S3 Binding brakes

Hi Guys

Looking for help on my binding brakes issue on my series 3. I believe i have changed just about everything likely to cause binding and they're still intermittently binding on. Its a single circuit with servo system 10" all round.

Changed:
Master cylinder
Servo
All cylinders on each wheel
All springs on shoes on each wheel
All shoes front and back
The three flexi hoses (two to front, one to rear)

Any ideas what else could cause it, crappy shoe lining maybe? clutching at straws a bit now and ready to rip it all off and put some later bits under her.

First things I would look at are return springs and adjuster. I take it they remain on when the pedal is released?

Yep, already done return springs and adjuster. They don't lock on but you can feel it dragging when driving and the offending wheel/s get warm on a local journey. It can be one on the back one day and a front on another.

I've also had it lock rolling backwards on a hill (usually first thing when driving off) but it drives off forwards ok leading me to think the trailing shoe is picking up in that instance. Its all a bit random making it difficult to pinpoint issue making me think as said, dodgy shoe lining grabbing intermittently???

Have you got about 1/16" (1.5mm) free play at the master cylinder push rod ? Take the six screws off the cover plate on the master cylinder/peddle box and check. Adjust using the two 1/2" a/f nuts.

That (master cylinder) was causing a problem and tbh i guessed the free play. I'll double check that tomorrow, cheers for the heads up. Just ruling one thing out at a time.

Have you chamfered the edges of the shoes top and bottom ie put a 45 deg angle on them.
Reversing if the edge of rear shoe is square allows brake drum to grab shoe and apply it , drove my landrover into garage after fiotting new shoes went back a week later to get it out and struggled to get it back out as brakes where self servoing onto drums.

that's why I like mintex shoes, they come ready chamfered

Yep chamfered them but the material didn't seem very hard which is why i'm thinking they make be inferior quality and grabbing

Ready chamfered maybe but adjuster pins have been falling out and the set I bought dusted up terribly.
I sent them back but give up on trying to get a report as too why they had failed will never buy Mintex again.
Also found the linings where bonded in the wrong position on the shoe compared tomy old set , if you still have the old ones compare the position of the lining.
Nickjaxe hjad similiar issue reckons to have cured it by filing the long edges to a slight chafer ie lining material was too wide.

The quality of the parts seems real hit n miss these days. More Miss than hit unfortunately!!

I have never had a problem with mintex shoes but then I did both series front and rear around the same time 2 years or so ago so my sample size may not be representative

if all above fails could you try driving with no servo assistance never herd of it befor could vavumn be leaking and appling small pressure on master cylinder

If vacuum fails it just makes brakes harder to apply.

one thing I had happen to a series 2a similar problem to yours tried every thing but eventuly it turned out to be a slightly ovel brake drum which seemed to pump up ressure