Full Version: M7 Bolts
I know there have been a number of threads on this but have been searching for an answer. Am wondering if anyone has found a supplier in North America for the M7 (Torx, Ribe, Socket head or ...) bolts that hold the two halves of the callipers together.
Pretty sure Eric (PMB fame) has mentioned these are not available anywhere....so good luck.
Perhaps somewhere in Europe?
Easier to find a unicorn here in the States.
Maybe can salvage some from trashed calipers?
Perhaps somewhere in Europe?
Easier to find a unicorn here in the States.
Maybe can salvage some from trashed calipers?
Might be faster to reach out to PMB. At least they can tell you where they are not. Wish I had more help.
n2j2ryan...
Do you or anyone have the dimensions of the bolt..or a pic
What caliper...
I can check my old brake parts bin...
Thanks...John
I wonder if trying 5/16” bolts might be a way to fudge the unavailable 7mm bolt? If not, perhaps some dismantlers may have some used ones.
1/4 will not work -unless you go long and install lock nuts on the back. They will also be loose in the bores which is not a good thing when the point is trying to keep two halves from shifting around. 5/16 may work but since its only .9mm bigger you risk cutting the thread crests short and may cause issues retaining torque.
7MM is out there. Don't let anyone tell you they are not.
7MM is out there. Don't let anyone tell you they are not.
Here is some info on the Ribe caliper bolts from Eric's "How To" article on PMB Performace's website (http://www.pmbperformance.com/brakehowto.html).
I put the last paragraph in bold to emphasize his conclusion about the original bolts.
From the website:
"Ribe (pronounced ree-bie) Bits – If we’re talking about any of the 911 series or early 914’s all but the very first few serial numbers use these Ribe Fasteners (fun fact: some of the first 100 911’s still used the 356 caliper which had standard hex cap screws). While these 5-point star bits look amazingly similar to a common torx bit, they are not the same. A Ribe bit and fastener has a much more pronounced shoulder with sharp edges. Word of caution: Torx bits will fit in Ribe fasteners. My general take on them is, they would be fine for “assembly” work but I would caution anyone from using them to disassemble a caliper that has been stuck together for 40 plus years. The main issue here is, these fasteners are NLA. If you ruin one, you’re going to have to purchase a core caliper in order to get a replacement. Throughout this tutorial we’ll be concentrating on the care required to extract these fasteners without damaging them and, how to treat them so they’ll last another 40 years. Ribe bits are an important part of this. Ribe bit sets can be found on Amazon for around $30.00. Here’s what you’ll need:
· M-Caliper (911 from 64-75 w/steel front caliper) – R8 bit for an M8 fastener.
· Rear M-Caliper (911 from 69-83) – R6 bit for an M7 fastener.
· A-Caliper and Wide A-Caliper (911SC and Carrera models through 1989) – R6 bit for an M9 fastener
· Rear Carrera Caliper (911 Carrera through 1989) – R6 bit for an M7 fastener
· 914 Rear Caliper (70-72) R5 bit for an M7 fastener
That pretty much covers the “Ribe” usage on Porsche models. I can’t stress this part enough. It’s the beginning of “treat your fasteners like gold”. Many of these odd size (7-9) fasteners are NLA in “any” configuration, let alone Ribe. Numerous calls to Ribe to have fasteners re-manufactured have been met with… “no”. About the only caliper you can readily get 12.9 fasteners for is the M-Caliper with its common M8 fasteners. Then again, they won’t be Ribe and they won’t be original. The rest are priceless."
I put the last paragraph in bold to emphasize his conclusion about the original bolts.
From the website:
"Ribe (pronounced ree-bie) Bits – If we’re talking about any of the 911 series or early 914’s all but the very first few serial numbers use these Ribe Fasteners (fun fact: some of the first 100 911’s still used the 356 caliper which had standard hex cap screws). While these 5-point star bits look amazingly similar to a common torx bit, they are not the same. A Ribe bit and fastener has a much more pronounced shoulder with sharp edges. Word of caution: Torx bits will fit in Ribe fasteners. My general take on them is, they would be fine for “assembly” work but I would caution anyone from using them to disassemble a caliper that has been stuck together for 40 plus years. The main issue here is, these fasteners are NLA. If you ruin one, you’re going to have to purchase a core caliper in order to get a replacement. Throughout this tutorial we’ll be concentrating on the care required to extract these fasteners without damaging them and, how to treat them so they’ll last another 40 years. Ribe bits are an important part of this. Ribe bit sets can be found on Amazon for around $30.00. Here’s what you’ll need:
· M-Caliper (911 from 64-75 w/steel front caliper) – R8 bit for an M8 fastener.
