600 Master Cyl & 850 caliper questions

[ramona300]

I'm using the stock rear brakes with new old stock linings and standard lines. I out brake all the cars I compete against, MGB's and Sprites, Alfasud etc. With the car light and AR1 Nankang tyres the car is a delight under brakes. I'll take a photo tomorrow from behind the wheel. It's easy to get to on the trailer.

 

[kmead]

Given how much actual braking rear brakes do (on older cars in particular) due to the bias in the design of the system, rear drums are more than up to the job required of them generally 10-20% of the actual braking being done. Locking up the rear brakes tends to cause one to exit stage right, backwards...

A rear engine car or one with a notable rear weight distribution (850s, X1/9, Porsche 911) the rear wheels can have quite a bit more traction and in the dry can tolerate a greater rear bias in the brake system design.

Going to 850/128/Yugo rear wheel cylinders would increase the rear brake bias over the OE 600 parts due to the greater wheel cylinder diameter.

We all fall in love with the idea of four wheel disks because hey four wheel disk brakes! They are really not needed on most non ABS cars (front wheel drive in particular) where the fast reaction of a caliper is needed to modulate the rear bias brakes (and effectively dynamic rear bias as a result).

 

[ramona300]

Given how much actual braking rear brakes do (on older cars in particular) due to the bias in the design of the system, rear drums are more than up to the job required of them generally 10-20% of the actual braking being done. Locking up the rear brakes tends to cause one to exit stage right, backwards...

A rear engine car or one with a notable rear weight distribution (850s, X1/9, Porsche 911) the rear wheels can have quite a bit more traction and in the dry can tolerate a greater rear bias in the brake system design.

Going to 850/128/Yugo rear wheel cylinders would increase the rear brake bias over the OE 600 parts due to the greater wheel cylinder diameter.

We all fall in love with the idea of four wheel disks because hey four wheel disk brakes! They are really not needed on most non ABS cars (front wheel drive in particular) where the fast reaction of a caliper is needed to modulate the rear bias brakes (and effectively dynamic rear bias as a result).

Drum brakes are much lighter as well!

 

[ramona300]

Couple of photos from today. The closest the Tokicos are to the inside of the wheel is the top. There is about 5mm clearance but only after the bleed nut is cut down. On a motorbike, they don't care about this but using John Edwards{RIP} adaptors there is ample clearance. Second shot is from the inside.

 

[boxy02]

Thx for the pictures. I mounted a CD3 to my front hub with the 66-68 850 caliper installed. I have about 5mm clearance at the points that the caliper/bracket stick out the most. A friend sent me this from autoricambi, I have no idea if they’d fit under my Cromodoras.

Wilwood Caliper Big Brake Kit - Stock Rotors

Wilwood big brake caliper kit for stock size brake rotors FIAT 124 Spider, Spider 2000 and Pininfarina - 1966-1985 FIAT 124 Sport Coupe - 1967-1975 - Auto Ricambi - BR3-523

autoricambi.us

 

[dnudelman]

So Mike, unless you missed the posts by kmead and Ramona above, why would you even consider the Wilwood brakes? They are for a front engine car much heaver than your 600. Maybe you want a drift car that spins the rear end around in front of you every time you brake?

If that $700 is burning a hole in your wallet, buy 124 calipers from Ricambi and make a $600 donation to the Salvation Army.

 

[boxy02]

Dnudelman, I’m new to Fiats, in general, and am looking at all options, pros and cons.
thx for your input,
Mike

 

[dnudelman]

Dnudelman, I’m new to Fiats, in general, and am looking at all options, pros and cons.
thx for your input,
Mike

Welcome to Fiats, I see by your avatar that you're a Bimmer Boy. The Fiat culture is very different than BMW. Fiats were/are cheap cars, built to be cheap but fun to drive. Likewise, Fiat owners are cheap, just ask our suffering vendors. Fiat built millions of these cars in a dozen or so countries. Many of the parts of interchangeable and because so many were made in Eastern Europe, North Africa, even Asia, parts are still cheap. No one ever claimed that a Fiat was the Ultimate Driving Machine. The number of BMW's made is minuscule compared to Fiat production, and I'm sure prices reflect that.

 

[ramona300]

I think I paid something like $120 for the Tokicos that came complete with new pads and SS braided lines off USA eBay.

 

[kmead]

Thx for the pictures. I mounted a CD3 to my front hub with the 66-68 850 caliper installed. I have about 5mm clearance at the points that the caliper/bracket stick out the most. A friend sent me this from autoricambi, I have no idea if they’d fit under my Cromodoras.

Wilwood Caliper Big Brake Kit - Stock Rotors

Wilwood big brake caliper kit for stock size brake rotors FIAT 124 Spider, Spider 2000 and Pininfarina - 1966-1985 FIAT 124 Sport Coupe - 1967-1975 - Auto Ricambi - BR3-523

autoricambi.us

Following up from before, the Wilwoods on a 124 are intended to take the place of the 48mm 124 calipers and would be complete overkill for an 850 and would move the brake bias way forward which is not what an 600 needs. I can lock up my 850’s front wheels with stock brakes (depending on tires).

