What Size Grease Fitting Does Lock N Roll Coupler Use

Published 07/28/2026

Question:

I have 3 questions. 1. I would like to know how to grease these. None of the needle style grease fittings I’ve tried from my local parts stores will grease these with the low profile grease zero that comes in them. 2. I would like to remove the low profile grease zero and install a stand grease zero to actually be able to grease these regularly. Can you confirm if the grease zero that comes on it has a hex head that can be removed with a wrench? Mine has no hex head it’s round and I can’t remove it with a wrench or anything else that I’ve tried. 3. Do you supply a trailer side lock roll that I can use to replace mine, which is worn see pictures attached to question showing mounting holes/bolts/etc.

asked by: Matt B

Lock N Roll
(click to enlarge)

Expert Reply:

Hey Matt, the current Lock N Roll articulating hitches like # 336VS511 use a 6 mm x 1.0 low-profile grease zerk (needle-style) for lubricating the pivot bearings.

Because it's a low-profile/needle zerk, a standard grease gun coupler often won't fit well like it sounds like you ran into. You'll typically need:

A needle grease adapter or a grease gun compatible with low-profile/needle-style zerks.

If the fitting is damaged or needs replacement, the correct thread size is M6 x 1.0 (6 mm x 1.0) low-profile grease zerk. A standard-height M6 x 1.0 zerk will thread in if clearance allows, but the factory fitting is low-profile.

Thanks for the picture of what's on the front of your trailer but we don't have anything from Lock N Roll that matches that style.

expert reply by: Jameson C

Matt B.

7/28/2026

Thank you. A couple of follow up questions. I’ve tried every single style needle grease gun fitting I can find and nothing works to grease it. I also can’t just simply unthread the low profile grease zerk, because it has no hex (it is rounded). 1. Any idea how I could remove it? 2. I have a bad vibration while towing my trailer and I suspect it’s being caused by this lock role hitch. The trailer side t connection has fairly significant up and down play. Is this a sign of wear or is that normal? I have a video of what I’m talking about but I cannot seem to find a way to attach it to this. Matt

Jameson C.

7/28/2026

@MattB you can pull the old one out with like vice grips or something similar. Basically you have to just get ahold of it solidly and then pull it out. The vibration could be from the Lock N Roll but typically it's like a tire with a flat spot or something goofy with the suspension so I would check that first.