Continual weep from nipple on FO8 calipers - what to do?

after reading this thread, what I took away is that the brake caliper bleeder holes have been buggered about with and are leaking.....

I am with Reggie. Forget all the clever bodges and replace the calipers, either with new F08's or better yet, four piston calipers, and move on to happily riding the bike. Throw on some better brake pads and braided steel lines "while you are at it"......

Paul LeClair
 
There are companies worldwide that specialise in 'bodging'.
They keep the wheels of industry turning.

Furmanite is a company that seals leaky flanges/pipes/valves while pressurised, freezes pipes to divert/stop flow ( or do a 'Stopple') and do on-site machining to fix things up.
So someone fucks something up and they trot along and fix it without shutting the plant down - accountants love them.
They have 75 offices on five continents and 1,600+ employees on all corners of the globe.

As for the calipers, with a bit or care and some skill they could be as good as new.
 
I am with PLC and Jock McJ here
attempt a repair? well maybe, because I am keen to mend where sensible, but a couple of days later, if I had any trouble or (with brakes) the slightest/tiniest doubt about safety, then I would definitely replace or even upgrade. Easily said because I am well known to stockpile when stuff is available as "useful spares" for later on. It's  shameful to admit but I have even broken a couple of triples that needed parts to repair them, which I had available (hanging head) such as a frame or engine rebuild, but that was when you could buy them for ?300!

In recent times this has definitely paid off and my shelves are getting more fresh air on them, all the Chott new old stock inventory is gone as is the Chott(s) , only two months ago I used for the first time a brand new old stock crank for TOG and two years ago a brand new old stock RGS head, it did pay to buy when possible 20 or even 40 years ago!

But for the calliper problem? get sorted with replace or upgrade and enjoy what's left of summer, you can always come back to the weepy calliper in the winter, when the pressure (pun unintentional) is gone.
CLEM
 
I too have just solved a weep from (what I thought was) the banjo on one of my front calipers. After replacing the copper washers three times and 4 brake bleeds..... the leak was actually from the banjo at the master cylinder, fluid was running down the hose overnight and the drip formed at the caliper banjo.
One of the disadvantages of clear coated braided lines ....... fluid running down the line is hard to see.
A trap for young players :-[
 
Vince said:
Your both the same age as me or near as damn, and you both probably did the big change over around 1st year at tech, 1975. I use a combination of both, still laugh at the 1st female apprentice I deal with asking all the old farts about what's a full 1/8 and whats a bear 1/8. Each was a pussy hair either side of a correct 1/8, simple as mud.

So did she supply the hair?  :o
 
Ha ha good to see that I put a cat amongst the pigeons excellent.

Understand Piet what you were saying I was just being exact and looked up the chart that the local tool supplier gave me for understanding drill sizing for taps...
as  funny thing on my FCR venture the throttle slide screws are 3.5mm ( who uses such a dumb size ) anywho was thinking 3mm would see me right but no went off to the local tool suppler and told him I needed to tap some 3.5mm threads so what size bit do you reckomend. I also told him that wanted to do some for 7mm. He comes back with a 2.9mm and a 6.1mm bits and a tap to drill size chart for me. ( they know I am a bit of a luddite when it comes to metric they even sold me some digital calipers to make life easier for me ) 

By the by grease a front end  who does that anymore ??? that went out with the arc me thinks you are flat out finding a grease gun these days in most of the dealers I visit. Not even the trucks ( Dodge Rams )  that we distribute have grease nipples in the front end anymore.



 
Brett said:
Ha ha good to see that I put a cat amongst the pigeons excellent.

Understand Piet what you were saying I was just being exact and looked up the chart that the local tool supplier gave me for understanding drill sizing for taps...
as  funny thing on my FCR venture the throttle slide screws are 3.5mm ( who uses such a dumb size ) anywho was thinking 3mm would see me right but no went off to the local tool suppler and told him I needed to tap some 3.5mm threads so what size bit do you reckomend. I also told him that wanted to do some for 7mm. He comes back with a 2.9mm and a 6.1mm bits and a tap to drill size chart for me. ( they know I am a bit of a luddite when it comes to metric they even sold me some digital calipers to make life easier for me ) 

Dellorto uses the same dumb size for the countersunk screws for the choke cable perches on VHB and PHF/PHB carbs.  Probably on some others as well...

piet
 
Brett said:
Ha ha good to see that I put a cat amongst the pigeons excellent.

