Brembo P2F08s

S

sjb

New member
Location
cornwall
My poor twin bleeds are quite leaky from the bleed nipples, the threads are quite loose and can't find anyone near me (Cornwall) brave enough to time sert them (assuming the seat is OK)

Do the single bleeds from Andover Norton fit without fettling (I know they may need threading)?
andover-norton.co.uk

Andover Norton - BREMBO BRAKE CALIPER LH P2F08N - 55.0440

BREMBO BRAKE CALIPER LH P2F08N
andover-norton.co.uk andover-norton.co.uk

Tried searching for this on the forum but failed.

Sorry if this is an obvious question.

Thank you
Stephen (1978 1200)
 
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The later un-threaded 08 calipers are machined square on the "inner" mounting surface while the early threaded calipers are machined on their outer mounting surface. The outer surface of the later type is not necessarily square to the disc and fork lugs, nor is the off-set guaranteed. It's generally not much and usually doesn't show up with used pads but new pads can cause grief.

You may get away with a simple bolt-on, but don't count on it. I've had to adjust many of these calipers to mount centrally and parallel over the discs.

piet
 
remove the bleeders and either clean them where they contact the caliper or buy new ones. you could run a tap thru the threads to clean them up but be careful not to get shavings into the caliper housing. better yet, split the caliper cases and service them with new seals from a Brembo rebuild kit. use thin washers to shim and center the caliper over the rotors. And of course use new washers for the banjo bolts and bleed the system.
 
Thank you, I have split the calipers, cleaned them, new pistons and seals. The bleed nipples are a little loose in the threads, one especially so, not aware that any were leaking before the strip (it may have just been decades of accumulated crap sealing them). I have cleaned all the threads with a chaser rather than a tap as it has a completely flat bottom so it couldn't get near the seats. There is a tiny ooze from around the base of the nipples, which I'm assuming is them not seating fully/properly and the fluid running up the threads (they've been uner pressure with the lever tied back to the grip to help the bleed process). Not brave enough to tighten them any further. They are new stainless nipples. I've just ordered some different nipples from Gutsibits in case the seal might be any better (the new one's are quite pointy).
Can't find anyone that might be able to re-seat them and really struggling to find engineering firms near me that want to risk a timesert. I'd rather keep the dual bleeders, but am exploring options...

Open to any suggestions

Sorry to be a pain
 
Ha! One hundred and one photos of my bike but none close up of the calipers with these nipples.
What I can tell you is that they stand taller than the originals so aesthetically they may not suit your taste.
I was unsure, but after at least six years and no issues and annual fluid changes, I'v had no issues.
I have now been able to source two NOS calipers and will in the near future swap out the old calipers as the piston support is worn
and will continue to use these Stahlbus nipples in the new calipers as they make bleeding easier.
If I can remember, I'll have a look tomorrow and take close up photos when back at the shipyard where I keep my bikes.
 
Old BMW ATE calipers fitted with Stahlbus bleed nipples.
 

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piranha-bro2 said:
I think fluid would still be able to escape through the central hole IF it is indeed the tapered seal that is allowing fluid to pass.
Click to expand...
That's a good point. I think the slight weep isn't enough to make it through the central bleed hole (forgive the technical jargon...) and have assumed, possibly stupidly, that the fluid is drawing up through the thread by capillary attraction.

I'm also going to try some brass bleed nipples, with the faint hope that the softer brass might deform to the seat better.

No idea if it's going to work, then probably the stahlbus route (my OCD will struggle a little with the aesthetics, but butter that than a single bleed, which is the much more expensive back stop)
 
Drill and ream a short piece of 6mm threaded rod down the centre to 3 or 4mm and screw it into the bleed bores. Run a 4mm end mill through the rod to the bottom of the bore by hand, a few twists and turns should remove enough alloy to form a sharp 90° edge at the bottom of the bleed exit. This will quickly form itself to an angled seal once the nipple is tightened into it.

No big deal if you have and can operate a lathe... or have a friend that could help out.

Guess much the same could be done with a rod turned to a point and used to re-grind the existing seat with grinding paste, but this is much more dependant on absolute concentricity.

piet
 
Thanks Piet

I have a m6 bolt with a 3mm hole down it, just ordered a 3mm end mill. To say this is beyond my skill set would show a mastery of understatement.

However, if all else fails...

How much aluminium is at the base of the bleed hole? I understand that I would need to do this by hand, just to get a feel for how close to utter failure I might be flying.

Thank you to all, I appreciate the help everyone has offered.
 
While obviously the taper needs to seal if you have a weep up your threads you can use a brake fluid compatible sealant.
Not many about, only 2 I could find are Permatex 54540 and I think Loctite 545. These sealers are formulated to not include anything that can get into and clog up the system which is one of the reasons tape is a no no.....................
 
Just spend a few hours disappearing down the rabbit hole of sealants. 54540 seems to be unobtanium in the UK, I have some 59214 and some loctite 545 (used on the rear diff on the car), so have some test threads as my appalling memory thinks it can be a bit powdery on disassembly, but we shall see.

Think I need to find a better seal first as that must be the root of the problem.

Also noticed the profile of the end of the bleed nipples is subtly different between the valve I have.

Going to wait until the selection of different sourced bleed nipples arrive see what differences there are and their effect.
 
Well, that was an eye opener...

My stupidity has found new depths, I made the really dumb assumption that all bleed nipples are created equally. Never come across this before in 45 years messing about with bikes.

My calipers don't leak and the threads are not that bad, depends which bleed nipple I put in. Having started after a major refresh, just assumed it was something I had done...

I've attached an image of the different bleeders, the width of them at the sealing end varies from 4.3mm to 4.8mm. The thread width ranges from 6mm to 5.72mm

Don't have the ability or equipment to measure the angle of the seal, but there are visual differences.

I think these have just exacerbated an undoubtedly ageing and worn caliper (as I'd not cone across this before)

Anyway, they seal and are leak free. No sealant required (the Loctite 545 on the test rig needed too much torque to break free for me to consider it for bleed nipples, the 59214 seemed ok, but didn't need it.

Sorry to have wasted everyone's time, but hopefully something the bear in mind?

Thank you again for all of your help.

Stephen

ps the brass nipples although in principle probably should have worked the best, shear way too easily. Ask me how I know...
 

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Don’t apologise, it’s an interesting thread (🤣)
I imagine there’s some standard that’s meant to be followed, but not all manufacturers are created equal
 
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