Zeus rear brake disc conversion

[missingsid]

2 hours ago, Snagger said:

Race cars are also a lot lighter than a Land Rover!

They’ll  have systems that use mechanical advantage like long pedals, long travel, small diameter master cylinders and of course special pads and disks with much higher friction coefficients than we use.

Not all are lighter than a Series 1! And better pads and discs are available.

However I accept your comments.

The biggest problem I will have is that I have reduced the leverage as a std brake pedal tower points the long M/C down so it hits the S1 dashboard so I have had to use a clutch pedal tower. Net result is I will probably have to look at another option for all the reasons that have been stated. But given that the brakes are for a heavy RRC it would be grossly over braked if the servo is fitted.

[Cornish Rattler]

Just ordered my rear disc brake conversion 

[Cornish Rattler]

As i was bored and on my day off i decided to strip the rear brakes down to the axle flanges ready for when the new kit arrives, will post pic's later 😀

Edited February 1, 2021 by Cornish Rattler

[Cornish Rattler]

41 minutes ago, Cornish Rattler said:

As i was bored and on my day off i decided to strip the rear brakes down to the axle flanges ready for when the new kit arrives, will post pic's later 😀

 

[Cornish Rattler]

The n/s/r

[Cornish Rattler]

And the o/s/r 

[Cornish Rattler]

Just now, Cornish Rattler said:

And the o/s/r 

The brake pipes will be replaced as was the fronts 😀

[Cornish Rattler]

Still not arrived but when ordering the lady on the phone did say they mite take 2-3 wks to arrive, my front conversion took 2 wks to arrive which I was hoping the rear's would be the same 

[Cornish Rattler]

Still not arrived so will have to ring em on Monday ☹️

[Badger110]

I feel for you, I dislike waiting for bits to arrive if  they’re delayed ☹️

[Landrover17H]

It happens in most brake threads. Snagger is clearly safe around brakes....

 

It ever amazes me how little effect full-time education has the working knowledge of even those you'd think would have been paying attention? As far as I can make out, save for Snagger there's little understanding of braking systems here.

Force is factor of friction. Nothing else - this not opinion. It is 'Laws of Physics'. Apply more force, and we improve brakes. Removal of drums will make brakes worse. Remove force and  it is required to be replaced. Discs the size of a barn-door, and 18 pot calipers painted red will make little difference where force applied remains the same. Wide tyres DO increase grip, but NOT because of the larger footprint / area per se. (look it up?). Increased pad area will NOT increase friction. Surface area is a factor of heat dispersal NOT friction.

Larger disc/drum diameters DO help, but that's 'Moments of Force' and not because of area, which is where we came in. Force.

 

If running discs,remove the stock S3 8" servo and go 10- 11" or more, or leave the things well alone.

 

OK, back to the befuddled logic....

 

Edited February 20, 2021 by Landrover17H

[Cornish Rattler]

5 hours ago, Badger110 said:

I feel for you, I dislike waiting for bits to arrive if  they’re delayed ☹️

Yeah they said on the phone when i ordered them that they would take 2-3 weeks to arrive and yesterday was the end of the 3rd week also they don't take money from your account till they are about to sent them out and the money is still in my account and they are closed weekends so can't contact them till Monday ☹️

[Daan]

On 1/26/2021 at 11:35 AM, Snagger said:

You cannot achieve reasonable braking with disks and a standard LR non-servo system pedal and master.  The callipers need far higher pressure than the drum system, so without some sort of boosting system or a mechanical system that increases leverage or uses a smaller bore, longer travel master, you just won’t get the pressure you need.  It’s just physics, not opinion.

 

On 1/7/2021 at 10:24 AM, Cornish Rattler said:

For now I'm using the std none servo master cylinder but once the rear disc brake conversion is done I will see how it goes and if needed I will buy a a better master cylinder and servo 

 

On 1/20/2021 at 12:29 AM, Landrover17H said:

I run a coiler NRC4772 servo on 4 x Heystee discs. Mine was undriveable without, and the reason is school-boy stuff,. Friction is a factor of force not area. Without a servo to make-up the force deficit now that the self-servo effect of the drums has been removed,  it can't be great. Got to give it to you, you've got balls. Force from the drums now removed, if it's an improvement, what state were the drums in!

 

 

Chaps, mr rattler is going to try, and make up his mind on what he thinks. We are comparing a zeus conversion with a heystee conversion and a rangerover setup, and think that is good comparison? Do we know how the caliper piston diameters compare? It could well be that the zeus conversion is using larger pistons and therefore is ok without a booster. 

So let's see how it pans out. I am more worried about the use of the same brakes at the rear as the front; This will result in too much brake bias to the rear, resulting in unplanned handbrake u-turns. I would investigate a brake pressure valve in the rear brakeline for this reason.

