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Discussion Starter #1
My Matta came with a brake problem. I found it. No idea how it happened. Anyone want to speculate? I know it was not due to the shoe cutting a groove on the inside of the drum, I've heard of that but there is no sign (very little) of damage to the inside of the drum.

I have 3 extra rear axles so parts aren't a problem to fix it.

Not sure if this is the right forum but I'm a 1900 guy so I hope this one is good.

Dan
 

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Fell off the jack ,when no wheel fitted - any sign of blood on it?
+1, you can see where someone tried to drill holes in the brake drum at about the 1:00 position, to stop the crack:surprise:

Those 1900 drums are much more primitive than that of the Two-Liter; I wonder if you could upgrade them by using different hubs, bearings and seals?

Mark
 

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Discussion Starter #4
Matta brake drums

The Matta has completely dedicated suspension and differential. Including much larger diameter axle's. And the diff locates totally differently. The brake drums are cast iron. The (typical) 1900 has aluminum drums with the steel insert as on the 2000. The hole you see is a drain hole. As I said, I have plenty of spares.

Falling off a jack sounds plausible but the PO had two extra complete diffs a few feet from the car. I can't imagine he would put the wheel back on without putting on another drum.

As for blood, maybe mixed in with the couple of inches of mud I washed off when I got it here.
 

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Discussion Starter #5
Probably didn't fall off a jack

Redmerlin,

The backing plate on a Matta is quite heavy duty, thicker steel than the usual Alfa and it shows no damage. If the car fell off a jack the backing plate (larger OD than the drum) would show some damage, maybe a lot. Still no blood found.

Dan
 

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The Matta has completely dedicated suspension and differential. Including much larger diameter axle's. And the diff locates totally differently. The brake drums are cast iron. The (typical) 1900 has aluminum drums with the steel insert as on the 2000. .
Perhaps I should have asked 'what a Matta is' but I guess it doesn't matta; you said you were a '1900 guy' so I thought it was one of them I'd never heard of.
Mark
 

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Discussion Starter #7
Matta matters

Sorry not to be clear Mark. The Matta is a 1900, at heart at least. The engine is basically a first series 1900, some small differences as with the dual oil pump to feed both the engine and the dry sump. Otherwise the Matta 4X4 Jeep-like vehicle and shares few components with a 1900. Alfa considered the Matta a 1900 giving it the designation of 1900 M AR 51, (the word Matta is a nickname).

I have two other 1900's, a sedan and a cab.

Still mystified how that drum got broken.

Dan
 

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The backing plate on a Matta is quite heavy duty, thicker steel than the usual Alfa and it shows no damage. If the car fell off a jack the backing plate (larger OD than the drum) would show some damage, maybe a lot. Dan
Well then perhaps it does matta; if it is a 1900 jeep, I have seen them. I suspect someone may have tried to jack the jeep up with a jack under the cast iron brake drum. The stresses appear to have been concentrated on the drum at about the 11:00 position as shown in your photographs. The jeep may have fallen off the jack on asphalt or dirt, cracking the drum only to fail later. You may want to find a dye penetrant test kit and crack test the remaining drums or take them to a Non Destructive Testing Lab (NDT).
RNDT, Inc. > Our Services > Liquid Penetrant Testing (PT)
Mark
 

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Discussion Starter #9
Another mystery

I have another damaged 1900 brake drum. The cause is a mystery to me. This time a regular 1900 aluminum drum off an SSZ. Anyone want to take a stab? The first photo is exactly the way I got the diff, the second is the damaged drum next to a good one.

And yes, my Matta is working just fine with a replacement drum.

Dan
 

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Maybe someone decided to fit a bastard wheel that just happened to match the bolt pattern, but was too small inside to clear the fins. We've seen this on 2000/2600s when someone thinks a 15" wheel, or even some 16" wheels, might work.
 

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Given it's a Matta, I'd suspect that off-roading in heavy terrain loosened the wheel nuts and the wheel came off ... been there and done that on a Land Rover ... brake drum was similarly affected.
 

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Discussion Starter #12
Sorry not to be clear. The post this week about a damaged drum is from a Zagato 1900. The original post is from my Matta. Maybe I should have started a new post.

The damage, if you look close, looks like the drum was turned down with a blunt tool. The aluminum fins almost looks galled off. The problem with a wheel coming off and the drum getting damage is the backing plate is fine, no sign of damage. If one put a wrong size Borrani wire on the damage would be more across the fins.

Hmm. I'm mystified.

D
 

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Discussion Starter #13
Sorry again

Allggerita,

So I looked again at the backing plate. There was rust and dirt so I cleaned some. There is damage on the edge. It looks like you are correct. The wheel may have come off and ran on the drum long enough to have the fins smashed and flattened. I'd expect more damage to the backing plate but it could have happened in even seconds I suppose, if the car was going fast enough.

Thanks for the responses.

D
 
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