Rear OUTBOARD Brake Conversion;

[PSk]

Quote:

Originally Posted by junglejustice Nobody is Selling a kit here... This is not a kit. The calipers come from Praggia in South Africa. The floating hat rotors come from a source in California. The pads are Ferodo from a large Mercedes van. We are custom making the brackets....

[inhistoryclass]

what size are the stock milano brakes up front?

[Rookie ROX]

Rotors are 268mm diameter and 22mm wide. Calipers are 2 pot Brembo items for most of the models - though in true Alfa fashion, some came with different calipers (ATE?).

ROCK ON
R~R

[inhistoryclass]

are there any good pictures of the conversion? id like to see how they made the bracket.

[ToonRboy]

Me too - once I had a deDion hypotenuse tear off (mostly) at the rear where it meets the rear (big) tube (corrosion started from a pinhole rust spot if you can believe it). Anyhow, when I sorted a replacement and got to check it out up close (real close). I was surprised to see how thin the walls are and how light the deDion unit is. Hell, I was thinking of fitting a couple of bracing triangles at the wheel bearing housings as a precautionary upgrade..!

I would think you'd have to design a whole billet collar or something to mount the calipers to. I certainly wouldn't weld the mounts (ears) to the deDion tube directly (and expect it to hold/last).

[junglejustice]

Geez this is an old thread! (My apologies to Barry again for all of the catty-ness back then - that whole thing was stupid... )

Any way, been done/being done plenty - welded right to the DeDion like that. Raced like that without problems for years on several cars in SA and in other places I'm sure... (...and the sky hasn't fallen yet... )

Here are some shots!

I'm sure that some or other billet modified setup there (a-la IMSA cars) with adjustable camber and toe would be awesome back there! (Send Bianci & Kopp the 5K Euro check for the carbon fiber DeDion unit while you're at it...) This works (but our new AP setups will have a cleaner billet aluminium bracket on steel welded bracket-arrangement when they finally come in...)

[Del]

The primary reason the rear brakes were designed for the inboard location in the Alfetta/Milano/Gtv6 series was to reduce the "unsprung weight" parts of the rear suspension, ie, the lighter the moving parts of the suspension, the quicker the suspension can react to forced movements. This means the tire can remain in contact with the pavement just that little bit longer. A good thing, and by the way, copied by other makes. Remember the rear axle hop of the older "solid" rear axle Alfa's when a bump was encountered in a hard fast turn? These solid rear axles were the worst examples of high unsprung weight, although they were acknowledged to be the better examples of this type of suspension.

The obvious drawbacks of inboard brakes are potentially less cooling, and more limited access to the brake assy. Your choice. Since the rear brakes work much less than the fronts, I like the inboard setup, for it's quicker response over bumps and uneven pavement in turns, over my previous older Alfas.

Going to larger rear brakes without matching that size change for the front can be overkill since you can use only so much of the rear braking potential while maintaining the proper front/rear braking ratio for directional stability. The only advantage would be that the brakes would remain pretty cool compared to the harder working fronts; however, brake pads change their friction coefficient with temp and would have to be picked carefully to reflect this difference in braking temps front to rear. Ideally you would want to maintain the same approximate braking temp front to rear to reduce this unwanted variable.


p.s. looking at the pix of the welded bracket of the brakes shown above, I might question the limited strength and torsional stability of the bracket design as welded to the cross tube. I also might question the use of aluminum for any bracketry in such an application.

[junglejustice]

Yeah, no - there's a whole entire other thread out there, that is sort of a missing link/gap to this one - part of the problem when reviving something this old...

Our entire system (the new setups coming) was re-designed mathematically (at least in theory - on paper - as close as possible) and proportionally engineered - with proper dual master cylinder sizing (front versus rear) and then also taking in to consideration such aspects as the friction coefficient of the selected pad compounds, total swept area of each disc, the manufacturer's duty-cycle/rate of cooling specifications for the selected discs, total surface areas of pads (versus discs), piston-diameters, vehicle weight and load-weight centers, tire and wheel sizes, brake pedal-ratios - on and on...

In addition we are installing Tilton adjustable bias bars and remote adjusters to be able to fine-tune the setups!

Del - buzz me - I may have the rim for you - 425.941.4747.

[ToonRboy]

Hey, you gotta hand it to those SA guys, they're friggin' crazy! The nose and the bearing housings of the tube looked like they were cast steel if I remember correctly. Perhaps they are a rough forge. I wouldn't weld to cast steel. The brackets looks simple enough & there is sufficient weld. If it holds, it holds. More power...
Are those 6 or 8 puck calipers in the rear? ;p
Makes you wonder what's up front...

[junglejustice]

Today - 4-piston rears and 8 pot fronts...

The new setups are GIANT 4-piston/4piston APs...

[5yearplan]

Thats not 1/8" is it? looks a little thin for brakes. But those welds are definitely solid. Good penetration for cast steel. But the money's in the prep work.