Exhaust woes - any advice?

[r.welfare]

So, you may recall when I bought my Mazda MPV it had an exhaust blow which the vendor assured me was "just a join".

 

I have done some further investigation and found two issues:

 

1. The downpipe has two horizontal cracks, on each side of the bend, about 5cm long. Weird, no?

 

2. The flex pipe, which resides behind the first of the two catatonic converters, has completely lost its' external braid, leaving it looking like a large highly coiled spring.

 

So the damn thing sounds like a Top Fuel dragster. There is definitely exhaust gas escaping through the cracks although I haven't yet been able to ascertain whether the flex pipe is also leaking.

 

I have tried Gun Gum, an exhaust bandage and latterly JB Weld on the downpipe but predictably (no doubt due to the gas temperatures) these have not worked. Neither did a bean can and jubilee clips, due to the bend of the pipe.

 

Because Mazda sold about 12 of the sodding things there appear to be no aftermarket exhaust parts available. I can find random Russian websites offering me a new downpipe for $400 but that ain't gonna happen. The car is not worth enough to have lots spent on.

 

There appear to be three options:

 

1. Get the downpipe welded up. Anyone had any success with this? As mentioned it is cracked, but does not appear to be rusty.

2. A Mazda 626 2.0 (with which the MPV shares running gear) downpipe is available for 28 quid. Will try and measure up but if the angles are slightly off can one bend the pipes? Presumably existing gaskets should be discarded rather than reused?

3. I have seen flex pipe repair sections - you cut off the existing one, offer up the section with a bit of cement and then clamp it all up. WCPGW?

 

Thoughts or advice? Years ago a bloke called Mike The Pipe used to advertise in various mags as a maker of exhausts, do such (reasonably priced) folk still exist?

[Forty-two]

Can't comment on price, but i am sure a power flow franchise could make the part you need.

[Taff]

if you can get it off, any decent welder could sort it out, surely?

[twosmoke300]

Jetex sell universal exhaust sections and flexi joints. Then off to your tame welder .

[purplebargeken]

There is a place near Heathrow that can make up exhausts, there may be someone similar nearer to your location but ^^ sounds like an option.

 

Good luck

 

Ken

[Lacquer Peel]

Is the downpipe straight?

[r.welfare]

It's got an 80 degree or so angle bend from the manifold with a foot of pipe before a foot of horizontal pipe where it bolts to the first cat.

 

626 part spec says 350mm length but looks like more of a 90 degree bend I think.

[dieselassist]

them flexi joints in various sizes seem to be well spendy in any of the local factors round here...if yer patient with a grinder you can nip off the top securing ring of the braided bit, n with gloves on pull it down like a sock to reveal the inner accordion like bendy tube - they usually break near the top, the inner accordion bit; if its split up there, just weld the pleats together on a low setting on the welder...

 

The dowpipe cracks can similiarly just be welded up...

[PiperCub]

Try an seek out a (for the want of a better expression) old school-type welder who can fabricate as well as weld, there's usually one tucked away in every big town. They will be able to either make the parts or adapt universal bits from your local M/Factor. Ask around.

 

I used to know of a great guy in Southampton for just this type of work, sadly he's now closed up and presumably retired (he was of that age). He did some superb stainless welding on a couple of bike exhausts for me years ago.

[sierraman]

Presuming the downpipe is cast iron... Get it welded up, finding someone capable of this is the tricky bit. From what I gather special rods are required and the piece has to be cooled down in vermiculite. If the braid is coming apart, bind it up with some wire. I had the problem with a manifold on a mondeo years ago ended up getting it welded as I was completely unable to get a replacement new or old for love nor money.

[KruJoe]

^ Cast iron downpipe? You're thinking of the manifold Shirley?

 

 

Anyway, about the gasket question, if you can't buy the proper gaskets for the right price, order a sheet of exhaust gasket material, about a tenner off the bay, and cut your own with tin snips. I've just got some, but not tried it yet. I think I'll 'stamp' out the correct shape using a sharp chisel onto a block of wood.

[Guest friskneyfreedomfighter]

I worked for a exhaust manufacture near skeg so yes they do still exist 

[r.welfare]

Got underneath the car today. The downpipe only appears to be leaking through the two splits so I am hoping some welding can salvage that. I did have a go at loosening the various nuts but no dice. However I was able to take off the manifold heat shield and it appears the manifold gasket is OK.

 

Sadly the flex pipe is leaking on top at the back, so I hope this can be cut out and a 10" universal 2-inch job can be welded in. The hanger is right at the end of the flex so again I am hopeful this can be reused. I'll have a word with the garage next week.

[cobblers]

Like laddo above says, powerflow places are a bit "chav fodder" but they could deffo lash you a downpipe together, probably for less than it would cost to buy the bits off jetex.

 

If you can corral a bloke with a welder, you can get flexies and stuff off ebay but from experience they aren't anywhere near as good as OE ones, you'll probably only get about a year out of them.

[UltraWomble]

The 1300 used to bust its 'zorst regular just where it went 2 into 1. 

 

Ended up getting welded up by some old geezer who fabricated another bit over the top of the joint. Never went there again