Understand Piet what you were saying I was just being exact and looked up the chart that the local tool supplier gave me for understanding drill sizing for taps...
as  funny thing on my FCR venture the throttle slide screws are 3.5mm ( who uses such a dumb size ) anywho was thinking 3mm would see me right but no went off to the local tool suppler and told him I needed to tap some 3.5mm threads so what size bit do you reckomend. I also told him that wanted to do some for 7mm. He comes back with a 2.9mm and a 6.1mm bits and a tap to drill size chart for me. ( they know I am a bit of a luddite when it comes to metric they even sold me some digital calipers to make life easier for me ) 

By the by grease a front end  who does that anymore ??? that went out with the arc me thinks you are flat out finding a grease gun these days in most of the dealers I visit. Not even the trucks ( Dodge Rams )  that we distribute have grease nipples in the front end anymore.

Hey Brett, you should let Brembo know that they are drilling their holes too small.
While you?re at it, perhaps you should also let these manufacturers of the finest high quality taps know that they also have it wrong.
https://www.dormerpramet.com/Downloads/2015_NAFTA_Dormer_Catalog-English.pdf  p270
http://www.goliath.com.au/Goliath%20Threading%20Chart%20A2.pdf 
http://www.suttontools.com/products/straight-flute-tap-sets-mc-t901/
At 6.1mm you have lost 10% of effective thread, add to that the fact that most external threads are undersize by 0.1mm to 0.2mm, you have now lost up to 30% effective thread on a 1mm pitch, if you consider that your caliper is made from soft anodised Aluminium that strips easily, then add to that 10,000psi hydraulics and brakes, a bleed screw that?s a millimetre undersize and you have a leak, a projectile and a time bomb ,how safe do you feel, multiple injuries or death and another Laverda gone.
Brembo use a 5.8mm tapping drill for M7 bleed screws to increase effective thread depth which is why you can screw an M6 bleed screw in but can?t stop it from weeping.
Try and put a 6.00mm drill into the hole, it won?t go unless it?s been in the hands of a mechanic. 
Put your old M7 bleed screws back in, put the rubber caps back on and ride it while you have the health to do so.
And remember for metric threads, to achieve 75% effective thread;
Od ? P = td, eg, M3.5-0.6=2.9
Jacko.
Brett, do you know what a sump plug is, or do you have to google it when you change the air cleaner.
6.10mm drills also cost much more than 6.00mm.
 
I want to keep the original F08 calipers on the bike, although the Brembo 30/34 four pots do look good.

After a bit searching (google images) and thinking about how to solve the problem I've found a possible solution:

Increase the diameter of the nipple hole by drilling out the thread altogether, re-tap the hole for a larger diameter (M10?) thread and insert a nipple bolt - similar to a banjo bolt but without the collar - into this bolt threads the nipple. The bolt is sealed against the caliper body by a copper washer or Dowty seal. No more leaking nipples, Tadah!
 
Laverdaton said:
I want to keep the original F08 calipers on the bike, although the Brembo 30/34 four pots do look good.

After a bit searching (google images) and thinking about how to solve the problem I've found a possible solution:

Increase the diameter of the nipple hole by drilling out the thread altogether, re-tap the hole for a larger diameter (M10?) thread and insert a nipple bolt - similar to a banjo bolt but without the collar - into this bolt threads the nipple. The bolt is sealed against the caliper body by a copper washer or Dowty seal. No more leaking nipples, Tadah!

Won't be easy if the calipers have 2 bleed screws, the bosses are a bit narrow for such a drastic "over-bore".  Probably be OK if they only have the single bleeder.

piet
 
Got a set of four pots sitting in the shed. I know this has been covered before but which M/C is the best to use? I prefer to have a solid feel at the lever without any 'sponginess'.
 
