A second Norge question Bleeding brakes

[fotoguzzi]

Rear brake pedal has no pressure, the line must have drained. Service book does not say how to purge air if you have no pedal action. How is it done?

I have a new bleed nipple on the caliper but it doesn’t seem to close completely, I continue to see bubbles with the valve closed tight, any ideas?

[docc]

Wow, man, I am so not the guy to make suggestions on these CARC bikes, but . . .

How about wrapping the threads of the new bleeder with some (plumbing) Teflon tape/ thread sealer and hanging a weight on the foot lever overnight?

[fotoguzzi]

The foot lever goes to the floor so hanging weight on it won’t do anything.

[docc]

8 minutes ago, fotoguzzi said:

The foot lever goes to the floor so hanging weight on it won’t do anything.

I seem to recall expert advice that the fully engaged lever position opens the valve in the master cylinder and allows the air to escape overnight.  I have actually seen this (surprisingly) work on my buddy's 1200Sport.

Otherwise, I'm out of my paygrade here

[Twin AH]

Positive Pneumatic bleeder is what I use.

You can start off with zero in the reservoirs with these units I believe.

 

Ciao

[GuzziMoto]

What Twin AH said. A vacuum bleeder can work, and they are cheap and readily available. But a positive pressure bleeder works way better. A vacuum bleeder tends to suck air into the system. While a positive pressure bleeder will force brake fluid from the reservoir through the system and out the bleeder. Trying to bleed the brakes by pumping the brakes and opening and closing the bleeder is probably the least efficient way. And if you aren't pumping brake fluid in the master cylinder it won't work.

That said, if you suddenly lost brake pressure, something went wrong. Have you identified the issue? You may have a leak. That would explain where the pressure in the system went and why you have air bubbles when you try to bleed it. The system is pretty much a closed loop system. The fluid level in the system should only change as a result of pad wear, and that change should be small and gradual.

Does your Norge have ABS? Most do, I believe. That adds complexity to the brake system, and in some cases requires telling the ABS system that you are bleeding the brakes so it will hold its valves open. Once you get air in the ABS system it can be difficult to bleed the air out. But for sure a positive pressure bleeder would be a good start. Some are pneumatic, and some you have a pump to pressurize them. The pump up versions are fairly inexpensive. https://www.fcpeuro.com/products/power-brake-bleeder-motive-mot0100

An old trick in a pinch is to remove the brake caliper and force the pads back into the caliper while holding it so the brake line is at the top. That forces fluid (and air) backwards through the system to the master cylinder. You can then work the fluid back and forth using that method, ending up eventually with all the air out of the system.

[dbarb3]

Probably wont work here but maybe try gravity bleed, top up master cylinder crack open the bleed screwand see if it will drain on its own

[fotoguzzi]

Guzzi Moto, yes I have ABS. The bleed nipple was broken off (not by me) so that’s how it lost pressure, it sat for a long time like that.

the gravity bleed probably won’t work since the ABS pump is up under the seat so high above the res and caliper. The book doesn’t say how to  tell the ABS it’s being bled, I was hoping I don’t have to crack it open at the valve but may need that.

 

depending on several factors and my patience this bike may get parted out. Not in a hurry to do that.

[Randy]

https://www.motionpro.com/product/08-0143

[fotoguzzi]

Sorry but no. Did you read the copy?

• Will not bleed air from a dry system

[80CX100]

Being winter and you have time to play around, I'd let gravity & time work for you.

I'd bungee the lever down(per Docc's suggestion),fill up the reservoir,remove the caliper put it down low on the floor,open the bleeder,put tubing on the bleeder extending over the height of the reservoir.

Every now and then cycle the lever or move the caliper pads in & out, and tap along the reservoir/M/C/brake line/caliper to loosen any surface tension on bubbles blocking things.

When I had such a biatch of a time bleeding my new clutch line this year, it took me probably 3-4 wks of dicking around on and off like that before I got a good firm pull.

Once you get the air & fluid moving and the system filled up with fluid, it should start to firm up much quicker, at that point I'd move the caliper up higher for the final bleed.

fwiw

[PJPR01]

I have found using a speed bleeder on my Norge works wonders...much easier to use, it's like having a 3rd hand when bleeding.  Keep filling the reservoir, pump gently a few times, watch the fluid/bubbles move thru until all the bubbles are gone, and you're done!

[audiomick]

On 12/8/2022 at 2:10 AM, fotoguzzi said:

... no pedal action...

No one has mentioned it yet, so here I am: you mentioned in another post, that "it stood like that for a long time". So: don't discount the possibilty that the master cylinder might not be intact anymore. If it's not pumping, you'll never get a pressure point.

Regarding strapping up the lever overnight: I've had success with that on a Kawasaki GTR 1000. The magic is not only that the lever ist clamped "behind" the return hole. The pressure reduces the size of any air bubbles that might be in there, and thus they have a better chance of wandering upwards overnight and (hopefully) exiting the system. I.e. this really does work, when the problem is such that it can be addressed this way.

[fotoguzzi]

Thanks, I got busy on other stuff, the poor beast sits in the heated garage but it’s 11 below zero F outside so I’m not motivated to cross the yard and go out to work on it.. I need to get in the right frame of mind so I can spend some quality time with it soon.