My take on a Series 3 Disc Conversion

[aaronledwidge]

Basically i have decided recently to fit some disc brakes to my series and after seeing a few of the older posts on here i thought i would sign up and show what i have come up with.

Im not to certain how they will pan out but im most of the way through the process of producing and fitting the kit so i thought i would wack a thread up. Any advice or opinions would be great.

after a bit of reading around the net I found some disks I thought would be suitable from a late 80's Toyota fj there just over 300mm diameter and should have a low enough hat dimension to allow for a flat bracket.

Ihad some girling m16 calipers knocking about so for now will be using theses, there only 2 pot which is a shame and means they have about 15% less piston area than defender calipers. That being said they should be adequate to stop the old series and much better than 10 inch drums.

Once I had the disks and calipers I mocked up the mounting, the series hubs have to be machined flat then the disk mounts on the rear. The stub axle has a 6x114.3 pcd, so I modeled that on cad then measured the offset of the caliper mounts from the centre, I tried 92mm but this is just touching the hub so ill space that out a little.

When I had it all designed I made up a crude bracket out of 12mm ply, this makes the disk a little tight so ill have the brackets laser cut from 10mm steel. The caliper will still have to have some spacers turned down to account for the offset but otherwise look good.

here are a few pics of the first test

IMAG2878 by darransandwich, on Flickr

I mocked it up and all seems to fit pretty well

IMAG2873 by darransandwich, on Flickr


IMAG2877 by darransandwich, on Flickr


IMAG2875 by darransandwich, on Flickr


IMAG2872 by darransandwich, on Flickr


IMAG2871 by darransandwich, on Flickr

I just need to triple check my measurements and get them cut, once that is done its only mounting the disc to the hub which should be simple

[dirtydiesel]

Welcome to lr4x4, excellent first post.

Great take on cardboard aided design!

[=jon=]

Hey Aaron,

Glad to see you made it over from the SXOC

I've seen the rest of the build pics on another forum we both frequent and there's a lot more progress to come (probably in the sub 5 post approval queue... )

[aaronledwidge]

Hey guys, thanks for the welcome and John thanks for the nudge. Ill get all up to date as the are approved buddy. How are you?

Right time for another little update, i have had my brackets laser cut and all looks good, i need to tap the bracket for the caliper mounts but think ive left it pretty close to the hub, hopefully it will be ok but time will tell when i kill a wheel bearing.

Here is the bracket straight from the laser cutters.

IMAG2881 by darransandwich, on Flickr

Fits nicely in the middle which is a good sign

IMAG2879 by darransandwich, on Flickr

Plenty of clearance for the disc

IMAG2883 by darransandwich, on Flickr

caliper mocked in place.

IMAG2884 by darransandwich, on Flickr

Tomorrow im going to properly turn the hub down and work out the best way to fit the disc to the hub. once thats done i should be about there with this.

[aaronledwidge]

Right so over the weekend i managed to get a little more done on this, first job as to turn down the series hubs so they could take a disc. The biggest difficulty in this is removing the webs on the back.

Theres a before

IMAG2888 by darransandwich, on Flickr

we opped it in the lathe and checked the runout with a dial gauge, impressively we were looking at about plus or minus 6 thou on the casting.

then turned off the ribs.

IMAG2889 by darransandwich, on Flickr

Once this was done the back of the hub had to be faced off.

IMAG2890 by darransandwich, on Flickr

That gave me a pretty good surface to mount the disc so the next job was finding a suitable PCD that would fit both the 6 stud discs and 5 stud hubs.

This was a little trial and error based but we settled on a place that would fit both and drilled the discs out to 5 stud 10mm mounting holes. We then drilledthe hubs to the same pcd and tapped them for an m10 thread.

IMAG2892 by darransandwich, on Flickr

IMAG2891 by darransandwich, on Flickr

[Serious Series]

Not a mechanical engineer but I wonder how much strength you have lost from hub by removing the webs?

[aaronledwidge]

On Sunday i set about mocking them up on my truck, this is where i realised i dropped a bollock and used 1980+ series hubs which means they wont fit my stub axles, i had 1 spare 80+ front stub but will have to modify a rear one to fit for the other side :annoyed:

Anywhoo i thought i should mock it all up on the truck, the bracket sat on really well

IMAG2895 by darransandwich, on Flickr

Then i whacked on the hub and the caliper. the offset was a little tight which is a shame so ill add a couple of mm to my bracket design but for now i shaved the caliper a little and fitted it all up

IMAG2896 by darransandwich, on Flickr
I have to say im bloody chuffed with how it looks, i just hope there powerful enough

IMAG2898 by darransandwich, on Flickr

my bearings and bits turned up from paddocks so i got the hubs fitted

First i cleaned up the old hubs ready for the new bearings, cut the disc bolts down and thread locked them in place befre building the hubs up on the bench ready to be slotted on.

