Upgraded to rear disc brakes ( from Blunt ) brakes will not bleed

[goodhobbes]

Upgraded to Rear discs bought from BluntTech. (I believe they are from a VW.?)  

Replaced master cylinder with a new one (Same type and size as original) .

However, the system does not pressurize enough and the pedal goes to the floor after bleeding as directed.

Removed the master cylinder and  blew out the lines to the rear , replaced master cylinder with the original, re-bled the brakes, and exactly the same thing happens.

It seems the front calipers will bleed well and I get a hint of pressure at the pedal when the fronts are being done, but absolutely no pressure generated when bleeding the rears.

My question is:  Do I need a larger master cylinder for use with the rear brake conversion?  OR what is going on and how can I address this.

Greatly appreciate any suggestions.

Thanks.  

[Simeon]

Some VW rear brake conversions need the calipers removed from the trailing arm to get the bleeder to point upwards. Bleed the brakes and then reinstall on the trailing arm. Is this one of those kits?

[jprocket]

You HAVE to dismount the rear caliper and make sure you tilt it downward to push out trapped air bubbles. When I mounted rear discs I left them on an they looked like there was no air when I was bleeding them - even with a pressure bleeder. 

[Son of Marty]

As Simeon said most VW kits I've seen need to be bleed with the caliper removed I'm not sure about blunts kit but if it uses the mk 2 or 3 caliper you'll need to remove it. I use a scrap of 1/2" plywood between the pads to hold the gap.

[goodhobbes]

Thanks you all!  I will try and turn the rear brake caliper upwards and try again.  

Regards.