Brakes Bleeding issue, HELP?!

[scratchfree]

Hello,

Ive recently refurbed my front brakes and rear.. Heres a list of new bits and original bits.

New: Pads, Shoes, Spring Kit, Rear Cylinders, Hoses, Rotors

Original: Drum & callipers (refurbed) , servo & fluid bottle as they were.


Now im trying to push out the pistons which are currently 50% out but now a bit stuck..

I have filled the bottle to full mark and i am depressing the pedal with all bleed nipples closed to fill the pipes and push out the pistons, but all i get is a hissing noise which is guess is part of the vacuum network..

I open a bleed valve to check fluid is circulating but nothing comes out...


Help would be much appreciated..

Model is Scirocco GT11 1.6 1986
James

[scratchfree]

Just a little update, just been out and pushed the pistons back in with a G Clamp, they moved in nice and freely smooth as butter, and it pushed fluid back thru the lines as the level changed in the reservoir. But when i depress the pedal they don't move back out!! Hmmmm


James

[Old Mac Rocco]

Should you not do each individual wheel with the bleed nipple open to ensure you have fluid all the way through ???
As far as I know any airlocks have to be pushed through the system til all air is expelled.
Recommended system for bleeding brakes is 1 - RH rear 2 - LH rear 3 - RH front 4 - LH front, No 4 being the one nearest the master cylinder.
Not sure where the hissing noise could be coming from ?????

[scratchfree]

Thanks ill try that technique, it does say that in my Haynes book but I thought depressing lever would fill pipes and just push out the piston... The hissing must be either noise from open reservoir cap or the vacuum. Zero leaks have appeared after 48hrs and numerous pumps of the pedal!


What i will do now then is the proper technique of bleeding brakes with help of a pal, then once all bled see if pistons push out!

[scratchfree]

Heres a link to the video of the brake noise!

http://www.youtube.com/watch?v=mQaty3dvkFg

[scratchfree]

Noise has been tracked down to a vacuum pipe coming off the Carb.. so that has been sealed with a bung, pedal feels more firmer now but still no fluid to pass whilst trying to bleed the rear o/s drum. Pistons still not moving when pedal depressed...


Hmmmm

[dozzum]

You need to bleed one wheel at a tine in the order as described.

Put some clear tubing over the bleed nipple, keep it closed for now get someone to pump the brake three times then press and hold it. While they hold it down you open the bleed nipple, make sure they hold the pedal down until you close the nipple again. Repeat this process until no more air bubbles then move onto the next wheel.

You say your pumping out the pistons? I assume your doing this with the calliper in place over the disk with pads fitted otherwise I have horrible images of pistons going everywhere...

[mark1gls]

I found when I bleed my brakes for the first time after the restoration I had to bleed and bleed and bleed them. I started at the master cyinder, undoing the pipe a little, then someone pressed the pedal, do up the nut etc till fluid coming out there then I moved to the wheel cyinder at the end of the pipe Id just blead, did this to all four then I started to get some brakes.

[scratchfree]

I am trying to push the pistons out so i can fit the dust seal, stupidly when i got the caliper back from painters i fitted the inner oil seal then placed the pistons in to check for smoothness, little did i know they would never come back out... so im having to put the pistons back on the lines pump the pedal to push the piston out...

But this is the problem im not having any movement or fluid flow from the pedal actuation..

[scratchfree]

Bleed the master cylinder ? explain ?

[mark1gls]

There is 4 brake pipes coming out of it which are fitted with nuts, go to the brake line which goes to the rear drivers side then losen the nut then get someone to press the brake pedal and hold it down so the fluid comes out, do up the nut then they release the pedal. Same as bleeding the wheel cyinders and calipers but you don't have a bleed nipple to let the fluid out, the fluid from the master cyinder will spray out around the nut/joint so use a cloth to catch this.
Bleed the rear drivers side wheel cyinder, go back to the master cyinder and work on the rear passengers side and so on.....
Doing this you know fluid is being pushed out of the master cyinder and there is no problems with it.

I found there is alot of air and and it takes longer than you think to bleed the system if it has been all taken apart, as mentioned get a clear hose on the bleed nipples by the wheel cyinder and calipers and look out for air bubbles, this also stops brake fluid going over the newly paint calipers etc as you can direct it in a container.

[dozzum]

Take the caliper off completely and use a compressed airline to blow it out, put some old rag there to catch it so you dont damage it

[Nate]

Take the caliper off completely and use a compressed airline to blow it out, put some old rag there to catch it so you dont damage it

correct. this is the best way to do it

as for bleeding the system, safest way to avoid damaging anything (like inverting the seals in the master cylinder) is to go round the bleed nipples one at a time with a vacuum bleeder (they can be bought for little money, and you don't need a helper then) or leave the nipples open for a few hours with something under them to catch the drips, regularly checking the fluid level.

[scratchfree]

Regarding the airline trick, i only have a car tyre attachment, do I need a different kind and do I connect to bleed valve or remove the hose and blow thru there ?

[dozzum]

Have you got a proper compressor or are you talking about an electric tyre inflator?

If its a proper airline then yes just remove the hose and blast the air in there. See video below but make sure you have some cushioning for the piston, if your careful it shoudnt come out as fast as that anyway.

http://www.youtube.com/watch?v=oN0zCcRgSxQ

If its not then it can be done with an electric tyre inflator but you will need to make a seal and build the pressure up using a bit of old flexi hose or something like that.

See this video for example, I've done exactly this with a footpump before.

http://www.youtube.com/watch?v=1jp2OCidBV4