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Aluminum Alloy Corrosion Rim Leaks

Just how common is this? How much can be done about it? Is it sometimes hopeless? Surely no one ever actually welds them up and then machines them back off?

Around here they wire brush or sand the bead area and prime and paint it.

They sure do. Repairing cracked, broken, corroded, bent ally wheels is a booming business around here. Last one I had done was a 22" that was cracked and poorly repaired previously. Cost $200 to fix.

I’ve repaired them with a tube of what is called Plastic Steel. Apply over the pitting, allow to dry a bit, and then sand it down. It’s easy to sand and apparently works as multiple (as in many) leaks went away and never came back.

A shop may not do this; a DIYer can.

I had a 1997 Malibu & a 2002 Malibu, both with alloy wheels. Seven of the eight rims had rim leaks. I’ll take good old steel wheels anyday.

I love steel wheels but you have to admit…alloy wheels look better. You also have to admit that alloy wheels have a tendency to leak as they age. We used to have a tire shop in the local area that would seal alloy wheels in some way or another. It was a fairly cheap procedure and worked well. My wheels are just fine for the moment but I found out recently that the tire shop has closed due to the death of the owner. When I start getting flats…I’ll look for a solution then.

I have my installers wire brush the bead and then apply some bead sealant before putting on new tires. Since I run snow tires with dedicated wheels I keep the number of tire changes on my alloys down to a minimum. I haven’t run into any leaks.

A friend has a late 80s Camaro with alloy wheels. She had the same experience and ended up getting steel rims for her car. No leaks with the same tires which still had a lot of wear left on them.

Agree with @bloodyknuckles‌ and I assume that every rim used year round will corrode, aluminum alloy or not. Steel appears to corrode quicker then “alloy wheels” but also appear more forgiving in repair when they do. Most of us who use steel rims for winter and alloys the the rest of the year seem to have fewer problems. And at least the problems are cheaper to fix. If this happens to be your situation, given the high cost of alloy wheels, I would consider it. I actually prefer steel rims on trucks, year round if I use them for off road.

But like said…alloys do look a heck-of-a-lot better.

clean up the rims and ask your tyre fitters if they have tyre seal that is used for fitting commercial tyres to split rims such as mobile cranes. that will seal it

Many years ago porosity to the extent of causing leaks in alloy rims was not uncommon. Ford in particular had a real problem on their Taurus wheels, but others had problems too. Modern wheels are cast differently, better alloys are used, and the wheels are coated with a thick plastic coating that prevents corrosion and leakage. I actually rubbed a rim against a granite curb a few years back and peeled some of this coating off the edge. It was surprisingly thick. I overcoated the spot with clear coat, and that seems to have done the trick.

I don’t think steel rims corrode more quickly than aluminum ones, at least in high salt areas. My 29 year old 66 Valiant with steel wheels had no rim leaks. My 98 Intrigue with aluminum wheels all leaked after 6 years.

I agree with oldtimer that steel wheels don’t corrode more quickly, at least on my GM cars. On the other hand I’ve seen steel wheels on many Asian cars that were solid rust.

Alloy wheels rarely develop leaks anymore. That problem’s been solved.

A casting process called “reverse gravity casting” has become commonplace for automotive parts. It’s a type of “lost wax” method wherein air exits via the top of the mold as the metal fills the mold from the bottom, the metal being fed from ports in the supply vat that are above the bottom of the vat. That allows vat slag to stay in the supply vat, contaminants that might cause inclusions to settle at the supply vat’s bottom, and air in the mold to exit via the top, carrying mold slag, wax, and contaminants with it. It creates a casting far, far freer of inclusions and occlusions (contaminants and voids) that is also much denser due to the mold filling under the weight of the entire quantity of the vat.

This process combined with the coatings now used creates an excellent casting, free of contaminants and voids. Leaks are truly a thing of the past.

Uber wheels are billet-cut, but that’s another story that doesn’t apply to normal cars. Billet-cut wheels are expensive, for high-end, hyper fast, and big-buck show cars only.

Another problem for alloy wheels was steel wheel weight clips. Steel and aluminum together create an anode/cathode situation where the aluminum becomes the anode and aluminum is corroded away, leaving a void.

The fix is to use coated wheel weights, so the clip is never in contact with the alloy. Most tire shops took a while to figure this out - and some still haven’t.

I always liked tape weights for alloy wheels.

@chugpug‌

Where are you at?

The reason I’m asking is you used the word “tyre”

the same mountainbike
Alloy wheels rarely develop leaks anymore. That problem’s been solved.

That ain’t what they’re telling me at the tire shops. Corrosion develops around the bead; aluminum much worse than steel.
I’m living it right now.

Did you notice that I used the word “rarely” and not “never”?
You do realize that tire shops work on rims of all ages?
How are you “living it right now”? How old are your wheels?

If you believe my understanding of the casting of aluminum alloys or my description of the modern process and its improvements is incorrect, please correct me on this. I’d love to learn from you. Especially if you have 40+ years of experience with alloy wheels, as I do, or you have a few decades+ of experience as an engineer in manufacturing, as I do. I’m always open to learning from someone with more knowledge or experience than I have.

the same mountainbike
Did you notice that I used the word “rarely” and not “never”?

Yes, and the tire people I’ve talked to disagree with you.

You do realize that tire shops work on rims of all ages?
How are you “living it right now”? How old are your wheels?

15 years.

If you believe my understanding of the casting of aluminum alloys or my description of the modern process and its improvements is incorrect…

I don’t, which is why I never said it.

I’m always open to learning from someone with more knowledge or experience than I have.

That ain’t me, but once again, the tire people I’ve talked to thus far have said that rim-leaking corrosion on aluminum wheels is not at all rare.