Reggie and I remain in agreement with the proper solution. If you do not want the four pots on your bike because you do not like to stop better, then the pair of brand new F08 calipers from  https://store.bevelheaven.com/Brake-Related-Parts/Brake-Caliper-Brembo-F08-Caliper-Pair/    is a smoking deal as they include all new parts including pins, rubber seals, piston, even brand new brake pads...... and this option would avoid the further bodging that seems to be in the works. No bodging with the brakes, bloody hell...........

can you imagine the bike being involved in a serious accident and the mechanical inspector and the lawyers finding out the brake calipers have been bodged, things would get very ugly very quickly.....

Paul LeClair
 
Paul LeClair said:
Reggie and I remain in agreement with the proper solution. If you do not want the four pots on your bike because you do not like to stop better, then the pair of brand new F08 calipers from  https://store.bevelheaven.com/Brake-Related-Parts/Brake-Caliper-Brembo-F08-Caliper-Pair/    is a smoking deal as they include all new parts including pins, rubber seals, piston, even brand new brake pads...... and this option would avoid the further bodging that seems to be in the works. No bodging with the brakes, bloody hell...........

can you imagine the bike being involved in a serious accident and the mechanical inspector and the lawyers finding out the brake calipers have been bodged, things would get very ugly very quickly.....

Paul LeClair

Sorry Paul and Reggie, these calipers are NOT the universal-fix-it-all option. 

They will only fit Laverda Marzocchi forks correctly.  I have found them fitted to Cerianis with a bolt and nut, but upon close inspection, fitment is very often crooked... 

The problem lies with the machined surfaces.  The Marzocchi forks carry threaded bosses upon which the calipers are bolted, the bearing surfaces of the caliper are machined flat and square.  The Ceriani forks have bored bosses, and the calipers fit "behind" these bosses.  The surfaces of the caliper that mate to the forks are un-machined and quite often not even top and bottom.  Result is a caliper not square and true to the disc.  Very often difficult to centre them properly over the discs as well.

I'm no fan of bodged brakes, but a properly repaired bleed screw should not cause any safety-related issues.  Even if a slight leak should develope, it will not allow a sudden total loss of braking pressure.  Besides, we all inspect our bikes closely before disembarking on a thrash through the woods, a leak would come to our attention imediately...  ::) ::) ::)

piet
 
sfcpiet said:
Sorry Paul and Reggie, these calipers are NOT the universal-fix-it-all option. 

They will only fit Laverda Marzocchi forks correctly.  I have found them fitted to Cerianis with a bolt and nut, but upon close inspection, fitment is very often crooked... 

The problem lies with the machined surfaces.  The Marzocchi forks carry threaded bosses upon which the calipers are bolted, the bearing surfaces of the caliper are machined flat and square.  The Ceriani forks have bored bosses, and the calipers fit "behind" these bosses.  The surfaces of the caliper that mate to the forks are un-machined and quite often not even top and bottom.  Result is a caliper not square and true to the disc.  Very often difficult to centre them properly over the discs as well.

I'm no fan of bodged brakes, but a properly repaired bleed screw should not cause any safety-related issues.  Even if a slight leak should develope, it will not allow a sudden total loss of braking pressure.  Besides, we all inspect our bikes closely before disembarking on a thrash through the woods, a leak would come to our attention imediately...  ::) ::) ::)

piet

Hi Piet

now for me to take the other side of the discussion. Buy the new calipers, then take a file and "true" up the caliper mounting surfaces, as a bodge has to be better than weepy nipples, right.......... ;)

Paul LeClair
 
Did look to see what forks OP has, wasn't sure about Ceriani fitment so fair point Piet. 

Got a set of four pots sitting in the shed. I know this has been covered before but which M/C is the best to use? I prefer to have a solid feel at the lever without any 'sponginess'.

Just use the standard master- works well- fit EBC Carbon Kevlar pads with the o/e discs.  My Firestorm one would be too squidgy I suspect, but it gives more power and feel again.  4 pots BIG improvent in feel even if you change nothing else.

 
I remember buying new calipers , and finding that the depth of the screw in from the lines was shallower than the screw on the end of the lines , steel braided which I had fitted previously.is there a standard depth to look for/ request on lines?
 
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