JIC Bulkhead Locknuts

Replacement locknuts for JIC bulkhead fittings. Clamps the bulkhead body to the panel.

Brand: Ayrtec – mild steel body with a plated finish, manufactured to the standards listed below.

Watch: Exploring Hydraulic Adaptors Part 1: Difference Between Branch Tee & Run Tee, Elbows Short and Long

Thread Standards

• JIC 37° Bulkhead Male – SAE J514 37° flare on a bulkhead body with a locknut. It seals on the 37° cone at each end; the bulkhead body passes through a panel and is held by a locknut, which does no sealing.

How to Choose

• This is a spare part, sold on its own so a damaged one does not mean replacing the whole assembly.
• Clamping only, no sealing. Tightening it will not stop a weep at the cone.
• Match the nut to the bulkhead thread.

Technicians Advice

If a bulkhead is loose in the panel, check the hole has not worn oval before you just do the nut up harder. A loose bulkhead in a worn hole works the line every cycle and will eventually crack it.

Where You’ll Find It

• JIC 37° Bulkhead Male – anywhere a line has to pass through a panel, chassis rail, tank wall or guard and be supported there – tractors, harvesters, truck bodies, tank installations and any tidy machine build.

Cross-Reference

• JIC 37° Bulkhead Male – SAE J514 37° bulkhead. Parker call the 37° range Triple-Lok. The long thread under the cone is for the panel and the locknut, not for sealing.

Parker, Gates, Aeroquip and Ryco all manufacture to these same standards under their own part numbering, so a fitting built to the standard above will mate with theirs.

Cross-references are given at series level as a guide to the standard, not as a part-for-part substitution. Always confirm the thread form, size and seal type against the port before ordering.

📐Dimensions & thread sizes – every size in this range

← Swipe the table sideways to see every measurement →

Part code	Hex	Material	Finish
JLN-07	17.5mm	Mild steel	Plated finish
JLN-08	19.1mm	Mild steel	Plated finish
JLN-09	20.6mm	Mild steel	Plated finish
JLN-12	25.4mm	Mild steel	Plated finish
JLN-14	28.6mm	Mild steel	Plated finish
JLN-17	34.9mm	Mild steel	Plated finish
JLN-21	41.3mm	Mild steel	Plated finish
JLN-26	47.6mm	Mild steel	Plated finish
JLN-30	54mm	Mild steel	Plated finish
JLN-40	69.9mm	Mild steel	Plated finish

Key: Hex across flats. Measurements in millimetres unless shown otherwise. Thread columns show what each end mates with. Dimensions are nominal – check critical clearances against the part.

Downloads

📄 Thread Identification Chart (PDF)

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