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Cornish Rattler

Zeus front brake conversion

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53 minutes ago, Gazzar said:

I'm happy enough, they supply an Allen key bung, which works after a fashion.

But the solution, for the stage bigj66 is at, is simply swap the swivel housings from side to side.

👍

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42 minutes ago, Snagger said:

The only issue that could crop up is bleeding the callipers, but as long as you have the bleed nipple uppermost, there shouldn’t be any problem.  Mechanically, the forces are the same on the discs, hubs, stub axles and swivels wherever the calliper is sited.

 

 

 

That’s what I was thinking. One bolt rotation might sort it out without causing any problems.

If I ever get mine I’ll do a sanity check.

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Posted (edited)

Fit a larger servo or be disappointed.  All else equal, discs reduce force, thus you'll not improve braking with discs alone. School-boy stuff.  We've to make-up the force deficit with a larger servo or a very strong ankle. Using a coiler servo means cutting the wing, such that it'll be visible with the bonnet shut.

Heystee do a larger servo, (no cutting) but from experience, it's not a large enough. Sadly,  an 'idiot alert' needs to be inserted here. This is brakes after all, and brakes threads usually degrade at this point. It's possible to show the money the state wastes giving education to all, to deprive those that could use a  decent one! Harsh but true.

In short, Quack 'Physics from the sales-leaflet' won't improve brakes with discs, you'll need a servo. Physics-quackery never mentions the servo, only how more pistons  in a caliper makes for better brakes or some other flannel?  Here we assume a proper understanding of brakes, we've removed self-servo remember. If this has not been considered...

Friction is a factor of force; NOT area; area is a factor of cooling... NOT friction... blah. Brakes sized as a barn-door don't increase friction from area. The greater diam. of some kits, my PS10 kit for example, and the later Heystee kits makes-up the force deficit to a degree, increased Moments of Force etc, but we'll not get away without something like these. Put the dunce-cap on now if we're ready to say otherwise. Here's what we want....

Type 80 In Yellow Series  12-05-12 01.jpg

Dual Diaphragm Servo 27-05-18  02.jpg

Edited by Landrover17H

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Posted (edited)

There's a reason coilers have larger servos. We need a Residual Pressure MC too.

Edited by Landrover17H

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I don’t believe anyone would disagree that some form of pressure boost is required for a drum to disc conversion although not necessarily a vacuum based system. In fact it was discussed in a previous but unrelated thread if I recall so thankfully we can leave our dunce hats in the cupboard for now 👍

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Posted (edited)

I will admit, I'm intrigued. How would we make-up force easily, or at all, without using vacuum? Where will this mysterious force be borne? We're looking forward to this... This will be good, damned good, tell more.

Edited by Landrover17H

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22 minutes ago, Landrover17H said:

I will admit, I'm intrigued. How would we make-up force easily, or at all, without using vacuum? Where will this mysterious force be borne? We're looking forward to this... This will be good, damned good, tell more.

Well an electric brake pump could be an option...similar to systems used in the Softdash RRC and P38s etc. The custom car guys use them a lot especially in the States.

Google will help satisfy your intrigue.

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Posted (edited)

Yes, but why? £50 for a used Type 50 or 80 works. In our case few would seriously contemplate much else, the fruit hangs so low. Would you, have you, if so why? And most create a vacuum anyway.

Here's a Type 50.

Grey Servo.png

Edited by Landrover17H

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No vacuum take off on the engine? Ability to package the pump elsewhere?

Better pedal feel?

For the fun of it?

A spare abs pump underfoot?

 

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2 minutes ago, Landrover17H said:

Yes, but why? £50 for a used Type 50 or 80 works. In our case few would seriously contemplate much else, the fruit hangs so low. Would you, have you, if so why?

Here's a Type 50.

Grey Servo.png

I didn’t say I wouldn’t use a vacuum servo, but you asked what alternatives there are to the vacuum system so I answered your question to help clear up the mystery 😉

I might use an alternative though.

Just because, but I’m undecided 🤷‍♂️ 

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It's the master cylinder that bothers me. Which one?

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Posted (edited)

All the pumps I've ever seen, including my own Hella type, can't create braking force per se, only vacuum. Force 'at application' arrives via vacuum, not the pump, and that vacuum is held via one type of servo or another. ABS pumps don't produce braking for per se either, they meter the valves. Are there 'road-use' pumps that actually 'create' fluid pressure? That's at least 200-300 Bar in milliseconds, one 'ell of a pump? Can't see how or why that'd work. No vac??   If so, please put up a link - I'm learning something and I like that.

 

MC? Using coiler servos you're down to coiler choices. If you've discs all round the Type 80 better proportions discs rear; drums up back? ... the Type 50. You'll likely need a prop. valve and RPV to the rear. The coiler uses a G valve which is difficult to duplicate, and you're trying to do exactly that, you're looking to duplicate the coiler system.

Edited by Landrover17H

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While you’re right, 17H, that disc brakes need significantly higher hydraulic (or mechanical, for that matter) pressure than drums, you are wrong in your assertion that pad area does not affect the friction, only cooling.  There is a reason the pads I use at work are angular (360 degrees, or circular) and that we have six discs and seven friction lining layers per wheel.  The same can be said of the multi layer clutch packs, which work identically, in an automatic transmission.

But you’re absolutely right that few of the brake conversion kit manufacturers mention the need to uprate the master cylinder or fit a form of assistance, be it vacuum, electric or otherwise.  The big diameter Defender servo does interfere with the wing top, like your photo of the yellow vehicle shows, but the longer but narrower Discovery type doesn’t need more than the folding back of the wing top’s return edge, is generally less prone to flexing and cracking than the Defender type, and gives excellent results in use.

