10 replies to this topic

[mini-mad-mark]

Hi All,

My rear brakes are "advised" every year at MoT as being not quite as good as they might

 

Car is a 1980 Mini City E but upgraded to Cooper S discs with Mk 3 style servo (actually Hillman Hunter) and Minifin rear drums.

 

I read in one of the mags that I should use GWC1102 (0.75" bore) and a manual regulator rather than a spring self setting version.

 

Handbrake is fine so no issue with pads or the actual mechanical parts seem OK

 

I have tried opening up the valve to allow more pressure but that doesn't seem to do much

 

What is the standard Cooper S size as it seems that would be better to start? unless anyone else can offer any ideas

 

Cheers, Mark

[Spider]

The Cooper S had 5/8" wheel cylinders,,,,

 

However,,,,,

 

What sort of Master Cylinder do you have?

 

If it's  a 'Yellow Tag', then 11/16" would be more appropriate.

 

Get the cylinder size right first before looking to the pressure valve.

 

Beware of having too much rear braking.

[Homersimpson]

How have you plumbed in the servo? A 1980 mini would have dual circuit brakes but if you have added a separate servo you may have only added servo assistance to the front brakes.

 

I did this once on a kitcar as a temporary measure to get it through its MOT until the disc and pads cleaned up, it was interesting to drive to say the least!

[absx2]

 

 

Beware of having too much rear braking.

 

Very wise words as usual Moke Spider.

 

The car will quickly swop ends in an emergency situation with too much rear bias.

 

This is the bit where I get hung but I can get the rear wheels to turn with my hands on most minis with the bakes full on. Its a bit of a struggle and I am strong but it goes to show the rear brakes don`t do a lot and if they did in our lovely british climate it wouldn't take long to have a brown trouser moment.

[timmy850]

There is a good list here of all the factory fitted brake combinations:

http://www.minispare...rt.aspx?1~9~105

[mini-mad-mark]

Thanks all,

 

Sorry not enough info from me now I have read my original post again

 

I converted to S discs WITH a single line brake setup master cylinder std 0.70" bore (think they were all the same master cylinder bore between std and S just larger capacity for S?) - and yes I understand about changing the safety aspect of dual circuit and insurance ramifications etc

 

Servo is plumbed to work all brakes therefore

 

Any further thoughts - I too do not want too much at the rear but I get earache each MoT (although I am on good terms and explain this so I get a pass)

 

 

In two years I wont need to worry if I have got any brakes at all, once it becomes MoT exempt.........

[cal844]

My advice is to ditch the servo and also match the cylinders

[gav]

GWC1101 is factory size, 0.625" bore.

[Swift_General]

What rear wheel cylinders do you have at the moment? Do you habe a limiter valve on the rear?

Edited by Swift_General, 02 October 2017 - 04:58 PM.

[mini-mad-mark]

Hi All,

My rear brakes are "advised" every year at MoT as being not quite as good as they might

 

Car is a 1980 Mini City E but upgraded to Cooper S discs with Mk 3 style servo (actually Hillman Hunter) and Minifin rear drums.

 

I read in one of the mags that I should use GWC1102 (0.75" bore) and a manual regulator rather than a spring self setting version.

 

Handbrake is fine so no issue with pads or the actual mechanical parts seem OK

 

I have tried opening up the valve to allow more pressure but that doesn't seem to do much

 

What is the standard Cooper S size as it seems that would be better to start? unless anyone else can offer any ideas

 

Cheers, Mark

[mini-mad-mark]

Thanks for the advice all  - will probably try the GWC1129 (11/16") first but will not be for a while - got to rebuild the engine for the other mini and get that back mobile again - will post the results when I do see what happens though

 

Cheers