· Rear M-Caliper (911 from 69-83) – R6 bit for an M7 fastener.
· A-Caliper and Wide A-Caliper (911SC and Carrera models through 1989) – R6 bit for an M9 fastener
· Rear Carrera Caliper (911 Carrera through 1989) – R6 bit for an M7 fastener
· 914 Rear Caliper (70-72) R5 bit for an M7 fastener
That pretty much covers the “Ribe” usage on Porsche models. I can’t stress this part enough. It’s the beginning of “treat your fasteners like gold”. Many of these odd size (7-9) fasteners are NLA in “any” configuration, let alone Ribe. Numerous calls to Ribe to have fasteners re-manufactured have been met with… “no”. About the only caliper you can readily get 12.9 fasteners for is the M-Caliper with its common M8 fasteners. Then again, they won’t be Ribe and they won’t be original. The rest are priceless."
QUOTE(jcd914 @ Jan 30 2018, 05:06 PM) 
Here is some info on the Ribe caliper bolts from Eric's "How To" article on PMB Performace's website (http://www.pmbperformance.com/brakehowto.html).
I put the last paragraph in bold to emphasize his conclusion about the original bolts.
From the website:
"Ribe (pronounced ree-bie) Bits – If we’re talking about any of the 911 series or early 914’s all but the very first few serial numbers use these Ribe Fasteners (fun fact: some of the first 100 911’s still used the 356 caliper which had standard hex cap screws). While these 5-point star bits look amazingly similar to a common torx bit, they are not the same. A Ribe bit and fastener has a much more pronounced shoulder with sharp edges. Word of caution: Torx bits will fit in Ribe fasteners. My general take on them is, they would be fine for “assembly” work but I would caution anyone from using them to disassemble a caliper that has been stuck together for 40 plus years. The main issue here is, these fasteners are NLA. If you ruin one, you’re going to have to purchase a core caliper in order to get a replacement. Throughout this tutorial we’ll be concentrating on the care required to extract these fasteners without damaging them and, how to treat them so they’ll last another 40 years. Ribe bits are an important part of this. Ribe bit sets can be found on Amazon for around $30.00. Here’s what you’ll need:
· M-Caliper (911 from 64-75 w/steel front caliper) – R8 bit for an M8 fastener.
· Rear M-Caliper (911 from 69-83) – R6 bit for an M7 fastener.
· A-Caliper and Wide A-Caliper (911SC and Carrera models through 1989) – R6 bit for an M9 fastener
· Rear Carrera Caliper (911 Carrera through 1989) – R6 bit for an M7 fastener
· 914 Rear Caliper (70-72) R5 bit for an M7 fastener
That pretty much covers the “Ribe” usage on Porsche models. I can’t stress this part enough. It’s the beginning of “treat your fasteners like gold”. Many of these odd size (7-9) fasteners are NLA in “any” configuration, let alone Ribe. Numerous calls to Ribe to have fasteners re-manufactured have been met with… “no”. About the only caliper you can readily get 12.9 fasteners for is the M-Caliper with its common M8 fasteners. Then again, they won’t be Ribe and they won’t be original. The rest are priceless."
Good post. If anyone has junk 914 or 911 calipers that are beyond rebuilding pirate the hardware and squirrel them away.
QUOTE(Jeff Hail @ Jan 30 2018, 08:16 PM)
QUOTE(jcd914 @ Jan 30 2018, 05:06 PM)
Here is some info on the Ribe caliper bolts from Eric's "How To" article on PMB Performace's website (http://www.pmbperformance.com/brakehowto.html).
I put the last paragraph in bold to emphasize his conclusion about the original bolts.
