---
title: LockNLube Pistol-Grip Grease Guns – Heavy Duty & Premium Models (LNL153-450 & LNL252-450) - Troubleshooting
description: Help
---

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1. [Macnaught Group Help](https://kb.macnaughtgroup.com/?hsLang=en-au)
2. [Product Troubleshooting & Maintenance](https://kb.macnaughtgroup.com/product-troubleshooting-maintenance?hsLang=en-au)
3. [Grease Equipment](https://kb.macnaughtgroup.com/product-troubleshooting-maintenance?hsLang=en-au#grease-equipment)

10 February 2026

# LockNLube Pistol-Grip Grease Guns – Heavy Duty & Premium Models (LNL153-450 & LNL252-450) - Troubleshooting

## High-quality one-hand operated pistol-grip grease guns designed for reliable, leak-free greasing. The Heavy Duty model (LNL153) features a rugged steel/cast head and outputs up to 5,000 PSI, while the Premium model (LNL252) has a lighter cast aluminum head and can deliver up to 8,000 PSI for the toughest fittings. Both guns include the LockNLube® Grease Coupler, a 20″ high-pressure hose with in-line swivel, an air bleeder valve, and a Loop & Lock™ handle clip for clean storage.

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- **Loading & Priming** 
    - Pull follower rod fully back and insert grease cartridge
    - Thread barrel partially, release follower, then bleed air
    - Use bleeder valve or slightly loosen barrel while pumping
    - Tighten fully once grease flows
- **Air Lock Issues** 
    - If pumping produces no grease, bleed air while pumping
    - Premium model primes especially easily due to follower design
- **During Use** 
    - Take breaks during extended greasing to reduce hand fatigue
    - Avoid forcing grease into fittings that are completely blocked
    - Use clog‑clearing tools if necessary
- **Hose & Coupler Checks** 
    - Inspect hose for cracks or bulges
    - Ensure coupler is fully locked on the fitting
    - Tighten hose and coupler connections periodically
- **Coupler Wear** 
    - Signs include grease leakage at tip or harder release
    - Coupler is rebuildable with inexpensive seal/jaw kits
- **Cleaning & Storage** 
    - Wipe coupler before and after use
    - Use Loop & Lock to store hose neatly
    - Store in a clean, dry place
    - Avoid leaving follower fully compressed when stored empty
- **Bulk Filling** 
    - Both models support suction fill
    - Use bleeder valve to remove air afterward
- **Model‑Specific Notes** 
    - **LNL252**: Stop pumping when handle becomes very hard; do not use cheater bars
    - **LNL153**: Ensure follower rod is properly latched to prevent grease bypass
- **Summary** 
    - Minimal routine maintenance required
    - Keep clean, properly primed, and inspect wear parts periodically

- [Product Applications](https://kb.macnaughtgroup.com/product-applications?hsLang=en-au#main-content)

    - [Grease Equipment](https://kb.macnaughtgroup.com/product-applications?hsLang=en-au#grease-equipment)
    - [Air Equipment](https://kb.macnaughtgroup.com/product-applications?hsLang=en-au#air-equipment)
- [Product Troubleshooting & Maintenance](https://kb.macnaughtgroup.com/product-troubleshooting-maintenance?hsLang=en-au#main-content)

    - [Grease Equipment](https://kb.macnaughtgroup.com/product-troubleshooting-maintenance?hsLang=en-au#grease-equipment)
    - [Air Equipment](https://kb.macnaughtgroup.com/product-troubleshooting-maintenance?hsLang=en-au#air-equipment)
- [Find Repair Kits](https://kb.macnaughtgroup.com/find-repair-kits?hsLang=en-au#main-content)

    - [Grease Equipment](https://kb.macnaughtgroup.com/find-repair-kits?hsLang=en-au#grease-equipment)
    - [Air Equipment](https://kb.macnaughtgroup.com/find-repair-kits?hsLang=en-au#air-equipment)
- [Warranty Policy](https://kb.macnaughtgroup.com/warranty-policy?hsLang=en-au#main-content)

    - [Grease Equipment](https://kb.macnaughtgroup.com/warranty-policy?hsLang=en-au#grease-equipment)
    - [Air Equipment](https://kb.macnaughtgroup.com/warranty-policy?hsLang=en-au#air-equipment)