Rear brake cylinder size

Evening all.

Back in 2019, I completely refurbished my rear brakes due to leaking cylinders, I changed everything for new using a kit from Heritage. It’s passed all mot tests since with no negative comments about the brakes, (same tester) this time round a different guy put it through the test, when he tested the rear brakes on the rollers they came up well short, he had to nip the handbrake a bit to get them to pass, he said they were only operating around 50%.

This got me thinking about the brake overall I did back in 2019, included in the kit from Heritage were a couple of new brake cylinders, these were the 14mm type.

My car is an 89 clipper, it has 2 brake pressure compensation valves screwed in to the master cylinder, but it doesn’t have a load compensator on the rear axle.

From my searching I’m now pretty convinced it should have the 17mm cylinders fitted, can anyone confirm this, also would the smaller cylinders account for the reduced braking pressure, seems like a lot for a few mm smaller cylinder.

Thanks in advance for any advice / info chaps.
 

I asked this question the other day on the MK1 faceache page for my '87 1.8 Carb Clipper which I think has the rear pressure valves under master cylinder/servo.

And the answer was 17.5mm slave cylinders.

Not sure how adjusting the hand brake would have helped unless it took up some of slack that the rears get when the self adjuster never self adjust?

Thanks for the reply, much appreciated.

The tester just pulled the handbrake a bit to test the efficiency of the shoes and drums while on the rollers, when I did that it passed the test just fine, this indicates the brakes are fine but the pressure from the pedal is the problem. I can lock the rears using just the handbrake.

I think I’m right in thinking the smaller brake cylinders are the issue, just not enough braking force, I know the rears don’t contribute a lot to the overall braking but I’d like it to be as good as it can be  

Cabriolets are not mk1 rabbits, or golfs IIRC @ 85 the Cabriolets used a different wheel cylinder looking at the werk 34 page they list different ones for the cabriolet vs the Golfs.

https://www.werk34.de/en/rear-wheel-cylinder-611.331.051-a.html
Product information

    fit for
    Golf MK1 GTI
    Golf MK1 Convertible (injector)
    Golf MK3 1.6 + 1.8

https://www.werk34.de/en/rear-wheel-cylinder-14.29mm-611.171.051-b.html

Product information

    suitable for
    Golf + Jetta 1.0-1.8 (also diesel) Bj. 2 / 74-7 / 88
    not GTI
    Golf I Cabrio (carburetor)
    Polo + Derby 0.9-1.3 yr. 8 / 74-2 / 85



The Proportional valves on the latter Cabriolets at least my 89, and 90's have the brake compensators on the master cylinder and not the rear axle.  My 81 Rabbit didn't have them on the Axle either it was attached to the right side inner fender well.

I have seen them on 84, and 84 Golfs, and IIRC I remember seeing one on a 82, 0r 83 Cabriolet.

Golf MC and the arrows were the proportional valves are located.