I had two John Deere mower decks come in to me from family and friends this spring with multiple cracks. Instead of buying new decks, we were able to fix them and put them right back into service. Read more to see how we did it.

The first mower repaired was a John Deere 445  which is I believe a 1998 model that had cracked at the front hooks on the mower deck. It had been previously repaired, but it was welded up while it was still on the mower so they could keep mowing and ended up cracking again.

Today, we are going to take the whole mower deck off so we can clean it up properly and weld it inside and out.

Cracked Hook at the front of the John Deere 445 Mower Deck.

You can see where it had been previously welded up but cracked again.

Here is a view of the 445 mower deck upside down. I have ground down the spots where it had cracked through.

TIP: If you can’t take the mower down for repairs, there is a temporary option commonly used on airplanes and bridges. By drilling a small hole at the tip of the crack, also called ‘stop drilling’ you can delay the crack from traveling further. The idea is that the round hole more evenly disperses the stress until the unit can be taken out of service for a permanent repair or replacement.

Here are pictures of the hooks on the mower deck after being repaired. We had discussed making some big gussets to tie them together but decided it would be overkill. To add some extra rigidity, look at the bottom of the hooks where I welded them to the lip on the deck. This should add a lot of lateral strength to the hooks.

Apparently I forgot to take pictures of the inside after I welded it up. I took a die grinder with a burr tip and ground out most of the cracks before welding up and grinding smooth.

Hooks welded up and welded to the lip of the deck for extra support.

Close up of the weld.

The other side. On this side I had to do two welds side by side because the crack was on the outside of where the weld was added.

That wraps up the John Deere 445 mower deck repair. All fixed up and should be good to work another 10+ years.

Next up is a smaller John Deere L110 that had even more issues. The mower deck on this unit had many cracks in different places. A couple of the brackets were near ripping off. It is worth noting that the thickness of the steel and design of the deck on the L110 was much lighter duty than the 445.

This is the cracked deck as it looked when I picked it up.

This main lift bracket had almost completely ripped off of the deck.

a look from the front side of the same bracket.

View from underneath the deck.

Same bracket, other side. It was also cracking though not as bad.

Once I found all of the cracks, I took an air die grinder with a burr bit and went to town grinding out the cracks so I could weld them up.

Burrs and an air grinder like these:

The air grinder above is really handy especially when working in tight quarters. If you will be using it for anything more than short bursts though, you will need a large air compressor. I have an old 30 gallon 3 cylinder air compressor and it seems to keep up fine. This kind of air tool will work with a smaller air compressor, you will just find yourself waiting for the compressor to catch up.

Big crack with the paint ground off and the crack ground so I could push it back into place.

Other side ground down.

There were also some small brackets welded on that had cracks beginning to spread from them.

Once everything was ground down where necessary, I started welding everything back up. I added more welding than came from the factory. To save costs, many of the brackets were only welded on one side which is generally speaking not as strong.

Welded all the way around the little brackets.

Top bracket welded.

Backside of the bracket.

Welded underneath too.

Bracket on the other side. I put an extra weld between the vertical bracket and the brace next to it in hopes that it would make the whole thing stronger.

All cleaned and primered.

All of the brackets reassembled and painted with some way too expensive John Deere spray paint

Both tractors back in action and still running strong months later. They should now be as strong if not stronger than how they came from the factory. If they break again, we have confidence in knowing that it can be fixed.

I hope if nothing else, with this post you realize that these parts such as mower decks don’t need to be replaced. Most often,  little love and some welding can make it just as good for A LOT cheaper. If you don’t have the skills, find a local welder that does and keep some dollars in the USA instead of sending our money overseas.

Good luck!

Paul
www.DIYMetalFabrication.com