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6 minutes ago, Landrover17H said:

All the pumps I've ever seen, including my own Hella type, can't create braking force per se, only vacuum. Force 'at application' arrives via vacuum, not the pump, and that vacuum is held via one type of servo or another. ABS pumps don't produce braking for per se either, they meter the valves. Are there 'road-use' pumps that actually 'create' fluid pressure? That's at least 200-300 Bar in milliseconds, one 'ell of a pump? Can't see how or why that'd work. No vac??   If so, please put up a link - I'm learning something and I like that.

 

MC? Using coiler servos you're down to coiler choices. If you've discs all round the Type 80 better proportions discs rear; drums up back? ... the Type 50. You'll likely need a prop. valve and RPV to the rear. The coiler uses a G valve which is difficult to duplicate, and you're trying to do exactly that, you're looking to duplicate the coiler system.

So another of your “if I haven’t seen it, it doesn’t exist” posts...🙄

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Posted (edited)

I lay prostrate, please educate me and others. How does greater area create greater friction at outset, yes area keeps  things cooler and takes longer to wear out.  How do these brakes and their shape, and area (not distance form axis), only area, increase friction for the same force? Without  lining material change? All else equal?

Please point me to a road or race pump that creates direct braking force, not via vacuum. All the electric brake pumps I've seen are vacuum. It's not possible to store hydraulic pressure, outside of a Citroen set-uo. How do they work so quickly? The Citroen system is the only thing I've ever seen, and clearly it's not that. Few would stay undecided for long, ie contemplate a Citroen system?  I would genuinely like to see.

 

This was always my understanding of friction/force/area:

 

Edited by Landrover17H

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Posted (edited)

Multiplate clutches simply create more area to get rid of heat and last longer, doing this in less space than a one piece (with the same area) which might not fit in the space? No?

Edited by Landrover17H

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23 minutes ago, Landrover17H said:

I lay prostrate, please educate me and others. How does greater area create greater friction at outset, yes area keeps  things cooler and takes longer to wear out.  How do these brakes and their shape, and area (not distance form axis), only area, increase friction for the same force?

Please point me to a road or race pump that creates direct braking force, not via vacuum. All the electric brake pumps I've seen are vacuum. It's not possible to store hydraulic pressure, outside of a Citroen set-uo. How do they work so quickly? The Citroen system is the only thing I've ever seen, and clearly it's not that. Few would stay undecided for long, ie contemplate a Citroen system?  I would genuinely like to see.

Here’s a common system that is used in both road and race applications and doesn’t use a vacuum servo.

These will outbrake anything from a standard vehicle.
https://apracing.com/race-car/pedal-boxes

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44 minutes ago, Snagger said:

So another of your “if I haven’t seen it, it doesn’t exist” posts...🙄

Well if the hat fits....

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Posted (edited)
Quote

 

These will outbrake anything from a standard vehicle.
https://apracing.com/race-car/pedal-boxes

How? I'm learning here - dunce-cap on, not just from my ankle, not from vacuum servo or  electric vacuum pump thus vacuum, where does the extra force come from. I can only see pedal-boxes?

 

Quote

I might use an alternative though.

Just because, but I’m undecided

How would this alternative work?

Edited by Landrover17H

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Deleted ... as 17h had nothing to learn from it ⬇️

Despite replying so quickly he wouldn’t have had time to watch it. 🤷🏻‍♂️ 
 

<outta here>

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Posted (edited)

Oh dear, that old chestnut. The Physics class conundrum. My 12YO could run rings around that Youtuber. Yes, wider tyres give more grip, but that's about maintenance of contact-patch, on an ever moving surface, and the air-gaps this creates - and the tyre wall, folding-in etc etc. A real Black-art. Not greater area per se.

Edited by Landrover17H

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15 minutes ago, Landrover17H said:

How? I'm learning here - dunce-cap on, not just from my ankle, not from vacuum servo or  electric vacuum pump thus vacuum, where does the extra force come from. I can only see pedal-boxes?

F1 cars use a similar principle, no servos there either, just big quads 😉

How would this alternative work?

I don’t know yet as I haven’t got that far and I’m undecided 🤔

 

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Posted (edited)
13 minutes ago, Bigj66 said:

 

OK, so you're witterin'? You don't know how to force-assist brakes without vacuum, be it pumped vacuum or not? You've not got that far. You've a fetish for red pedal-boxes. But... you do know: "These will outbrake anything from a standard vehicle."

Wish you'd said.

 

Edited by Landrover17H

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I love your enthusiasm and how engaged you are - but you’re sentences are not always easy to understand and you’re coming across as quite rude at the moment  - which is why that is being reflected back to you. Not sure if that’s your plan ? 

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17H, friction is a result of frictional coefficient (determined by materials and surface finish), speed, pressure and surface area.  That why ice skates, sleds and such have small contact areas, and why racing bikes have as narrow tyres as can be achieved.  It’s also why high performance vehicles have large rotors, larger pads and often have multipack discs, like I work with.The multipack clutches in automatic transmissions are made that way to increase bite.  Their heat is dissipated through the oil and heat exchanger.

Power brakes use electric compressors and hydraulic accumulators.  ABS systems use this principle to stor hydraulic fluid under positive pressure for rapid activation, the pump then recharging the accumulator.  There is no vacuum on many such systems, such as the brakes on Range Rovers and later LR models.  Do you really think it likely that aircraft use vacuum servos for their hydraulically actuated brakes, rather than the 3000psi system pressure generated by pumps?

For someone who likes to extol their knowledge of science and engineering, your knowledge is very weak and flawed.

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