From the website:
"Ribe (pronounced ree-bie) Bits – If we’re talking about any of the 911 series or early 914’s all but the very first few serial numbers use these Ribe Fasteners (fun fact: some of the first 100 911’s still used the 356 caliper which had standard hex cap screws). While these 5-point star bits look amazingly similar to a common torx bit, they are not the same. A Ribe bit and fastener has a much more pronounced shoulder with sharp edges. Word of caution: Torx bits will fit in Ribe fasteners. My general take on them is, they would be fine for “assembly” work but I would caution anyone from using them to disassemble a caliper that has been stuck together for 40 plus years. The main issue here is, these fasteners are NLA. If you ruin one, you’re going to have to purchase a core caliper in order to get a replacement. Throughout this tutorial we’ll be concentrating on the care required to extract these fasteners without damaging them and, how to treat them so they’ll last another 40 years. Ribe bits are an important part of this. Ribe bit sets can be found on Amazon for around $30.00. Here’s what you’ll need:
· M-Caliper (911 from 64-75 w/steel front caliper) – R8 bit for an M8 fastener.
· Rear M-Caliper (911 from 69-83) – R6 bit for an M7 fastener.
· A-Caliper and Wide A-Caliper (911SC and Carrera models through 1989) – R6 bit for an M9 fastener
· Rear Carrera Caliper (911 Carrera through 1989) – R6 bit for an M7 fastener
· 914 Rear Caliper (70-72) R5 bit for an M7 fastener
That pretty much covers the “Ribe” usage on Porsche models. I can’t stress this part enough. It’s the beginning of “treat your fasteners like gold”. Many of these odd size (7-9) fasteners are NLA in “any” configuration, let alone Ribe. Numerous calls to Ribe to have fasteners re-manufactured have been met with… “no”. About the only caliper you can readily get 12.9 fasteners for is the M-Caliper with its common M8 fasteners. Then again, they won’t be Ribe and they won’t be original. The rest are priceless."
Good post. If anyone has junk 914 or 911 calipers that are beyond rebuilding pirate the hardware and squirrel them away.
I try to remember to bring all those to Hershey each year and hand them over to Eric.
He can use the parts.
Thanks for all of the input. It is kinda crazy. I found 1/4 bolts, all 16 for $6, but they are too narrow and allow for too much play. I have found a supplier in the UK with 7mm Allen/Socket head. Will cost about $50 for all 16 which I guess is not crazy. I could just reuse the old ones, but since I am replacing just about every other bolt on the car, I might as well do those as well. Maybe I could sell the ones I have to cover the cost? The other funny thing is that my front callipers had the RIBE bolts and the rears had the Socket head. They both looked original but I guess someone could have already swapped out the bolts in the rear.
Thanks for the offer John. I do have the used ones, but wanted to replace with new. I think I have finally found a supplier.
n2j2ryan...
Do you or anyone have the dimensions of the bolt..or a pic
What caliper...
I can check my old brake parts bin...
Thanks...John
QUOTE(johnhora @ Jan 30 2018, 12:10 PM)
n2j2ryan...
Do you or anyone have the dimensions of the bolt..or a pic
What caliper...
I can check my old brake parts bin...
Thanks...John
QUOTE(n2j2ryan @ Jan 30 2018, 10:20 PM)
I found 1/4 bolts, all 16 for $6, but they are too narrow and allow for too much play. I have found a supplier in the UK with 7mm Allen/Socket head. Will cost about $50 for all 16 which I guess is not crazy.
Are the ones you found the correct grade?
Unless your old bolts are damaged or stripped, I would replate and reuse.
QUOTE(r_towle @ Jan 30 2018, 08:30 PM)
QUOTE(Jeff Hail @ Jan 30 2018, 08:16 PM)
QUOTE(jcd914 @ Jan 30 2018, 05:06 PM)
Here is some info on the Ribe caliper bolts from Eric's "How To" article on PMB Performace's website (http://www.pmbperformance.com/brakehowto.html).
I put the last paragraph in bold to emphasize his conclusion about the original bolts.
