Mower deck maintenance. Is it worth it?

Phew - wish there was a simple answer to all that. And best practices can vary by region since different conditions make different problems. In the northeast, and likely the PNW as well, rust is the primary killer of decks. And that comes from not cleaning the undersides of the deck - religiously. I have never seen a mower deck (in constant use) that was washed out after each cut have anything other than very light surface rust under it. It's the sticky rye and blue grasses that are typical to the NE and PNW that build up under the deck, even if the grass is "dry" when cut. Rotary mowers tear the gras, and that juicy, healthy grass, sprays moisture while the mower blades commit assault and battery. SHARP mower blades help a BUNCH but you can't fight Mother Nature on this one. The golf courses wash down their equipment every day it goes out. They cut in the dew and the rain, and their stuff lasts for decades and thousands of hours of use. Seals may or may not be a little more robust on equipment like that but one thing I saw that consistently made for excellent performance, was a good grease that was intended to perform in wet environments. Ie: Marine grease, or boat trailer wheel bearing grease. It's not hard to find, I'm a shameless AMSOIL fanboy and love their flavor, but you can find it under many brands, on the shelf at any Tractor Supply, auto parts stores, and even Wally World.

Under a mower deck is a very abrasive environment in any area of the country, but especially so in areas with sandy soils, desert regions, or even just having a dry summer season. Most paints and paint-like coatings don't stand a chance. When I worked for a Deere dealer, I was blown away when I learned how many replacement mower decks were sold for machines under 10 years old in some areas. It was just typical to wear through a deck made from 12ga steel or thinner (as is typical to many residential-quality machines). Some commercial operators were destroying 7ga fabricated decks just through (lots of) normal use.

Once a deck starts to show cracks around stress areas, it's time to make a doubler plate and weld that in. Make sure you are doubling up the general area around the stressing component, not just the crack. Sometimes adding gussets to factory fixtures like gauge wheel brackets, or main hangars, is great insurance. A reinforcement ring for where the spindles bolt on - etc. Your time and tools usually dictate how far it makes sense to take it.

 

I did a lot of "bodywork" to mower decks back in the day.

 

They were actually. Wheelhorse, Deere, MTD, AYP etc. All of them before the mid 90's were pretty "flexible" actually. Not very tolerant of abuse or even "oopsies". The metal didn't get any thicker in the 90's, but the manufacturing sure did, especially for Deere post-'92. I think the 38" decks on the STX 38, and the 100 series (160/165, 170/175, & 180/185) were some of the first good, sturdy, mower decks on residential grade machines that I can remember and while nostalgic, nobody really missed the earlier designs like the 37", 46" or 50" decks that were so common under the 200/300 series garden tractors. The mower decks were glaringly fragile compared to the tractor with those models. The 46 sure did hang around awhile though! Could get it (new) as late as Y2K on some Sabre/Scotts models that were based on the STX 46. Wheelhorse unfortunately always had a relatively weak mower deck under a bomb-proof tractor, and that was part of their undoing IMO. As the '90s progressed, the industry ran (not walked) towards mowing performance and productivity (and operator ergonomics) vs tractor versatility and durability. Hence the rise of the residential zero-turns. Pretty pathetic as a "tractor" but mows circles around just about anything else.

Gotta get a "Jungle Jack" for those. Super versatile tool if you need to lift many kinds of mower on the regular. Commercial walks, ZTRs, even lawn tractors although there are better lifts if you are just dealing with a tractor. But the JJ takes up a LOT less room when not being used.

Jungle Jack Lawn Mower lift Version 2 – Jungle Jims Accessory Products (junglejimsap.com)

 

Some of the best deck designs ever built were/are stamped. Residential or commercial equipment. It's not how it's made, but what it's made of that matters, along with the final finish. Plenty of cheaply made fabricated decks on the market claiming to be better than a stamped design. And they just.... aren't. Fabricated decks can be great, both in performance and durability, BUT, they came about because fabricating a HD mower deck from 1/4" flat stock takes a paper print (or a fixed jig, if you fancy) $2k welding machine and a welder making $30/hr whether you are building 1 or 10,000. A small to medium OEM could complete an entire season's production run before approaching what it would take to develop the die needed to stamp ONE deck from 7 gauge sheet. Forget what a 1000+ ton press would cost. Stamping makes a lot of sense, for performance. But you need huge volume for it to work economically and only the largest OEMs can afford the risk if there are hiccups along the way.

Commercial Mowers | 7-Iron & Mulch On Demand Mower Decks | John Deere US

 

There's nothing wrong with them. Exmark's UltraCut deck will out-cut the best of them in all but the worst (wet) conditions and take as much or more abuse. But there's this narrative out there that a fab'd deck is a better performing, more durable deck and that stamped decks aren't even worth looking at. And that's just as silly as saying you need a V8 to tow heavy or go fast. (Inline 6's would like a word...)

Especially in the residential equipment market, for a machine that only I am operating, I'll take a better performing deck any day over one that's made from thicker materials, but of inferior design.