 

Daan

[Cornish Rattler]

27 minutes ago, Daan said:

 

 

Chaps, mr rattler is going to try, and make up his mind on what he thinks. We are comparing a zeus conversion with a heystee conversion and a rangerover setup, and think that is good comparison? Do we know how the caliper piston diameters compare? It could well be that the zeus conversion is using larger pistons and therefore is ok without a booster. 

So let's see how it pans out. I am more worried about the use of the same brakes at the rear as the front; This will result in too much brake bias to the rear, resulting in unplanned handbrake u-turns. I would investigate a brake pressure valve in the rear brakeline for this reason.

 

Daan

Thanks Daan, the only thing I know with the rear zues brakes is the rear discs and calipers are smaller than the fronts, the front calipers are 4 pot but the calipers are a lot smaller then coil sprung front calipers and the rears are 2 pot calipers and think are of similar size of coil sprung rear calipers but not sure how the pistons compare with coil sprung caliper pistons 

[Daan]

Ok, I was under the impression they were the same. In that case, you are probably ok.

Daan

[Cornish Rattler]

53 minutes ago, Daan said:

Ok, I was under the impression they were the same. In that case, you are probably ok.

Daan

Yeah like i say if needed i will fit a bigger master cylinder and a servo but up to now with the fronts the brakes are tonnes better 🙂

[missingsid]

6 hours ago, Cornish Rattler said:

Thanks Daan, the only thing I know with the rear zues brakes is the rear discs and calipers are smaller than the fronts, the front calipers are 4 pot but the calipers are a lot smaller then coil sprung front calipers and the rears are 2 pot calipers and think are of similar size of coil sprung rear calipers but not sure how the pistons compare with coil sprung caliper pistons 

Hmm, Std coiler calipers use the same pistons front and rear. So if Zues fronts are smaller than coiler fronts but the rears are the same as coiler then the front to rear ratio will be more rear biased than a coiler?

[Cornish Rattler]

34 minutes ago, missingsid said:

Hmm, Std coiler calipers use the same pistons front and rear. So if Zues fronts are smaller than coiler fronts but the rears are the same as coiler then the front to rear ratio will be more rear biased than a coiler?

I don't have the zues rears to hand but looking at pic's they look similar size but could be smaller 

[Snagger]

On 2/21/2021 at 12:13 AM, missingsid said:

Hmm, Std coiler calipers use the same pistons front and rear. So if Zues fronts are smaller than coiler fronts but the rears are the same as coiler then the front to rear ratio will be more rear biased than a coiler?

The LR spec pistons are smaller in the rear callipers of 90s, RRC and Discovery.  I’m not sure if they’re also smaller than the front in the 110 and 130.

[Snagger]

On 2/20/2021 at 5:17 PM, Daan said:

 

 

Chaps, mr rattler is going to try, and make up his mind on what he thinks. We are comparing a zeus conversion with a heystee conversion and a rangerover setup, and think that is good comparison? Do we know how the caliper piston diameters compare? It could well be that the zeus conversion is using larger pistons and therefore is ok without a booster. 

So let's see how it pans out. I am more worried about the use of the same brakes at the rear as the front; This will result in too much brake bias to the rear, resulting in unplanned handbrake u-turns. I would investigate a brake pressure valve in the rear brakeline for this reason.

 

Daan

It’s a valid concern.  The 90 and 100” wheelbase models have callipers with half as many pistons, which are also slightly smaller than the front pistons, smaller pads AND a biasing valve to reduce the rear brake pressure.  I know 110s and 130s lack the biasing valve, and still have two-pot rear callipers with smaller pads than the front, but as I said above, I don’t know if they also have smaller rear pistons.

If the aftermarket kits use callipers with similarly proportioned piston sectional areas and pad areas, then I think they’d be OK as is on a 109, but an 88 would benefit from a biasing valve.

[Cornish Rattler]

Update from phone call, they had a delay at the foundery and will be sending the kits out early next week ☹️

[missingsid]

9 hours ago, Snagger said:

It’s a valid concern.  The 90 and 100” wheelbase models have callipers with half as many pistons, which are also slightly smaller than the front pistons, smaller pads AND a biasing valve to reduce the rear brake pressure.  I know 110s and 130s lack the biasing valve, and still have two-pot rear callipers with smaller pads than the front, but as I said above, I don’t know if they also have smaller rear pistons.

If the aftermarket kits use callipers with similarly proportioned piston sectional areas and pad areas, then I think they’d be OK as is on a 109, but an 88 would benefit from a biasing valve.

Odd, RRC, and 90 solid disk calipers are all 51mm pistons front and rear.

[hurbie]

for the record , old 110's have 4 piston's at the front 46mm and later disc brake rear's have 2 41mm piston's.

[missingsid]

13 hours ago, missingsid said:

Odd, RRC, and 90 solid disk calipers are all 51mm pistons front and rear.

My mistake they are 41mm front and rear.

[Cornish Rattler]

Its looking like i will be ringing them again on monday 6 wks now, fuming 😡