From the website:
"Ribe (pronounced ree-bie) Bits – If we’re talking about any of the 911 series or early 914’s all but the very first few serial numbers use these Ribe Fasteners (fun fact: some of the first 100 911’s still used the 356 caliper which had standard hex cap screws). While these 5-point star bits look amazingly similar to a common torx bit, they are not the same. A Ribe bit and fastener has a much more pronounced shoulder with sharp edges. Word of caution: Torx bits will fit in Ribe fasteners. My general take on them is, they would be fine for “assembly” work but I would caution anyone from using them to disassemble a caliper that has been stuck together for 40 plus years. The main issue here is, these fasteners are NLA. If you ruin one, you’re going to have to purchase a core caliper in order to get a replacement. Throughout this tutorial we’ll be concentrating on the care required to extract these fasteners without damaging them and, how to treat them so they’ll last another 40 years. Ribe bits are an important part of this. Ribe bit sets can be found on Amazon for around $30.00. Here’s what you’ll need:
· M-Caliper (911 from 64-75 w/steel front caliper) – R8 bit for an M8 fastener.
· Rear M-Caliper (911 from 69-83) – R6 bit for an M7 fastener.
· A-Caliper and Wide A-Caliper (911SC and Carrera models through 1989) – R6 bit for an M9 fastener
· Rear Carrera Caliper (911 Carrera through 1989) – R6 bit for an M7 fastener
· 914 Rear Caliper (70-72) R5 bit for an M7 fastener
That pretty much covers the “Ribe” usage on Porsche models. I can’t stress this part enough. It’s the beginning of “treat your fasteners like gold”. Many of these odd size (7-9) fasteners are NLA in “any” configuration, let alone Ribe. Numerous calls to Ribe to have fasteners re-manufactured have been met with… “no”. About the only caliper you can readily get 12.9 fasteners for is the M-Caliper with its common M8 fasteners. Then again, they won’t be Ribe and they won’t be original. The rest are priceless."
Good post. If anyone has junk 914 or 911 calipers that are beyond rebuilding pirate the hardware and squirrel them away.
I try to remember to bring all those to Hershey each year and hand them over to Eric.
He can use the parts.
same here.
The strong 7mm bolts needed for the calipers are not available anywhere. The reason is that the calipers were designed before ISO standardized bolts sizes. The 7mm was skipped in the standard and therefore nobody makes them except the very low grade.
Your options are:
1. Reuse old ones.
2. Drill and re-tap the holes for 8x1mm bolts. Only the newer calipers need tapping. Pay attention that you need 8x1 (fine thread) and not the regular 8x1.25 thread.
Your options are:
1. Reuse old ones.
2. Drill and re-tap the holes for 8x1mm bolts. Only the newer calipers need tapping. Pay attention that you need 8x1 (fine thread) and not the regular 8x1.25 thread.
Oh my found some "GOLD" in the brake parts bin 
yes I only have used ones....
unless you are building a 100 point show car ...take what you have and reuse them
Click to view attachment
Click to view attachment
yes I only have used ones....
unless you are building a 100 point show car ...take what you have and reuse them
Click to view attachment
Click to view attachment
Hi,
I found these on German ebay (maybe they are made of pure gold...): https://www.ebay.de/itm/3-St-Zylinderschrau...rsAAOSwqu9VTGIP
Regards
Norbert
I found these on German ebay (maybe they are made of pure gold...): https://www.ebay.de/itm/3-St-Zylinderschrau...rsAAOSwqu9VTGIP
Regards
Norbert
I am not sure of the standards for brake caliper bolts. Would these work. Company out of the UK.
M7 x 60mm Socket Capscrew
sale quantity one unit
Major Diameter 7.00mm
Thread Pitch 1.00mm
Length under head 60mm
Thread Length 25mm
Cap Diameter 11mm
Hex wrench size 5mm
Thread Included Angle 60°
Material Grade A2-70 (304) stainless steel
Manufacture Cold-forged, Rolled Threads
Applicable Standard DIN912
Application
M7 x 60mm Socket Capscrew
sale quantity one unit
Major Diameter 7.00mm
Thread Pitch 1.00mm
Length under head 60mm
Thread Length 25mm
Cap Diameter 11mm
Hex wrench size 5mm
Thread Included Angle 60°
Material Grade A2-70 (304) stainless steel
Manufacture Cold-forged, Rolled Threads
Applicable Standard DIN912
Application
My other question is this. Some of the comments on this post have talked about going to a larger bolt and retapping. All of my calipers had through bolts with nuts on the other side. Does this mean they were drilled through or did earlier calipers come unthreaded with nuts. The reason being was then it would be easy to thread the 7mm side to 8mm and get the readily available M8 bolts.
