Mazda MX-5 Miata banner

1 - 4 of 4 Posts

·
Registered
Joined
·
440 Posts
Discussion Starter · #1 ·
Just swapped my decaying standard backbox for a Roadstersport backbox and after the usual fighting getting rusted nuts and awkward mounts off, I managed to get it all lined up and back on.


The standard midpipe has a slightly protruding pipe from the flange with what looks like a coiled spring for a gasket around it. This pipe mates perfectly with the standard backbox.

The Roadstersport backbox flange is flat, but larger diameter hole than the standard midpipe pipe. So, I used a lot of fibre gum putty around the edge of the midpipe pipe, then put a load on the Roadstersport backbox flange and put it all back together and tightened the nuts and fired the car up.

Unfortunately it's blowing slightly from that flange.


So, can anyone suggest a solution apart from taking it all apart, putting more liquid gasket on there and tightening it all back up again?


Thanks.
 

·
Registered
Joined
·
8,237 Posts
Are you sure you haven't used 2 gaskets or something ?

It came off a std mid piped car and I swapped a std back box back on with no probs.

IIRC the gasket you are describing should be a round disc not looking like a spring I wonder if that is the problem ?
 

·
Registered
Joined
·
440 Posts
Discussion Starter · #3 ·
Are you sure you haven't used 2 gaskets or something ?

It came off a std mid piped car and I swapped a std back box back on with no probs.

IIRC the gasket you are describing should be a round disc not looking like a spring I wonder if that is the problem ?
I'm not using any gaskets, as far as a I can see. I took the gasket off, it looked like a very narrow and thin metal ring until I tried to pull it off, when it revealed itself to be wound around several times like a spring. It wasn't anything substantial, so I just took it off and didn't re-use it.

I put a load of exhaust sealant gum on both surfaces and tightened the bolts. I guess the problem might be that I had to reuse the nuts as the bolts were seized into the midpipe and one of the nuts was pretty well knackered, so I couldn't do it up that tight, but I think it should be tight enough to seal it if it's going to seal.

I guess I'll have to take it apart, re-gum it up and replace the nuts to get a tight seal.

When you took it off the last car, did you chop the barbs off the end of each of the hanger bars on the backbox? The end of the hanger bars look like they've been cut, and there's no barbs on them to stop them coming off the rubber mounts?
 

·
Premium Member
Joined
·
19,520 Posts
Are you sure you haven't used 2 gaskets or something ?

It came off a std mid piped car and I swapped a std back box back on with no probs.

IIRC the gasket you are describing should be a round disc not looking like a spring I wonder if that is the problem ?
I'm not using any gaskets, as far as a I can see. I took the gasket off, it looked like a very narrow and thin metal ring until I tried to pull it off, when it revealed itself to be wound around several times like a spring. It wasn't anything substantial, so I just took it off and didn't re-use it.

I put a load of exhaust sealant gum on both surfaces and tightened the bolts. I guess the problem might be that I had to reuse the nuts as the bolts were seized into the midpipe and one of the nuts was pretty well knackered, so I couldn't do it up that tight, but I think it should be tight enough to seal it if it's going to seal.

I guess I'll have to take it apart, re-gum it up and replace the nuts to get a tight seal.

When you took it off the last car, did you chop the barbs off the end of each of the hanger bars on the backbox? The end of the hanger bars look like they've been cut, and there's no barbs on them to stop them coming off the rubber mounts?

[/quote]

FWIW I've seen loads of exhausts with no ends on the hangers, it won't fall off.
 
1 - 4 of 4 Posts
Top