How Can I Determine What Size Zerk Grease Fitting I Need For A 1986 Ranger Boat Trailer?

Updated 02/03/2026 | Published 07/23/2024

Products Featured in This Question

Replacement Grease Zerk for Ram Jacks

(3)

$1.94

Replacement Brass Grease Zerk for Weld-On Hinges - 6 mm x 1.00 STD

$2.57

Replacement Brass Grease Zerk for Weld-On Hinges - 8 MM x 1.00 Fine

(1)

$2.93

Question:

I have a 1986 Ranger boat trailer that is missing the zeros grease fittings. I can’t figure out what size they are to replace them. How can I find what size to get?

asked by: Tabitha

Expert Reply:

Thats a good question Tabitha, and thanks for reaching out. The most common size for a grease fitting or zerk fitting is the standard 6 mm x 1.00. The only way to truly know what size you will need would be to measure one, and with yours missing that will be tough. Zerk fittings are fairly inexpensive so what I would do is purchase two of the most common sizes and see if either of them fit. With your trailer being so old, there is no way to look it up to know this information, so test fitting a few really is the only option. I recommend trying the standard 6 mm x 1.00 part # MA35ZR, as well as the 8 MM x 1.00 fine thread # MA95ZR as it is most likely going to be one of those two sizes.

If that doesn't work out, the only other option is to replace the component containing the zerk fitting. Like if the zerk is on a suspension bolt you will need to just replace the bolt entirely.

expert reply by: Jesse M

Jesse M.

2/3/2026

Hey Tabitha, did either the 6 mm or 8 mm grease fittings end up fitting your Ranger trailer? Knowing which one worked could really help others trying to replace missing zerks on older trailers.