Should Thread Locker Be Used On The Hardware When Installing A Trailer Hitch?

Updated 10/29/2025 | Published 10/22/2025

Question:

Hello, Im doing research for a possible hitch for a newly purchased Mazda CX-50 Hybrid. I see that the C33MJ Curt Hitch is compatible with the CX-50, can you tell me the size and threads of the bolts that come with it? Would I need to use thread locker in addition to torquing down those bolts? Thanks in advance

asked by: Jake T

Expert Reply:

Hi Jake!

The Curt Trailer Hitch Receiver - Custom Fit - Class III - 2" # C33MJ for your 2025 Mazda CX-50 uses M12-1.25 x 45mm hex bolts for the install. And only four of them, so it is a pretty easy install. You could use thread locker, but I typically tell people not to. Reason being; it does change the torque specs.

You typically want to reduce the torque specs by around 20% to 30% when you use it, which always sounds very weird and imprecise to me. If I were installing this hitch, I would skip using it and torque everything to what the manufacturer says it should be. That way you know you are getting the correct capacities out of it.

What are you planning on using a hitch for?

expert reply by: Lazer S