A Couple of Corrosion Questions

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90blkgt
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A Couple of Corrosion Questions

Post by 90blkgt »

Does anyone have any real world long-term experience with rubberized undercoating on a vehicle? I read that it hardens with age, cracks, and allows moisture, and in my region, road salt, to come in contact with the undercarriage. Once the intrusion has occurred, the moisture migrates under the surrounding undercoating, causing severe corrosion.

Also, what are the Beretta's corrosion weak points? Specifically on the undercarriage? The car is a 1990, if that makes a difference.

Thanks


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Re: A Couple of Corrosion Questions

Post by heavywoody »

Beretta's main areas for concern are the rockers, inside the door jamb by the hinges, and the rear suspension/spring perch area.


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Re: A Couple of Corrosion Questions

Post by woody90gtz »

I'm not a fan of rubber undercoating. It causes more issues than it solves.

The most effective solution to fight salt is a yearly dose of oil sprayed underneath. It's a mess, but I've had friends doing it with success. They oil the hell out of it and then fly down a dirt road to keep it stuck all winter.


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Re: A Couple of Corrosion Questions

Post by Rettax3 »

woody90gtz wrote:I'm not a fan of rubber undercoating. It causes more issues than it solves.

The most effective solution to fight salt is a yearly dose of oil sprayed underneath. It's a mess, but I've had friends doing it with success. They oil the hell out of it and then fly down a dirt road to keep it stuck all winter.
:D My '97 Z-24 has minor rust issues -nothing cancerous, but it is present. I had issues (thank you Fel-Pro, for providing the world's WORST RTV silicone, that DISSOLVES with synthetic oil!) with the turbo's oil-return line into the pan several years ago, and once the undercarriage was 'oiled', I decided to let it stay oiled. Ya, it works! Ya, it is messy.

However, POR-15 also makes a coating (it isn't paint, it applies like paint, but it is a coating) for frames and chassis that is PERMANENT. Their demonstration is to coat a strip of metal with it and let it cure, then bend the metal strip back and forth until it finally breaks from metal fatigue. The coating remains intact. It does not turn brittle with age either, from all reports and feedback I've ever heard. I used to work at a restoration shop and we were also a POR-15 dealer, and sold to a few local body-shops, so we got feedback from a few sources that used the stuff ALOT. Look for it from ebay or a similar source, and it can be cost-effective too.

I've used the rubberized undercoating limitedly, and haven't had issues with that either (yet?). If you keep the coating relatively thin, it shouldn't crack easily. Apply a good quality paint first, and use the coating more as an armor to protect it from rock-chips, and that would be a good direction to go too.


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90blkgt
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Re: A Couple of Corrosion Questions

Post by 90blkgt »

Thanks for the info. When I get up to 5 posts, I will post links to photos of my car's undercarriage, just to get some other points of view on the amount of corrosion. If I think the rust is going to be too much of a problem, I might just part ways with the car. I like the car, except for the seat/shoulder belts in the door. I think if I do decide to walk away from it, I would look for a 1991 to 1993 Beretta where the seat and shoulder belts were mounted on the B pillar.


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Re: A Couple of Corrosion Questions

Post by Browser »

Grease is good. As living in Europe where salt is the most common thing to be sprayed on roads (at least in Estonia), then good undercarriage maintenance is must have. We have different companies who offer undercoating and inside frame services. That means they spray all the undercoating, engine bay, rockers, door jambs, doors, trunk lid etc with special oil based liquid. This will climb itself to some points and prevents rusting. Also it will stop current rust to keep going.

For some points they have to drill new holes to get the tube in and later on it will get rubber caps. This should be done every year over hear if you want to have your car outlive 5 years. As modern car industry aims to max. 5 year life expectancy then most manufacturers and clients just ignore this and sells the cars to next unlucky owner :D


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Re: A Couple of Corrosion Questions

Post by Rettax3 »

In general aviation, the inside of steel-frame structures (such as engine cradles) are typically supposed to be coated with hot boiled linseed oil for corrosion prevention. While the excess is supposed to be drained out and the structure sealed, there is no schedule for retreating, so it should keep a good efficacy . How long would it last in an unsealed rocker-panel? Who knows. But this would be a safe, eco-friendly option too.


1989 SuperCharged 3800 Srs-II (First)Six-Speed GTU
1990 Turbo 3.4 5-Speed T-Type
1990 4.0L 4-Cam 32-Valve V-8 5-Speed Indy GTi (Project)
1990 Stock(!) 3.1 MPFI Auto Indy
1995 LA1/L82 4T60E Z-26
1995 3.4 DOHC Turbo 5-Speed Z-26
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Re: A Couple of Corrosion Questions

Post by Browser »

Rettax3 wrote:In general aviation, the inside of steel-frame structures (such as engine cradles) are typically supposed to be coated with hot boiled linseed oil for corrosion prevention. While the excess is supposed to be drained out and the structure sealed, there is no schedule for retreating, so it should keep a good efficacy . How long would it last in an unsealed rocker-panel? Who knows. But this would be a safe, eco-friendly option too.
I have seen tests where they disassemble the car completely. Around 100000km or 5 years. Then they inspect every detail and that includes cavity check with little camera. Most manufacturers still had a good coating after 5 years, so there might be the starting point for that. If you do full coating in every year, then you should do good. At least inside of panels :D


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Re: A Couple of Corrosion Questions

Post by 90blkgt »

I took close look at the undercarriage. The corrosion has gotten too much of a head start for me to correct. At first glance, the rust does not look too severe, but when probed with a screwdriver, the rust gives way to some serious holes. Below are a couple of photos of the rear spring area. The rust in the driver side rocker panel was just as bad. It easily crumbled to open up a 4" hole. The car has been garaged for 12 years due to coolant in oil. I was going to finally take a shot at getting it going again, because the body still looks decent. The undercarriage corrosion is a self-inflicted wound not just because of the rubberized undercoating, but also because I let the car sit for years on a concrete floor with no plastic underneath as a moisture barrier.

