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Model specific boards => Golf mk3 => Topic started by: MowatGTI on 21 November 2010, 19:08

Title: Bleeding Brakes
Post by: MowatGTI on 21 November 2010, 19:08

I've recently chanaged the following:

Rigid pipes to both rear brakes
Both front calipers
All pads front and back
All flexi hoses front and back

I'm now trying to bleed the brakes.

Bought a gunson eezi-bleeder and have bled them twice.

The pedal isn't as solid as I want tho.

Does it matter if the ignition is on when bleeding or not?

I found that I bled them and the pedal was solid, but i then turned on the igntion and it went soft again.

I'm sure I have no external leaks.

Not sure if i'm doing something wrong, or possibly my naster cylinder is goosed.

Any ideas?

Cheers

Title: Re: Bleeding Brakes
Post by: mar_k on 21 November 2010, 19:12

i have the engine running when i bleed my brakes,
i know some people wont agree with this method but i find its what works best for me.

you also need to start with the furthest wheel away from the master cyclinder

Title: Re: Bleeding Brakes
Post by: Wayne on 21 November 2010, 19:35

No need to have the engine running.

Title: Re: Bleeding Brakes
Post by: MowatGTI on 21 November 2010, 20:04

Yeah - i'm doing them in the correct order.

Can you have any possible explanations why is isn't as solid when the igntion is on?

Also, in the haynes book, it says never to touch the bleed point on the master cylinder, anyone know why?

Cheers

Title: Re: Bleeding Brakes
Post by: AudiA8Quattro on 21 November 2010, 22:27

The pedal will sink further when the engine is running because the servo is operating.
Has you car got a rear pressure regulator fitted? (pre-1995 only i think)
If one is fitted, clamp it before bleeding the rears.

Title: Re: Bleeding Brakes
Post by: MowatGTI on 22 November 2010, 18:17

Not sure mate - but it's a '94 16v.

Bled them AGAIN today using the two man method (with jar)

Again, no air coming out, but the fluid comes out at a hell of a slow rate.

Not sure if i need to keep bleeding them or if something else is goosed.

After i bled them, the pedal wasn't soft, but hardly solid.  I decided to take it off stands and see what it was like.

The brakes worked, but only just.  No way would i consider driving on the road with them.

Another thing i noticed.  I pumped the pedal as hard as it would go, then started the engine which caused the pedal to sink a bit more, this shows the servo is working correctly according to haynes anyway.

Not sure if my master cylinder is leaking internally or what.

Has anyone bled a master cylinder before?

Cheers

Title: Re: Bleeding Brakes
Post by: boneybradley on 22 November 2010, 19:36

well that will have the pressure regulator....and can be a swine to bleed (same rear callipers as the mk2 with the badly located bleed screws!! an easi bleed should sort them)

Title: Re: Bleeding Brakes
Post by: MowatGTI on 22 November 2010, 20:16

Ok cheers.

I did notice today that my two rear calipers aren't the same......

Tried the gunson easi-bleed the other day.

Will give it another crack.

I'm getting right pissed off now! 

Title: Re: Bleeding Brakes
Post by: AudiA8Quattro on 23 November 2010, 00:04

Clamp the rear pressure regulator, it sits by the rear axle.

Title: Re: Bleeding Brakes
Post by: javalin on 24 November 2010, 12:17

have you got ABS?

Title: Re: Bleeding Brakes
Post by: MowatGTI on 24 November 2010, 18:34

I sure do.

Why?  Please tell me you know something i don't!

Please!!!!!!

Title: Re: Bleeding Brakes
Post by: javalin on 24 November 2010, 20:28

if you've emptied, or induced air into the system - I believe you have to put the pump into "being bleed" mode.  You'll need VCDS (Vagcom) for that.

http://www.ross-tech.com/vag-com/cars/absbleeding.html (http://www.ross-tech.com/vag-com/cars/absbleeding.html)

James

Title: Re: Bleeding Brakes
Post by: MowatGTI on 24 November 2010, 22:36

Oooohhh - cheers.

Another thing i've realised is that because I've changed the pads and not the discs - a pad might be riding a groove on the disc and springing back on the piston.

Will check out both and post back when its sorted.

Cheers