county 110 brake upgrade to defender rear disc

[asmit]

Hi there,


When I got my 1985 Land Rover 110 it was standard with dual circuit brakes and drums on the rear.
I decided to upgrade it to rear disc brakes, so I used defender/perentie rear axle disc brake parts including STC1268, STC1269 calipers and solid discs.
This works great, however the vehicle now appears to have 50/50 or maybe even rear braking bias.
I would like to bring the braking bias to the front, and upgrade the system as a whole for increased braking performance.
I would like to stick to standard Defender parts, because I think that will be more maintainable in the future than the perentie PBR master cylinder P10316 and VH524 booster setup.
So I've been trying to figure out which combination of brake master cylinder, servo booster, front calipers and proportioning valves will work best.
I realise by doing this I am altering the original braking system of the vehicle, and among other details I will have to make new brake lines.


I have a few specific questions:


If the original LH caliper is part number RTC5573 will the later model part STC1267 and subsequently SEB500470 fit the bolt holes and clearances on the 1985 swivel housing?
Can I simply fit a post 1994 model defender master cylinder (STC441) and servo booster (STC442), and copy the braking system used on those vehicles?
Do I need to fit the valve part number ANR1415 or NRC7871 or any other of the various listed brake valves? The Defender workshop manual states that only Defender 90's had PVR's fitted pending regional requirments.




To add a little more complication, I have recently replaced the whole front axle assembly with one from a 1995 discovery. At which point I re-used the original calipers from the 1985 110 axle because of the brake pipe setup, so I'm using discovery front swivel hubs.

[Red90]

110s don't use bias valves. The rear discs should be less prone to locking up than the drums. Changing the master/booster won't do anything to the bias. Changing the front calipers won't do anything (they are the same piston size and pad area in the newest ones as the oldest ones).

Really you probably just need better quality front pads.

To fit the later style booster/master, you need to either modify the pedal box or change to the later pedal box.

If you really want a bias valve, I would install an aftermarket adjustable one, which will let you set it up to the best amount of bias.

[asmit]

Hi Red90, thanks for the comprehensive response, that solves most of my questions.

Just one thing is bugging me:


Changing the master/booster won't do anything to the bias.
I am struggling to understand the difference between my earlier style master cylinder with the 2 outputs and the later defender style with 3 outputs, which Defenders seemingly transitioned to at the same time as rear disc brakes, leading me to believe the 3 output master cylinders are better suited to this application?

thanks

[Red90]

The three output master has a dedicated line to each front wheel. The single goes to the PDWA and then splits to each front wheel. They both do the same thing.

[clive22]

Hi

Years ago I converted my County from Drums to disks.

I ended up using a discovery 1 master cylinder & modified by the pedal box to suit. File job mainly.

Worked much much better than the county master.

Valve ratios are different fro disk and drums. Plus you get a second circuit which is a good thing

I cant remember exactly but there are some old but very good threads from RidjiDidj and SClarke which detailed everything you needed to do.

Back in 2008,9,10 i thnik

Clibe

[eeyore]

I've done this is conversion recently too, and agree with Clive. Fitted an early Disco 1 master cylinder as per the AULRO thread and have found the braking to be vastly improved. No noticeable change in bias, plus much better pedal modulation (and of course, far more braking power). My is a ute too, so would be susceptible when empty to any new rearward bias.

[asmit]

So I bought a new master cylinder (turns out mine has been leaking) NRC8690 and brake booster STC2878. These are original 110 county parts.
I upgraded to defender brake callipers and vented disc combination after a bit of research. It took me a while before I realised county front callipers are very different from defender ones, and the pads are slightly larger in defender callipers too. Here is a photo of the 3 different calipers I have right now, Defender vented vs county vs discovery 1, (also defender 90 and perentie rfsv/6x6 rear).

142133

New later model defender brake callipers SEB500470 and SEB500460 and EBC pads DA4159 (green stuff defender front).
DBA brake rotors, DBA086S woohoo vented, I went with the slotted ones because I couldn't get a good answer from google weather it's worth it or not to go slotted, so I figured I'll have to try it.
Also I had terrafirma stainless braided brake lines laying around so I've fitted them also, hoping the steel lines help my pedal feel.
It was very handy to also have new swivel housing brackets FRC7201, FRC7202 and brake pipe sections (from caliper to flex hose) available ANR2946, ANR2947.

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At this point, I'm worried I have made the wrong choice of parts and should have got a disco 1 master STC1285 and booster STC1286, or even defender parts STC441 & STC442.

Ah well, I'm half way through this setup, so I'll give it a try.

[asmit]

pedal box reco, new booster, master all painted and fitted!

I just scraped old gaskets and used loctite blue maxx to seal the pedal box to bulkhead, and servo to pedal box.

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[asmit]

So I've done a 1500k or so now, and I'm happy with the braking performance. It has very good instant touch. The 200k bed in period was no problem.

One other thing I did at the time was swap the primary (rear) and secondary (front) outputs from the master cylinder where it goes into the safety valve as I previously has rear brake bias, and because this master cylinder is for a drum brake rear axle I'm thinking it might push more fluid to drum brakes, but I dont really know.

So my braking bias is definitley to the front axle now.

The EBC green pads do appear to be pretty dusty, but no big deal.

The reason I replaced the master cyl is because the old one was leaving around the reservoir, I got TRW this time and it appears the same as the one I had previous, so hopefully it lasts longer. The new Allmakes brand booster works very well too.

Also, replacing all 4 drive flanges at the same time with terrafirma ones has made a big difference to my drive-train backlash making it a more pleasant drive.

[clive22]

Hi

It's a good converting a County to Disk even better when you use better late model Defender gear.

I loved by Disk rear conversion and I only used Disco rear calipers and stayed with County fronts.

Don't rate drums for off road cars. Fill up with mud. Water ingress impact brake performance

Drums on rear are real hairy when backing down a failed hill climb. The shoes are opening the against the rotation and so you have to press harder on the pedal- but, due to the normal front bias, this then locks the unloaded fronts- pivoting the car around sideways to the hill. Even worse if the drums are wet from say a creek crossing.

So is replacing the driveflanges, high wear item if you ask me.

Clive Austin

[Red90]

The drums on a Defender are not front biased. They are the same in both directions.

[justinc]

In my 1985 110, I have Defender front and rear brakes, booster and master cyl. Straight off a donor. Totally improved the brakes out of sight! Also fitted front and rear sway bars, so handles like a 'newer' defender now, too.
I've had a few people drive it and comment on its road manners.

JC

[asmit]

In my 1985 110, I have Defender front and rear brakes, booster and master cyl. Straight off a donor. Totally improved the brakes out of sight! Also fitted front and rear sway bars, so handles like a 'newer' defender now, too.
I've had a few people drive it and comment on its road manners.

JC

Sounds really good, did you use the brake lines to the front wheels off the donor and do away with the PDWA valve?

I figured all civilian 110's had a rear sway bar factory? I do find the county with rear sway bar has much better road manners than a perentie. I've never driven something with a front sway bar too.