Rear disk brake set ups - show me what you've got

[Fat650]

For the life of me i cant get anything to fit this damn car!
I started with the new fiat 500 arbarth brakes....no good. They dont fit behind my wheels. I just picked up a set of fiat X1/9 rear brakes which should fit behind my X1/9 wheels but at first try they dont seem to fit either.
I want to know what people have on their cars that 100% fits and works!
In Australia 4x98 wheels are pretty much non existant so i have to work with what i have.

[Gadge]

Why aren't they fitting? Where are they rubbing?

[drcdb15]

It takes more than just the wheel and brakes off another same model to ensure fit. The X1/9 parts will all fit together perfectly - but only on an X1/9, because that was designed from the outset so that all the bits fit together - seems stating the obvious, but it's a point often overlooked. Every part on a car - and I do mean EVERY part - is designed to fit in with every other part. Once you change one part for something different, you start a cascade of modifications that can too often spin out of control, which is why so many well-intentioned custom cars end up as 'unfinished projects'.

Your X1/9 brakes will only fit in your X1/9 wheel if they are both fitted to an X1/9 hub, within an X1/9 wheel arch and on an X1/9 suspension. But you don't have that set up.

And it's no good asking what other people have because no-one else will have EXACTLY the same as you. We've had examples on this Forum where people changing the rear suspension (say, from Bis to a/c or vice versa) have found the clearances on each side are not even the same ON THE SAME CAR! So when attempting something as radical as you are, you will be best advised to work from first principles. If you keep on just buying parts and hoping they will fit you will spend a lot of time and money and only get it sorted by pure chance.

You might find this site helpful in actually quantifying what you have. Once you know key dimensions and more importantly which dimensions you can influence (for example, you can vary an ET by using spacers, you can vary arch clearance by rolling the arch. You can NOT change the size of a brake caliper, or the profile of a rim) then you can start to specify the wheel/brake parts you need, and hopefully have a more structured search:

https://blog.racetechnologies.com/2015/07/31/how-to-measure-your-wheel-for-proper-brake-clearance/

Also, once you know the critical dimensions, you can search other makes, instead of limiting yourself to only Fiat parts.

I hope you find a solution to this issue, as you have made a huge investment of time and effort so far (I dread to think what in must have cost!).

[Fat650]

Why aren't they fitting? Where are they rubbing?

Physically the X1/9 brakes are too large to fit because of how the axle and adaptor plate sit behind the wheel.
I just need something that is physically smaller. Not sure if you've seen a set in real life but they are actually quite large.
No joke,  there is a honda accord type R at the mechanics near me and the rear calipers on that are smaller than the X1/9 ones.

[Gadge]

Right I see...... The thing is the X1/9 had 13 inch wheels so I don't understand why they wouldn't fit? So I would think that the problem is that the caliper sits too far into the wheel and is touching the inner face of it so perhaps a spacer would sort it. X1/9 callipers are a popular upgrade on the rears as are the Abarth/stilo/fiat 500 rear calipers.

[Fat650]

It takes more than just the wheel and brakes off another same model to ensure fit. The X1/9 parts will all fit together perfectly - but only on an X1/9, because that was designed from the outset so that all the bits fit together - seems stating the obvious, but it's a point often overlooked. Every part on a car - and I do mean EVERY part - is designed to fit in with every other part. Once you change one part for something different, you start a cascade of modifications that can too often spin out of control, which is why so many well-intentioned custom cars end up as 'unfinished projects'.

Your X1/9 brakes will only fit in your X1/9 wheel if they are both fitted to an X1/9 hub, within an X1/9 wheel arch and on an X1/9 suspension. But you don't have that set up.

And it's no good asking what other people have because no-one else will have EXACTLY the same as you. We've had examples on this Forum where people changing the rear suspension (say, from Bis to a/c or vice versa) have found the clearances on each side are not even the same ON THE SAME CAR! So when attempting something as radical as you are, you will be best advised to work from first principles. If you keep on just buying parts and hoping they will fit you will spend a lot of time and money and only get it sorted by pure chance.

You might find this site helpful in actually quantifying what you have. Once you know key dimensions and more importantly which dimensions you can influence (for example, you can vary an ET by using spacers, you can vary arch clearance by rolling the arch. You can NOT change the size of a brake caliper, or the profile of a rim) then you can start to specify the wheel/brake parts you need, and hopefully have a more structured search:

https://blog.racetechnologies.com/2015/07/31/how-to-measure-your-wheel-for-proper-brake-clearance/

Also, once you know the critical dimensions, you can search other makes, instead of limiting yourself to only Fiat parts.

