What to do about this rust?

[dekeman]

I've got a weird problem I've never seen before. I've just done my springtime engine bay detail, and found some rust under the strut mounting brackets.

A closer view:

It's an 03 Mazda Protege, and the pic is of the passenger side strut tower; driver's side is the same. We get very harsh winters up here in Northern New York. There would often be road salt leeching up from the strut tower under the brackets and sit on the area that's now rusted. They use that nasty calcium chloride salt on the roads up here, the kind that make your car slimy to the touch. I cleaned it out well last spring, and it returned over the winter. I'd occasionally hose it out throughout the winter, but I guess it sat long enough to do the damage you see. What can be done about this? I don't want to just let it sit like it is- it'll get worse over time, and that's a bad spot to have it rust through... (nervous) I've never disassembled a strut, so I'm not sure if I can just remove those brackets or if more needs to be done before they come off. Should it be sanded and repainted, or just touched up? Any info you can provide will be helpful- thanks!!!

 

[imported_wagonproject]

Don't just touch it up without sanding it. You could get away with just sanding it in like it is and touching it up. But its not a 100% fix. Proper way would be to remove the strut and bracket and sand (and media blast the rust spots if that is an option) and then seal/paint it and reinstall.

 

[Accumulator]

Mazdas are cheaply build...I had to deal with some stuff like this on my MPV.



Yeah, to do it *right* you need to disassemble and media-blast, and then have a pro refinish the area.



To DIY it in a reasonable manner:

1. Scrape off the visible rust with something abrasive
   
2. Treat the area with a rust converter
   
3. Consider sealing the area with a "paint over rust" product
   
4. Apply topcoat/paint
   
5. Hope you're lucky with regard to future recurrences
   

FWIW, I've done surprisingly well DIYing with Eastwood brand products.





For the first step, they make filament pens that can work well once you get the worst of the rust off via some more aggressive means (wire brush on a Dremel, sandpaper, etc.).

 

[dekeman]

Right- sanding will be done no matter what. I just wasn't sure if sanding/prepping/primer/spray paint was really the way to go, or if touch-up paint would be okay. I'm going to try to remove those brackets and confirm my suspicions that the rust is underneath them as well. Judging by how corroded they are, it's probably worse underneath there. I'll pick up some new brackets for when the repairs are done. Does anyone know if removing those three nuts is safe? I just had a 4-wheel alignment done when I got new tires in the early spring. I'd hate to throw it all off kilter if those nuts are what determines the toe and or camber.

 

[efnfast]

My (probably unpopular, hehe) opinion is just the leave it, not worth the effort. By the time it actually rusts through and becomes an issue, you'll have long since sold the car (and not because of that issue).

 

[Accumulator]

.. Does anyone know if removing those three nuts is safe? I just had a 4-wheel alignment done when I got new tires in the early spring. I'd hate to throw it all off kilter if those nuts are what determines the toe and or camber.

I don't know but I'd sure find out before you do anything



Actually, I think that, since you're gonna do it right, I'd have some shop handle the whole thing and expend your efforts towards trying to a) find a decent shop, and b) prevent them from somehow messing up the paint on the rest of the car, and c) figuring out a way to keep the new parts from rusting.



The shops I use for such stuff wouldn't charge all that much for such a repair and it'd stay fixed for a good long time. Sometimes it's best to just bite the bullet and spend some money.

 

[dekeman]

Well, it'd sure be easy to just leave it! I'd like to keep this car for a long, long time though. I'm very happy with it (03 Mazda Protege LX), I love driving it, and my wife and I have committed to living debt-free. It'll be paid off soon, and this baby's staying put! I think this is something I can take care of, but if removing the brackets reveals more unpleasantness, I think I'll take Accumulator's advice and bite the bullet. I'll chime back in with any updates. Am I seriously the only person that this happens to with the road salt leeching though there?

 

[efnfast]

I'm very happy with it (03 Mazda Protege LX), I love driving it, and my wife and I have committed to living debt-free.

That's a good goal to achieve :clap:



In any event, I still think you're over-reacting to nothing....if hte road salt is causing some rust there, chances are I can put it on my lift and show you things FAR worse underneath (e.g., to the extent of perhaps being able to pull pieces off your fender that are compeltely rusted through on the underside).



don't get me wrong - I'm not against trying to keep your baby in the best shape possible - I'm just against pushing money down the drain on something that really isn't a problem, and making a project out of something with minimal gain.

 

[dekeman]

That's a good goal to achieve :clap:



In any event, I still think you're over-reacting to nothing....if the road salt is causing some rust there, chances are I can put it on my lift and show you things FAR worse underneath (e.g., to the extent of perhaps being able to pull pieces off your fender that are completely rusted through on the underside).

Nope- I put it on a lift every time I do an oil change/tire rotation and there's none of the major damage you mention. In rechecking my engine compartment, though, and re-looking all of the corrosion on fasteners and brackets, I was reminded of the garage it used to be in. Before we moved to another house in the area, we had a separate garage that used to be WAY humid. I'd venture to say that it was always at 100% humidity, judging by the paint cans and other metal items (lug wrench, floor jack, etc.) that have rust problems now which did not before (just from staying in that garage). The blacktop floor was ALWAYS dark with wet in the winter months.



Our new place has an attached garage with none of the humidity problems, so the damage is mitigated. The road salt leeching up wasn't helping matters, but I now think that the damage is from the humidity working on everything metal in the engine compartment. The salt corrosion was trapping the moisture, causing the rust contamination. Throughout the winter, I regularly (at least twice a month) take each of my vehicles through the touchless car wash, and go VERY SLOWLY over the undercarriage wash to thoroughly clean off the bottom of the vehicle. Many many vehicles in this area have major rust damage in the usual places (wheel wells and door thresholds) and I'm not playing with that!