IMAG2915 by darransandwich, on Flickr


IMAG2916 by darransandwich, on Flickr

once i had them fitted i tried on the wheels but unfortunately with the caliper centred the rims fouled the caliper. I decided to turn the old ddrums into a spacer but as i couldnt get acess to a lathe this was quite a slow process although they turned out prety well and will do until i can make some better ones.

Thats whats left of the old drum

IMAG2920 by darransandwich, on Flickr
and the spacer on a spare hub.

IMAG2919 by darransandwich, on Flickr
Overall im pretty happy with how it turned out and it will do for now, here is how it looked finished.


IMAG2921 by darransandwich, on Flickr

[aaronledwidge]

Right once thats was sorted i test fitted a wheel and it was spot on so i moved on to fitting up the other side before bleeding, i had a bit of a nightmare with the bleeding until i realised i had put the calipers on the wrong sides so the nipples were at the base. Not my brightest moment.
This meant i needed some new hard pipes so i bent up these bad boys.


IMAG2917 by darransandwich, on Flickr


IMAG2918 by darransandwich, on Flickr

once they were flipped they bled up pretty well although i had to clamp the back s off to get a decent pedal. Ill have a look at them one evening this week or at the weekend, if there not the issue ill have to have a think about a bigger master. Does anyone have any suggestions?

Aaron

[Gremlin]

Not a mechanical engineer but I wonder how much strength you have lost from hub by removing the webs?

Mine are the same, and they have been running for the past 4-5 years, no issues. This was also brought up when i posted my disc brake build.

Congrats to the OP, i built mine with similar tech (wood mock up) and didthe same with my hubs exactly, its looks like a good build keep it up!!

G

[aaronledwidge]

Hey gremlin it was your post that gave me a lot of the ideas for this conversion so that would make sense, its been a lot more straight forward than i had imagined to be honest but time will tell when its all finished.

[Gremlin]

They will be fine, although mine are more or less work as a matched system, ie 90/110, as all brake components are land rover.

I am very pleased with mine especially now that i did the rears as well, i was glad i did them myself as a concept, machining was done by others, but still an achievement!

I am also happy my build has been an inspiration to others to follow.

G

[Phil Hancock]

With disks there is less fluid needing to be moved as the pistons dont retract like drum pistons so a smaller master is fine. Also although the calipers are smaller than a 110" a series weighs approx the same as a Disco 1 and they have smaller front caliper pistons which are the same diameter as early 90 and RRC.

[aaronledwidge]

Cheers guys, i had another play tonight and it seems to be set up ok. Ill try and get it an mot so fingers crossed she will get through. it seemed to go from having a really low bite to a really high one so maybe the calipers were playing silly buggers.

Gremlin your post was a big help to be honest, always nice to see other peoples takes on things.

[BSF]

Just a thought on balancing front to rear. The discs will require a higher pressure to get the same braking effort as the drums on the rear. Achieving the pressure for the discs is not a problem (push the pedal a bit harder), but stopping the rear wheels locking s a bit more of a problem.

I've done three conversions with bought in bits; on the 109 the problem was solved by substituting the 3/4" wheel cylinders from the 88. On the Series 1 and the 2b I got around the problem by using a remote servo that only worked on the discs with the rear drums using unboosted pressure direct from the master cylinder.

It seems to work.

[Gareth Dickens]

Being a bit OCD, I wanted coil springs, Salisbury front and rear, vented discs front and solids rear, with the large wheel bearings and thick stub axles and CV's/ Birfields instead of UJ's. I managed to achieve this. I widened my Salisbury axles to just about the same width as coiler axles. I had them cut and welded by an engineering shop and while they were busy with the front, changed the series flanges to defender 7 bolt flanges. From here it's all defender spares. 298mm vented discs up front with 4 pot calipers and 298m solid discs at the back with 2 pot calipers. I'm using a early defender brake master and servo. Only issue I have is because of my Toyota box I have to run 2 sets of calipers at the back, a set from a Audi turbo for the handbrake mechanism.

With the back axle widened I'm running the same side shaft on both sides of the diff.

[missingsid]

Mine are the same, and they have been running for the past 4-5 years, no issues.

