Rusty bottom

September 14, 2018

Hi folks

OK so I have a rusty bottom....(of my Aygo). The worst is around the sub frame and wheel arches. Please share any tips, hints and experiences of treating and /or preventing rust?

Converter vs remover? Paint vs spray? Grease vs Waxoyl? or anything else you think might be relevant?

Product recommendations (or warnings) welcome

Thanks in advance......

September 14, 2018

Hi Neil, (A fine name to be Christened with, if I may say so )

A couple of years ago, I noticed that the underside of our Aygo's are finished in primer, as is under the bonnet and so, at the next service, I got my local, independant garage to underseal mine for me. They used the Hammerite, brush-on underseal and did the entire floor pan and rear wheel arches and charged me, if memory serves, about £100, all in.

Since then I have used black hammerite to protect that weld/join/jack placement ridge which is at the bottom of the sill, between the wheel arches and I have much more peace of mind.

I know that the Aygo only has paint where you can see it to keep both costs and (surprisingly) weight down and I know that modern cars don't rust like they used to but I just feel better with mine undersealed and protected....It might just be me but it seems to make the car a bit quieter as well.

If you are doing the job yourself, a 2.5 litre tin and an old brush will do the job.....BUT....(and you probably know this but it's worth mentioning for others that might read this)....Don't rely on the jack!!!! As you will have to take the rear wheels off and get a good way under the car, axle stands are a must as a minimum. I have heard that some garages rent out their ramps or pits for a Saturday morning and that might be an idea, although I've never heard of one that does in my area.

Anyway, a good jet wash under your car, leave it to dry, give the underside a bit of welly with a wire brush and you are good to go as that is exactly what Hammerite recommends. For rusty bits that you are worried about, like around the subframe mounts, Hammerite "Kurust" is a good little product and well worth the extra tenner to do a proper job.

Good luck and all the best!

September 14, 2018

I had a rust prone car, rusting on the wheel arches from the inside, doing a bit of paint bubling, and under the door sills, where you jack up the car, from front wheels to the back.

I bought 900ml of the black gunk, dont remember the brand, it was some years ago, and cleaned the whole thing, applied rust converter, cleaned again and coated with undercoat.

On both sides of the rear wheel arches i applied some used oil from previous services, did this 1x per month, for 2-3 months during summer months.

Fast forward 2 yrs, the rust went through undercoat, on some places where it was thinner it chipped and it was holding water.

Where i put the oil, there was no new paint blistering, or any obvious signs of rust further spreading.

My vote goes for grease, or oil, or combo of both, whichever is easier to spread on the car. If your get them thin enough and warm, you can probably spray it on.

Yes it's dirty and not fancy looking, but it works.

September 16, 2018

Yes, old oil and grease are a great anti corrosion treatment. You can't spray it, just remove all the dirt and other crud then lather it on with a brush.

September 18, 2018

When i bought my 2015 it was nice hot weather so really dry,i used spray grease on all seams and suspension.Its simple for me as i used a ramp at work.

October 16, 2018

Hi guys

Having had rusty cars in the past I've always waxyoil. It seems to work and you can buy a hand held plastic sprayer to do the job easier. It's better to underseal on a warm day as the underseal is more thinner. You can also squirt it behind panels that have drain or access holes with the tube provided in the application kit. I personally wouldn't you old engine oil as it may contain acid from use.

Regards peter