66 replies to this topic

[miniGTS]

Normally the bottom port is connected to the Fronts.

Cool, thanks

[Ethel]

The yellow band master connects the rear circuit to the bottom. As it uses different sized (metric) unions you're not likely to mix them up.

 

The lower bore, being bigger, generates less pressure relative to the pedal pressure. So that's an extra factor when matching wheel cylinders & limiting valves. An alternative is an inertia valve, which can be fine tuned by its mounting angle. Because of that it doesn't even need to be Mini specific, which might help sourcing spares given your location.

 

As Spider said the usual convention is to connect front to the bottom as it'll potentially be less likely to run low on fluid. The reservoir will have a divider anyway.

[miniGTS]

Thanks Ethel, I don't have the yellow tag one though. I have the older one that has the plastic switch screwed into the side.

[Ethel]

No worries,

 

I mentioned it as much for anyone who might stumble across this thread in the future 

[Spider]

No worries,

 

I mentioned it as much for anyone who might stumble across this thread in the future 

 

Yes, thanks.

When I posted the recommendation, I was aware that miniGTS is running a Black or Green band master. These are the same cylinder, the difference being the thread in the ports, the Black being 3/8" UNF and Green being M10 x 1.0.

With the Yellow band types, the rears are normally connected to the lower port.

[miniGTS]

I found a 2nd hand pressure regulator, likely the 21A2031 as it's off a drum braked car. I can get it for the equivalent of around 6pounds and figured that might be worth getting and changing the spring and servicing it.

 

I don't see any service kits available but the springs are. I can probably get the seals matched up at a supplier. 

 

Are these easy to take apart and service?

[Spider]

They are usually easy to take apart but if you find the piston inside seized in place, save yourself any further agony and toss it in the bin. Once they get to that state, there's no saving them.

In regards to a Service Kit, they do come up from time to time on ebay, though there's nothing special about the rubbers in them. If you popped down to your local friendly Brake Shop with it all in bits and clean, with the old rubbers, I'm sure they'll be able to sort you from loose seals.

[miniGTS]

They are usually easy to take apart but if you find the piston inside seized in place, save yourself any further agony and toss it in the bin. Once they get to that state, there's no saving them.

In regards to a Service Kit, they do come up from time to time on ebay, though there's nothing special about the rubbers in them. If you popped down to your local friendly Brake Shop with it all in bits and clean, with the old rubbers, I'm sure they'll be able to sort you from loose seals.

Thank, yes I'm sure the seals won't be an issue.

 

The problem is finding the spring. MiniMania and Classic Mini spares NZ have it but the shipping is crazy! 45USD for shipping alone is silly

[mbolt998]

 

if I understand correctly, if a master cylinder fails whether dual or single, diagonal or front/rear, the entire system fails anyway?

 

Yes, you are understanding me correctly here.  The idea of a Tandem System is supposed to be fail safe (in the event of a hydraulic failure), however with the Green, Black (you have one of these types) and Yellow Tag masters, I have simulated failures in these and with all, in a failure mode, the pedal goes all the way to the floor with no pressure there what so ever. A failure is very easy to simulate, just crack open a bleed nipple on either front or rear.

 

Pedal goes flat to the floor, but it often does that anyway. If you pump it a bit, does the non-leaking circuit still work? Or does air find its way around the whole system, in precisely the way it's supposed not to (but I am skeptical)?

[Spider]

 

 

if I understand correctly, if a master cylinder fails whether dual or single, diagonal or front/rear, the entire system fails anyway?

 

Yes, you are understanding me correctly here.  The idea of a Tandem System is supposed to be fail safe (in the event of a hydraulic failure), however with the Green, Black (you have one of these types) and Yellow Tag masters, I have simulated failures in these and with all, in a failure mode, the pedal goes all the way to the floor with no pressure there what so ever. A failure is very easy to simulate, just crack open a bleed nipple on either front or rear.

 

Pedal goes flat to the floor, but it often does that anyway. If you pump it a bit, does the non-leaking circuit still work? Or does air find its way around the whole system, in precisely the way it's supposed not to (but I am skeptical)?

 

 

Pumping the pedal doesn't help one bit, though, it might make you feel better that at least you've tried !

 

In most cars and also the way these are supposed to work, the pedal will go down a bit past 1/2 it's travel before they start to get pressure and end up about 1/4 up from the floor in a hard stop, but the reality with the Master Cylinders I've tried is there is simply nothing, just like a dry system.

[mbolt998]

http://if I understa... am skeptical)?

 

 

Pumping the pedal doesn't help one bit, though, it might make you feel better that at least you've tried !

 

In most cars and also the way these are supposed to work, the pedal will go down a bit past 1/2 it's travel before they start to get pressure and end up about 1/4 up from the floor in a hard stop, but the reality with the Master Cylinders I've tried is there is simply nothing, just like a dry system.

 

Yes because the dead circuit will lose you about half of the travel. But in my car anyway there's very little travel to play with ever, which is why I often pump a bit in normal driving anyway-- to compensate for drum fade and also just to get the pedal where it like for blipping.

 

Was watching "Furious Driving" on YouTube the other day. He had a fluid leak from a rear wheel cylinder in a Land Rover Freelander, and reported immediate loss of all braking. So dual circuit brakes don't seem to do much for you even on newer cars.

 

Edited by mbolt998, 26 March 2024 - 10:42 AM.

[sonscar]

I thought it said when you experience a brake fail then you should push the pedal and not pump it and it will allow you to stop with much reduced braking.Do not continue driving.Or words to that effect.Steve..

[stuart bowes]

One of the advantages of having a handbrake operated via cable separate to the hydraulic system

 

pull it up as hard as you can and soil your pants until you come to a stop

 

in fairness any mechanical system can fail, that's why regular testing and maintenance is required isn't it (even more important to remember if the car is old enough to be exempt from MOT's) including checking the brake lines and fittings for any signs of weeping or wear or bulging, etc

Edited by stuart bowes, 26 March 2024 - 01:04 PM.

[miniGTS]

 

They are usually easy to take apart but if you find the piston inside seized in place, save yourself any further agony and toss it in the bin. Once they get to that state, there's no saving them.

In regards to a Service Kit, they do come up from time to time on ebay, though there's nothing special about the rubbers in them. If you popped down to your local friendly Brake Shop with it all in bits and clean, with the old rubbers, I'm sure they'll be able to sort you from loose seals.

Thank, yes I'm sure the seals won't be an issue.

 

The problem is finding the spring. MiniMania and Classic Mini spares NZ have it but the shipping is crazy! 45USD for shipping alone is silly

 

 

 

Anyone know of a supplier for the spring that goes into the 21A1774? Part Number 27H6620

[Spider]

https://www.somerfor...egulating-valve

 

or

 

https://www.classicm...a1774-reg-valve