Help with rusty sills

[Ro55H]

My car is at a body shop at the moment getting the sills redone to try and remove as much rust as possible and then plate them back up. I believe there is some drainage holes that run through the sills and then drain out the bottom of them, and i was wondering is there anyway of diverting them so they dont run through the sills, or if there is any modifications that can be done to help with the drainage. Also would filling them with waxoyl help or does it just clog the drainage holes up? They are a daft idea from what i can make out, because the sitting water inside them means they rot from the inside, ive been told by the body shop that they cant put any guarantee on the job and they could be rotting back through again within a couple of years.

Ross

[bluetone]

I use an old coat-hanger to check the drain holes are clear each time I wash the car. There are also a pair of them toward the front of the sills.

I have not seen/heard of any modification to avoid this issue; a design weakness I guess.

[snotrag]

Conversely, I'd say its far from a weakness.

If you 'seal' the cavities - they will still get water in. It gets in anywhere.

But it would be much less likely to run out.

[bluetone]

I was just suggesting using the sills as drainage ducts was maybe not the best design idea Mazda ever had, given that there are two types of Mk1 - those that have had their sills re-done and those that need it.

LOL...

Edited by bluetone on Wednesday 25th February 20:00

[Ro55H]

I went to see my car at the body shop today, and it seems the sills are just starting to rust on the inside, would you recommend putting full new sills on, or just having them repaired and putting some sort of rust treatment on the existing ones, i forgot to take some pics, will get some on here asap. The guy at the body shop said that if he plates it up, it will only be temporary as the rust will now set in, the only rust that was visable was bubbling on the join but now it has been opened up you can see surface rust on inside of sill. They are solid apart from the surface rust, so i dont really know what to do.

Ross

[bluetone]

Ro55H said:

I went to see my car at the body shop today, and it seems the sills are just starting to rust on the inside, would you recommend putting full new sills on, or just having them repaired and putting some sort of rust treatment on the existing ones, i forgot to take some pics, will get some on here asap. The guy at the body shop said that if he plates it up, it will only be temporary as the rust will now set in, the only rust that was visable was bubbling on the join but now it has been opened up you can see surface rust on inside of sill. They are solid apart from the surface rust, so i dont really know what to do.

Ross

Personally speaking Ross, I would not go to the expense of putting full new sills in, I would get the current repaired and treated. I got both rear wings repaired last year for £200, this on a 14 year old car...

[MX-5 Lazza]

The sills aren't used as drainage ducts. The only reason water gets in there is because the drain-tubes get blocked so the water overflows and ends up flowing down through the bodywork and through the sills. Keep the drain tubes clear and the only water that should get in the sills should be condensation (which will happen to any car).

[kevham]

Not quite true Laz.

Water can get in through the seam between the outer panel and the inner panel at the wheel arch. That's where the rust starts on Mk2s. Condensation is the real killer though. The rear wing panels on the Mk2 are not well treated and rust badly from the inside out.

[MX-5 Lazza]

kevham said:

Not quite true Laz.

Water can get in through the seam between the outer panel and the inner panel at the wheel arch. That's where the rust starts on Mk2s.

Yeah, but that's due to a fault rather than by design

[Rob13]

My car isnt 8 years old yet and its showing rust on the rear of the sill and on the rear arches. Ive got it booked in next month to have the whole lot treated and sprayed. It probably wont last 2 years but at least itll be better than what it is now.

[kevham]

Rob13 said:

My car isnt 8 years old yet and its showing rust on the rear of the sill and on the rear arches. Ive got it booked in next month to have the whole lot treated and sprayed. It probably wont last 2 years but at least itll be better than what it is now.

My car was just 6 years old when the first signs of rot appeared. Within a year, it was perforated - a hole the size of a 50p. Since then, the whole wing has started to go.

[bluetone]

Well whatever the design, it is def' the case that if your drain holes aren't kept clear, the sill can collect water, to the extent that it can be heard sloshing around.

At MOT time if a sill is found to be corroded (structural corrosion) then this can become a failure at which point repair/replacement would become necessary. Thankfully it seems to generally be the outer wing/cosmetic corrosion that goes, which is not so much of a big deal to repair. Here are my before and after shots (Mk1 owners of a nervous disposition should look away now LOL)..









Bit embarrassed I let it get that bad tbh; once the MOT man had a good poke and announced non-structural, the holes he made spread alarmingly quickly - this is a daily driver..

[Rob13]

Mine is a daily driver too. Its pretty shocking that rot has set in this quickly. On a Rover yes, but I thought Mazda had better build quality. Im getting the repair done now rather than later (however I suspect it wont last more than 24 months). The 16 inch sport wheels are just as bad, totally pitted with flaking paint. Another job on the list this spring.

[Leeson Girl]

Hi all,

I wonder if anyone can point me in the direction of someone who could facelift the sills on my poor little MX5? they are quite shocking! worse than the ones above!!

I'll post a pic up tomorrow

[skinny]

whereabouts are you?

[MX-5 Lazza]

skinny said:

whereabouts are you?

Says Staffordshire in her profile

[Leeson Girl]

Hi, yeah Staffordshire. I want to be able to replace its sills rather than sell it cuz i really enjoy driving it and don't think anything comes close to it in its price range.

[Leeson Girl]

Look at these bad boys

[skinny]

yup sorry looks like those will need cutting out and i think you'll find more brown badness inside...

[themx5restorer]

shame you are so far away from me