Brakes #2: Rear backing plates

The rear brake plates on an SS are the same as those on a Sprint Veloce. The gas tank capacity on these cars was increased by growing it in the direction of the differential so that it effectively surrounds the aluminum differential housing. To accommodate this, the emergency brake actuators had to be relocated so that they were in front of the rear axle assembly. Many other parts besides these backing plates changed, but I will go into those changes later when I talk about the emergency brake assembly as a whole. Important to the backing plates is that the new emergency brake actuation was via a single cable that was pulled from the center through a perch, and each end of the cable was secured to the backing plate by a welded on bracket.

My SS was missing the correct backing plates but Alfa Parts Exchange, a local Alfa wrecker, had a set still attached to a Veloce rear end. I bought all the emergency brake parts they had. One of the brackets on the backing plate was broken off but included and had to be welded, and both had major rust pitting. I spent an hour and blasted the plates to remove as much rust as possible. One of my friends at my shop was doing some welding so I had him weld the broken bracket back into place while he was at it. After the repair I painted them with POR 15, followed by a primer then a coat of epoxy based appliance paint.

The plate on the left is a standard Giulietta part and the plate on the right is the modified Veloce part.

Looking at the picture above you can see several subtle changes that Alfa made to the brake plates. In addition to welding the bracket in place, the bolt circle that mounts to the axle housing was welded up and re-machined about 10 degrees clockwise and a second keying feature was added probably 170 degrees from the original one. All of the brake components that mount to the plate are standard.

The metal that forms the two legs visible here is roughly the same thickness as the backing plate. The square section on top of it is very this sheet-metal, about the same as the body panels of a Sprint. The welds attaching the bracket to the plate are of good quality, those attaching the thinner metal are a lot rougher, probably because the thinner metal is a little more difficult to weld.

The actual clamping mechanism can be seen in this picture and the picture above it. The lower clamp holds a ferrule at the end of the cable and the second fastening hole screws to a loop on the cable itself to help locate it. It looks like a coat of POR 15 needs to be applied inside the clamp.

Fake Sprint Veloces and SZ’s are out there and one of the tell-tales of a poorly done fake will be the presence of a standard gas tank and rear brake plate/emergency brake set-up. It’s no guarantee that a car is a fake if it doesn’t have these, as people are restoring cars now that may have been stripped of these rare parts when they were not viable restoration candidates in years past, it’s just something to look for. Either way, there is a certain amount of value to having these items on a standard Sprint or a reproduction or even fake, just as there is a loss of value in a genuine Veloce if it lacks these parts.

Up next in brakes will be the ‘floating’ rear wheel cylinders, shoes and springs and whatever else I have to work on to get the rear brakes ready for assembly onto the car.
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3 thoughts on “Brakes #2: Rear backing plates

  1. Hello Matt,

    do you know if the square bracket in thin sheet metal (clearly shown in the picture above) welded to the 2 legs is present on right and left wheels or only right?

    Thank-you

    Carlo

    • Carlo

      I’m not sure as I’ve only seen the two pairs I had -Can’t remember what was on the second pair. I would guess it would be there to keep the cable going into the bracket at a favorable angle on the right side since the yoke is biased towards the left of the car quite a bit. It being a guide, it couldn’t hurt to have it on both sides, but I understand the desire to be ‘correct’.

      Regards,
      Matt

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