cudak888 

I've been working on this pair of Cd'A Delta brake calipers for Pastor Bob recently, and came across these cracks on the front plate fixing cones:

Rear caliper:


Front caliper:




Near as I can figure it, these cone-shaped sections are under absolutely no pressure or tension from the cable or housing. The cable adjuster itself, even if bottomed out, is supported by the threaded tube upon where the adjuster sits - and there is a steel reinforcement above the cone.



That said, I'm assuming that these cracks are either normal (as are cracks on NR/SR crankarms), or as a result of someone torquing these things down too much (pressuring the cone from the threaded, steel plate it sits upon).

Anyone here familiar with the track record of the Cd'A Deltas in this respect? Is this common? Unusual? Ready to explode at any moment?

-Kurt

91MF

send them to me and i'll let you know if they break.

cudak888 

Very funny. Bob and I can perform that test too.

Come to think of it, I do have a Guerciotti in a condition about on par...



-Kurt

Bianchigirll 

those are awful looking. I would atleast try them. keep an eye on them and look for spares or parts you could make spares from.

OH I just check my parts book and they are quite different from C Record. I do not think any CRecord parts will work on these . here is the actual Campi part numbers if it helps.

top; 'adjusting sleeve' # 7203045

bellows; 'Bellow' #7201042

bottom; 'locking sleeve' #7203044

the diagram does not show it but I think there should be a spring in the bellows????

beech333

Is this really all that common? I've never used anything Campy before, but I may be getting some soon and it has me a bit nervous. Are certain years worse than others?

Chombi

I've heard of cracking Campagnolo cranks, but can they really be considered as "normal"???!
I would say they should end up in the trash, regardless if they are classic NR/SR cranks, if you see any cracking on them, lest someone ends up with cracks on bones in their bodies when they do fail catastrophically.......or people can just donate them to me to mount on my Vitus Carbone CF bike that's just eager to explode into CF splintering smithereens on the first large divot it rides over on the road!
Hope those De Aune's are indeed salvagable, becuase they are some of the best looking brakes from Campy ever and marks the zenith of the whole classic "Aero" component movement that started in the mid 80's.

Chombi
84 Peugeot PSV
85(?) vitus Plus Carbone 7

Chombi

luker

common, not normal though. The approved way to make gross adjustments of the cable length on these babies requires a 3.5 mm allen key. Most people don't have that allen key, and so over-exercise the other two options, the barrel adjustment, and the (really cool, actually) pad adjustments. I've seen both screwed up, apparently by allen-keyless owners.

I don't think that it'll be a safety issue. Whilst I'm ranting, also beware of that 3.5 mm allen screw. Overtightening can crack the little piece that it screws into...and that is really, really a safety issue.

cyclotoine

yes, almost every campy record crank set I have come across has had at least small cracks beginning except one VGC and low mile 165mm strada set from 1984 (i.e. near the end of production run and low miles). I have 4 sets of record cranks on bikes I own and all have been filed out of necessity of removing the beginnings of cracks. Only one set is in regular use and it is on a bike I NEVER stand out of the saddle on (cruiser-basket-grocery bike) so if they fail things shouldn't go to badly. Another set is from 1985 and is on a track bike and didn't really have cracks to begin with but I filed them anyway, they other two sets are rarely used. I would never run campy record on a daily use fixed gear for fear of failure. I'm 180lbs 6'3" and put out a respectable amount of torque, I cracked the TA cranks on my fixed gear after less than 2 years of use. Now I use 2004 centaur cranks and feel much safer.

paulkal

My brakes have the same cracks, so it probably is a common. But they do work, so I would worry about it.

ricohman

I've seen this before. Ugh, I may have been the cause of it.
Way back in my hack days though. And my buddy is still not over it.
The cracks haven't changed much in 20 years though.

cudak888 

I, personally, would have no qualms of riding them as-is (though I won't be the one riding them), for the cone/locking sleeve does little more then hold the plate in front. Thing is, if that thing cracks all the way through, the front plate won't be secured.