The kit wouldn’t fit your uprights as the suspension parts are very different between the 124 and the rear engine cars.

 

[boxy02]

I think I paid something like $120 for the Tokicos that came complete with new pads and SS braided lines off USA eBay.

Thx, I’m leaning towards this option, I don’t mind doing a little fab work to get it done. And 850 drum rears sound like a good bet to use along with.
I know the wilwoods are way too much for this build. I had 993 twin turbo Brembos on my 77 930 for the track and they would practically pop my eyes out while threshold braking preparing for turn 1 at Willow Springs. But yeah, my 600 is 320HP & 1200 Lbs less, so yes, overkill.
Thanks for all the good opinions and considerations. Lots of collective experience participating in this forum helps folks like me who are new to this marque.
Mike

 

[kmead]

Thx, I’m leaning towards this option, I don’t mind doing a little fab work to get it done. And 850 drum rears sound like a good bet to use along with.
I know the wilwoods are way too much for this build. I had 993 twin turbo Brembos on my 77 930 for the track and they would practically pop my eyes out while threshold braking preparing for turn 1 at Willow Springs. But yeah, my 600 is 320HP & 1200 Lbs less, so yes, overkill.
Thanks for all the good opinions and considerations. Lots of collective experience participating in this forum helps folks like me who are new to this marque.
Mike

We are definitely good with folks asking questions (just be tolerant of us going off topic as we are want to do), occasionally we can help.

 

[kmead]

I needed to log into my desktop to grab the brake calculator file. It is a fun thing to play with. I roughly filled out your car. Unfortunately it is set up for calipers not wheel cylinders. Unfortunately in inches not millimeter so some math to put in your info.

Anyway play around with it.

Had to zip it to be able to upload here.

 

[boxy02]

I needed to log into my desktop to grab the brake calculator file. It is a fun thing to play with. I roughly filled out your car. Unfortunately it is set up for calipers not wheel cylinders. Unfortunately in inches not millimeter so some math to put in your info.

Anyway play around with it.

Had to zip it to be able to upload here.

Wow, thanks! Just downloaded it.
Mike

 

[boxy02]

I finally got the brakes figured out and fitted. I opted to switch the front spindles to series 2 and continue with mods for the Tokico caliper installation. Worked out pretty good. I chose not to widen my calipers, and to remove 0.75mm of material from each side of my new rotors instead. I’m replacing all the old front suspension bushings and kingpins before final installation of the brake system. Installed the 850 rear backing plates after modifying them to fit on 600D rear hubs. And installed the drum brakes as well. Replaced front and rear bearings while everything was apart. Thx for the help!
Oh, and I did need to remove some material from the outside half of the caliper so my Mg Cromodora CD3s would fit (with spacers).

 

[ramona300]

Interesting mod to fit the callipers, I would not have thought of that! My rotors are 7mm thick and have not been a problem. My car is light but it easily outbrakes the other cars in my class, MGB's, Sprites etc and these are high spec race cars! The saving of unsprung weight helps with the handling as well.

 

[kmead]

I finally got the brakes figured out and fitted. I opted to switch the front spindles to series 2 and continue with mods for the Tokico caliper installation. Worked out pretty good. I chose not to widen my calipers, and to remove 0.75mm of material from each side of my new rotors instead. I’m replacing all the old front suspension bushings and kingpins before final installation of the brake system. Installed the 850 rear backing plates after modifying them to fit on 600D rear hubs. And installed the drum brakes as well. Replaced front and rear bearings while everything was apart. Thx for the help!
Oh, and I did need to remove some material from the outside half of the caliper so my Mg Cromodora CD3s would fit (with spacers).

Nicely done.

I hope the disks don’t warp as that is quite a bit of material to have removed.

 

[boxy02]

Interesting mod to fit the callipers, I would not have thought of that! My rotors are 7mm thick and have not been a problem. My car is light but it easily outbrakes the other cars in my class, MGB's, Sprites etc and these are high spec race cars! The saving of unsprung weight helps with the handling as well.

My rotors are at 10.42mm currently. I think the max wear limit is 9mm +-, so I’ll not be that far off. Should be ok. At least the series 2 rotors are A LOT cheaper than the series 1 rotors.

 

[fiatfactory]

Worked out pretty good. I chose not to widen my calipers, and to remove 0.75mm of material from each side of my new rotors instead.

The stock discs are only 10.8mm (some brands are 10.5mm) thick when new, so if you've removed 1.5mm of material then I can't see how they are still 10.42 thick.

7mm thick machined discs, I would think you'd have issues with rotors warping... you obviously have never had them hot enough (yet) to warp them

SteveC

 

[ramona300]

The stock discs are only 10.8mm (some brands are 10.5mm) thick when new, so if you've removed 1.5mm of material then I can't see how they are still 10.42 thick.

7mm thick machined discs, I would think you'd have issues with rotors warping... you obviously have never had them hot enough (yet) to warp them

SteveC

I keep an eye on them and I'm surprised they have held up so well. My car is three times the weight of the Suzuki 750 but my rear brakes do some work now they have been adjusted up correctly.