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#1002666 - 12/23/17 03:59 PM Re: Bleeding front brakes - no joy! [Re: AndyS]  
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dirtrider Offline
The Oracle
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Morning Andy


NO, NO, NO. NEVER EVER DO THIS. That PTFE tape 'flows' when compressed and can find itself inside the break lines and work its way to critical components. Again NEVER do this.-- I guess I wouldn't say it quite this harshly but there is a lot of truth in not using PTFE tape for any hydraulics or fuel system thread sealing.

The company that I work for has banned all the PTFE type thread tapes in the shop areas due to possible contamination of hydraulic & fuel systems. We had a couple of vehicle fires (carburetor days) & some ABS failures due to the PTFE thread tape getting cut by the threads in a fitting then migrating down into the systems (this would be especially important on the top fittings on the BMW ABS-II modulator as the bleed fittings are directly on the top)


Originally Posted by Lowndes
To eliminate Eckhard's geysers, just drop a quarter (25 cent piece) in the reservoir.

Good idea. Just make sure it is clean and remove it after you have finished bleeding the system,
-- A standard quarter works good (especially if left in place) but personally I use a clean utility knife (carpet knife) blade as it fits the bottom of the reservoir perfectly & is MUCH easier to remove when full of fluid using a small pocket magnet or paper clip with end bent into a hook to go into one of the blade holes.


D.R. ___
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#1002667 - 12/23/17 04:22 PM Re: Bleeding front brakes - no joy! [Re: Ben There]  
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dirtrider Offline
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Originally Posted by Ben There
Haven't bled the ABS, so I'll look into doing that and try the other suggestions also. Thanks!


Morning Ben There

To eliminate the small air bubbles in the bleed fluid & to make bleeding easier just use an old water bottle or other container. Then run a hose in through the top & have the bottom of the hose end up (& stay below) the level of fluid in the bottle. (once you start bleeding then the fluid flowing into the bottle will have enough fluid level to cover the end of the hose).

The fluid in the bottle with the hose end being under the fluid acts as a check valve to keep the bleed hose full of clean fluid.

You can put the container on the floor but that will still allow air to be sucked it at the bleeder fitting threads due to hose siphoning effect (works great otherwise but you will still see the small evenly spaced air bubbles)

If you place the container just above the bleeder fitting height (but below fluid reservoir height) that will break the air-siphon effect so there will be no more air bubbles (no air entering at bleeder fitting threads) as the hose will remain full of fluid all the way back to the bleeder screw threads.

Once you get the fluid flowing by pumping the lever or brake pedal you don't even have to close the bleeder screw as the hose end being below fluid level will act just like a sort-of check valve & prevent much if any backflow. (so just pump the lever or pedal until the fluid runs clean with no air bubbles coming out of the hose under the fluid in the bottle)-- Just keep an eye on the fluid level in the reservoir so it doesn't run dry).

This methods works especially good on dry systems (mostly void of original fluid) as it allows moving massive slugs of fluid (line diameter size slugs) so it tends to push the air down & out which is something air in the fluid doesn't like to do (air likes to move up in the fluid not down) when pumping the lever then closing the bleeder fitting between pump strokes.

[Linked Image]


D.R. ___
Sent from my rotory dial wall phone!
#1002669 - 12/23/17 04:58 PM Re: Bleeding front brakes - no joy! [Re: Ben There]  
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Ben There Offline
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DR, et Al, thanks for all the suggestions! I'm on my way to trying them - after Xmas.

Thanks again.


T
'98 R1100 RT
'87 K100 LT (long gone)
'63 XLCH (long gone back in the days of wild youth)
#1002678 - 12/23/17 09:55 PM Re: Bleeding front brakes - no joy! [Re: Ben There]  
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eddd Offline
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Watching that stream of tiny bubbles, wondering if they will ever stop, can be annoying. A simple way to eliminate one source of the bubbles, without resorting to Teflon tape, for anyone bleeding brakes or clutches is to put a small gob of petroleum jelly or other grease where the bleeder screw mates with the caliper or slave cylinder. Spread it all around the bleeder to prevent air from entering via the bleeder screw's threads.

Of course you must maintain a tight seal between the tip of the bleeder and the hose attached to it to prevent air from entering at that junction, but the good thing here is that it is usually easy to know when air enters at this junction since it is generally because you moved the hose slightly allowing the air to slip by.


12 Kawasaki EX650
13 Yamaha XT250
16 KTM RC 390
96 R1100RT - forced retirement at 175,000

#1002679 - 12/23/17 10:04 PM Re: Bleeding front brakes - no joy! [Re: dirtrider]  
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Sam Taylor Online
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DR, brilliant observation about raising the fluid bottle above the caliper but below the reservoir. Thanks.


Sam
02r1150RT
Sonoma, CA
#1002686 - 12/24/17 02:45 PM Re: Bleeding front brakes - no joy! [Re: AndyS]  
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Lowndes Offline
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Originally Posted by AndyS
Originally Posted by Lowndes

Try using some white PVC plumbers tape on the bleed nipple threads to eliminate those bubbles and dripping DOT4. Sometimes requires 3-4 wraps.


NO, NO, NO. NEVER EVER DO THIS. That PTFE tape 'flows' when compressed and can find itself inside the break lines and work its way to critical components. Again NEVER do this.


Originally Posted by Lowndes
To eliminate Eckhard's geysers, just drop a quarter (25 cent piece) in the reservoir.

Good idea. Just make sure it is clean and remove it after you have finished bleeding the system,




AndyS,

"... white PVC plumbers tape...", i.e. the cheap stuff. PVC is different. Also, when the tape is applied to the threads of the bleeder it is not "in" the hydraulic system, nor is it part of the seal at the bleeder. Mine have been there more than a year now, same with the quarters, no problems. I found it a lot less messy to just leave them in.


Old Fart Newbie
#1002745 - 12/26/17 02:46 PM Re: Bleeding front brakes - no joy! [Re: Lowndes]  
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JamesW Offline
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Originally Posted by Lowndes
Been There,

To eliminate Eckhard's geysers, just drop a quarter (25 cent piece) in the reservoir. Works really well. Mine just stay there, front brake MC and hydraulic clutch MC.


Well aren't you just a genius! I never would have thought of that.


James
'93 R1100RSL / '10 FJR1300A
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