Craftsman Mower Deck Belt: Size, Part Number, and the Swap
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The short answer
Most Craftsman 42–46 inch decks run the 137153 deck belt, a 1/2 inch x 83 inch aramid-cord belt. Confirm against the sticker under the seat, drop the deck to its lowest setting, release the belt from the PTO pulley, walk it off the idlers and spindles, then route the new belt following the decal under the footrest.
UDC Parts 137153 Craftsman Deck Belt
Exact 1/2 x 83 inch aramid-cord replacement — resists the stretch that causes slipping and jumped belts.
Symptoms that point at the deck belt
- A squeal the moment you engage the blades, then it settles.
- An uncut stripe down the middle of a pass — one spindle is slipping.
- Blades stall in grass the mower used to eat.
- Rubber dust on top of the deck when you blow it off.
- The belt has jumped a pulley twice in a month — it is stretched.
Confirming the part number
The 137153 belt covers a large share of Craftsman 42 and 46 inch decks, but Craftsman built many decks over many years, so confirm it against the model sticker under the seat before ordering. Aftermarket aramid-cord versions of 137153 are built to the OEM 1/2 x 83 inch spec and cost noticeably less than dealer stock, which matters because this is a wear part you will buy again in a few seasons.
| Check | Where | What you want |
|---|---|---|
| Model number | Sticker under the seat | Matches the belt listing's fitment |
| Belt width | Old belt or spec | 1/2 in (some heavy decks 5/8 in) |
| Outside length | Part number, not tape | 83 in for 137153 |
| Cord type | Listing detail | Aramid — resists stretch |
The swap, step by step
- 1Park level, kill the engine, pull the key and the spark plug wire.
- 2Lower the deck to its lowest setting to slacken the belt path.
- 3Photograph the routing, or read the decal under the footrest.
- 4Release the belt keeper pins and slip the belt off the PTO pulley at the engine.
- 5Walk the belt off the idlers and spindle pulleys, removing belt guards if your deck has them.
- 6Route the new belt around the spindles and idlers, then onto the PTO last — rotate the PTO by hand to walk it on.
- 7Re-seat every belt keeper, raise the deck, and engage the blades at low throttle for the first test.
Frequently Asked Questions
- What size belt does a Craftsman 42 inch deck use?
- Most take the 137153 belt, 1/2 inch wide by 83 inches outside length. Confirm against your model sticker, since Craftsman decks vary by year.
- Do I have to remove the deck to change the belt?
- Usually no. Dropping the deck to its lowest setting and removing the belt guards gives enough slack on most Craftsman decks.
- Why did my new Craftsman deck belt squeal?
- A seized idler pulley, a bent keeper or a misaligned spindle. Spin every pulley by hand before buying another belt.
The Gear We’d Buy
Everything referenced in this guide, in one place.
UDC Parts 137153 Craftsman Deck Belt
Top pickExact 1/2 x 83 inch aramid-cord replacement — resists the stretch that causes slipping and jumped belts.
Typically $18 - $30
Deck Idler Pulley Kit
Cheap insurance while the guards are off — a seized idler is what kills a brand-new belt.
Typically $12 - $25
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Key Takeaways
- 137153 = 1/2 in x 83 in, fits many Craftsman 42–46 in decks.
- Confirm the part number on the seat sticker, do not measure the old belt.
- Deck to lowest setting; PTO pulley comes off first and goes on last.
- Inspect idlers — they are what kill new belts.
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We buy, borrow and break lawn tools on our own yards — clay in the back, sand-cut Bermuda in the front — and write down what actually changed the result.
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UDC Parts 137153 Craftsman Deck Belt