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Discussion Starter #1
Several other threads here and on other boards have covered the use of 4 pot Girling calipers from the Volvo 240 on the Alfa 116/119 platform. The front pads on the Alfetta are pretty small; the pads in both the early GTV6 calipers and the Brembos on the later cars are not much bigger. Although the handling of my Alfetta GT is superior to my Mazda 626 beater car, and the engine performance is comparable, the 626 (disc/drum) has significantly better braking. The first photo shows the Alfetta front pad on the left, the Volvo 240 pad in the center, and the 626 pad on the right. Even allowing for the fact that the 626 is FWD and has a higher ratio of front to rear braking needs, I think the Alfetta could use more pad at the front.

The other threads cover the use of 5 x 98 rotors with the Girling calipers. For the 4 x 98 cars, most people have opted to redrill a 5 x 98 rotor with 3 new wheel stud holes. When I found out that the new Fiat 500 had a 4 x 98 bolt circle, I figured that there would now be a source for new wheels for the Alfetta, and maybe the 500’s brake rotors could be made to work on the Alfetta. (When I am talking about sourcing parts, I mean on this side of the big pond.) I did some research on the Brembo web site (drawings of their street rotors there), and determined that the Fiat 500 Abarth front rotor had an OD of 284mm, which should be about right for the Girling calipers. The second picture is the drawing of the Abarth rotor. Obviously the center hole would have to be opened up to 72mm to fit on the 116/119 hub. And the hat offset is quite a bit less, but it is better if it is less rather than more, as it is easy to add a spacer between the rotor hat and the hub flange to center the rotor in the caliper span. Since the Abarth is very new to the US, I could only find the Abarth rotors at Tire Rack.

The third photo shows the stock Abarth rotor on the right and the modified rotor on the left. I then temporarily mounted the rotor on the Alfetta hub, put the hub and caliper on the spindle, and checked for proper OD of the rotor and determined what thickness of spacer between the rotor and hub that I would need. The fourth photo shows that the OD of the pad friction material is flush with the OD of the rotor. Good. I determined that the spacer would need to be between 5.5 and 7mm thick; which worked out well, since I could get ¼” (about 6.3mm) thick wheel spacers for cheap at any local auto parts store.

The fifth photo (next post) shows the ¼” Dorman wheel spacers that I got at Autozone. The ID of these spacers was OK for fitting on the hub, but too small to fit over the big radius on the inside of the hub flange. I could have opened up the ID of the spacers about half an inch, or put a big chamfer on the ID of the spacers (like what is on the OE Alfetta rotor). I chose to do the chamfer thing. Other generic wheel spacers from other manufacturers will have various IDs which may or may not need rework. I have also seen 5mm thick wheel spacers that are 4 x 98 advertised on Fiat 500 specialist web sites. If these are really 5mm, they are too thin; but if they are really 1/4” thick, they are just right.

The sixth photo shows the completed rotor/hub assembly: OE hub, modified Abarth rotor, Dorman wheel spacer, and Dorman wheel studs. Since the studs have to go thru the rotor, spacer, hub, and wheel hub, they have to be fairly long; 45 to 55mm depending on the hub thickness of your particular wheels. None of the long studs that I could find had the correct knurl OD for the 13.2 mm holes in the Abarth rotor. So I had to ream them out a few thousands for the studs I picked.

The seventh photo shows the brake line between the caliper and flex hose that I had to make. The thread in the Girling caliper for the brake line is that same as the OE Ate caliper (10 x 1 mm), which is nice. I bought an 8” long male/male brake pipe from NAPA, cut off the bubble flare on one end, removed one make fitting, put on a female fitting (that I got from Fedhill), made female double flare, and bent the line into a 270 degree loop. An important note regarding the brake line and the 240 caliper: for most of the almost 20 years Volvo used the Girling calipers on the 240, they used some goofy dual brake line setup that also had multiple bleed valves. At the end of the 240’s run, Volvo added ABS as an option, and changed the caliper to use a single brake line and a single bleed valve. This caliper was only used on the 91-93 cars. The single line 240 caliper is a little harder to find, but a lot easier to plumb.

The eighth photo shows the caliper on the spindle with the new brake line. The 2 ends of the line are very close together, so getting everything lined up so the fitting threads engage easily is a challenge. I discovered (the hard way) that it is far easier to remove the flex hose from the car, tighten the hard line in the caliper, then assemble the hose/bracket assembly to the caliper/line assembly, mount this assembly on the spindle, and then finally connect the other end of the flex hose to the fitting on the car body. Bleeding was easy.

This project came about because I had decided to change from 14” BWA wheels to 15” wheels. I still want to be able to use my 14” wheels on the car. I discovered that the Girling calipers will actually fit inside a typical 14” rim, but the outside of the caliper hits the BWA’s spokes. I determined that if I make some 10mm thick wheel spacers for the front, I can run my old BWA wheels. I will make these in the future when I am motivated.

My requirement for this brake modification was that it be totally and easily reversible. I can remove the Abarth rotor and spacer from the hub, put the OE Alfetta rotor back on, unbolt the Girling caliper and steel line, and bolt the Ate caliper and OE steel line back on; and everything is back the way it started. The Girling caliper is only slightly bigger and heavier that the Ate caliper; it even mounts on the spindle without modifying the stone shield.
 

