2012 Rear Brakes Efficiency ABS version.

I'm having trouble getting my 2012 with ABS  through it's MOT. Failed at two different places on rear brake efficiency, although it feels fine on the road to me.

Lots of advice on here about non-ABS with brake bias valve, but can't find anything relevant for ABS cars.

Shoes and drums have about 10,000 miles on and look good. Pistons not seized. Shoes adjusted carefully and bled the fluid. Hand brake performance is fine.

It feels fine on the road, but the brake tester (at 3 different test stations!) say it's below required efficiency.

There's a "compensator valve" near the ABS in the parts drawing... but i don't understand what that's doing, given it's got ABS. Any info about that? (I've not noticed it before, and can't see the car because it's at the garage still. So I'm assuming that drawing is right!)

Any ideas welcome!

Have you checked the condition of the rear flexible pipe, it might not be obvious to an external visual examination but it could potentially be partially internally defective maybe? Otherwise what are the roller readings as I would expect 2 to 3 hundred kg force for the front and around a hundred on the back. Notwithstanding the 2 failed tests what about getting the tester to use a tapley[sp] meter the one they place in the passenger footwell instead of doing it on the rollers?

Thanks.
I've not seen the readings - I'll ask tomorrow.
Good idea to check the rear flexible hose - it does look good from the outside though.
I'm keen to understand what's wrong - but testing with a Tapley is a good last resort, although most places don't seem to have them anymore.

Quite a few places have Tapleys. If you tell them it is a 4x4 they won't roller test it for fear of breaking the transmission so they have to use a Tapley.

I don't think either of mine ever had a roller test, nor the Rangerover or the Rav4

One month before it is MOT-time I buy new shoes for the rear brakes so I have time to run them in and there is max thickness. Driving in sand alot they wear off fast.

Thouroughly clean the drums for any dust or dirt, and ever so often I try to buy the bracket kit for the drums with springs, or I select the best looking ones from my stock of used parts.

Been doing it like that since the SJ and have not had any problems passing MOT since.

Edit: cant remember ever having to change the drums.