I hope you find a solution to this issue, as you have made a huge investment of time and effort so far (I dread to think what in must have cost!).

There is every point in asking what others have. Cause it gives me a better idea of what my options are. It also gives me a reference point for comparison.

Dont get me wrong,  im not interested in wasting money but when you embark on a project such as this the money matters far less than the end result. This is a concept that i fear is harder to understand for those who mearly wish to restore or up keep their vehicle.

Its actually my wheel limitations that stuff me up. That and the fact its illegal to use spacers on the street here otherwise the fiat 500 arbarth brakes that i have would actually fit....

Im going to start looking for brakes that are physically small regardless of make

[Fat650]

Right I see...... The thing is the X1/9 had 13 inch wheels so I don't understand why they wouldn't fit? So I would think that the problem is that the caliper sits too far into the wheel and is touching the inner face of it so perhaps a spacer would sort it. X1/9 callipers are a popular upgrade on the rears as are the Abarth/stilo/fiat 500 rear calipers.

The adaptor plates i have dont fit the X1/9 calipers so i would need to get some new ones...or make some. Im going to have to spend some time on this i can see....

[drcdb15]

... its illegal to use spacers on the street here ...

I didn't know that. Certainly that must limit your options quite severely. I wonder if wobble bolts are also outlawed?

I am curious about the spacers... these are allowed in most other countries I'd imagine, certainly in the UK and ultra-safety conscious USA, so

a) what is the reason for them being banned in Australia? and

b) how would anyone ever know you are using them? Would the police literally jack the car and remove the wheel to check???

[Fat650]

... its illegal to use spacers on the street here ...

I didn't know that. Certainly that must limit your options quite severely. I wonder if wobble bolts are also outlawed?

I am curious about the spacers... these are allowed in most other countries I'd imagine, certainly in the UK and ultra-safety conscious USA, so

a) what is the reason for them being banned in Australia? and

b) how would anyone ever know you are using them? Would the police literally jack the car and remove the wheel to check???

Not 100% sure about the wobble bolts but I'd say no.
I live in one of the most policed states in Australia when it comes to modifications. I have the rule book somewhere and when i read it next i can confirm the exact reason.
To give you an example though, if im in an accident and they inspect the car and find i have them then my insurance is void and i have to pay for everything. If i hit am expensive car im screwed.
They have specific police units here along with the road and traffic authorities that setup in specific places and pull you over and go over your car. They go hard on you too. Even 1 issue with your car and you get defected and your car gets towed.
You need an engineers certificate to be safe. Even then some cops will still try to issue fines.

Come to Australia.....its awesome! Haha

[1973/126]

 Have you thought of Fiat 124 rear calipers? I think they are quite popular in your part of the world.
 I used FSO calipers on our Spider and got some new ones from Poland for a very reasonable price. From memory they are fairly small and have a mechanical handbrake.
 I`ll try to find a picture of them for you.

 There might have been two types of rear calipers on the x1/9. Are you 100% sure the ones you`ve got are from an x1/9? Have a look on eBay or such for reference.

[1973/126]

 Couple of pictures for reference of the FSO calipers.
 
 

[Fat650]

Have you thought of Fiat 124 rear calipers? I think they are quite popular in your part of the world.
 I used FSO calipers on our Spider and got some new ones from Poland for a very reasonable price. From memory they are fairly small and have a mechanical handbrake.
 I`ll try to find a picture of them for you.

 There might have been two types of rear calipers on the x1/9. Are you 100% sure the ones you`ve got are from an x1/9? Have a look on eBay or such for reference.

Yeah im sure. I got them off a guy who has the most powerful NA X1/9 in Aus. I'm slowly getting to know a couple guys in the fiat club here. Im not sure what an FSO is?

[stuey]

Although I haven't fully fettled them yet I have an x19 set up-

[Fat650]

Couple of pictures for reference of the FSO calipers.
 
 

These look very similar to the ones i have just picked up....

Another thing that worries me is that when i put my 13 inch wheels on i jacked the car up and for some reason just spun them and i noticed that the wheels wobbled... I thought my wheel was buckled so i tried another...same deal?! so i put the standard one back on and did it....same thing again!? i figured this can be right so i did it on the other side....same thing again...then the front...same again?! 

This is why im saying it hits the caliper and may not fit. As you spin the wheel it seems to clear and then at a certain point in the revolution it hits. It may be that the bearings are all gone which is fine cause i have new ones but what are the chances that all of them are gone?

Has anyone had this experience?

[Fat650]

Although I haven't fully fettled them yet I have an x19 set up-

What adaptor plates did you use?