Thread: Stage One V8 disk brake conversion

Originally Posted by rover-56

I always wonder about these disk conversion threads, If you are able to lock the wheels under braking then the stopping distance is only dependent on tyres and road surface, Disk and drum will be the same.

Locking wheels is very achievable with properly set up drum brakes - I have a S1 and a S3 which will lockup all wheels on dry bitumen any time I want.

OK, I know disks have an anti fade advantage, so a heavily loaded LR in hilly country is better with disks.

Just my 2c worth

Cheers,
Terry

It is not all that simple. The major advantage of discs over drums is that the brakes require much less maintenance, are much more resistant to fade, and are almost unaffected by water. But mostly, people seem to judge the brake efficiency on how much pedal pressure is needed to lock the wheels! This does not depend on any of the above! It depends almost entirely on the amount of leverage applied by the hydraulics and the amount of assistance (both power assist and self servo). The decision to change to discs should not be based on anything except a need to reduce maintenance, reduce fade, or reduce sensitivity to water.

Also important, but usually ignored in these discussions, is the need to have a proper balance between front and rear braking. It is essential for safety that the front wheels lock before the back. This means that the rear brakes must be not powerful enough to lock the rear when unloaded; in the absence of any sort of proportioning valve, this in turn means that the rear brakes will be less powerful than they could be when loaded.

John

What John says is very true, what is also true is that long wheelbase series Landies have very poor brakes in reverse. This is related to the mechanical advantage of the leverage of leading Vs trailing shoes. A 109" has 6 leading shoes (4 front 2 rear) and 2 trailing shoes on the rear. In reverse this means 2 leading shoes and 6 trailing shoes.

There are people who have retrofitted 11" front brakes to the rear and swapped their sides. This creates 4 leading shoes and 4 trailing shoes in both directions with the front:rear proportioning accomplished by the relative inefficiency of the leading shoe in reverse. Ideally it would be 3" systems on both ends.

Originally Posted by JDNSW

It is not all that simple. The major advantage of discs over drums is that the brakes require much less maintenance, are much more resistant to fade, and are almost unaffected by water. But mostly, people seem to judge the brake efficiency on how much pedal pressure is needed to lock the wheels! This does not depend on any of the above! It depends almost entirely on the amount of leverage applied by the hydraulics and the amount of assistance (both power assist and self servo). The decision to change to discs should not be based on anything except a need to reduce maintenance, reduce fade, or reduce sensitivity to water.

Also important, but usually ignored in these discussions, is the need to have a proper balance between front and rear braking. It is essential for safety that the front wheels lock before the back. This means that the rear brakes must be not powerful enough to lock the rear when unloaded; in the absence of any sort of proportioning valve, this in turn means that the rear brakes will be less powerful than they could be when loaded.

John

Completely agree John, I am certainly not trying to argue that drum brakes are better than disks, just that series drum brakes set up properly and maintained are quite servicable.

Also with insurance companies looking for reasons to disallow claims, I would be a bit uneasy about changing from manufacturers original design.

Cheers,
Terry

My mate has just modified rangie axles, by welding leaf spring mounts to them for his series3 wagon. If you set the front up correctly with the front pinion at approx 6deg you will have the correct steering geometry settings. The track rod clears the front springs by about 25mm! Above the springs.
I can be done. Alot of maths and measuring as well as sacrificing some old series diff housings for the spring plates. The rangie and series chassis are so close to the same widths that the spring mounts line up where the bump stops are on the rangie axles, a little modification of 1 of the u bolts and Bobs your uncle!

Originally Posted by landrover dave

My mate has just modified rangie axles, by welding leaf spring mounts to them for his series3 wagon. If you set the front up correctly with the front pinion at approx 6deg you will have the correct steering geometry settings. The track rod clears the front springs by about 25mm! Above the springs.
I can be done. Alot of maths and measuring as well as sacrificing some old series diff housings for the spring plates. The rangie and series chassis are so close to the same widths that the spring mounts line up where the bump stops are on the rangie axles, a little modification of 1 of the u bolts and Bobs your uncle!

Make sure he also puts his front prop 45 degrees out of phase.

why didn't he just put the coils and all in the Series 3 , not much more work really than swapping over the spring perches would have been

Originally Posted by goingbush

Make sure he also puts his front prop 45 degrees out of phase.

why didn't he just put the coils and all in the Series 3 , not much more work really than swapping over the spring perches would have been

Its a lot more work. Welding leaf perches on and a new steering linkage is easy. Coiling adds panhard mounts, spring mounts on the chassis, radius arm mounts, new Xmember on the rear, low link mounts, mounting the A-frame, exhaust, clearancing body work etc.

Originally Posted by Slunnie

Its a lot more work. Welding leaf perches on and a new steering linkage is easy. Coiling adds panhard mounts, spring mounts on the chassis, radius arm mounts, new Xmember on the rear, low link mounts, mounting the A-frame, exhaust, clearancing body work etc.

My bad, wrong use of english, having done it both ways and knowing the end result of each the coil conversion is easier , and probably not MUCH more work than cutting all the coil mounts , radius arm lugs Panhard mounts off a Rangie housing & then setting up the geometry for the spring perches that had to be cut & ground off a series housing..

Well after the end result the coiled vehicle any amount of work involved is soon forgotten & Im left wondering why I did all that work for not much gain on the leaf sprung truck at the expense of a Salisbury and a weaker new diff in the rear end

Originally Posted by goingbush

My bad, wrong use of english, having done it both ways and knowing the end result of each the coil conversion is easier , and probably not MUCH more work than cutting all the coil mounts , radius arm lugs Panhard mounts off a Rangie housing & then setting up the geometry for the spring perches that had to be cut & ground off a series housing..

Well after the end result the coiled vehicle any amount of work involved is soon forgotten & Im left wondering why I did all that work for not much gain on the leaf sprung truck at the expense of a Salisbury and a weaker new diff in the rear end

Also having done both, I'm still really surprised you think coiling is not much more work.