Brake Caliper Bolt Fancy Socket

1996 defender 90 300Tdi
Got new wheel and pivot bearings lined up and while I'm changing them I'll be investigating a wheel wobble on braking.
Anyway, as the caliper bolts have been off a few times over the last 22 years I thought I'd put new bolts on. Searching through old threads I reckon need part FTC3375 - am I right?

Now the magical 13mm double hex socket. This has 12 points so is this a double hex? Or, is there some sort of other mysterious double hex type socket I need to learn about?

It is 13mm double hex that's needed, isn't it?

it is ftc3375 and its bihex ,a 1/2 bihex socket is a better fit eventhough it is a metric bolt

Yes thats fine as long as it is a good make and good fit. Can also be called a triple square head

jamesmartin said:

it is ftc3375 and its bihex ,a 1/2 bihex socket is a better fit eventhough it is a metric bolt

Click to expand...

Bloody hell, I meant to say bihex. Is that picture a bihex socket then James?

Kwakerman said:

Yes thats fine as long as it is a good make and good fit. Can also be called a triple square head

Click to expand...

Now I've never heard of that one! Any more geometric multiples it can be referred to as?

Al2O3 said:

Bloody hell, I meant to say bihex. Is that picture a bihex socket then James?

Click to expand...

yes in the past the most common socket type whilst now single hex is the most common

jamesmartin said:

yes in the past the most common socket type whilst now single hex is the most common

Click to expand...

Cheers, James
I suppose it could be a quad triangle, but that got me thinking.
Interior angle of a hexagon = 120 degrees
Interior angle of a square = 90 degrees
Interior angle of equilateral triangle = 60 degrees
Just thinking

The corners on a triple square are well square (90 degrees), Bi-hex are 120 degrees (have a google). Cant say I've really looked at calliper bolts in that detail but if JM says Bi-hex then Bi-hex they are!

Triple square

Kwakerman said:

The corners on a triple square are well square (90 degrees), Bi-hex are 120 degrees (have a google). Cant say I've really looked at calliper bolts in that detail but if JM says Bi-hex then Bi-hex they are!

Click to expand...

I presumed they would be 120 degrees cos it'll just be two hexagons superimposed. Just find things like this interesting.
As per usual, I reckon he's right.
The angles on this are greater than 90 degrees

Not a great picture though.

I've bought a set of new bolts and a new 1/2" and a 13mm bihex socket.
Thanks for your help, gents.

Al2O3 said:

I've bought a set of new bolts and a new 1/2" and a 13mm bihex socket.
Thanks for your help, gents.

Click to expand...

funny enough i noticed these the other week , lol

https://www.ebay.co.uk/itm/BERGEN-T...364336?hash=item1eaf60a0f0:g:6w0AAOSwjKpXHHxx

gstuart said:

funny enough i noticed these the other week , lol

https://www.ebay.co.uk/itm/BERGEN-T...364336?hash=item1eaf60a0f0:g:6w0AAOSwjKpXHHxx

View attachment 149520

Click to expand...

There are many different forms of heads and sockets, flank drive sockets seem to be ok (only got a couple so limited testing), they drive on the flats of a hex head rather than the corners so apparently less chance of rounding the corners.

Flank drive

Kwakerman said:

There are many different forms of heads and sockets, flank drive sockets seem to be ok (only got a couple so limited testing), they drive on the flats of a hex head rather than the corners so apparently less chance of rounding the corners.

Click to expand...

I have a set of draper expert flank drive deep sockets and they are great. I bought them as additional to my normal set but they are now my go to set for everything. I have never managed to round off a bolt head with them an have been successful with them where someone else has rounded it off previously.

They also come in lots of pretty colours, which initially I hated. But after a while it does make finding the correct size easier as you know what colour relates to what size, and they are the same across all drive sizes so it makes swapping between different ratchets easy as well.

Kwakerman said:

There are many different forms of heads and sockets, flank drive sockets seem to be ok (only got a couple so limited testing), they drive on the flats of a hex head rather than the corners so apparently less chance of rounding the corners.

Click to expand...

many thks , another type of sockets i found invaluable are irwin sockets , where someone in the past has seriously rounded off a bolt / nut

been a lifesaver on a many occasions where nothing else worked

I've got both in 13mm and 1/2".
The 1/2" is a very tight fit but never slips, the 13mm slips if the head isn't perfect.
13mm isn't a branded make though, the 1/2" is a britool donkies years old.
The 1/2" is kept in my "landy special tools" box along with the crank locking kit, propshaft bolts spanners, cut down spanners for the FIP stop solenoid and master cylinder push rod.

gstuart said:

funny enough i noticed these the other week , lol

https://www.ebay.co.uk/itm/BERGEN-T...364336?hash=item1eaf60a0f0:g:6w0AAOSwjKpXHHxx

View attachment 149520

Click to expand...

essential if you work on many cars

jamesmartin said:

essential if you work on many cars

Click to expand...

cheers , going to try and treat myself next month as i will be stripping all my brakes and EPB down later this year

anything to make life easier, lol

Get some new bolts to go with it: SYP500090
Then you can have the pleasure of putting it all back together with nice fresh ones.