How To Read a Metric Bolt Specification

Updated 05/01/2020 | Published 04/29/2020

Question:

I will try your brush suggestion but I checked with local Toyota dealer and he indicated this bolt size: M 10 x 1.25 x 40 x 40. your spec sheet shows a different thread size M10 x 1.25 x 36. Is that my problem?

asked by: Paul

Expert Reply:

There really isn't any mechanical difference between those two bolts, one is just slightly longer than the other. When reading a metric bolt specification, the 3rd number indicates the length of the bolt, so I can't imagine the 4mm difference making a huge difference between the M10 x 1.25 x 36 and M10 x 1.25 x 40 bolts. With that said, the slightly longer bolt size might help and definitely won't hurt anything, so feel free to use either one.

In most cases, when installing the Curt # C12341 on your 2012 Toyota Venza, a good cleaning of the weld nut holes should allow you to get the bolts to thread in.

expert reply by: Erik B