If you're out in the field and something snaps, having a john deere 640 hay rake parts diagram on your phone or printed in the shop can save you a massive headache. There's nothing quite like the frustration of seeing a row of hay half-finished while you're staring at a bent bar or a missing tooth, wondering exactly what part number you need to tell the guy at the dealership. The John Deere 640 is a classic side-delivery rake, and while these machines are built like tanks, they aren't invincible.
Keeping an old 640 running smoothly mostly comes down to knowing how it's put together. These rakes are famous for their reliability, but after a few decades of bumping over uneven ground, things wear out. Whether you're looking for a specific bolt or trying to figure out how the gearbox attaches to the frame, the diagram is your best friend.
Why the Diagram is Your Best Friend
It might seem simple enough to just look at the machine and guess what's wrong, but the john deere 640 hay rake parts diagram offers a level of detail you just can't get by squinting at a greasy frame. These diagrams use what's called an "exploded view." It basically looks like someone took the rake apart and suspended all the pieces in mid-air so you can see exactly how they fit together.
The real magic happens when you look at the reference numbers. On the drawing, you'll see a little number next to a washer or a bearing. You then match that number to a list that gives you the actual John Deere part number. This is crucial because "that round thingy near the wheel" isn't going to help the parts department find what you need. When you have the exact part number from the diagram, you know you're getting the right fit the first time.
Understanding the Main Sections
When you pull up a parts diagram for the 640, you'll notice it's broken down into several sections. You don't want to scroll through the entire manual if you only need a new tire. Usually, the sections are divided into the frame, the reel (the part that actually moves the hay), the drive system, and the wheels.
The Reel and Teeth Assembly
This is usually the most visited page in any john deere 640 hay rake parts diagram. The reel is the heart of the machine. It's got those long bars (often called rake bars or pipe bars) that hold the teeth. If you hit a hidden rock or a thick clump of brush, you might bend one of those bars or snap off a dozen teeth.
The diagram will show you the "rubber-mounted" teeth that the 640 is known for. It'll also show the clips and bolts that hold them on. If you're replacing teeth, take a quick look at the diagram to see if there's a specific orientation for the mounting hardware. It's a common mistake to put them on backward, which messes up the flick of the hay.
The Drive System and Gearbox
The John Deere 640 is ground-driven, meaning the movement of the wheels powers the spinning of the rake. This involves a series of universal joints, shafts, and a gearbox. This section of the diagram can look a bit intimidating because there are a lot of small pins, keys, and bearings.
If you hear a grinding noise, you'll want to check this part of the diagram. It'll show you the internal seals and the specific bearings used in the drive housing. Often, a small $10 seal fails, leads to oil loss, and eventually kills a much more expensive gear. Catching that early by identifying the seal on the diagram can save you hundreds of dollars.
Common Parts That Need Replacing
Let's be real: some parts just don't last forever. If you own a 640, you're eventually going to be looking for these specific items on your diagram:
- Rake Teeth (Tines): These are the most common "consumable." They break, they lose their spring, or the rubber mounts rot over time.
- Stripper Bars: These are the long metal bands that the teeth pass through. If they get bent, they'll start rubbing against the teeth, which sounds terrible and wears everything down faster.
- Bearings: Specifically the ones at the ends of the rake bars. If these seize up, the whole reel can lock or start vibrating like crazy.
- Tail Wheel Components: The little wheel at the back takes a lot of abuse. The bearings and the swivel assembly often need a bit of love after a few seasons.
Tips for Finding the Right Diagram Online
The easiest way to find a john deere 640 hay rake parts diagram today is through the John Deere online parts catalog. It's free to use, though it can be a little clunky if you've never used it before. You just type in "640" and select "Hay Rake" from the list.
One thing to watch out for is the serial number. Over the years, John Deere made small tweaks to the 640. Sometimes they changed a bolt size or a bearing type mid-production. The diagram will usually specify "Serial Number XXXXX and below" or "Serial Number XXXXX and above." Make sure you know your rake's serial number—usually found on a plate on the main frame—before you start ordering parts based on the drawing.
Don't Forget the Hardware
One of the most underrated uses for the parts diagram is identifying hardware. We've all been there: a bolt shears off, and you can't find the other half. Instead of digging through a bucket of random rusty bolts hoping to find a match, the diagram will tell you the exact size, thread pitch, and grade of the bolt.
Using a Grade 5 bolt where a Grade 8 is required can lead to another breakage pretty quickly. The diagram takes the guesswork out of it. It'll also show you where there are supposed to be spacers or lock washers that might have fallen off in the field without you noticing.
Maintenance vs. Repair
While the john deere 640 hay rake parts diagram is great for when things go wrong, it's also a helpful tool for routine maintenance. If you look at the exploded views, you'll see every grease fitting (zerk) on the machine. It's easy to miss one or two when you're just walking around with a grease gun.
I like to use the diagram as a checklist at the start of the season. I'll look at the wheel hubs, the pivot points, and the drive shafts on the drawing and then make sure I've actually hit all those spots on the physical machine. A well-greased 640 can easily last another thirty years.
Final Thoughts on the JD 640
The John Deere 640 is a bit of a legend for a reason. It's simple, effective, and it creates a great windrow. But even the best machines need a little help now and then. Keeping a copy of the john deere 640 hay rake parts diagram nearby is just smart farming. It turns a confusing repair into a straightforward project.
Next time you're heading to the shop to fix a rattling bar or a wobbly wheel, pull up that diagram first. You'll spend less time scratching your head and more time actually getting the hay off the ground. After all, the sun only shines for so long, and you don't want to spend those prime hours waiting for the wrong part to arrive because you guessed at a number. Stay prepared, keep that old rake greased, and it'll keep taking care of you for a long time to come.