If you've ever tried buying a set that isn't NOS, you'll find out how common the cracks are. Owning Record cranks entails either putting up with the cracks, or filing them out. "No cracks" isn't an option.

Except that either adjustment bears no effect upon the locking sleeves - the one and only purpose of these things are to hold the front plates in place.

Makes sense. If more then one set has it, the phenomenon isn't isolated.

What caused it?

-Kurt

pastorbobnlnh 

You know, they look better at some distance! Like at least 10+ feet!

Chombi

Anyone notice that the knurling on those cracked cones seemed to be rolled on the part and not machined on. Maybe the knurling process might have weakend these, I suspect, thin section parts at the factory promoting this cracking later in their lives with the most minor stresses that they encountered. The cracks are not on the knurling, but they do line up with them.
JMOs

Chombi
84 Peugeot PSV
85(?) Vitus Plus Carbone 7

luker

I used to race with guys who would remove the plates to make the brakes a little lighter (wish I had that pile'o'covers now...). The plates only make things prettier. But, of course, if the thing fails it won't take long for the cover to disappear.

The one and only purpose of these things are to hold the front plates in place.

I am looking at a c-record, not a croce, but the spring bears down on the cover holder. It would be subject to a considerable pressure if a butt as large as mine had to be hauled down from speed...

<edit> you are right. The cap is only subject to the pressure of the spring </edit>

What caused it?

Indeed. What caused it?

ricohman

Pliers.
The barrel was frozen so I used pliers. Big ugly pliers. Two pairs!
Now that I have admitted this in public my conscience is now cleansed..........

cudak888 

Chombi and ricohman have some interesting points there. It doesn't look as if someone took pliers to these (and ricohman, you are forgiven), though pressure from pliers or knurling would have the possibility to weaken it.

Perhaps the process of pressing the steel center into the aluminum might have something to do with it as well.

When all else fails, blame it on a fixie rider.

-Kurt

miamijim

There's some type of stress on those pieces otherwise they wouldnt have cracked.

cudak888 

Perhaps the steel inserts are larger by mere fractions of a millimeter, generating microcracks during production?

-Kurt

T-Mar

Yes, I suspect the insert is a interference fit and caused the cracks. This could happen for a number reasons, Either the insert or the adjuster could be out of tolerance or the tolerances could be incompatible when they are at there extremes. Finally, an employee may just have been too heavy handed with the press.

While the cracks may line up with the knurling, they are at the opposite end of the adjuster, so it's improbable that the knurling operation has anything to do with the cracks.

Assuming they are from the press fit, the cracks were probably there from the very beginning and simply escaped the inspectors. As stated, they are no additional stress in normal operation and the cracks should not propogate. However, if you want to err on the side of cautioun, you can mark the ends of the cracks and inspect regularly or drill a small stress relief hole at the end of the crack. If you wanted to take things to the extreme, it would take much effort for a machinist to fabricate duplicates.

miamijim

I'm thinking there's some type of 'vertical' stress when the brakes are applied. The steel insert in pressing down which in turn is compressing the knurled piece against the delta piece. Or is that not how it works?

cudak888 

Not if one examines this photograph:



Any cable housing forces are put on the adjuster barrel and are transferred to the threaded cable receptor (even if bottomed out). Granted, this would suggest a downwards force, but the threaded section is fixed, and would put force on the main body only.

That's the thing - the locking nut just sits there.

-Kurt

sced

Maybe put some super glue (the really runny kind) in the cracks and clamp them gently between wood blocks in a vise. I don't think it can hurt.

cudak888 

!

It would make them worse.

-Kurt

sced

How so?

T-Mar

I'm not intimately familiar with the Croce d'Aune version of Delta but Record appears very similar and in it the barrel adjuster does not transfer any forces to this piece. The piece slides over the shaft of the barrel adjuster and is actually a collar to retain the top of the front plate. A coil spring sits between the flange of the barrel adjuster and the sleeve of front plate collar, providing the downwards force to keep the front plate collar in place. When you want to remove the front plate, you push up on the collar. The aluminum, outer case of the collar sits around and on top of two 1/2 necks provided by brake body and front plate. It receives only the constant load from the small coil spring.