G

Good thread well done, it is interesting the different routes taken.

I am in the middle of a long build using RRC parts as I wanted to use as many un modded parts as possible. Not sure about the front but at the rear a RRC but will fit a late SIII stub axle with equal size bearings instead of the early stub axle.

This does of course mean non series look though and a spacer to cover the 3mm diference in stub axle lentgh.

This wouldalso cover the lost axle width with the removal of the drums.

You have the advantage that the axle is clearly std and therefore may help retaining DVLA points which is important to me as I am very close to the limit.

Marc

[Gareth Dickens]

That's one great thing about being in Africa. Less rules and regulations, and the ones there are, are hardly enforced. That being said though, I have no death wish and want my family to be safe. My goal is the safest non - electronic vehicle possible. If I apply the brakes, she must stop. Using std. spares is also not a compromise I can make.

Very well done on this build.

Please let us know what the braking performance is like.

[aaronledwidge]

Wow sounds like a few really novel approaches there. I was tempted to mate disco flanges but didn't think I would be able to jig them up well enough, any pics of both setups?

Aaron

[Gareth Dickens]

Here's what the axles look like. I still need to attach the brackets for the radius arms, coils, shocks and anti-roll bars.

[aaronledwidge]

Ah cool nice and tidy job they have done there, did you reset the castor on the front? Or is that dine with the coil mountings?

[Gareth Dickens]

Ah cool nice and tidy job they have done there, did you reset the castor on the front? Or is that dine with the coil mountings?

That will be done with the coil mounts and radius arm mounts.

Can anyone give me the standard defender/RRC axle tube widths for front and back? I'd like to see how close mine are to standard.

Mine are currently 1095mm (front) and 1390mm (rear)

The reason I took this approach was that I really love the big 4 pot calipers and 12" vented discs from the defender puma up front and the 2 pot calipers on 12" discs at the back. I wanna be able to lock up the 33" x 12.5" BF Muds if I have to.

I'm looking for some time to assemble the front axle so I can measure the required front sideshaft lengths. I'm hoping for standard lengths, but if not will have some chromolly shafts made. Found a company that sells 4340 (basically EN24) here.

[aaronledwidge]

Ahthatsfair enough mate I'd imagine you would have a bloody capable braking setup then. I don't need anything too overkill just brakes that will be reasonable when income out of water.

[missingsid]

Hi,

RRC Rear axle tube flange to flange is 1,394mm

RRC Front as above is 1,087mm

Marc

[Pollywog]

Just a thought on balancing front to rear. The discs will require a higher pressure to get the same braking effort as the drums on the rear. Achieving the pressure for the discs is not a problem (push the pedal a bit harder), but stopping the rear wheels locking s a bit more of a problem.

I've done three conversions with bought in bits; on the 109 the problem was solved by substituting the 3/4" wheel cylinders from the 88. On the Series 1 and the 2b I got around the problem by using a remote servo that only worked on the discs with the rear drums using unboosted pressure direct from the master cylinder.

It seems to work.

When I fitted my Heystee kit a few months ago I left the rears completely standard and fitted a defender pedal assembly with the type 50 servo and master. I don't have any problems with the rears locking up and that's on a swb truck cab. I have tried doing emergency stops on wet road and in quite sloppy mud, it pulls up nice and straight.

[Gareth Dickens]

When I fitted my Heystee kit a few months ago I left the rears completely standard and fitted a defender pedal assembly with the type 50 servo and master. I don't have any problems with the rears locking up and that's on a swb truck cab. I have tried doing emergency stops on wet road and in quite sloppy mud, it pulls up nice and straight.

What's the type 50 servo? I've got the early servo. The servo is smaller than the later ones, but the master is much bigger with 2 outlet ports.

Hi,

RRC Rear axle tube flange to flange is 1,394mm

RRC Front as above is 1,087mm

Marc

Thanks very much for the info,Mark. That is very close to my own, and given that I had to measure around the crown wheel, they might be identical and I may even be lucky enough to be able to run standard shafts. I have one standard shaft to measure with so far.

Ahthatsfair enough mate I'd imagine you would have a bloody capable braking setup then. I don't need anything too overkill just brakes that will be reasonable when income out of water.

I mentioned in some older posts that we travel long distances (3000km round trip is still short) at high speed here (+/-120kph) with a fully loaded vehicle and trailer, so I cannot take chances with braking performance. We also have large game (kudu) that suffer from "nightblindness" at dawn and dusk and tend to wander into the roads at theses times as well a unpredictable local drivers and pedestrians.