thing.

I gave my nuts a good spray this morning and will continue to do so as and when. At some point I'll get a socket on them and see if they turn. If they don't, I might just give it to the garage and save the ballache. But where's the sense of achievement in that? Nah, I'll probably use it as an excuse to buy a new angle-grinder and cut the bugger off.

Glad I held off today anyway as there's loads of good tips on this thread. Think I was lulled into a false sense of security because the one and only exhaust replacement I've done before was so easy.

Cheers!


 
Posted : 20/08/2017 9:16 pm
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Fully expected the replacement for a Nissan Bluebird I had, to come in sections. No. Whole thing from manifold back was one piece and had to have it poking out the window to get it home. Wrangling it into place resulted in the back end of the car being lifted about 4 foot off the floor.

On the current car, cheapest option was a custom fitted stainless.


 
Posted : 20/08/2017 9:27 pm
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This should be done by now, right? 😉


 
Posted : 03/09/2017 12:15 pm
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Of course not.

I'm surprised you can't hear me driving around.

Might do it next week. I did buy some Holts Firegum last week so that's progress. Oh, and a new angle-grinder cutting disk as lo & behold - the nuts on the clamp to the cat were seriously shot.


 
Posted : 03/09/2017 8:16 pm
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Full stainless? No? Let me tell you where I am. I'm out.


 
Posted : 03/09/2017 8:47 pm
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Get it done man! Most come apart ok. The worst I've had (a van exhaust) needed a bit of manhandling and had to be cut in 3 places to get one section out. Even so it only took a few hours.

Done loads over the years. Obviously some are harder than others, non are impossible.

You can use unbridled brute force on old exhausts as it won't be going back on. Remember if you can't cut it in-position, you can drop it at the manifold joint (or whichever joints you can get undone), pop the hangers off to manoeuvre and get better purchase.

Don't buy paste in a tub, it's shite. Last exhaust I did a few months back I used [url= https://www.amazon.co.uk/Autogem-GTP07-Exhaust-Jointing-Cartridge/dp/B00MHTWEC4 ]Autogem GTP07[/url]. Bosal was the best jointing compound I've used but doesn't seem to be available any more.

Oh and don't forget the manifold expansion joint nearly always has a [url= https://www.amazon.co.uk/Bosal-256-520-Seal-exhaust-pipe/dp/B00CJ2XUMC/ref=sr_1_22?s=automotive&ie=UTF8&qid=1504473882&sr=1-22 ]Sealing Ring[/url] miss this and it will blow like **** 😆


 
Posted : 03/09/2017 10:38 pm
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Man fail is increasing in this thread. Get some rust in your eyes - it's one of things that still makes a man...er a man in 2017


 
Posted : 03/09/2017 11:59 pm
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Get it done man!

😀

It's happening! Kind of.

Well, today is 'reconnaissance day'. Just offered her up and everything looks right. Can't actually do the job now as, it's hard to see from the photo but the drive is on an incline. Jacking up the rear will be very very stupid. So will need to find a flat spot.

All nuts thoroughly lubed. Plan of attack decided upon. The brackets holding the front section to the cat will need to be cut - angle grinder at the ready.

My question today is: how best to make the sections fit? As you can see from the photo, the two sections will slip together with some paste and brackets, but as they are they're a little tight. Embiggen the overlapping one? Squash the smaller one with a bracket? Don't want to mess up the seal here. But want to make sure they fit together now before I get the old one off.

[img] [/img]


 
Posted : 12/09/2017 1:31 pm
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Also, looking at the supplied kit, there are three brackets. I'm assuming that one is to connect back-box to mid-box, and the other two are to connect mid-box to cat (two brackets on the one junction). On the existing exhaust there seems to be a sleeve here, held in place with two brackets with the rusted nuts and bolts. I'm hoping that my new exhaust slides over the cat pipe...

[img] [/img]


 
Posted : 12/09/2017 2:06 pm
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You've never lived if you haven't smashed your fingers to bits fitting an exhaust.. I once did an old Alfa GT Junior one that had been on the car from new, not that there was a lot left on it but what there was was a random snake of razor shards attached by perished rubber fixings..
Mind the front inner engine mounts were just the same.

I loved that car 😕


 
Posted : 12/09/2017 2:35 pm
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Done once. And never again. Best tool to apply is a visa card.


 
Posted : 12/09/2017 2:52 pm