We might as well get all the cans of worms out in one hit.. welcome to another one. Again, there are numerous options, and everyone will tell you something different if you ask them, so here are my thoughts on the subject.
Option 1: Refurbish existing calipers with new standard discs on the front and replace drums and standard cylinders with new units in the rear
Option 2: Fit 4-pot calipers with new standard discs on the front and replace drums and standard cylinders with new units in the rear
Option 3: Fit 4-pot calipers with new vented discs on the front and replace drums and standard cylinders with new units in the rear
Option 4: Fit 4-pot calipers with new vented or standard discs on both the front and the rear
There are a plethora of other optional variations on the above, but this was my shortlist.
Option 1: This was my starting point, but found the car didn't pull up on standard brakes that well. Now you could blame this on old brake fluid, lack of correct adjustment, needing new pads and a whole host of other things I'm sure, but psychologically, for me, they didn't work as well as I would have liked. Add to this that I would like to take the car over to Europe (think Alps), I'm sure everyone would agree that the 'standard' brakes might struggle a bit when they are faced with those conditions… I therefore ruled out this option.
Option 2: My chosen option… basically because I'd ruled out all the others for various reasons which have been explained.
Option 3: I wanted to keep the standard steel wheels… I like them, and they look 'right' on the car in my opinion. Vented discs are wider than the standard ones though, so I would either have to go for a different wheel, or fit wheel spacers. Having had wheel spacers before and messing about lining them up on a roadside when swapping to a spare in the pouring rain, I decided it wasn't an experience I wanted to revisit in a hurry… I therefore ruled out this option too.
Option 4: I suspected that this option would probably lock all four wheels almost instantaneously.Without ABS, this would leave me with the old method of cadence braking, which although possible, I am well out of practice with and would almost certainly forget to do naturally in an emergency situation… I therefore ruled out this option too.
Option 2 it is then… so after doing more research on the few options out there for 4-pot calipers, I went with BCC brakes in Redruth (https://britishclassiccarparts.com/). You can buy them direct, or through the usual outlets, but they are at the big shows selling direct, and offer good discounts, so it's worth going down that route if you can wait.
Now on to the choice of discs and pads. This was far easier and there are less options out there once you've picked your choice of caliper. As far as discs go… your choice at the moment seems to be the standard solid discs, as available from most of the usual outlets, or EBC. I explored so many avenues and kept coming back to these two options. Brembo used to do some discs for the TR6, but these now seem to be discontinued. I ended up going for the EBC Turbo Grooved GD199 discs.
As far as pads go, if you opt for the BCC calipers, they fit a standard pad from the following, all of which are the same pad:
Vauxhall Astra MKII Hatchback (1979-86)
Vauxhall Astra Belmont MKII Hatchback (1985-91)
Vauxhall Cavalier MKII Saloon (1981-88)
Vauxhall Carlton MKII Saloon (1982-86)
The pad specification is 100mm x 59mm x 15mm and the EBC Ultimax pads recommended for them is the DP325. Now, being the person that I am, I ended up going for the Ferodo DS Performance pads (part number FDS173), just to be different (I also happen to be a big fan of Brembo and Ferodo brakes too).
Add to the above a new brake master cylinder and servo (I found new original stock ones), Goodridge braided brake hoses, new copper brake lines (I nearly went cupro-nickel, but I understand these can be more tricky to get the flared ends right and I didn't want any leaks), and silicon brake fluid (again, another contentious point but I'm obviously not a good enough driver to feel the 'sponginess' in the pedal attributed to this fluid) and you have, in my opinion, a very well balanced and effective braking system for the road.
I had to wait for the EBC brake discs as they were swapping from the 'old' style to the new ones and I wanted the new ones, so we put some standard discs on just as a temporary measure
Now what they look like with the EBC discs fitted
Rear brakes before drum fitting
Front brakes from the inside