Stupid question about wrench sizes

[thejon]

Stupid question ahead so don't make fun of me . I'm still a newb.
Long story short, I plan on replacing the rear struts on my 03 Highlander fwd V6. With my order, I was going to get a couple camber bolts because some have suggested having some on hand (I plan on getting an alignment after but users on other forums mentioned their aftermarket quick struts had bolt holes that were bigger than OEM and had to use camber bolts to get it good enough to drive to the alignment shop. Idk.
Anyway, all the ones on rock auto are advertised as 15mm. I called Monroe and asked what size the holes were and they said 15mm. That sounded small compared to what I saw when I looked under the car so I put a fitting wrench on the bolt head that was there and it was a 3/4 size wrench. What an I missing?

 

[Elkins45]

You asked about the size of the hole, not the size of the bolt. The bolt is always bigger than the hole.

 

[SC Maintenance]

3/4 x 25.4 = 19.05mm.

19mm head usually equates to a 12mm bolt, which sounds about right for a camber bolt?

15mm sounds small?

 

[Leo99]

I used quick struts on my old Corolla and reused the bolts and didn't need an alignment. An impact wrench made it a lot easier. The Ryobi one is on sale for $100.

 

[ctechbob]

Stupid question ahead so don't make fun of me . I'm still a newb.
Long story short, I plan on replacing the rear struts on my 03 Highlander fwd V6. With my order, I was going to get a couple camber bolts because some have suggested having some on hand (I plan on getting an alignment after but users on other forums mentioned their aftermarket quick struts had bolt holes that were bigger than OEM and had to use camber bolts to get it good enough to drive to the alignment shop. Idk.
Anyway, all the ones on rock auto are advertised as 15mm. I called Monroe and asked what size the holes were and they said 15mm. That sounded small compared to what I saw when I looked under the car so I put a fitting wrench on the bolt head that was there and it was a 3/4 size wrench. What an I missing?

3/4 = 19mm Pretty much interchangeable.


--edit-- got beaten to the punch.

 

[thejon]

You asked about the size of the hole, not the size of the bolt. The bolt is always bigger than the hole.

Pardon the question but how does a larger bolt fit in a smaller size hole?

 

[thejon]

3/4 = 19mm Pretty much interchangeable.


--edit-- got beaten to the punch.

Them I wonder why all of the camber bolts are advertised as 15mm and not 19mm if what's on there is 19mm?

 

[Astro14]

When you describe a bolt, the number in question is the thread diameter. Next number is thread pitch. Next number is thread length.

You don’t describe a bolt by the size of the head.

So, an M10x1.0x80 is an M10 bolt, with a standard thread pitch that is 80mm long.

There are a couple of different standards for head size. ISO, DIN and JIS. The same size bolt (threads, diameter, etc.) will have different head sizes under those two standards.

So, your M10 bolt will be a 16mm head under ISO, 17mm under DIN and 14mm under JIS.

For your suspension, they are probably M12 bolts, and depending on which standard, they would have 18, 19 or 17mm heads. If it had a 19mm head - you have a 12mm bolt manufactured to DIN specifications.

There is no “15mm” bolt under any of the standards, but your camber bolt may have an eccentric that measures that size.

https://boltdepot.com/Fastener-Info...9bVr5vwCvpac64v4HTxTLDPSDNlebGWaLWQkdKVuz_dWV

 

[Timmastertech]

Bolt head size is not bolt shank size. Normally on a Toyota a 14mm shank bolt will have a 19 or 21mm head.

 

[doitmyself]

Seems to be a problem with semantics here. Maybe confusion between the bolt shaft diameter vs. the bolt head diameter vs hole diameter?

If the hole diameter is 15mm, then either an M12 or M14 bolt should fit there. Since you stated that a 3/4 inch wrench (19mm) fits on the bolt head, it "seems" that your bolt is an M12. I'm not sure how camber bolts are classified.

(checked for copyright)

 

[thejon]

I used quick struts on my old Corolla and reused the bolts and didn't need an alignment. An impact wrench made it a lot easier. The Ryobi one is on sale for $100.

We're the bolt holes on the quick struts the same size as your original? Or larger?

 

[thejon]

Thanks for the replies. So, from what I understand, the original bolt (shank I guess... The long part) is 12mm. If Monroe is correct in telling me the hole diameter is 15mm, then it is, in fact, bigger than factory (which is what some on other forums we saying), which would require the 15mm camber bolts they suggested. I may or may not have that right.
If so, what a PITA. I did a lot of research when choosing the Monroe quick struts compared to other quick struts in my budget (FCS, Detroit axle, TRQ, A-premium, etc)... I guess I can see if the camber bolts make it right or research some other brands that have the same diameter holes as factory (none of them advertise hole size, I'd have to call).

 

[Nukeman7]

We're the bolt holes on the quick struts the same size as your original? Or larger?

I have installed quick struts or replacement strut cartridges on over a dozen vehicles using various brands including OEM, KYB, Monroe, Bilstein, Sachs, Gabriel and cheap Sensens. All of them had the same size bolt holes as the original struts they replaced. However, for your specific application, YMMV.

 

[D60]

Actually perhaps OP is British . Whitworth bolts used wrenches labeled for the bolt's nominal dia and not the distance across the flats of the hex head.

I believe Whitworth bolts are frequently used on Toyota, no? <------kidding

 

[thejon]

Actually perhaps OP is British . Whitworth bolts used wrenches labeled for the bolt's nominal dia and not the distance across the flats of the hex head.

I believe Whitworth bolts are frequently used on Toyota, no? <------kidding

Definitely not British...

 

[ElectroMechanoMan]

Actually perhaps OP is British . Whitworth bolts used wrenches labeled for the bolt's nominal dia and not the distance across the flats of the hex head.

I believe Whitworth bolts are frequently used on Toyota, no? <------kidding

And I thought metric bolts were bad!

 

[Chris142]

Bolts are measured by the threads or shank. Not the bolt head / wrench size unless working on an old British car.

 

[grasscutter]

You asked about the size of the hole, not the size of the bolt. The bolt is always bigger than the hole.

Not quite. If the bolt hole is not threaded, it needs to be ever so slightly bigger than the bolt.

The wrench size is always bigger than the bolt size.

People need to stop referring to bolt sizes by the wrench size they take.

 

[thejon]

If the bolt hole is not threaded, it needs to be ever so slightly bigger than the bolt.

Maybe that's it. Do you think that's why Monroe told me the holes (non threaded) are 15mm, yet the (threaded) bolt that comes out of the OEM strut is 12mm?

 

[Nukeman7]

Maybe that's it. Do you think that's why Monroe told me the holes (non threaded) are 15mm, yet the (threaded) bolt that comes out of the OEM strut is 12mm?

Yes!
I bet if you measure the hole diameter in the steering knuckle after removing the bolts and strut assembly, it will be ~15 mm too.