Finding bolt size

General Discussion
1

How would i find the size bolts i need for my 89 4 runner skid plate. I tried online search with> 8mm bolt with about a 10mm head. Or a 100mm bolt with a 12mm head

Anybody know for sure?

Thanks

2

@badbearing…when I run into this kind of problem I just find the closest tap that will fit and make it that size when it’s something like a skid plate. Then you will know for sure. BTW…I have used this technique successfully on just about everything that I’ve ever put back together.

3

Yeah. That would work but it would be easier for me to find bolt size. I just dont have a tap or much experience with tapping.

Thanks

4

That’s fine. The next thing that I would do is buy several bolts at the hardware (keep the sizes handy) and try one until it fits. You can also pick up a plastic size chart to identify the threads quickly. My hardware store used to give them away for free but that was “the good old days.”

5

Meteric I would guess

6

Thinking back a little, metric is a little easier than SAE I believe. The diameter is the one figure so all you have to do is measure the existing bolt hole. Then the number of threads per mm is the next issue. Only a couple common ones, but there are thread guages that you can use to identify the threads.

7

Find another bolt on your Toyota that fits, take it to the hardware store and buy several.

But I am confused a bit - this is a bolt to attach an aftermarket skip plate into existing threaded holes? It didn’t come with the needed bolts?

8

Junk yard purchase. There are no bolts. I found it laying loose. That junkyard is unorganized to say the least. Its oem. Ill just but some 10 and 12mm bolts. I believe they are 12mm

9

Thanls

10

k

11

The Japanese are pretty good about using common metric sizes so I would imagine the bolts are 8 MM X 1.25 or 10 MM X 1.50 threads if there are threaded holes for them.
Those are the 2 most commonly used intermediate sizes.

Sizes are determined by the diameter of the shank; not the bolt head size.

12
Bing 1:04PM Thinking back a little, metric is a little easier than SAE I believe. The diameter is the one figure so all you have to do is measure the existing bolt hole. Then the number of threads per mm is the next issue. Only a couple common ones, but there are thread guages that you can use to identify the threads. - See more at: http://community.cartalk.com/discussion/2294906/finding-bolt-size#latest

Metric bolt thread pitch is in mm per thread, not threads per mm. SAE bolts have thread pitch in threads per inch.

13

Should be 8 X 1.25.

14

Be very careful. You want DIN bolts with an “8.8” stamped on the head. This is the European equivalent of SAE grade 5. Some bolts are not rated for automobile usage and would not be a good choice of this application.