MK2 MX5 Rear arch repair

[Ashley Burton]

Both rear arches have gone on the MK2 MX5 me & my brother have bought for a track car project

Welding aside, Could I be letting myself in for a can of worms?

I get the impression that inner rear arches could need replacing also, The lower sills seem solid

But it's not until I cut the outer arch out that I find the fun stuff

Does anyone have any actually hands on experience to comment?

I can see this being a more involved job potentially

 

[Tigman]

well known for being rotten , sills fill with water and rot from the inside out !

 

[Ashley Burton]

well known for being rotten , sills fill with water and rot from the inside out !

Sweet!

Sounds the dream

 

[anjum]

If it's "only" a track car you could weld the inner arch (or remainder of) to the outer arch.
You could seam or stitch weld before you put the outer arch section on. Might actually wind up being stronger.

 

[Tigman]

have a look on youtube shows people clearing holes in sills and the water pouring out !

 

[Ashley Burton]

@anjum I think I'm going to bite the bullet & find out one way or the other

 

[seanc]

Rust is always at least twice as bad as you think. If the putters are rotten the inners will be and most likely some of the sill

 

[Ashley Burton]

I will keep you all updated when I uncover the damage!

 

[stuvy]

Iv done a mk1 mx5 it wasn’t as bad in the inner arch as I’d expected.

before you do anything to it, pop the bonnet and check the front inner rails as these are the crumple zones and are terminal

granted as it’s a track car you could brace the body and chop these out and should be ok

 

[Ashley Burton]

before you do anything to it, pop the bonnet and check the front inner rails as these are the crumple zones and are terminal

Seems solid from what I've seen

 

[stuvy]

Get off here and get that grinder out ash!!

 

[Ashley Burton]

I'm waiting for the repair arches to turn up first. Realistically want to cut out & tack the new ones in the same day

 

[rtcosic]

Seems solid from what I've seen

Then it must be unique! I've yet to see a Mk 2 or 2.5 with solid ones. The extra layer added to meet the revised offset barrier test introduced a dreadful rust trap.

Have you checked the photos and videos here:

https://www.themx5restorer.co.uk

I'm not overly impressed with the apparent quality of the work shown there but it gives you a good idea of what to expect once you start poking the apparently solid panels.

Edit: his repair panels are a good fit I'm told though.

Edit edit: No 3 son tells me 'his front chassis leg sections are OK but not ideal. Better than rusty old heap. Worse than original design.
Not thick enough really and they do not replicate Timoshenko crumple zone bit.'

Enjoy the journey.

 

[Ashley Burton]

The damage so far...

 

[stuvy]

That doesn’t look bad at all, I’d be looking at where the axle stand is. You’d be better off jacking it up on the diff and supporting the axle mate

 

[Ashley Burton]

@stuvy I was surprised also! Not touched the other side yet, So don't want to talk too soon

I could move the stands, But seems to be all good

 

[SierraV6]

@stuvy I was surprised also! Not touched the other side yet, So don't want to talk too soon

I could move the stands, But seems to be all good

I’d move them just in case they’re causing any flex or distortion in the area you’re repairing, it doesn’t look like you’re touching the structure but better safe than sorry IMO.

 

[Ashley Burton]

Couple more pictures as I know you all love them!

Nice to actually use the welder

 

[RWD3M]

We just sold our Mk2.5 (needed something more 'baby friendly'!) and the chap that ended up with it spent about a grand with a specialist in Bristol having the sills done. Have to say he made a bally good job of it. But then that was for retail not track. Yours doesn't look that bad but as others have said, I'd have a closer look at where you have the axle stands. That's pretty much exactly where they tend to go.

Nice start on welding up the arches though!

 

[Ashley Burton]

As much as I would love to rebuild the whole car

I'm literally cutting out the scrap stuff & welding in some solid metal

Going by what I've seen this one is in not too bad condition

It's a 20 year car, So not expecting it to be great

We are literally going to throw it round a track, burn some rubber until it dies

We picked up the car cheap, So probably worth more in parts