- My model of MX-5 is: 99’ NB MK2
- I’m based near: Bucks
- I’m looking for technical help or recommendations on: I got failed on the MOT due to a bit of corrosion on the front Chassis rails, It’s not as bad as I thought after cleaning it up, but still thought I’d do it right, so I don’t need to worry about it for the foreseeable.
My cars currently at a shop, it’s fine, not being worked on so it’s not costing me money right now. The issue I have is I was gonna pick up the chassis rail set from MX5 Restorer. He is out of stock.
Now. What’s the best way of doing this the right way. Honestly, I don’t know what i’m really doing. I’ve found another set on ebay, Link bellow. But I don’t know any feedback for these.
If i’m throwing money at it, I want it done right. Any suggestions?
I understand I haven’t given alot of info here, because I’m not sure what info to give.
Please, ask any questions that will help you to help me.
Link to eBay set.
I used a pair off of ebay on my Mk2.5. Looks like the ones you have shown.
They were well made, fitted fine and all the pre-drilled holes are in the right place.
I primed the inside before fitting and then injected loads of waxoyl in when done.
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I bought those exact ones, I forget which company they’re actually from but they’re more annoying because they’re one piece rather than 2 pieces of the MX5 Restorer ones. With these I had to cut one of the sides off (outer) and then installed the inner side with the underside as one piece and then welded the outer in as well. I made up a steel template so I could be sure these new ones were in the exact place the old ones were, measure hole distances etc.
One thing to note is it WILL be worse once you get inside. Externally mine had a small hole on the outer which after attacking with a hammer became a lot bigger. Due to the rails being double skinned from factory they rot inside out so anything you see outside will be amplified once you get in. Also as the sway bar mounts are welded to the rusted chassis rails those were a nightmare and had to just be cut out entirely necessitating replacements which were those V8 Roadster ones because they were beefier.
Hopefully yours won’t be bad but honestly think the worst going in because it’s likely pretty bad in there and a massive bummer once you start cutting away to see the layers of rot like a particularly depressing onion. 
Ahh brilliant, that sounds like the set that just arrived today!
Pretty sure the sway bar mounts are bolted x2 with a spot weld in the middle? I may be wrong though. the main plan was to drill out the spot weld and maybe making up some new brackets for the old sway bar. But I have a feeling this is gonna cost me a fair bit more than I original anticipated. Joy.
“think the worst going in because it’s likely pretty bad in there and a massive bummer once you start cutting away to see the layers of rot like a particularly depressing onion.”
Well this put a smile on my face anyway! Hahha cheers guys appreciate the help.
I’ll keep you posted.
Yeah the sway bar mounts are indeed bolted and spot welded but mine didn’t want to come off easily due to the rot so to save my blood pressure I just hacked them out along with the rest of the chassis rails.
I installed a set of V8 Roadster reinforced sway bar mounts but had to weld up some of the sway bar mounting holes on them, re-drill and weld in new nuts. Once I’d got those in I bolted them to the new chassis rails and gave them a nice bead of weld too.
The chassis rails are less terrible a repair than rotted sills and arches, currently in the process of doing those now. Hopefully it’ll be back out in the sunshine before too long.
Good luck, I hope it isn’t too crusty inside!
Fortunately my arches and sills seem unscathed. After I get this done I might send an endo scope in so I can cry a bit though.
I’ve looked at the V8R mounts, for the price, and the lack of precision required on that bit, i’ll make my own if necessary!
Cheers. Would love to see some pics of yours though.
Update. Car’s Sorted on that front - https://imgur.com/a/vJtvUva I bought these rail repair panels - Set of Mazda MX5 Chassis rails repair panels | eBay
Even got a sill sorted, I did ask for a very quick fix on this part as I honestly didn’t want to find out about further sill rust. Apart from a little bit of clean up around the wounds I didn’t do any of the work myself. I wanted to, but this is my daily and I can’t have it off the road for weeks, and without a lift, it would have been. Very happy now though.
I don’t think the mechanic advertises much or at all, honestly though if you like what you see in the photos send me a message and i’ll give the contact.
Hopefully that’s not breaking any rules. If it is, just let me know.
I’ve an NA not an NB so I don’t get the same front rail issues (I’ve resolved more than my fair share elsewhere though) . It’s frustrating not being able to crack in and finish a job without the necessary bits and to that end I do hunt around for bits too.
For anyone reading this who is less familiar with parts and garages though I do try mx5 Restorer regularly if I think they might have the bits as, while I’ve never met them as I’m at the other end of the country, I do buy stuff from them and find them extremely helpful and a really valuable resource to all of us keeping these fantastic rust buckets on the road. They even phoned up to check an order as they thought I’d got one order wrong, corrected it and still got the parts out same day.