QUOTE(n2j2ryan @ Feb 2 2018, 11:00 AM)
My other question is this. Some of the comments on this post have talked about going to a larger bolt and retapping. All of my calipers had through bolts with nuts on the other side. Does this mean they were drilled through or did earlier calipers come unthreaded with nuts. The reason being was then it would be easy to thread the 7mm side to 8mm and get the readily available M8 bolts.
However for the purist, custom made bolts can fill any need or requirement!
http://www.cnb-inc.com/custom-made-bolts.html
QUOTE(n2j2ryan @ Feb 2 2018, 02:00 PM)
My other question is this. Some of the comments on this post have talked about going to a larger bolt and retapping. All of my calipers had through bolts with nuts on the other side. Does this mean they were drilled through or did earlier calipers come unthreaded with nuts. The reason being was then it would be easy to thread the 7mm side to 8mm and get the readily available M8 bolts.
I don't know if you can drill out the caliper halves and have enough metal left for proper strength. I'm not going to be the one to test it.
I don't think stainless steel will work in this situation.
PMB replates the factory caliper bolts. They end up looking like new. I've never seen or heard of a broken bolt through normal use. Stripped maybe but thats easy to see.
I dont think A2 stainless is good enough. You need 12/9 grade
QUOTE(mepstein @ Feb 2 2018, 11:09 AM)
QUOTE(n2j2ryan @ Feb 2 2018, 02:00 PM)
My other question is this. Some of the comments on this post have talked about going to a larger bolt and retapping. All of my calipers had through bolts with nuts on the other side. Does this mean they were drilled through or did earlier calipers come unthreaded with nuts. The reason being was then it would be easy to thread the 7mm side to 8mm and get the readily available M8 bolts.
They always have nuts. I don't know if you can drill out the caliper halves and have enough metal left for proper strength. I'm not going to be the one to test it.
I don't think stainless steel will work in this situation.
PMB replates the factory caliper bolts. They end up looking like new. I've never seen or heard of a broken bolt through normal use. Stripped maybe but thats easy to see.
Good concern Mepstein. As a reference, before I enlarged the holes in my cooling fan assembly, it seemed the 7mm bolts were 'swimming' in the holes. I only had to 'ream' them enough to get a 'semi-interference' fit with new 8mm bolts.
So if the caliper holes are of similar large dimension as the cooling fan, then there is barely any material removal to fit an 8mm bolt. Possibly around 0.020"-ish diameter increase from what I recall. That would be plenty strong, especially since the head and nut of the 8mm bolt would cover more caliper material than would be lost in the reaming.
QUOTE(Bartlett 914 @ Feb 2 2018, 02:34 PM)
I dont think A2 stainless is good enough. You need 12/9 grade
That is correct, some calipers are threaded on one half, and some used through bolts with nuts
Hi,
I now found a source in Germany that offers the bolts you need at an 'affordable' price.
tola-tools Germany
I'm quite happy having found this scource... need such screws for my Opel, too.
Regards
Norbert
I now found a source in Germany that offers the bolts you need at an 'affordable' price.
tola-tools Germany
I'm quite happy having found this scource... need such screws for my Opel, too.
Regards
Norbert
QUOTE(nordfisch @ Feb 2 2018, 03:44 PM)
Hi,
I now found a source in Germany that offers the bolts you need at an 'affordable' price.
tola-tools Germany
I'm quite happy having found this scource... need such screws for my Opel, too.
Regards
Norbert
OK. So I did a test. I tapped an 8mm thread on the one side of the callipers and then drilled out a 7.94mm bit on the other side. I purchased an 12.9 M8 Allen bolt for 50 cents and it slid perfectly into the hole, with a lot less play than the M7 bolts in the original holes. Tightened it up and seems to work beautifully. Over twice as much thread as a nut , but maybe not as strong steel? Comments? Concerns?
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