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After a mowing season and a half, I noticed some surface rust on the underside of the mower deck of my lawn tractor. Here’s what I did to fix it.

I have a Huskee 42-inch lawn tractor that I have turned into a multi-tasker. I’ve said before how I don’t like tools that only do one job if I can help it, so I’ve gotten a couple of attachments to expand the functions of this tractor. As I was removing the mowing deck for the winter, I noticed some rust accumulating where I know it will cause future problems.

Research

I read online forums and watched YouTube videos made by DIYers like me as well as professional landscape managers. Opinions varied widely, as always, but they all ended up in a similar place: prevention is easier than cure. I’ll get to that part later; now that I’m in this pickle, I need to do something. I need to clean off what’s there and put something over the bare-metal surface to protect from further issues. The factory painted the underside of the mowing deck, but that wore away pretty quickly.

Cleaning It Up

There isn’t any rocket science in the first few steps. Remove the blades, then disassemble the mower deck to the point where you have free access to the entire underside. For me, that was a complete disassembly to remove all the screws that were sticking down below the surface of the deck. I took the opportunity to clean all the pulleys and wipe down the top of the deck, too. A big help was to take pictures from a couple of different angles so I know where everything goes back to.

A putty knife and wire cup on my drill were the weapons of choice for the majority of the cleanup. I simply scraped away the “chunks” of grass with the putty knife, then went after the chipped paint, dirt, and surface rust with the wire cup on the drill. Grinding away all the rust to bare metal isn’t necessary. I cleaned up the surface a bit, then got on with turning that rust into something else.

Rust Conversion

I’m so glad I discovered Rust Kutter in my research. This stuff is awesome! After I wiped away the debris from the clean-up process, I sprayed the rust converter on and walked away for a couple of days.

Rust Kutter, like other products in its class, changes the chemical composition of the rust (oxidation) to a phosphate. This makes it non-corrosive, stopping the damage the oxidation is doing. Depending on conditions, it turns the surface either black or chalky white. In my case, it turned black.

Another quick wipe-down to make sure everything is smooth, then it’s on to preventing future rust.

Sealing the Mowing Deck

This is where the online opinions varied the widest. Some said don’t do anything but keep it clean, others advocated truck bed lining, others a coat of paint or oil, and still others automotive undercoating. I went with undercoating, as it seems to me it will hold up well but not be as expensive as bed lining. Bed lining is also not smooth, which I think will be a problem for keeping things clean.

I got the best undercoating I could find; I wanted to test it, too, for touching up a few things on the underside of my truck. The 3M rubberized undercoating went on really easily and dried quickly. I sprayed the entire underside, all the way to the rolled edges of the metal.

Reassembly and Final Points

Reassembling the mower deck was pretty easy. I noticed a gouge in the belt, so I grabbed the spare off the shelf and replaced it. Remembering where one of the springs goes took me a minute; the pictures I took during disassembly were a huge help at this point. I went ahead and sharpened the blades before I reinstalled them, and the deck is ready to reinstall. I added a deck wash attachment that I think will help in keeping clumps of grass from staying stuck to the inside of the deck.

All in all, this job took about 5 hours of effort: an hour each for disassembly and reassembly, about two hours of clean-up, and an hour total between rust conversion and undercoating. I spread the effort over a couple of weeks due to other pressures on my time, but I could see it getting done in a few days. The Rust Kutter takes a couple of days to work, and I’d recommend giving the undercoating a solid day or two to fully cure depending on weather conditions.

Right now, I am very happy with the results. The deck looks great and I think it will hold up well for the season. Time will tell – I’ll let you know what it looks like next time I take the mower deck off.

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