Exhaust Flange Damage

[bluegrass]

I have found a leak at my exhaust flange joint/manifold. On closer inspection, the flange on the pipe has a slight outward kink in the place where is leaks from.( Left hand side in picture) Whats the best way to repair it and get a good seal? How is it best to clean it up, sandpaper?

Thanks for any help

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[bmcecosse]

That 'nip' is caused by the clamp design. You need to dress the flange correct using a ball pein hammer, coat with a little exhaust paste and refit to the manifold which you can attack with a wire brush. You may want to consider a new clamp. Support the exhaust in place with a jack under while doing up the clamp.

[bluegrass]

Thanks for the reply, much appreciated.

[Biggles1957]

I make up a folded strip of aluminium foil spread with gungum and wrapped around the joint, then put the clamp on and smooth it all off after tightening - makes a very neat gas tight joint

[bmcecosse]

Not sure that Al will last long in there - it can glow red!! But I have seen that some use a circle of Copper wire in between to make a seal.......

[Biggles1957]

Well I wondered if it would last but it surprisingly did! I folded a strip about 6" wide over and over till it was about 1" then smeared gungum along it quite generously so it worked like a bandage - wrapped it snug round the joint then put the clamp on and finally smoothed the paste nicely. When I took it apart after about 2 years I was amazed that the foil was still good - so I did the same again when I put the new manifold on

[JOWETTJAVELIN]

Fireputty or exhaust jointing compound is the best for this joint as it will withstand the temperatures.

When I have used Gun Gum in the past for this joint, it tends to blow again after a week or so.

[bmcecosse]

Only a thin smear of paste should be used -or necessary!

[stag36587]

Would a propriety exhaust bandage trimmed neatly to fit be a suitable alternative to the aluminium foil idea?

[bmcecosse]

NO!!! If the flanges are properly prepared it doesn't need ANYTHING!! Just a wipe of paste - a good clamp and good free running screws with brass nuts........ Do it as it was designed -it works........

[stag36587]

NO!!! If the flanges are properly prepared it doesn't need ANYTHING!! Just a wipe of paste - a good clamp and good free running screws with brass nuts........ Do it as it was designed -it works........

hmmm it hasn't so far

[bmcecosse]

Line the pipe up accurately - adjust the hangers if (probably) necessary - and put a jck under the front pipe to hold it firmly in the correct place. Clean the clamp of any old/hard paste, and around the manifold end too - and then fit the clamp doing it up securely - but not so tight it distorts the flange on the pipe.....

[JOWETTJAVELIN]

Just another word of caution about over-tightening the manifold clamp - don't forget it can crack the cast iron. Not so much of a big problem on a Minor, but for those who run cars for which the spares may be harder to find.

[MarkyB]

Try and position it right first time, the more you move it about, the more paste will be moved from where it needs to be.

[myoldjalopy]

And don't tighten the nuts so hard they strip off their threads! I did that once when I couldn't get a seal - turned out it was a distorted pipe flange when I looked closely and all was OK again after I reformed it with a pair of pliers (and got a new nut). There's a right way and a wrong way to do everything.............and I did it wrong first time round.