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Tom - thats fantastic !

I've been searching for an alternative to the solid rotors for ages and I was just about ready to throw my old Simmons rims and 4 stud hubs out and buy 5 stud hubs from a wrecked 75 (and new rims).
If i can just get my hands on a set of Arbarth rotors I'll be right.


Mark my words, you have started somehting here. i have had many discussions wiht people in the Alfa club down here - there will be many a folk follow this path

oh .. its a good call about the Arbarth rims too, I wonder if they are 15 or 16inch?

sam
 

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Folks... can anyone help here...
I just got a quote for Fiat 500 Arbarth rotors from the Fiat dealer down here in Essendon - Melbourne, Australia.

$940.00 AUD each !!!!

I'm not sure if its because Arbarth are dearer (i.e. you pay for the name?) or what, but I wont be paying ~$1900.00 for a set of rotors.

I wonder if standard 500 discs or maybe the Punto discs would fit?
Does anyone know how I can find out?
Are they the same size???
 

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Have you tried other parts places bedsides the dealers?
Turin Imports, The Spares Place in SA or Italian Automotive Spare in Melb??

I'd think the cheapest and easiest way would be get some 75 rotors, re-drill them(like many have done in the past) and some 75 Brembo calipers and stick them on.

Everything will bolt up and the only thing you will need to do is re-drill the rotors, any other option you will need to muck around with spacers/adapters and making sure everything lines up. You also know that the 75 rotor will fit under a 14inch wheel if you ever get ride of the Simmonds.

The Abarth rotor doesn't look like it will @ 284mm dia plus adding to un-sprung weight as well at the front of the car with a bigger disc and depending on what caliper you use.

So if you use the 75 stuff and re-drill there isn't too much more added weight, but if you use the Abarth and the Girlng caliper.
 

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I found a place in the UK that will send me a set of Arbarth callipers (they also fit MITO) - delivered to my door for $185.00.
So the price is no longer an issue.
I heard that re-drilling the 75 rotors means some holes are extremely close to the original ones and which can cause the area to crack, furthermore my understanding is that the the practice is not legal.
Now this may be hearsay and I don’t know if it’s real or not, but I thought the Arbarth rotors would eliminate those concerns as there is no re-drilling involved.
BTW what's the diameter of the 75 Rotors?
 

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From memory the 75 rotor is about 268mm.

it isn't too much smaller, but you'd need to machine the Abarth one down to that to use the 75 Brembo caliper. I guess machining down a vented disc there is a possibility that you may crack the internal vents in between the two disc faces. So there is always the concern of cracking.

In regards to re-drilling not being legal, using spacers or adapters on brake components isn't legal either. Same thing with using wheel spacers, unless the car came with them from the factory, We all know the Alfetta didn't.

So it's a case of you're dammed if you do dammed if you don't, but as mentioned I'd assumed the quickest and easiest would be to re-drill the 75 rotor and grab a set of the Brembo calipers and fit them up. the benefit, it's all off a standard car, and the brake hose will simply screw in, if not get a 75 brake hose. Forgot to mention that earlier, if you use a different caliper, may need to work out what brake hose to use as noth fittings might not have the same thread.
 

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Discussion Starter #11
Fiat 500 Abarth Rotors

It would not be a good idea to try to use the Abarth rotors with the 116/119 Brembo calipers.
 

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So how do they feel? Nothing on here about the performance and I'm just wondering how much better they are? Also, is the OEM master cylinder up to the task?
 

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Alfetta 116 Front Brakes

I am looking at converting the front brakes on my Alfetta GTV to Volvo 2 or 4 pot calipers. I have located some from a 240GL. Will they bolt on to the Alfetta without modification. I realise the brake lines may need to be modified.
 

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Rockauto has Abarth rotors in various brands starting at $25.

Standard 500 rotors are about an inch less in diameter.

Rockauto also have rebuilt Volvo 240 calipers at $40 outright.

The pad area has no effect on the braking force; more pad volume increases life. However the larger rotor increases brake torque as a result of the larger pinch diameter. And the 4 piston calipers will increase pinch force in proportion with total piston area. What are the piston sizes for both the original and Volvo calipers?

The trick here is to keep a proper front/rear brake balance.

The Volvo 4 piston calipers are a popular conversion on BMW 2002s as well.
 

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Discussion Starter #15 (Edited)
My car was down for about 8 months while my original SPICA pump was at Ingram's waiting to be rebuilt.
My Alfetta has the early 20 mm master cylinder; some of the later Alfettas have a 22 mm MC. Pedal travel is fine. F/R balance is fine for the street. If I were to track event the car, I would have better data on F/R balance, but the last speed event for this car was many decades ago. In any case I am very happy with the setup.

As mentioned at the top the early Volvo 240s had weird 2 brake hose Girling calipers. In 91 (when Volvo made ABS available on the 240 I think) they changed to a normal single hose setup on the car; so the later Girling calipers are the preferred ones to use.

BTW, the hugely expensive Abarth rotors mentioned above are for a limited edition Abarth version of the 500 that was not brought to the US. It has a completely different brake system than the US Fiat 500 Abarth.
 
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