Motor Trike Rear additional brake caliper upgrade - what master cylinder to use?

I see from a few posts on here that folks have fitted additional rear brake calipers to their MT and prob a few other machines too!

So question is - what large rear master cylinder did you use? Obviouslt stock one will not work and you now have doube or more the piston volume to move?

Ours is a 08 Goldwing GL1800 and someone put VW Golf GTi rear calipers with hand/parking brake function then fitted and addition 2 x 4-pot calipers for good measure. Result = NO rear brake - piston bottom on in master cylinder before it can move enough fluid.

As a gues as the oem m/cyl is 11/16" / 17.5mm it needs to go up to either a 19mm or better still a 22mm bore cylinder - again preferabley another Nissin unit but strugling to find one.

Anyone help?

3/4 and 7/8 are popular and should be available

[COLOR=#000000][FONT=verdana]For reference, 19 mm=.748 or 3/4 of a inch and 22mm =.864 or 7/8 of a inch.

You may also try a residual check valve in line, unless you already have one[/FONT][/COLOR]

[QUOTE=Jack Klarich;892525]3/4 and 7/8 are popular and should be available

[COLOR=#000000][FONT=verdana]For reference, 19 mm=.748 or 3/4 of a inch and 22mm =.864 or 7/8 of a inch.

You may also try a residual check valve in line, unless you already have one[/FONT][/COLOR][/QUOTE]Sure did help my rear brake feel on our Lehman with drums. I used a 10 psi one because drums have return springs.