Hi All,
Can you please help or offer advise… I am currently pulling my hair out!!!

I sadly bought the EMPI rear disc package form Classic as they were $400 inclusive and gave me my desired 5x130 stud pattern, But have not come close to properly working brakes no matter what I have tried!!!
I have bought 4x hose clamps (ones that allow you to block off the flexible brake hoses in situ. they gently but firmly squeeze the hose to stop any fluid going any further.) I bought these because I have not had any luck getting rid of my massively spongy pedal. I followed the following steps.

1. Clamp off all lines to test the Master Cylinder
RESULT: hard and solid brake pedal they way it should feel. So now I am fairly convinced the master cylinder has good pressure.
2. Undo one line at a time and bleed again.
RESULT: All bleeding well.
3. Next, undo two front lines pedal still hard and high. Great
4. Put front clamps back on and undo rear clamps … spongy pedal…!>!!!F@#&
I am sure that I have all the air out BUT decide to pull rear left caliper apart and check. All looks good, pull piston out and check all good. Bleed once more with piston and bleed nipple held high to ensure no cavities or air pockets. Accidently push piston out while bleeding and have to start again!!!

BUT this is where it gets interesting. I wedge a piece of timber into the exposed caliper to stop the piston moving (simulating the caliper in place pushing on the pads.) and once bled again held high to ensure all air is pushed through, I test before refitting the caliper and the pedal is hard and high. I start thinking, finally I have solved the problem. At this stage the sliding part of the caliper is still on the rear arm assembly and piston part of caliper is loose (off car but attached to brake line)

BUT when it goes back together nothing has changed and there is too much spongy pedal. (I think most of the flex is related to the sliding mechanism)

From what I can see it looks like the EMPI caliper is flexing and that is what I am feeling through the spongy pedal. Can you help???

I AM ABOUT TO CHUCK THE CRAPY CALIPER IN THE BIN! or DO I TRY A BIGGER M/C???
If I throw t in the bin, I will lathe down the existing hub and fit a ford hub over the top and an EA FALCON caliper like others have done. Is that my only option? The mounting thickness of the EMPI hub is 18mm.

Thanks. If you have read this much, Sorry for the 20mins you just lost

Aaron

What happens if you place the caliper on the disc but don't bolt it on. I'm thinking the caliper bracket may not be true, giving the flexing you describe. This will push the pistons back further than neccessary when pressure is released.
Cheers Dave

that's what I thought initally. I had to space the caliper evenly over the disc but not the is zero movement at the mounting plate

Dave's idea sounds very feasable, otherwise diagnosing as you have done is the go. The next test as you have been doing (blocking hoses etc.) is, whie still having the hoses blocked off, release one rear and clamp the piston movement of that (rear) caliper without fitting and check pedal. That will proove weather it's air or not. Do the test with both rears individually. If the low pedal is definately not caused by air in the system, the problem must be either mismatched piston diameter or I have seen comment on other forums regarding the need for residual pressure valves. Read this product description http://www.vwparts.net/MB16-3155.html  . I have just fitted a pair of 10lb valves with drum rears when I fitted my cutting brakes.

Have you changed to a dual circuit master cylinder? I use the same kit but switched to dual circuit and haven't had this problem. I've had most of the other problems thou! and they must be the worst calipers to bled ever made.

You are right! There should be zero movement at the caliper bracket. If the caliper bracket is not true the flexing is transfered to the caliper. That is why I suggested unbolting the caliper and test the pedal for movement/travel.
Drum brakes retain residual pressure in the lines which is overcome by the return springs. If you have residual pressure on a disc brake, the pads will drag. Cheers Dave

nothing like that empi quality

I will unbolt and give it a go

Search on Youtube " Empi Rear disc brake conversion" and see the horror stories and what is probabley happening with yours , then do your self a favour and through them in the bin and by a decent set from Vintage , problem solved