Minimal Pedal after complete rebuild

[quickro]

This car is the absolute bane of my life, bought to tinker with and has been one nightmare after another although they are all sorted except the brakes.
I have stripped and replaced with new parts the entire system with the exception of the following hardlines - BMC to front flexi and the BMC to the first joint above the front chassis Y.
i have the classic symptom of a pedal which appears to do nothing until the last portion of its stroke.

The car is on blocks level with all four wheels off.
I cant find my eze bleed so have been getting my son to UP/Down.
I leave a ring spanner on each nipple with a 3 foot long clear silicon pipe attached which is held up above the height of the reservoir.
On the first bleed, starting at the back left i got plenty of air from all corners and then solid fluid with not trace of any air.
With pads in I can see ~1mm of movement at the pads on all corners
No braking until the bottom of the stroke but drag on each corner from half way
After the first bleed i thought BMC must have gone so replaced that (LM50014 NOS still in a sealed bag) i know and have checked the displacement calcs kindly sorted by DaPinky so i'm not worried about this ATM and the feel after swapping was exactly the same as before and the old BMC seals are perfectly fine.
Rebleed including from both sides of each proportioning valve as these were stripped ( internals where fine just claggy old fluid). Still the same pedal feel.

Rears
New seals, no fluid under the blue cap
Checked HB cable action pulls and returns the arms back to the stops
HB action 5 clicks one side and 6 on the other - I could try and even this up but would normally want to bed the brakes in first
With no pads in both HB push out and retract ~1mm using the foot brake.
Using the HB arm the pistons come out 5-10mm. These have then been returned by screwing back in and then pressed back out numerous times - happy the mech is working fine.
Sliders are fine and calliper moves freely back and forth

Fronts
All new seals
With no pads in both HB push out about 5-10mm and retract ~1mm using the foot brake.
Using a pry bar to return the piston a few times to displace an trapped air.
Sliders are fine and calliper moves freely back and forth

People say these can a be nightmare to bleed but im lost at the moment the only odd things is as pictured the brake rod to servo appears to have ~ 10mm free play at the rod which is a fair bit of travel.

HELP and sorry for the disjointed ramblings i'm not a big poster

[Tuga2112]

At the rear calipers, did you tilt the caliper while bleeding them?

They have a little air pocket if you don't do that, it's small enough to let some cars pass the MOT, but the difference at the pedal feel is noticeable

[quickro]

Each time i have bleed the system it has been with the callipers in situ. I will try the rears off the carriers tonight. Just very surprised this setup seems to be such a pain.

Last car i did was my Avantime where i had to use Renault software to bleed the ABS, that was a breeze compared to this !

[Tuga2112]

You did say you are aware they can be a nightmare to bleed.

I think a detailed video on the process may be valuable...

[quickro]

From the amount of posts about this subject i get they are a pain. From the layout its a std. setup with nothing out of the ordinary beyond the proportioning valves where as most German / French cars where by this point using load valves same outcome different setup. so i dont get why it is such a nightmare i have worked on far more convoluted systems.

Any ideas about the servo / pedal free play ? That is far more of concern

[MPx]

We all differ on this, but I was amongst those who didn't like the pedal feel on the standard set up at all which led to a complete upgrade/replacement (HiSpec based). So you may not be able to get the feel you want even if they work perfectly adequately. However the new set up is no silver bullet as its also a pain to bleed. You need to ensure the bleed nipple you're working on is the highest point when doing the corner (so rear callipers off). The other issue can be the proportioning valves. The casings benefit from being tapped to dislodge bubbles. Doing all that on a pushed down pedal is asking a lot. Maybe worth finding your easibleed? Good luck...

[Tuga2112]

theres always a bit of movement, from your pictures i cant tell whats going on, reason why videos are more handy.

what i have noticed from experience is that you have a initial movement where the inner rod moves and theres practically no resistance, it is working and adding pressure, but you probably wont realise it.
when the outer cilinder starts moving you feel more resistance and as a placebo effect think thats when the brakes start working (not very noticeable at low speeds, but if your car is in the air and your spinning the wheels by hand, i assure you will notice).
when you feel hard resistance form the pedal, there will be more movement available, but at that point you will be effectively pushing very hard and get the real brake effort.

from my experience is almoust as if the brake booster runs out of effort before the full pedal travel ? i never really discussed it with anyone. just what comes to mind at this very moment... its just another topic to discuss at CC later this month with the other owners.

as i was writing MPX posted. so to note on top of he's mention.
one thing that i was told in the past. was to setup the bleeding pressure and start the flow and reach underneath and tap along the lines, specially the proportiioning valves. in order to try displace any air bubles that may be "clinging" to the walls

[Tuga2112]

also something i noticed, although nobody else has seemed to experience, is that the handbrake setup makes a difference. (in my opinon)

in my opinion, (and mind it may all be placebo) i believe if the handbrake is setup right, the rear pistons need to move less before contacting the disk. this "free of resistance" movement translates to more "pedal free movement" where the pressure goes to the back to make the pads sit where the front is already touching.. dont get me wrong. there is still pressure being added to the front. but the proportioning valves wont be doing adding much resistance 'yet'

truth is, i noticed a difference after spending a whole afternoon setting up the rear calipers. but as i said. may all be placebo.. who knows ?

and well.. setting up the handbrake is a bit of a faff because you can rotate a certain amount with the lever, but you may need to remove the whole thing, then reach the piston and rotate that 90 degrees inwards, to then rotate the screw using the level. untill the whole thing sits just about 2-3 ticks in the hanbrake before touching. hard to explain in writing, and in fact i needed 2 phone calls with Dave Pink while doing it untill it actually made sense and i got it right.

[quickro]

I will try and get a video tonight but hopefully the following will clear up the picture.
I have worked on plenty of brake systems and from my experience unless a measurement for free play is stated, it is feels free which would be less than 0.5mm free play making sure you have or haven't greased the ends again depending on what is stated. The manual says free play but i have +5mm closer to 8/10mm which seems excessive. Also the interface looks like degraded plastic does anyone have any pictures of the open end of the servo showing this point ?

Picture 2
On the left the pedal is in its natural free position, "up" or the "top of its travel".
On the right the pedal has been pushed down until it has just made contact with the servo any further movement and the servo will move.
At the servo end this movement is in the region of 5-8mm where as i would expect this to be ~0.5mm

[Tuga2112]

are you on the facebook group ? let me know when your there and ill post a couple of pictures of my NA as it stands in the garage right now

[quickro]

So to round up. With the car on blocks level all wheels off clear silicon hose on each bleed nipple.

Rear
Loosened the top bolt , removed the bottom, then rotated the calliper till the nipple was uppermost tapped the body and bleed - no bubbles
Handbrake good and solid both sides

Fronts
Took them off the hub tapped them and bleed them - no bubbles

No difference to the pedal feel.

Loosened the servo rod and removed the free play so there was just perceptible free play and confirmed the servo was not acting when the pedal was up.
I now have a perfectly normal pedal. Took it for a 5 minutes spin ( on my private race track as it is SORN) and managed to get some bedding in, enough to knock of the high spots and get some pad on the rotors.
Handbrake has come down a notch on each side and im happy it will balance out with some use and minor adjustment
In for an MOT on Monday and then its for sale.

[Tuga2112]

Loosened the servo rod and removed the free play so there was just perceptible free play and confirmed the servo was not acting when the pedal was up.

have someone confirm if the brake light is operating as intended.

also. id be interested on a quick description of that task. because im willing to try that