Brake Bleed Fail

[coupe72001]

This is almost too embarrassing to admit to, but I have failed to bleed the brakes on a (rough) project car.

I replaced rear wheel cylinders, brake master cylinder, and front callipers with new items and filled master cylinder with brake fluid.

I cracked open the nipple on the furthest rear wheel, started pumping the brake pedal and... nothing.

I can't get the bloody brake fluid to travel down the brake lines to escape from the wheel cylinder nipple at the drum.

Worse, I actually have the same problem with the clutch. I have replaced clutch master and slave cylinders, and also the line between the two, and for the life of me I can't get the fluid to drain down the reservoir to the bleeding nipple. I can't even blame corrosion in the line - it's new from end to end!

Err... suggestions. Shame to have done all this work only to still not have brakes and clutch.

[Plattsy]

had the same problem on an old mini.....

had to start the engine.

then it worked!

[coupe72001]

That's just bizarre... but will give it a go for sure!

Cheers

[Plattsy]

That's just bizarre... but will give it a go for sure!

Cheers

yea my old man didnt have a clue why it wasnt working.... ran the engine for a few mins and boom here comes the flow!

[Daleo]

If it's all new; the master cylinders aren't primed, that's why you're not getting anything. Once you have fluid through the master; the system will pump fluid.

Sometimes you need to apply pressure (only a small amount) to the reservoir; or use a vacuum bleeder to draw fluid through.

[coupe72001]

Just ebayed vacuum bleeder. Never knew they existed, but now I have one in the post.

Out of interest, by applying pressure to the reservoir do you mean find something the same diameter as the inside of the reservoir and compress the brake fluid down the lines, like a syringe?

Also will see if I can get flow by running the car as an experiment.

[ARTZ]

Your meant to pump then crack the nipple, which lets air out then tighten nipple

pump,crack,close

pump,crack,close,

Continue till fluid comes through with no bubbles

dont crack the nipple then pump..your just sucking more air into the system..

[89CAL]

On top of that, its a 2 man job if you dont have the right tools.

One person has to sit in the car, pump the pedal then hold it down, the other person at this point cracks the bleed screw and then tightens it back up when nothing more comes out. Then the person in the car can release the pedal and start pumping again - repeat till no air comes out. And keep topping up brake fluid or youll just suck air back through

Clutch works the same, you will need to start at the master by the sounds of it though

[Duncan]

did the mini have vacuum boosted brakes? if so, starting the engine created vacuum that sucked fluid into the system enough to allow you to bleed it

[coupe72001]

I'm using a one man bleeder (hose with a ball valve in the end).

Normally I've got away with leaving the bleeder nipple open and just pumping away, but I suppose that is with some fluid already in the lines.

I guess for completely dry lines I'd have to use your method Artz.

If it stops raining for a bit Ill test some of the suggestions out!

[blind_elk]

It will work much better if you RTFM. Start by bleeding the master, then bleed each of the wheels, starting at the longest line in the system.

Duncan, you're having a lend of us, right?