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M16 Brake Bleeding Quesion
mcg - 13/9/18 at 10:16 AM

Have bled them through a few times, then suddenly there is a rush of bubbles coming through. I have had a bit of a search and it seems that the bleed nipple could be letting air in.

It suggests adding some PTFE tape on the threads, or getting some new bleed nipples.

Anyone have any experience of this issue and solutions?

I guess i will need to bleed the whole system again if i have taken the bleed nipples out?

Many thanks

Matt

loggyboy - 13/9/18 at 10:20 AM

New nipples not PTFE.

nick205 - 13/9/18 at 11:36 AM

Replacing the bleed nipples seems a good move, but I'd not be happy introducing PTFE tape into the braking system. Whilst I don't know for sure I'd be concerned that brake fluid might eat away at PTFE and more concerned that particles of PTFE would get into the brake circuits and cause harm (worst case = loss of brakes).

[Edited on 13/9/18 by nick205]

daviep - 13/9/18 at 12:18 PM

Seems unlikely to me that you have a problem with bleed nipples, if the nipple is below the level of the master cylinder then a leak will cause the fluid to drain before any air enters the system.

1. Are all your bleed nipples at the top of the calipers??? It may be possible to fit the calipers to wrong side and end up with nipples at the bottom, often rear calipers must be fitted upside down due to clearance for handbrake cable.

2. How are you bleeding the brakes? Pumping the pedal only, pressure bleeder on master cylinder, vacuum bleeder connected to nipple? Pressure bleeder combined with pumping pedal is usually the most effective method.

Cheers
Davie

gremlin1234 - 13/9/18 at 01:15 PM

the threads of the bleed nipples do not seal, it is the conical end that does that.

mcg - 13/9/18 at 02:39 PM

Thanks for the replies..

Been mainly using the traditional 2 man method.

Nipples at the top of the caliper.

Nipple in relation to MC is 10cm higher.

Got some nipples coming tomorrow.

motorcycle_mayhem - 13/9/18 at 07:05 PM

Get thyself a pressure bleeding kit, or make a locost one from a small plant sprayer (plant as in green things).

You don't need a lot of pressure at all, just a few psi, slowly pushing the pedal while the fluid is pumping will really help.

It'll bleed 109 Series TLS brakes (where the bleed screw is on the bottom cylinder.... I kid you not) so it'll bleed a pair of MI6's

nick205 - 14/9/18 at 08:26 AM

quote:
Originally posted by motorcycle_mayhem
Get thyself a pressure bleeding kit, or make a locost one from a small plant sprayer (plant as in green things).

You don't need a lot of pressure at all, just a few psi, slowly pushing the pedal while the fluid is pumping will really help.

It'll bleed 109 Series TLS brakes (where the bleed screw is on the bottom cylinder.... I kid you not) so it'll bleed a pair of MI6's



Just bought myself a Gunson Ezibleed for carrying out the same task on a car. Not used one before, but they seem well rated and it didn't cost a lot either <£20.

rusty nuts - 14/9/18 at 12:16 PM

Just make sure when using an Easibleed you do not exceed 20 PSI , you will get leakage from the cap.