after speaking with others and doing more reading, id like to quote bigruss (hope you dont mind russ if your reading this
"Today I've been fitting new calipers to improve the brake performance of the front brakes, one of them was sticking slightly.
Hoses clamped off and calipers changed with no problems
Time to bleed the brakes and thought I'd do it properly on the T4, the sequence is as follows:
Select brake to be bled on screen menu after fitting bleed tube to bleed nipple.
Open bleed nipple and depress pedal to expell air until it runs clear ensuring resevoir is topped up.
Next press continue on the T4 menu to bleed the secondary circuit with the ABS pump until clear.
Finally tighten bleed nipple while pedal is depressed.
All was going well until it came to bleed the secondary circuit........... Absolutely full of air
Took a total of 4 bleed sequences on each side to get it free of air and 1/2 litre of fluid.
The pedal is now solid when depressed.
The problem for members is that normal bleeding or pressure bleed kits only bleed the primary circuit, in order to bleed the secondary circuit you will need to use suitable diagnostic equipment capable of using the ABS pump to bleed it properly.
I wonder if this is why some owners suffer from sinking pedal syndrome.
Russ"
after flushing the old "tea/coffee" coloured fluid out yesterday and appearing to successfully bleed each corner using the correct sequence. i can confirm the following:
Engine OFF:
brake pedal goes down slightly (servo air wushing noise can be heard) had this on all the 75s ive had.
press the brake pedal 3-4 times and leave overnight, the brake pedal is still rock hard. start the car with your foot on the brake and the pedal does sink by around 3 inches and then stops. - it doesn't sink any further. no where near the carpet. (i have experienced this on other cars too. engine off- pump pedal - now rock hard at the top, foot on brake, start engine, pedal falls away slightly and then stops and doesnt sink any further.
driving - abs works and stops the car in a straight line.
placing your foot on the pedal, slight pressure (taking up the spring on the back of the brake pedal) now pressing beyond this and the brakes begin to act - brakes acting right at the very top of the pedal travel. applying a little more pressure and the pedal does require more force but the brakes slow the car quicker.
i know this is simply repeating my original comments however as bigruss stated in his thread about bleeding the secondary and having a much firmer brake pedal, im just wondering if this is what i am experiencing as i cant imagine my brake pedal being much firmer so not sure if im just experiencing new brakes and panicking for nothing?
perhaps the best thing i could do is have a t4 carried out just be on the safe side?)
is toaf able to perform the abs bleed?
also checked the servo and vacuum hoses and the small fabric covered hose that runs to the egr (mine bypassed) and all is well thankfully.
previously the brakes were softer/supple but the discs were badly warped. new brakes - harder pedal, less of the supple feel through the pedal