Battery Isolator-which one!

[Dave Mann]

I use the Lucas switch as illustrated by Roland and over many years I've had no problems with them other than the knob securing screw coming out and knob and screw rolling around the passenger footwell.

[David Cochrane]

I've used both types - the battery terminal type in the Cup and the red key type in the RP.  A previous owner had relocated the battery from under the driver's seat to the bulkhead (a bit like a Ruby) so it was a relatively simple matter to mount a 'red key' switch on the bulkhead (visible just this side of the cutout).

[John Mason]

David, Is that a hydraulic master cylinder showing in your photo. Do you have hydraulic brakes.

John Mason

[David Cochrane]

Yes it is - hydraulic brakes were fitted by the man who restored it more than 10 years ago. And a right pain they were to get working properly! All the slave cylinders had to be changed because they had seized and were leaking, and all the shoes had to be replaced because they had got soaked in hydraulic fluid. The system has been filled with modern fluid which is said to be better than the ordinary stuff. I have to admit that the brakes do work quite well now.

[Steve kay]

Gosh, does this mean that you'll soon be offering a hydraulic conversion kit, David? Then again, what exactly does work "quite well" mean.

[Tony Press]

Gosh, does this mean that you'll soon be offering a hydraulic conversion kit, David? Then again, what exactly does work "quite well" mean.

Why?

"a right pain they were to get working properly! All the slave cylinders had to be changed because they had seized and were leaking, and all the shoes had to be replaced because they had got soaked in hydraulic fluid."

Cheers, Tony P.

[David Cochrane]

No plans for a hydraulic conversion kit - I still think that cable brakes are more suitable for our cars. It would have been even more trouble to have converted them back to cable so I kept them. Work "quite well" - if you tread on the stop pedal the car slows down satisfactorily, but seems to be about the same as the Ruby I had a few years ago. However it is an added incentive to take the car out in the winter months to stop the b*gg*rs seizing up!

[Steve kay]

That wasn't an entirely serious comment about hydraulic conversions. After all, if David, let alone a dozen customers turned up at the Metropole Hotel car park for a LCES event with hydraulics, the epidemic of swooning with horror would cause medical history. 

If anyone offered Bowdenex conversions that would be different. Doing events such as VSCC autosolos, the tightening of the front cables when on full lock becomes noticable. Using an Ulsteroid  years ago, the split brakes made it easy to have a rather slack front brake cable, these damned modern Rubies with coupled brakes are a bit more of a challenge. I've noticed that competitive Autosolo Seven specials, both two and four wheelers, benefit from Bowden brakes. 

None of which has anything to do with master switches!

[Chris KC]

If the OP will indulge one further comment on this detour -

Modern hydraulic brake systems are extremely reliable and should last the expected life of a modern vehicle (let's say 20 years) without trouble. The most common cause of incident is accidental contamination with either solid matter or incompatible fluids (especially mineral oil, which will rapidly kill the EPDM rubber seals in quite small concentrations).

Older systems, with cast iron or steel master cylinders perhaps, were somewhat less durable. Glycol based brake fluids are hygroscopic and absorb water from the atmosphere (principally through the hoses, which are micro-porous). The uptake of water is typically 1.5%/ year until saturation is reached at about 3 or 4%. The principal difference between the grades of DOT brake fluid is boiling point, the higher the grade the higher the BP. However add 3% water and the BP of your DOT4 will plummet below that of a DOT3. This is why your brake fluid should be changed every 2 years. The fluid contains a corrosion inhibitor pack but this of course is not inexhaustible. A system which has been sitting for extended periods with 'vintage' fluid in it will almost certainly be corroded inside leading to seizure or at best rapid wear of seals, which themselves are likely to have aged, hardened and set. This is why fluid soaks your linings.

At one time Castrol fluid was reckoned to have higher lubricity than most, which tends to enhance durability. Not sure if this is still the case.

For the purposes of an A7 system, any modern fluid will do, the mere fact of having fresh fluid and a good air bleed is likely to improve things. Higher DOT grades need only be considered if heavy brake applications in rapid succession are contemplated. From a practical perspective DOT4 is easier to come by (in the UK) than DOT3 these days so it's a no-brainer. I would not advocate DOT 5 or silicone fluid. This is incompatible with glycol-based fluids and most of the arguments in its favour are weak (it is mostly used by the US military, due to its lower viscosity in arctic conditions, scarcely relevant to most 'classic' use).

The great merit of hydraulic systems of course is that they balance the force applied to the shoes evenly at each brake. One brake suddenly becomes four! They have little advantage over a perfectly adjusted cable system (I know, easier said than done). I for one turned my back on 'upgrades' of this kind many years back, if it's a Spridget you want why not just buy a Spridget... I've even taken off the Bowdenex conversion recently and reverted to the standard A7 system, which initially works better! Though yes Steve you are right about steering lock! I haven't quite mastered front cable adjustment yet, the arc compensator doesn't seem to do a lot.

Apologies if I've bored everyone, I'm in post-op and need something to occupy me! Perhaps somebody learned something!

[Tony Press]

If the OP will indulge one further comment on this detour -

Modern hydraulic brake systems are extremely reliable and should last the expected life of a modern vehicle (let's say 20 years) without trouble. The most common cause of incident is accidental contamination with either solid matter or incompatible fluids (especially mineral oil, which will rapidly kill the EPDM rubber seals in quite small concentrations).

Older systems, with cast iron or steel master cylinders perhaps, were somewhat less durable. Glycol based brake fluids are hygroscopic and absorb water from the atmosphere (principally through the hoses, which are micro-porous). The uptake of water is typically 1.5%/ year until saturation is reached at about 3 or 4%. The principal difference between the grades of DOT brake fluid is boiling point, the higher the grade the higher the BP. However add 3% water and the BP of your DOT4 will plummet below that of a DOT3. This is why your brake fluid should be changed every 2 years. The fluid contains a corrosion inhibitor pack but this of course is not inexhaustible. A system which has been sitting for extended periods with 'vintage' fluid in it will almost certainly be corroded inside leading to seizure or at best rapid wear of seals, which themselves are likely to have aged, hardened and set. This is why fluid soaks your linings.

At one time Castrol fluid was reckoned to have higher lubricity than most, which tends to enhance durability. Not sure if this is still the case.

For the purposes of an A7 system, any modern fluid will do, the mere fact of having fresh fluid and a good air bleed is likely to improve things. Higher DOT grades need only be considered if heavy brake applications in rapid succession are contemplated. From a practical perspective DOT4 is easier to come by (in the UK) than DOT3 these days so it's a no-brainer. I would not advocate DOT 5 or silicone fluid. This is incompatible with glycol-based fluids and most of the arguments in its favour are weak (it is mostly used by the US military, due to its lower viscosity in arctic conditions, scarcely relevant to most 'classic' use).

The great merit of hydraulic systems of course is that they balance the force applied to the shoes evenly at each brake. One brake suddenly becomes four! They have little advantage over a perfectly adjusted cable system (I know, easier said than done). I for one turned my back on 'upgrades' of this kind many years back, if it's a Spridget you want why not just buy a Spridget... I've even taken off the Bowdenex conversion recently and reverted to the standard A7 system, which initially works better! Though yes Steve you are right about steering lock! I haven't quite mastered front cable adjustment yet, the arc compensator doesn't seem to do a lot.

Apologies if I've bored everyone, I'm in post-op and need something to occupy me! Perhaps somebody learned something!

Good explanation and the original topic had run its distance- unfortunately these gems will be difficult to find under the heading !

Cheers, Tony P.