Campagnolo "Differential" brakes - Yay or Nay?

[De Sisti]

They're nice. How much did the cost You?

[Oxford_Guy]

They're nice. How much did the cost You?

£95 (was £104, but he accepted my offer).

The only real issue I can see is whether that mark on the pivot nut is just a mark (e.g. with a pen) or an actual crack...

[Brucey]

to me it is pretty clearly a crack. Check the threading on both parts carefully, but it might be the same part as is fitted to the centrebolt.

cheers

[Oxford_Guy]

to me it is pretty clearly a crack. Check the threading on both parts carefully, but it might be the same part as is fitted to the centrebolt.

The thing is, on another photo it looks like the line extends to the washer behind the bolt, which seems odd, unless it's a pen mark, or a reflection. The seller hasn't posted them out yet, I've sent him a message to clarify.

[Little Jim]

I've got a set of 10 speed Record callipers, so similar vintage to those and that nut on mine is an aluminium lock nut with a small grub screw in the side to lock the lock nut (if that actually makes sense!)  The nuts on mine are both split presumably as a result of the previous owner being over-zealous when tightening them.  The aluminium is also very fragile and the nuts are prone to just falling apart so really need replacing with some normal nuts made out of "proper metal".  So the nut in that picture s almost certainly split/cracked.

[Oxford_Guy]

I've got a set of 10 speed Record callipers, so similar vintage to those and that nut on mine is an aluminium lock nut with a small grub screw in the side to lock the lock nut (if that actually makes sense!)  The nuts on mine are both split presumably as a result of the previous owner being over-zealous when tightening them.  The aluminium is also very fragile and the nuts are prone to just falling apart so really need replacing with some normal nuts made out of "proper metal".  So the nut in that picture s almost certainly split/cracked.

If so, should I cancel the purchase, as original spares don't seem to be available, or do you think I'd be able to find a suitable generic steel or to nut to replace it with? I did also have my eye on some nice silver Athena dual pivot callipers too, though...

[Little Jim]

You will be able to get a "generic" nut to fit without too much problem.

[Oxford_Guy]

You will be able to get a "generic" nut to fit without too much problem.

Okay, that's re-assuring - though I guess as it won't have the grub screw to keep it in place it'll need some threadlocker applied?

[Little Jim]

Well, either thread lock or make sure it's "nipped up" against the other nut to lock it in place.  Brucey will be along shortly to tell you where I'm going wrong!  It has, however worked fine on mine

[Oxford_Guy]

Well, either thread lock or make sure it's "nipped up" against the other nut to lock it in place.  Brucey will be along shortly to tell you where I'm going wrong!  It has, however worked fine on mine

Thanks, would a titanium nut work for this application, or would steel be better?

[Oxford_Guy]

to me it is pretty clearly a crack. Check the threading on both parts carefully, but it might be the same part as is fitted to the centrebolt.

He's sent a couple of new photos, I can't see any evidence of a crack in either pivot nut in these, unless I'm missing something? I'm thinking either it was possibly a trick of the light (reflection) or just a pen mark or similar that he's cleaned-off, or else he's replaced the nut with one from another yet of brakes (perhaps the most likely explanation)... The brake I thought I saw a crack on the pivot nut was the rear one I think (shorter centre bolt):

(Click to expand the images)





Compare with this from his original set of images (you can also see here the line on the nut seems to extend to the washer):

[Brucey]

He's sent a couple of new photos....

are they even of the same brakes....?

BTW the threading on the centrebolt where there is a similar nut is usually M7x1mm. The threading on the side bolt will either be M7x1 or (more likely) M6x1mm. The grub screw is (IIRC) 'belt and braces'.

cheers

[Oxford_Guy]

He's sent a couple of new photos....

are they even of the same brakes....?

Well, who can tell with eBay? I did notice that in the second batch of photos the cable adjuster bolts are reversed, but perhaps he did that to prepare for transit, or maybe not...

BTW the seller does offer "14 days refund, buyer pays return postage"

BTW the threading on the centrebolt where there is a similar nut is usually M7x1mm. The threading on the side bolt will either be M7x1 or (more likely) M6x1mm. The grub screw is (IIRC) 'belt and braces'.

Thanks!

[Oxford_Guy]

The seller has said:

"I removed this nut and I cleaned it from strong "dirt". It looked like a crack on the photo really. "

I also asked about the reversed cable tensioner bolts in the later photos, he said:

"because of safe shipping. Like this do not drop from the arm. For you necessary to insert the adjuster screws in a good position into the holes."

Sounds plausible, I said to go ahead and ship, will have to see what I get...

[giropaul]

Do be careful tightening the brake pad bolt. The dished washer inside the arm is especially subject to cracking if too much torque is applied.

[Oxford_Guy]

Do be careful tightening the brake pad bolt. The dished washer inside the arm is especially subject to cracking if too much torque is applied.

Thanks. Are there actual official torque settings for the various bolts? I do have a torque wrench.

[Samuel D]

When the brake is fitted to the bicycle, only cable tension prevents the barrel adjuster from falling out. Reversing the barrel so the rubber O-ring wheel holds it in place during shipping is a common practice.

Are there actual official torque settings for the various bolts? I do have a torque wrench.

Yes. From memory, 8 Nm for the brake pads, 8 Nm for the recessed nut, and 5 Nm for the cable clamp. Somewhere on the Campagnolo website are user manuals for older products. Worth looking up (I didn’t immediately find them just now) and following.

[Brucey]

there is also a list of torque settings (for different manufacturer's parts) on the park tool website
https://www.parktool.com/blog/repair-help/torque-specifications-and-concepts

cheers

[Oxford_Guy]

Thanks for the info. about torque settings.

I know much of this info. is in the depths of the Campagnolo website, but they don't make it easy to find, unless I'm missing somewhere where all the documentation is indexed?

[Oxford_Guy]

The seller has said:

"I removed this nut and I cleaned it from strong "dirt". It looked like a crack on the photo really. "

I also asked about the reversed cable tensioner bolts in the later photos, he said:

"because of safe shipping. Like this do not drop from the arm. For you necessary to insert the adjuster screws in a good position into the holes."

Sounds plausible, I said to go ahead and ship, will have to see what I get...

The pivot nuts are not cracked, got the callipers in the post yesterday. They look in very decent shape actually, not far off mint to my not very educated eye, though obviously (lightly) used.