Series III Braking Systems

[Retroanaconda]

I'm back again

Question this time is brakes. I've been doing some research and have found out that my 1972 Series III SWB should have standard 10" drums all round, on a single-line non-servo system. As far as I can tell this is the case, although it has had one of those 'remote servo' kits added. Since I am going to be re-building or replacing most of the braking system during the course of my reconstruction, I thought I'd take the opportunity to upgrade to the post-rationalisation (1980) dual-line and power-assisted system, that I am led to believe consisted of a 11" twin-leading-shoe setup on the front, and standard 10" on the back albeit with the larger bore pre-1980 SWB front slave cylinders, I imagine for better front/rear balancing.

Series III servos are readily available, but servo-assisted pedal boxes are like gold dust so I have a brake servo and pedal box coming which originated in an early 90/110. Hopefully this will fit under the bonnet (I have heard that it will....and it came cheap)

I also have a brand new genuine dual-line master cylinder NRC6096, which I got for £23 on eBay. Bargain!

The vehicle currently has single-line brakes and as such no PDWA valve, from what I have read these are largely unnecessary apart from hindering bleeding?

My plan is this:

• Early 90/110 pedal box and servo fitted to Series III bulkhead
• NRC6096 dual-line master cylinder
• No PDWA valve
• 11" post-1980 twin-leading shoe on front
• 10" post-1980 standard on rear

Does this sound plausible? From everything I've gathered from the parts books/workshop manuals it seems to be the norm, but it would be lovely to hear it confirmed by some people with Series experience. I imagine it would have been a popular upgrade in the days.

The only thing that concerns me is reports I've read of the twin-leading-shoe brakes being naff at holding you on upward hills? I can see the logic here, but with a relatively light soft top SWB, and some 'normal' shoes on the back wheels I can't see it being a major issue surely?

[rtbarton]

I think you've got that pretty well sussed.

As for holding it on a hill, I'd be inclined ( ) to use the handbrake, a sort of sticky-out lever near the drivers seat.

One thing that might be an issue is locking the front brakes while braking hard, fitting 750 x 16 tyres will reduce this risk.

[Retroanaconda]

I think you've got that pretty well sussed.

As for holding it on a hill, I'd be inclined ( ) to use the handbrake, a sort of sticky-out lever near the drivers seat.

One thing that might be an issue is locking the front brakes while braking hard, fitting 750 x 16 tyres will reduce this risk.

Oh that's what that thing is for? I always thought it was for impressing ladies with sideways antics...

Heh, thanks

7.50 x 16s will be going on, that's the current plan anyhow

[Soren Frimodt]

I'm not sure they had the twin leading shoe setup as per 109's did they? Didn't they just have an 11" version of the normal 88" setup? The same as fitted to a 109 Rearend?

Anyhow that's what I fitted in front on my 88" series 2 and it helped a lot on the stopping power. I installed this kit exactly because I did not want the double leading setup from the 109" because of poor brake quality in reverse.

[Retroanaconda]

According to my parts book:

1980-on SWB has TLS setup on the front

[92a]

When I built mine,(I used a 90 bulkhead)I had to shorten the pedal box by 25mm to get the bonnet to close.Also pedal had to be shortened. My Haynes manual has a seperate chapter for later 11" brakes on the swb,

[Soren Frimodt]

Okay I see. Well I've never looked into it that much as I knew I didn't want the TLS setup. So you could consider doing it the way I did it if you are worried about the braking power when going backwards. But if I am to be honest I don't see it as that much of a problem since all the weight will be on your rear wheels anyway.

[missingsid]

I am confused.

Why would you compromise you forward braking ability due to a limited reverse braking reduction?

Single leading and trailing brakes are this way cos its cheap and easy, not so that its the same braking in both directions.

TLS was an improvement for safety.

Marc.

[Soren Frimodt]

Well I didn't "weaken" the braking power on my S2. I still enhanced it by fitting this compared to stock. And so would Retroanaconda do if he installed this setup.

But as I wrote, looking back on it I'm not sure it matters that much as the weight is mostly at the rearwheels. But it is simpler to do it the way I did because you use the same wheel cylinder as it does on the stock brake setup.

[paulnb57]

Reg

My Series 1 88 has late Series 3 axles and brakes TLS at the front and holding on the brakes on a hill is not an issue at all - it feels a bit less effective if reversing though..........the Series 3 servo is also fitted - the brake master cylinder has 2 outlets and I just installed a t piece into the single line sysyem - all works well..........TLS are a bit of a pain to adjust though.

Paul

[Retroanaconda]

Thanks for the responses guys.

I think I will go TLS on the front, it does make sense given that I am unlikely to be doing a huge amount of distance or speed in reverse

Soren, if I was 'upgrading' a working vehicle then I would likely just go to standard 11"s all-round as you say, but since I will be replacing most of the braking system anyway it makes sense to go TLS while at it. If the front slaves do turn out to be servicable (unlikely) then they can go on the rears, as it's the same part pre-change front and post-change rear on 88"s.

[CJRH]

The brake servo and pedal box from an early 90/110 does fit under the bonnet, the only thing you have to do is make the slot longer in the bulkhead where the pedal fits through. I've got the same on my 2a but with disc brakes up front.

Chris