Lock Nut

Ensure optimal performance and safety with the Case Construction Lock Nut #131-91. Designed for heavy equipment, this durable lock nut provides secure fastening, preventing loosening under vibration. Perfect for maintaining the reliability of your machinery on any job site.

Compatible equipment

This part fits CASE CRUZ-AIR WHEELED EXCAVATOR, CASE CRAWLER TRACTOR, SERIES - CASE UNI-LOADER SKID STEER LOADER, CASE UNI-LOADER SKID STEER LOADER, CASE UNI-LOADER SKID STEER LOADER W/DEUTZ ENGINE, BACKHOE, BACKHOE FOR 450, 450B, 850, 850B, AND W14, CASE TRENCHER, CASE LONG TRACK CRAWLER TRACTOR, CASE CONSTRUCTION KING LOADER BACKHOE, IND - CASE CRAWLER TRACTOR, CASE CONSTRUCTION KING LOADER BACKHOE - 4WD SUPPLEMENT, CASE CONSTRUCTION KING LOADER BACKHOE - TURBO SUPPLEMENT, CASE SUPER-D CONSTRUCTION KING LOADER BACKHOE, CASE SUPER-E CONSTRUCTION KING LOADER BACKHOE, CASE CONSTRUCTION KING FORKLIFT, MINI CRAWLER EXCAVATOR, CANOPY - STAGE V, MINI CRAWLER EXCAVATOR, ELECTRIC, ROLL-BAR, MINI CRAWLER EXCAVATOR, CAB - STAGE V, MINI CRAWLER EXCAVATOR, 2 PIECE BOOM, CAB - STAGE V, MINI CRAWLER EXCAVATOR, 2 PIECE BOOM, CANOPY - STAGE V, MINI CRAWLER EXCAVATOR, CAB - STAGE V MY24, MINI CRAWLER EXCAVATOR, CANOPY - STAGE V MY26, MINI CRAWLER EXCAVATOR, 2 PIECE BOOM, CAB - STAGE V MY24, MINOTAUR COMPACT DOZER LOADER, SNEAKER - SERIES-C TRENCHER, SNEAKER C - 25+4XP TRENCHER, SMALL ARTICULATED LOADER, SKID STEER LOADER - TIER 4F - NA, MINI TRACK LOADER 1000 - STAGE V, COMPACT TRACK LOADER - TIER 4F - NA, COMPACT TRACK LOADER, CASE WHEEL LOADER including models 1085C, 1150E, 1155E, 1500, 1529, 1550, 1700, 1816, 1816C, 1835, 1835C, 1840, 1845S, 26, 26B, 26D, 26S, 35, 350, 35C WL, 360, 450B, 450C, 455B, 455C.

Frequently asked questions

What is the part number?

The manufacturer part number is 131-91.

Is this a genuine OEM part?

Yes. Southeastern Equipment stocks OEM and quality aftermarket parts for heavy equipment. Contact us if you need a specific OEM source or aftermarket option.

Will this fit my machine?

See the compatible equipment list above. If your model is not listed, call us with your machine's serial number and we can confirm.

Where does this ship from?

Southeastern Equipment Company ships parts nationwide from our US warehouse. Orders placed before 2 PM ET typically ship same day.

Ships nationwide. In-stock parts ordered before 2:30 PM ET ship the same business day. Your exact shipping cost and delivery estimate are calculated at checkout from your ZIP code and the part’s size and weight; oversized and truck-freight items may need extra transit time and freight charges.

Free branch pickup is also available across Ohio, Indiana, Michigan, and Kentucky — just choose it at checkout.

30-day returns. New, unused parts in original packaging may be returned within 30 days. Some items — including electrical, special-order, and direct-from-supplier parts — are non-returnable. See our full return policy.