brake bleeding issues

[adyw]

Hi gents, can someone please help

so i've just replaced all brake discs and pads and last on the list is the fluid,

So got myself a little bleed kit which worked for getting all the old fluid out, but when it comes to putting new in i am having a nightmare.

Basically i am getting 80% fluid to air on the fronts and 10% fluid to air on the rears, when trying to pull it through with the vacuum pump.

So i've looked at the bleed nipples and even if i just loosen them by a quarter of a turn then are loose. So i though get some new ones. previous advice had said they are M10 x 1, 28mm long, I got a new set today, put them in the rear brake of the car, but no change, still loose the the pump is just pulling air from the bleed nipple thread and not the system.

There is fluid up to the nipples as i can see it ozze out when i change them.

Help.

if it was normal house hold plumping i would use PTFE tape, but not in this case.

Any suggestions or have i just got the wrong size bleed nipples.

[scottliv]

Hi I had a vacuum pump but it was no good. Had the same issue as you. Got a Gibson Easy bleed and was great. Start from furthest away from the servo and work towards it.

[TwinKam]

You have air creeping down the nipple thread.
Remove nipple, slather the thread with brake grease*, refit, bleed.
If you don't want to actually remove the nipple, just run a ring of it around where the nipple meets the caliper, it's a bit messier, but achieves the same end. You will see the airless result in your bleed tube when you've 'sealed' the air leak.

• Typically red, used when reassembling cylinders and calipers, important that it is 'compatible' with brake fluid, but equally important that it is sticky and viscous. I actually use a clear silicone grease, but I wouldn't be happy using a mineral based grease.

Edited by TwinKam on Saturday 23 April 21:15

[phillpot]

adyw said:

So got myself a little bleed kit which worked for getting all the old fluid out, but when it comes to putting new in i am having a nightmare.

Too late now but you should have pulled the new fluid through with the old, not drained the system

Hopefully greasing your nipples will get some vacuum going.

[Belle427]

The gunson eezie bleed is very helpful I find if your on your own, think Halfords sell them.
Never had much success with vac bleeders.

[phillpot]

Belle427 said:

The gunson eezie bleed is very helpful I find if your on your own, think Halfords sell them.
Never had much success with vac bleeders.

Yep, wouldn't be without mine, invaluable

[lesR]

You are using a vacuum to remove the fluid, so if there is any leak air will be drawn in via the nipple/pipe which is not a problem.

Using a vacuum to refill the line will also draw in air, as in draining but this time you can't tell if it is in the brake lines or coming from the nipple/pipe as they are located by the vacuum hose/pump.

If you use the pressure of the master cylinder via the peddle to push the fluid down the system any leak at the nipple area will only allow fluid to seep out so will not show air bubbles unless they are from inside the brake line and not the false air from the nipple area.

Have a look in the wedge pages to see the fun I am having with my 450SE.

[adyw]

thanks gents,

a bit of grease and all sorted on all 4 corners