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De-cat/cat gasket woes
Posted: Wed Apr 17, 2013 3:40 pm
by Pushki
At my MOT I had an advisory that I had a minor exhaust leak in one of the de-cat gaskets.
I bought one off-the-shelf gasket for one end, and I made one for the odd shaped end out of gasket material.
After fitting them both this morning, they now leak worse than before.
I've tightened them up with all my strength but they still leak.
Any advice?
Old picture for reference. I avoided using any paste this time.

Posted: Wed Apr 17, 2013 3:41 pm
by 4thgenphil
get stronger?
refit oem exhaust?
tried a bit of exhaut paste on either side of gasket
Posted: Wed Apr 17, 2013 3:42 pm
by indigolemon
4thgenphil wrote:tried a bit of exhaut paste on either side of gasket
This. Even the best gaskets can't fully accommodate for the slight variations, this is why paste was invented

Posted: Wed Apr 17, 2013 3:45 pm
by Donald
You have a decat?!

Posted: Wed Apr 17, 2013 3:46 pm
by 4thgenphil
Donald wrote:You have a decat?!

seriously donald, WTF is wrong with you?
Posted: Wed Apr 17, 2013 3:50 pm
by Donald
How do you mean?
I'm just surprised that Pushki has such a mod going on!
Posted: Wed Apr 17, 2013 3:50 pm
by Pushki
indigolemon wrote:4thgenphil wrote:tried a bit of exhaut paste on either side of gasket
This. Even the best gaskets can't fully accommodate for the slight variations, this is why paste was invented

The MOT guy frowned when I told him I used paste last time.
To be honest, I really can't be bothered to climb under there and go through it all again.
Lol at Donald.

Posted: Wed Apr 17, 2013 4:07 pm
by 106pete
Some gaskets are too soft, so when you pull them up really tight they compress around the bolt and the flange just bends opening out the flange between bolt holes.
The reason they frown about exhaust paste is because you should never use it before the cat, and I guess they can't get that out of their heads.
Your solutions? Fit more paste or remake the decat with 10mm flange!
Posted: Wed Apr 17, 2013 4:08 pm
by Mudgey
How did you get through an MOT without a CAT in the first place?
Posted: Wed Apr 17, 2013 4:09 pm
by Pushki
Mudgey wrote:How did you get through an MOT without a CAT in the first place?
BB4!