Passenger side rear spring area before probing with screwdriver
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Hole opened up after minimal probing
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Re: A Couple of Corrosion Questions

Post by 3X00-Modified »

I doubt the lack of a moisture barrier is the true cause of this... you stated road salt in your region, and when I bought my 95 back in 2001 to commute to school and back, it was quite rust in the back end early on... so I would not be surprised if this car had the start of this rust from salt and other exposure and then just got worse as it sat. It really does take something like salt to cause rust to get that bad, just a bit of moisture I doubt would scale up pieces like that.


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Re: A Couple of Corrosion Questions

Post by 90blkgt »

I always went to the self-service car wash and rinsed the undercarriage throughout the winter. The car was parked in the winter. My mistakes were not rinsing the undercarriage at home, then parking it, and also letting the car sit unused for 12 years. I originally planned to only have the car off the road for one month. When months stretched into years, well that was the undoing of the car.


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Re: A Couple of Corrosion Questions

Post by yellow3800 »

I’ve undercoated with non rubberized, standard shake it spray can from auto parts store, a car 20yrs ago. It’s not driven in salt, or rain on purpose and has held up like it was sprayed last month. ....so it’s not self-defeating. I’m currently using rubberized 3M brand, $15 a can, on a car now. I’m happy with it! Just putting one coat too. I also have two quarts of dupli color (10% mix with acetone to spray) that I’ll use next month. I expect it to be comparable.


90blkgt
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Re: A Couple of Corrosion Questions

Post by 90blkgt »

You have had good luck if your undercoating has remained pliable. If you keep your car out of corrosive conditions, why do the rubberized undercoating? Was it a daily driver at one point before it was restricted to being operated only in dry, clean road conditions?


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Re: A Couple of Corrosion Questions

Post by yellow3800 »

How about sound absorbtion? The car is a daily driver, but I don't drive it in salt water. I have not tested a before and after. its thicker, and so more abrasion resistant. I'll also add that I did not wipe down the surface with alcohol or wax-grease remover... just sandblast, prime [spray can] and shot this stuff on, all within a few hours. High pressure air it off to remove dust prior to primer... I did do that as a precaution. It looks great and feels great. The feeling of having an older car that is not rusting gives me that 'new' feeling, and that is my reward.

boiled linseed oil as mentioned above. One time I took part in welding a 2" square reinforcer beam along the driver side front to rear wheel wells to help stiffen up the car again from rust damage. Had some oil, put that in the tube and undercoated the outside.

If you play with fire... What attracted me to the beretta, as a resident of lower Michigan at the time was the fact that the cars were dipped in a galvonic bath [like crossing a river without a bridge... DUNK! and it came up the other side]... I don't know what other cars have seen this type of dipping because its not like its an advertising point. they did a good job I think. Problem is... introduce those salt-belt roads and eventually they will succomb to wounds in door jambs, rear spring perches, the vertical walls of the rear shock towers, shock towers, and most importantly, the hard point where jack stands fit in front of the rear wheels at the corners. rust attacks that part hard. its thick, so it can take it for a while. Moving on... GM then used excellent primer, in regard to it being specially designed to adhere to the galvanized steel. Who didn't get the memo was the paint side... particularly metallics. ever see leprosy paint? their paint won't stick to the primer, so then we have a weakspot... primer being porous... allows moisture in, moisture opens the door to salt water, the gap increases and add time and voila! ...rust like a mustang. Look under the car, particuarly those tube runners next to the spare tire well. See the paint flake/peel off? moisture gets under, spreads and the primer sticks... it goes through the primer and pushes the paint right off - no sun involved, so its detrimental both ways this lousy paint that is used.

Don't forget to treat and shoot inside the tube runners beside the rear tire well that goto the 'corners' that I described above. Some undercoat cans have the red straw to help direct it in hard to get to places. For this, I use a rust converter-to-primer [not gel, not the kind that needs a water hose rinse] after hitting it as well as reasonable with sand blasting. then shoot the undercoat in there.


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Re: A Couple of Corrosion Questions

Post by 90blkgt »

Wow, you are very thorough in your underbody maintenance. My 1990 Beretta looked excellent on the topside, but the underneath it was a lot of rot in the places you described. I had the rubberized undercoating applied with the car was new. It was my daily driver, and living in the upper Midwest USA, road salt was generously applied during the winter. I would frequently go to the self-service car wash and thoroughly rinse the underbody to get the salt off, but it still succumbed to rust. If I could go back in time, I would skip the undercoating and treat with Fluid Film prior to every winter. Also, I think it did not help that early in its life, the car was hit while it was parked on the street. It was damaged enough that the drivers side quarter panel needed to be replaced. The repair was rusting within a year.

I would like to eventually get another Beretta, partly for nostalgia and party because I liked the car - even though now I prefer vehicles that have a higher driving position. My Beretta had the seat/should belts mounted in the doors. That was the only thing I did not like about the car. If I do get another Beretta, it will be from one of the years where the restraints were mounted on the pillar, not the door.


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