These freaking brakes

So after losing heart with this car for about a year I took today and tomorrow off to get it sorted.  Brakes are killing me. 

Mk2 master cylinder and servo conversion - both brought new 
Mk4 callipers both brought new
Removed regulators from rear lines which were by the bulkhead/servo - horrible job
Spent today bypassing the rear load sensor so not direct piped from master cylinder to each corner. 
Rear offside  to front (closest to slam panel) offside of the master cylinder
Front near side to the front near side of the master cylinder 
Rear near side to the rear near side of the master cylinder. 
Front off side to the rear offside of the master cylinder. 

Issue is the brake system is pressurising and binding on.  Only the rears is think are doing this not the fronts - although as I type this it could be the whole system.  

There is nothing left in the system to hold pressure so I am at a loss as to what the heck it could be. 

Anyone know if I am missing something.  

Need to get it sorted as want to sell it, but obviously not a great feature that you can o pay drive about 2 miles before you have to stop and bleak some pressure out of the system. 

Thanks for any wide heads out there. 

Quick following thought. I am going to check the from calipers in the morning and make sure they are not sizing a little.  Maybe they are binding on and causing an issue. But that still does not explain system pressure.  The rear brake light is sticking on when it happens. Meaning the master cylinder forwards is maintaining pressure.  

Also I have just jacked up the rear and pumped the brakes a few times and cannot get it to pressurise.  

Thought it may be a pinched flexi on the rear beam. Checked all clear.  Put back in the floor and now want pressurise while sat still.  Will take for a drive in the morning and see if it fixed itself.  Doubt it but one can hope

Have you removed, if you have them,  the hexagonal  thingies lower down under the master cylinder (one way valves i think)

Yes these are gone - the compensation valves.  

Hence the head scratching. 

Some Google search suggest 2 more things to check

Vacuum system on the new 9 inch servo is not effectively applying the breaks for me.  Would make sense that I see it when I drive but not when working on it.  


Second one is the servo rod is not well adjusted.  To be fair and from memory I just screwed this right in and bolted it on. Don't think there was any specific adjustment.  

Jobs for tomorrow before I have to work again 

servo rod adjustment could be it. i remember having to fiddle with mine a bit. not sure if it's the same for yours, but worth checking. good luck!

I do recall reading somewhere , when fitting the mk2 servo the rod should be cut down and there was a measurement which i dont remember…

This makes me both happy and sad. Happy I might be on the right path. Sad I have to now find out what I need to do and take the whole servo end apart again. 

Hopefully I shall get there. At least some new exhaust runners come today.  Surely I can't mess that up 😂

Work around actually worked.  Loosened off the servo with master cylinder and everything still attached. Only had to move the expansion tank out the way and add some water back in after.  

Put a nut on each thread as a spacer between that and the mounting bracket. 4 new nuts on the back to secure and has had the same effect as shortening the servo thread.  Just done a little 3 mile drive whilst waiting for new exhaust hangers and it parks up and roles freely. 

Thanks to all with little tips on this and other threads that just pointed me in the right direction a little. 

Also did a pre work test drive to makes sure the issue still existed.  Mess about half the distance and brakes came on. Instead of loosening the brake line this time I simply removed the vacuum hose.  Instantly the brakes released and we were rolling again. 

My logic is that the vacuum on the servo causes it to effectively brake a little a sort of pre loading and without enough play in the servo then the brakes are applied.  Why it does not reset when the engine is off I don't know maybe something to do with the valves and takes too much time.  Anyway what started out as a fuel tank change and then a beam refurb and then a disc conversion is finally finished after 2 years and a lot of time just not wanting to bother.  

You reminded me, was over 25 years ago,  thats what i did spaced the servo out..