Technical caliper holder bolts dimension

[Wawa]

Hi folks,

On a disk/brake job on a 2012 500 model 1.4 L, I am unable to remove the calliper holder bolts. All the Youtbe DIY clips say that it take a 13mm open wrench, but noooo, it is a little bit to big. I tries a SAE wrench, but nooo.

Do you have any ideas?

 

[chris3234]

Most of clips you have seen are likely to be from the EU car which is significantly different to the US models so could easily be a different sizeed bolt

 

[Ralf S.]

If 13mm is too big then it could be a 12mm head that has become corroded and deformed.

Chip the rust off the bolts, or scrub them with a wire brush... then force an M12 ring spanner onto it. The bolts are going to be metric, even if the car was made in Mexico (I think).

Once your ring spanner is on board, remove it, and use a 12mm socket to actually remove the bolts, to prevent them getting rounded off. I dunno if the ring spanner will clear the suspension components... but anyhow, don't use an open ended spanner or you could damage the bolt heads.

I would also buy some new bolts in the meantime... if they're corroded they may become rounded/damaged if you need a lot of elbow grease to remove them. Don't give moody fasteners a second chance.


Ralf S,

 

[vexorg]

The carrier bolts or caliper bolts?
The carrier bolts are usually very tight, they tend to be better made too with high tensile steel, so clean up better.
Irwins easy outs might be needed if you've chewed or damaged the head of the bolt.

 

[Ralf S.]

The Carrier bolts are usually enormous... 17mm or 19mm heads.

I'm assuming we're talking about the bolts on the end of the caliper sliding pins, which on at least one of my old Alfa's is a 12mm.
I know they're not 13mm for sure.. since I always guess "13mm" and then have to go back into the garage to get a 12mm.

Ralf S,

 

[vexorg]

12mm is a very japanese size.
Reminds me of the old wheeler dealers I was watching again with the lamboghini, one end of the cluch pipe with metric thread, the other end with american unf, because itialians just grab whatever's lying around to build cars.

 

[Wawa]

If 13mm is too big then it could be a 12mm head that has become corroded and deformed.

Chip the rust off the bolts, or scrub them with a wire brush... then force an M12 ring spanner onto it. The bolts are going to be metric, even if the car was made in Mexico (I think).

Once your ring spanner is on board, remove it, and use a 12mm socket to actually remove the bolts, to prevent them getting rounded off. I dunno if the ring spanner will clear the suspension components... but anyhow, don't use an open ended spanner or you could damage the bolt heads.

I would also buy some new bolts in the meantime... if they're corroded they may become rounded/damaged if you need a lot of elbow grease to remove them. Don't give moody fasteners a second chance.


Ralf S,

Exactly, too big or too small which probably means that the head of the bolt is rounded off (hard to see). I am "weekend" mechanic and french speaking so could you explain what is a M12 ring spanner along with a picture if possible? I really appreciate your answer.

 

[John202020]

Ring spanner

 

[John202020]

Personally if they're rusted I would use a "impact socket" they are great for removing even rounded bolts given the socket design, not drive on the tips or flats but overall fit to drive provided you have enough access, link for example https://www.ebay.co.uk/itm/36354177...S5rzkR6SUW&var=&widget_ver=artemis&media=COPY

 

[vexorg]

Any decent 6 pointed socket will be fine, far less likely to damage the head.

 

[Lounge lizard]

These are what are used on our 2011 T/A needed an E16 socket. Very tight, luckily I had access to an impact wrench.

 

[John202020]

These are what are used on our 2011 T/A needed an E16 socket. Very tight, luckily I had access to an impact wrench.
View attachment 424947

They are not Torx are they ?

 

[DaveMcT]

The thread looks about right for the caliper bolts. The head is a Torx. Use the correct socket and no worries. They are likely to be all over the car so get yourself a set of impact spec Torx sockets and keys..

 

[Lounge lizard]

Genuine Fiat BOLT. 51794407. FRONT brake caliper mounting bolt E16 head M12x1,25x29mm.

From the invoice when I bought new ones.

 

[chris3234]

They are not Torx are they ?

They are usually e torx on most fiats these days

 

[vexorg]

Never quite sure the proper name for them as torx are the other way round, pointy version of allen bolt.. Seen them called star sockets, E-torx, female torx.

 

[Wawa]

Personally if they're rusted I would use a "impact socket" they are great for removing even rounded bolts given the socket design, not drive on the tips or flats but overall fit to drive provided you have enough access, link for example https://www.ebay.co.uk/itm/36354177...S5rzkR6SUW&var=&widget_ver=artemis&media=COPY

There is not enough space to use an impact

 

[Wawa]

They are not Torx are they ?

Ther is no space to use a socket. I have tried a ungrip stuff along with a vise grip tool without success

 

[DaveMcT]

A short extension bar and a ratchet works fine. Turn the steering outwards so you can avoid the anti roll bar.

If you are changing brake pads but keeping the discs, remove the M8 bolts holding caliper to itscarrier and lift the caliper away. Ideally, use new bolts (which have a patch of thread lock) but I have always used blue thread lock on the old bolts without any issues.

 

[chris3234]

Is this the front or the rear brake disc?
Unsure on the specs of the USA cars
But that layout looks very unusual to what it normally is on the front