Roush Axle Backs Fitting Question

[pat_y]

I had a set of Roush Axle backs fitted last weekend by my Local American car restoration specialist, i noticed when i picked it up that there was a small amount of leakage around the joins where the old exhast was cut off and new back boxes clamped on (both sides).
I spoke to them about this and asked why, they told me that the diameter fit between the stock system and the Roush system was quite large, to mitigate this they used exhaust sealing paste and tack welded the pipes on, wound up the clamps as tight as possible. Seems the mitigating action was still not quite right in my eyes.
So the questions is, a few of us have these Roush systems, did anyone else come across this and how was it fixed?
I am very tempted to take it to my local exahust fabricator and ask them to re-do the whole thing, unless this is one of those 'they all do it sir' instances, feedback welcome.

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[Nookie]

The cut and clamp joint between the existing exhaust and RAB's is always somewhat doomed to potential leakage due to the fact that Ford, in their wisdom, have the underside (only) of the exhaust coated in underseal in Zeebrugge, which I'm sure doesn't help to ensure a perfect fit, and I expect Roush have to be 'generous' with the flange size on the pipes leading to the backboxes as they are designed to be a DIY fit, and the average household garage is unlikely to have one of those whacking great hydraulic flaring machines that you can find in most exhaust fitting shops.

Exhaust paste is an option but primarily (to my knowledge) designed to prevent leakage of gases in the system (and thus undue loudness/rasping/hissing) rather than leakage of water vapour... which I presume is what you're speaking of here?

'Water always finds a way' as the saying goes... and if this is all it is, I wouldn't personally worry about it.

Not aware of any problems with my RAB's... but never looked to be honest!

 

[pat_y]

Cheers Adrian, i can actually feel exhaust gasses blowing slightly and water/condensation leakage, i cannot hear any peculiar blowing noises and the noise the silencers make is awesome, i'm just wondering if i'm making a big deal out of a small issue.

 

[Manders Mustang]

Everyone who has a clamp fitted exhaust (which, unless youre stock) is everyone here. They all leak a little bit of carbon out (Black circles around the clamps) because, as nookie said, even with a hydraulic driver to ram the clamp tight, they'll still leak out a little bit. It's actually 'sealing' the hole if anything. Ford mentioned it ot me when my car went for underseal, and the 'mustang tech' said it was normal for clamped exhausts to do that. Spoke to a few others to confirm, looked at a few peoples... everyone has the same "Issue" (It isn't an issue)

 

[Nookie]

Have you tried re-tightening the clamps?

Possible once the paste has heated and dried/shrunk slightly that the joint's just loosened a bit.

Only other possibility is that they've cut the exhaust a little too short (it's supposed to be cut right at the tangent, i.e. just at the point at where the curve begins) and there's not a lot of room for error with this as it affects your ability to adjust the tailpipes so they fit evenly through the cut-aways in the rear valance.

I certainly wouldn't worry about water vapour/condensation leaking from the joint... the less water that rests in the system the better, and if it sounds OK and you can't hear any undue hissing or rasping from the joint itself then all is good in reality!

The probably all do it... but your attention has just been drawn to it as a result of the visible aspect... i.e. the water leakage.

 

[pat_y]

Cheers guys, i will get under there this weekend and see if i can give the clamps bit bit more encouragement. I have the original back boxes so can assess how long the remaning down pipe was left, will see if what has been left was possibly a bit short. Apart from that, the noise from these is just awesome, exactly how it should have been from the factory, not stupidly loud but enough to let you and everyone within 100 metres know something is happening.

 

[Harebear72]

I have the Roush and never had any paste put on. My exhaust is spot on.

 

[Pedestrian]

Roush on mine also just has the butterfly clamps on, never had any issues.

I was told however to double check them in the varying temperatures as mine were done in the Summer, come winter they needed a tighten up a bit.

 

[slowhand99]

No leakage putting on the MagnaFlow system (first exhaust I've ever done that didn't leak a bit) but I did use a torque wrench to tighten the clamps which went way tighter that I would have done just by feel. Check your clamps with a torque wrench.

 

[MagnaFlow]

No leakage putting on the MagnaFlow system (first exhaust I've ever done that didn't leak a bit) but I did use a torque wrench to tighten the clamps which went way tighter that I would have done just by feel. Check your clamps with a torque wrench.

Most band clamps, including ours, will need 40ft/lbs to seal properly, which is usually tighter than most people are expecting.

 

[Manders Mustang]

Most band clamps, including ours, will need 40ft/lbs to seal properly, which is usually tighter than most people are expecting.

I've been needing to know this for bleeding ages.

[MENTION=8914]Big_G[/MENTION] this will solve the carbon leak !

 

[slowhand99]

I've been needing to know this for bleeding ages.

[MENTION=8914]Big_G[/MENTION] this will solve the carbon leak !

It's in the instructions :doh:

 

[Manders Mustang]

It's in the instructions :doh:

HAVE YOU NOT NOTICED, I DON'T DO INSTRUCTIONS :lol::lol::lol::lol::lol::lol:


I was doing lego without instructions as a kid... If it looks like it goes there, it goes there ;)

 

[bennno]

My roush axle back is spot on, fitted with clamps and no leakage.

 

[kapiteinlangzaam]

My roush axle back is spot on, fitted with clamps and no leakage.

Same here.

It shouldnt be leaking at any of the joints, full stop.

If it is, there is something wrong.

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