Brake calipers joining bolts torque setting

[Barrieb]

Guys,
Checked out library and links and can't find a value for the calipers joining bolts (k100 non abs 8 valve)

Calipers to forks s 23.5lbs, which will be my planned setting if I can't get confirmation.

Does anyone know?

Thanks Barrie

[motodude]

If these are the 2-pot calipers, you may have difficulty getting them back together and not leaking.

Tighten them as much as you can and check closely for leaks.

Don't ask me how I know,
Tom

[Barrieb]

That does not sound good Tom

I take it clean the joining surfaces well and just join dry with new o rings? As I'd planned

Barrie

[Howard64180]

I have to count myself as being very fortunate then.  I split all three of mine, put new 'o' rings in the front calipers (one each) but I'm fairly sure I re-used the (2) 'o' rings in the rear caliper.  Everything was cleaned well, I nipped them up as much as I could before bolting them on and re-tightened once on the bike.  This was back in May and I have had no leaks.  My brakes were fully stripped for cleaning as the bike had been stood for twenty-odd years.  All seals were replaced at the front (M/C too) but re-used at the back.

PS, Tom, you just made me run outside to check  :eek:

[motodude]

That was my experience.  YMMV.

I cleaned, tightened, etc.  I'm not sure what, nipped means.  Since then (several years ago) I've heard others warn against it.  My understanding is that they get warped during assembly.

I have rebuilt mine several time over the years since then, but I don't take the halves apart (anymore).

Barrieb, you may have the same experience as Howard.  I hope you do.  To answer your original question, I think getting both bolts the same torque would be more important than a specific torque.  Given the lack of a spec.

Tom

[Scott_]

When I got my caliper kits for my 4pot Breembo callipers, they included the interior o-rings and new bolts, instructions, but no torque spec for the bolts----
needless to say I did not split my calipers either.
I just pulled the pistons, removed all the seals and just flushed the dickens out of them real good. New seals and pistons, good to go.

[Howard64180]

I had seen warnings about splitting four pot Nissin calipers in the past, and I have seen a set of four pot Brembo calipers that were very warped (junk).  As Tom says, there are warnings about splitting these calipers - which I hadn't seen when I did mine.  As I said, I've been lucky so far.  I'll think twice before I split them again. 

I hope yours go as well as mine did, Barrie.  Tom, how did you fix yours when they leaked?

 

[Barrieb]

Thanks guys, some good advice - I'm hoping the warped calipers were due to heat not over tightening.   I may rethink selling the spare pair of front ones I have.

But I can't imagine there are too many problems with these calipers, as I have had the spares on eBay at just £45 (including free uk postage) for a couple of weeks without any interest.

Sod's law the front calipers only had one o ring so I ass u me d that the back one was the same, need to order 1 o ring.

I was going to match up with o rings I already have, but given potential issues I,m now aware of, I'm ordering the right one!

Will let you know how I get on

Barrie

[motodude]

I attempted to reface the mating surfaces with some emory paper and a piece of glass.  I attempted several times during the process to see if they'd seal but didn't have any success.

I eventually purchased used calipers and rebuilt those without splitting them.

Tom

I had seen warnings about splitting four pot Nissin calipers in the past, and I have seen a set of four pot Brembo calipers that were very warped (junk).  As Tom says, there are warnings about splitting these calipers - which I hadn't seen when I did mine.  As I said, I've been lucky so far.  I'll think twice before I split them again. 

I hope yours go as well as mine did, Barrie.  Tom, how did you fix yours when they leaked?

[Howard64180]

Thanks for the reply Tom; a cautionary experience! 

[Barrieb]

Hope the moderator does not mind, but have been looking for the answer to the same question 4 years later for my R65!
Funny how things come round again
(R65 is surprisingly not as enjoyable as the K to work on, going to have to get another brick)

[Scott_]

From the BMW manual for k75's and k100's, Caliper to fork(front) and caliper to rear mount, 32nm...
The bolts for assembling the caliper halves(if you split them) is 30nm.

for the 1100's the caliper mount torque is 40nm.

[matjas]

I thought I will chime in with my experience on rebulding the front calipers in k1100 - if they dont leak in the middle you dont have to split them to have all of the pistons out.

What you need to do is to do pistons in pairs. Have all the pistons fully in /if they are VERY dirty, clean them first as you will f,,k up your seals/ - then insert about 8mm wooden piece into the caliper and secure it to one side of the caliper. A piece of rope in eights around the wooden block and the back of the caliper will do the trick just fine - then apply compressed air into the caliper /keep those fingers out!/ the pistons will pop out to their max - then take out the wooden piece and the pistons will be possible to remove with your fingers, literally.

Clean, polish, replace seals, etc - whatever is needed, insert the pistons fully back lightly covered with DOT4 - remount the wooden piece to this side and then repeat for the other side.

Good luck and happy riding.