I'm going to keep my eye on this for the next couple of months. If it doesn't get worse, I figure that I was right with my theory. We're moving south to VA in the fall, so I don't anticipate that I'll have any more issues with the road salt.

 

[Jason M]

Removing those three nuts is fine and will not effect your alignment. If it where me I would sand all the areas with a wire brush on a dremel. Spray with POR-15 and then topcoat. You might also want to put some felt or a thin piece of urethane on the underside of the strut brace to prevent it from happening again.



Oh yeah, don't forget to put the three nuts back on

 

[LouisanaJeeper]

you should be OK just removing the three nuts and bracket. I believe the caster/camber is set by the center nut in the joint.



Sand it, prime it, repaint it (preferably a solvent resistant paint), let the paint cure, apply a thin layer of grease or antisieze between the parts & reinstall.



I think it is disappointing that an 03' is already rusting out. Salt or not, unacceptable for a manuf. to accept that.

 

[imported_wagonproject]

you should be OK just removing the three nuts and bracket. I believe the caster/camber is set by the center nut in the joint.



Sand it, prime it, repaint it (preferably a solvent resistant paint), let the paint cure, apply a thin layer of grease or antisieze between the parts & reinstall.



I think it is disappointing that an 03' is already rusting out. Salt or not, unacceptable for a manuf. to accept that.

I've seen worse on 05 vehicles...

 

[dekeman]

Removing those three nuts is fine and will not effect your alignment. If it where me I would sand all the areas with a wire brush on a dremel. Spray with POR-15 and then topcoat. You might also want to put some felt or a thin piece of urethane on the underside of the strut brace to prevent it from happening again.



Oh yeah, don't forget to put the three nuts back on

Thanks! Great idea with the felt/urethane- I'm going to do just that!

I think it is disappointing that an 03' is already rusting out. Salt or not, unacceptable for a manuf. to accept that.

It's actually the only rust on the entire vehicle (besides the aforementioned corroded engine compartment nuts & brackets from the humid garage :wall). The rest of the body's almost mint!

 

[Jason M]

Now that I thought about it more I would lean towards the urethane. The felt could hold salt water. The last thing I would do is run a bead of clear RTV around the edge ot the strut tower bar and also around the area where the studs from the strut enter the engine bay. This should keep any moisture out period.

 

[Accumulator]

IME no matter *how* clean you keep them, some Mazdas simply have corrosion issues. I keep the underside/etc. of the MPV virtually concours all winter long (yeah, it *is* a real chore) and I've still had some rust appear in places.



I've discussed this with Ron Ketchum from AutoInt, who's worked with Mazda at the OEM-level on this and, well, they just don't build 'em all that well.



Mine has even suffered the infamous (well, among MPV owners..) "right front door lower left-hand corner rust-out", which is 100% a matter of shoddy construction that Mazda won't acknowledge. Sorta makes me thing twice about buying another one of their vehicles...



efnfast- heh heh, you assumed that somebody *here* doesn't take good care of the underside?

 

[gofastman]

I you want to leave it, I would spray it with some Amsoil heavy duty metal protector (black can) Its a wax-like product that, IME, slows the progression of rust like that dramaticly.

 

[Accumulator]

I you want to leave it, I would spray it with some Amsoil heavy duty metal protector (black can) Its a wax-like product that, IME, slows the progression of rust like that dramaticly.

That Amsoil HDMP is good stuff :xyxthumbs Dries mighty dry/clean for something like that too.



I use it for electrical connections/grounds on the undercarriage and stuff like that, doesn't stay tacky and attract/retain dirt the way a lot of products do.

 

[My5ABaby]

I've discussed this with Ron Ketchum from AutoInt, who's worked with Mazda at the OEM-level on this and, well, they just don't build 'em all that well.

Although unfortunate, there is a reason Mazdas aren't particularly expensive. This is coming from the owner of 2 Mazdas ('86 RX-7 and '07 6) so I obviously like the company.

 

[dekeman]

Although unfortunate, there is a reason Mazdas aren't particularly expensive. This is coming from the owner of 2 Mazdas ('86 RX-7 and '07 6) so I obviously like the company.

Yeah, I'm pretty happy with mine, although I do see the construction defects you all speak of. The carpet is pretty thin, and there isn't much between the driver and the floorpan. That's the way it stays light and gets good mileage, though. It's been dang reliable, too, especially as compared to my Ford Crapstar, oh, oops, I mean, WINDstar. No rust on that either, except on the steel wheels where the wheel covers have openings. Still have to take care of that.



What is this Amsoil HDMP you all speak of? Never heard of it, though I'm quite familiar with Amsoil stuff. Not so much, maybe?

 

[dekeman]

IME no matter *how* clean you keep them, some Mazdas simply have corrosion issues. I keep the underside/etc. of the MPV virtually concours all winter long (yeah, it *is* a real chore) and I've still had some rust appear in places.

I'd love to be able to do that, but don't know how I'd manage it up here in the -10F/3 feet of snow hell that I live in. The hose would freeze up in a heartbeat, and I'd stick to the ground! Maybe with a lift, but that ain't happening! I just do like I said before, take it to the touchless and drive SLOWLY over the undercarriage wash. Don't reallly know of a more feasible way to keep it corrosion-free in these weather conditions in the winter months.

efnfast- heh heh, you assumed that somebody *here* doesn't take good care of the underside?

LOL- see above!