Liftmaster K11-3503, TAKE-UP BOLT
The LiftMaster K11-3503 is a replacement take-up bolt used in the chain tensioning hardware on select commercial slide gate operators. Its job is simple but important: it gives the installer a controlled adjustment point for setting the correct amount of slack in the drive chain. Too much slack can allow the chain to sag, slap, or jump teeth; too much tension can overload bearings, sprockets, shafts, and the gate operator frame. This part is most clearly listed for LiftMaster SL585U and SL595U slide gate operators, and older parts lists also associate 11-3503 with SL580 and SL590 style slide gate assemblies. Because several slide gate operator generations use similar-looking chain adjustment parts, match the original take-up bolt length, thread, and mounting arrangement before replacing it.
Compatible With
- LiftMaster SL585U slide gate operators
- LiftMaster SL595U slide gate operators
- Select SL580 and SL590 slide gate operator assemblies where the parts diagram lists 11-3503 / K11-3503
- Various LiftMaster commercial slide gate operator chain tension applications when confirmed by the parts breakdown
Also Known As / Related Part Numbers
- K11-3503
- 11-3503
- G113503
- Take-up bolt 11-3503
- LiftMaster take-up bolt K11-3503
Features & Specifications
| Manufacturer | LiftMaster / Chamberlain Group |
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| Product Type | Take-up bolt / chain tensioning bolt |
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| Part Number | K11-3503 |
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| Application | Commercial slide gate operator chain adjustment |
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| Compatible Operator Type | Select LiftMaster slide gate operators |
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| Dimensions | Published aftermarket reference lists approximately 4.35 in. x 0.5 in. x 0.5 in.; verify actual part before ordering |
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| Notes | Used for chain tension adjustment, not as a general-purpose bolt |
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Technician Note
This is a fitment-sensitive mechanical service part. Check the original part number, operator model, shaft length, keyway or flat location, retaining hardware, and parts diagram before ordering. Similar LiftMaster shafts may look close in photos but may not share the same diameter, length, or hardware position.
Before Ordering Checklist
- Confirm the complete LiftMaster operator model and suffix from the nameplate.
- Compare the original shaft or bolt to the parts diagram callout.
- Inspect related sprockets, bearings, collars, keys, chain hardware, and retaining clips.
- Do not substitute a similar-looking shaft unless the part number or diagram confirms the match.
- For operators that move unsafely, bind, or have damaged drive hardware, have the system inspected by a qualified gate technician.
Professional Advisory
Gate operator drive components are under load and may be connected to heavy moving gates, chains, springs, or high-voltage operator sections. Disconnect power where required by the manufacturer instructions and use a qualified gate technician when drive-train disassembly, electrical work, or unsafe gate movement is involved. Do not bypass required safety devices to test or operate the gate.
Product Q&A
What does the K11-3503 take-up bolt do?
It provides the adjustment point used to set chain tension on compatible LiftMaster slide gate operators.
Which models are most commonly listed for K11-3503?
SL585U and SL595U are the clearest current compatibility references, with older SL580 and SL590 style references appearing in parts lists.
Can chain tension be set too tight?
Yes. Over-tightening can put extra load on bearings, sprockets, shafts, and the operator frame.
Is this the same as a chain bracket or chain guard?
No. K11-3503 is the take-up bolt used for adjustment; brackets, guards, and chain assemblies are separate parts.
What should be checked before ordering?
Confirm the operator model, chain size, bolt length, thread condition, and parts diagram callout.
