Possible Exhaust Rust/Corrosion on MK1 Aygo

[Asura]

I've been experiencing a more noisy exhaust system, and decided to check the underneath. It's my first time doing this sort of thing, but I have to begin somewhere.

These are the crappy pictures I managed to take. But from the looks of it and doing a quick sound test, there's 2 areas of corrosion from what I can see, in which is on the backbox?

I guess, I'd have to get a replacement back box?

IMG_8950.HEIC IMG_8951.HEIC

[flash22]

its not corrosion or rust, its exhaust soot where the joint has been blowing, a new gasket and clamp required (the bolt is likely to snap)

eg.

https://www.citycarparts.co.uk/toyota-aygo-citroen-c1-peugeot-107-108-rear-exhaust-silencer-gasket-back-box-gasket-63082-p.asp

https://www.citycarparts.co.uk/citroen-hyundai-peugeot-kia-toyota-rear-silencer-exhaust-clamp-53mm-emcp014-52338-p.asp

[Derek.w]

First use a angle grinder to cut rhe bolt then refit a new nut & bolt this may just take up the slack without a new gasket.

[Asura]

What would be the size of the nut and bolt?

[flash22]

it's not worth messing about, you will not get the clamp to tighten down, at a minimum you need a gasket

[Vandals01]

What you are looking at is basically where the middle pipe joints the rear silencer.  It is held together by an exhaust clamp with a single bolt that is visible in the picture.

The bolt (if I recall correctly) should be a 14mm.  However, do not expect you can loosen it by regular hand tools as the bolts is heavily seized up.  I mean, you can try but better get ready for plan B & C.

Plan B is use an Impact Wrench (which is what I've used when I replace the silencer on my cousin's 2007 C1).  Plan C is use and Angle Grinder / Reciprocating Saw or a hand saw and cut the Clamp.

(https://www.gsfcarparts.com/za042485)

Controversial to some of the suggestion above.  There are NO GASKET available.  In fact I would argue there was never intended to be one - as it is just 2 pipes where the middle pipe slotted into the silencer.  There are 2 bulges, one on each end.  The clamp simply crimp the 2 bulges together to create a seal.

 

Based on my preliminary assesment, your problem is probably at the Clamp.  The middle section swollen too much to the point it no longer held the 2 bulges together.  So definitely a new clamp.  You can also smear some Exhaust Paste in between the 2 pipes (to act as a gasket) if that helps you feel any better.

[flash22]

A gasket (malleable metal) is listed on the Mk2 and some aftermarket items on the mk1

the back box rubbers could also be stretched, causing the join to flex open

Regarding the clamp, these single sided clamps can stretch, you may be lucky and get away with soaking the bolt with penetrant, but Murphy's law says you will snap the bolt, if you dont have a new clamp to hand (standard 53mm clamp with M8 bolt/nut(s), 13mm socket)

[fordulike]

20 minutes ago, flash22 said:

Regarding the clamp, these single sided clamps can stretch, you may be lucky and get away with soaking the bolt with penetrant, but Murphy's law says you will snap the bolt, if you dont have a new clamp to hand (standard 53mm clamp with M8 bolt/nut(s), 13mm socket)

I've replaced the back box twice on Mk1's and the clamp bolt is a pain to remove.

I sprayed penetrant fluid on the bolt nut, at least half a dozen times in a 12 hour period leading up to removal.

Even then, the bolt was pretty done for, so a new clamp and bolt was fitted each time.