Exhaust Repair Bodgery Advice

[GLPoomobile 958]

I've had a leak on the back box on my Volvo V70 for the last few years. Every year I bodge it up with Gun Gum for the MOT but it doesn't last long before the dry putty gets blown out again. MOT is due again in next few weeks and I want to see if I can make the bodge last a little longer this time (eventually I'll be getting a full SS system but funds won;t allow it at the moment).

 

This pic shows the type of box and where it's blowing......

 

...it's double skinned and the top skin has rotten through and I've pulled half of it off. The actual leak is at the seam where the top and bottom half of the inner skin have been pressed together. I usually just work the Gun Gum in around the lip and that is good enough for a temp seal.

 

Are there any better products to use than Gun Gum? I was thinking possibly use the Gun Gum to form the seal, then after drying put a layer of P40 glass fibre over the top as it's pretty strong stuff (and since it's the back box and I don't drive the car hard it doesn't get stupidly hot). It would be hidden from view once back in place.

 

Thoughts please*

(*respecting the fact that this is just a short term repair, and just needs to seal and hold and not look pretty)

[GLPoomobile 958]

My main concern with adding P40 is whether it will be OK with the heat, in terms of producing fumes even after is has fully cured.

[Anthony 1,003]

If the surrounding metal is fundamentally solid, can you not get someone to weld it for a few beer tokens?

[GLPoomobile 958]

Sadly I don't know anyone with welding equipment so nobody to turn to for a freebie. As it's right at the lip it wouldn't be that simple a repair either IMO - it's ever so slightly crusty in the immediate area so prob couldn't just put a blob of weld there to bung it up. Access would be a bit of an issue too as the box is rusted solid to the mid-pipe, so I expect to be able to drop it down far enough to peek at it but may not get it far enough down to do any welding there (I usually stick the Gun Gum in by feel, reaching up above it with the box in place).

[steve@cornwall 100]

Can you cut a patch, (scissors and coke/beer can) smear liberally with gun gum and secure with self tappers or rivets?

[GLPoomobile 958]

Not really Steve. As I said above, it's right on the seam where there's a lip, so it would be really awkward. It's not like an obvious hole, just a separation of the two skins where they join (well, that's what I think from what I've felt with my fingers).

 

I'm now thinking that Quicksteel might be worth a go.

[dcc 855]

Just buy a new backbox, or 2nd hand one in good condition

[GLPoomobile 958]

OK, I'll buy one with all the spare cash I don't have kicking about.

[dcc 855]

Well the two other options (which are bloody good options) on the table you're quite negative about, so short of begging for a free backbox from somebody on a volvo forum, not really much else can be done, is there?

[dobboy 231 2 Cars]

This might be worth a shot, but get a price before you waste your time removing anything.

 

http://www.scbvehicledismantlers.co.uk

 

They have 4 cars in, and one is fairly recent.

[juice willis 2]

You might try using araldite perhaps with some metal filings mixed in.

[GLPoomobile 958]

Right, thanks for the replies, but I think I'll just try Quick Steel this time around.

 

I'm not going to replace the back box, whether it be new or used

a} because of cost - not just the fact that I am totally bloody skint, but also the fact I don't want to spend money on a short term replacement (when bodgery will suffice) when I'm trying to save for a replacement SS system

b} because the back box and mid section are rusted together and will be an angle grinder job followed by arsing about cleaning up the joint and having to fit a sleeve = more pennies on clamps and tubing. My days of pissing about with old rusty exhausts whilst lying on an uneven gravelly floor are well behind me!

[dobboy 231 2 Cars]

Your getting soft GLP!

 

Might be worth try a smaller exhaust place to weld it for you, you could try calling "Noisebuster" at Newmains, bit of a trek for you but they'd probably weld it for you for £10/£15 if it was just a quick weld you need.

[GLPoomobile 958]

Getting soft, getting old, whatever, I won't argue with that (side note: I used to be surprised when my dad reached an age where he stopped doing any work on his cars, having grown up as a wee boy with him always spannering. Now I'm a similar age I totally get it. It's fun when stuff goes to plan and you have good tools and working conditions, but sliding around on your back in all weathers, straining muscles and fighting seized nuts and bolts ain't my idea of fun).

[dobboy 231 2 Cars]

Getting soft, getting old, whatever, I won't argue with that (side note: I used to be surprised when my dad reached an age where he stopped doing any work on his cars, having grown up as a wee boy with him always spannering. Now I'm a similar age I totally get it. It's fun when stuff goes to plan and you have good tools and working conditions, but sliding around on your back in all weathers, straining muscles and fighting seized nuts and bolts ain't my idea of fun).

Tell me about it, I spent the heart of winter doing a scrapheap challenge with my Saxo at my back door, in rain and snow with a portable light. Some nights I couldn't feel my fingers! and I could have cried when I thumped myself with hammers etc.

 

Long Johns, a balaclava, and multiple fleeces help!

 

I've now got a 10x5ft of 1" thick waterproof rubber foam to lie on; it's even comfier than my bed 8)

 

I don't have a welder btw or I would have helped you out.

[steve@cornwall 100]

Soft Northern whippersnappers!

[toolie72 67 1 Cars]

Soft-cheeky!!!

 

Jb weld and lard it on

Ps you've got to really work it in with your fingers, oh sorry my mind wandered there for a minute

[GLPoomobile 958]

Soft Northern whippersnappers!

Cheeky. May I remind you that I'm originally Steve@Devon, so I'm actually a soft southern farmer.

[steve@cornwall 100]

Cheeky. May I remind you that I'm originally Steve@Devon, so I'm actually a soft southern farmer.

Steve@Devon would have lain in a freezing puddle and got it sorted........am I right ??? :-)

In all seriousness my local not station will usually run a quick weld on a seam etc for beer money (pouch of tobacco is good currency too) despite being a tyre/ exhaust centre, so may be worth just asking, obviously the tester himself, def not the reception ;-)

[B1ack_Mi16 67]

Can you not just make some metal plate patch and pop rivet it on, seal it with some stuff before tighteing the rivets?

[B1ack_Mi16 67]

I've refused to buy a new backbox for my 405 TD for the last 10 years. I believe this is how it now looks after the second bodgy repair before MOT last year

Welding thin rusty metal like this however is not easy and takes time because of all the crap.

 

So if one would have to pay someone to do the job, I guess buying an used box on eBay would work out cheaper.

 

 

[welshpug 1,657]

a new box for a p2 v70 is £50, many come with fitting kits.

[GLPoomobile 958]

If I asked you lot to design me a kitchen I'd probably get a fricken bathroom instead!

[jackherer 543]

What you're asking for isn't possible so you're only going to get alternative suggestions.

 

Traditionally you would bodge an exhaust with something like a tin can wrapped around it and held with jubilee rings or similar. The actual sealing is done with exhaust paste, the can is used to hold the paste in place.

 

As you can't add anything to hold the paste in place due to the shape of your backbox the paste just falls off as you have found. Anything you put on there will fall off due to different expansion rates. It will only stay in place if it is held mechanically somehow or welded.

 

If you want another answer you'll need to change the laws of physics.

[GLPoomobile 958]

THanks Jackherer. That was a useful explanation. I've already bought some Quick Steel type epoxy (a different make) so I'll give it a go.