A Tale of Three Calipers, Tell me about different RIBE hardware Options

[zoomCat]

And for those who might be intested in what a dead inner adjuster looks like:



The adjuster on the left is now a very small paper weight, because it's too small to be a boat anchor. The other looks pretty good, at least to me, even though it does show signs of wear.

[PatMc]

Now I just have to get the very rusty bleeders out of my donor M calipers. I suspect that the piston bores are not salvageable anyway.

Grab a torch (even a propane plumbing torch is fine) and get the bleeders to glow a bit...as soon as the color goes away, give it a try. 95% of the time they come out...the other 5% they break.

As for bores, keep in mind, the bore is not the sealing surface....the piston is. In thousands of calipers I've rebuilt, I can count on one hand the amount where the bore was not serviceable after a good blasting.

[Superhawk996]

Duly noted though that Home Depot fasteners are OK to use on brake calipers. (IMG:style_emoticons/default/biggrin.gif)

Just to be clear, I was not lobbying that these fasteners were OK to use. (IMG:style_emoticons/default/stirthepot.gif)

Not just a question of tensile strength. Due to the nature of the caliper geometry, the fasteners are exposed to bending loads which is something you don't want but can't be avoided in this application.

Knowing that there are bending loads involved, surely don't want a full threaded shank in there where bending loads are imparted on the root of the threads that can act like a stress riser. Would also want a rolled thread vs. something with a cut thread form. Rolled threads being less of a stress riser . . . to a degree.

Likewise, don't buy your highly stressed SHCS fasteners at Home Depot. If it's critical enough to warrant a grade 12.9 fastener, I'm not getting it at Home Depot. (IMG:style_emoticons/default/happy11.gif) I'll also add there are fastener grades above 12.9 and I honestly don't know what the Ribe fasteners are but assuming they are AT LEAST 12.9 but may be even higher.

For those that are interested Eric has a wonderful website on caliper rebuilds complete with a picture of the proper Ribe fasteners. (IMG:style_emoticons/default/first.gif)

https://www.pmbperformance.com/brakehowto.html

[Robarabian]

This was an educational thread. Can anyone remind those of us still learning the nuances of 914-6, how you tell the caliper difference between a 4 and 6 rear caliper by looking at it?

I figured out from this thread, the Ribe heads may be a tell, but any other way to tell at the SWAP meet?

[Superhawk996]

Piston diameter is 38mm for /6 and 33mm for /4 will be the easy giveaway.

[gandalf_025]

Bigger pistons, takes larger brake pads
and generally costs a lot more....

I'm sure there are threads here that
describe the appearance differences
in detail..

[Eric_Shea]

Duly noted though that Home Depot fasteners are OK to use on brake calipers. (IMG:style_emoticons/default/biggrin.gif)

Just to be clear, I was not lobbying that these fasteners were OK to use.

Oh I know you weren't... (IMG:style_emoticons/default/wink.gif)

I should expound. Sites like this have an "amazing"... literally "astonishing" amount of information. The only problem is, it's the end-users job to sift through the mounds of rubble to find the gold. I can't think of "any" thread I've seen @Superhawk996 weigh in on where his advice is anything but solid gold. (IMG:style_emoticons/default/smilie_pokal.gif)

12.9 for the Ribe and Verbus fasteners used on our cars.

[PatMc]

Duly noted though that Home Depot fasteners are OK to use on brake calipers. (IMG:style_emoticons/default/biggrin.gif)

Just to be clear, I was not lobbying that these fasteners were OK to use. (IMG:style_emoticons/default/stirthepot.gif)

Not just a question of tensile strength. Due to the nature of the caliper geometry, the fasteners are exposed to bending loads which is something you don't want but can't be avoided in this application.

Knowing that there are bending loads involved, surely don't want a full threaded shank in there where bending loads are imparted on the root of the threads that can act like a stress riser. Would also want a rolled thread vs. something with a cut thread form. Rolled threads being less of a stress riser . . . to a degree.

Likewise, don't buy your highly stressed SHCS fasteners at Home Depot. If it's critical enough to warrant a grade 12.9 fastener, I'm not getting it at Home Depot. (IMG:style_emoticons/default/happy11.gif) I'll also add there are fastener grades above 12.9 and I honestly don't know what the Ribe fasteners are but assuming they are AT LEAST 12.9 but may be even higher.

For those that are interested Eric has a wonderful website on caliper rebuilds complete with a picture of the proper Ribe fasteners. (IMG:style_emoticons/default/first.gif)

https://www.pmbperformance.com/brakehowto.html

Agreed.

I've always assumed they were 12.9 strength simply due to the fact that the later calipers using hex bolts are 12.9...and I'm pretty sure the non-button heat Ribe screws are marked 12.9 (at least some of them)...and they're the same size and everything else. The only thing that changes is the thread engagement (1x diameter rule doesn't apply in cast iron).