Sprint Dual Circuit Brakes

[gav]

I always felt that a single circuit braking system was inherently weak in terms of risk and being a coward, thought I'd split the circuits in two.

I purchased a dual master cylinder and set about splitting the circuits using copper lines and goodridge hosing.

So far so good - but the volumes weren't right and I didn't like the shove which was needed to effect full braking - hmm.

Enter dual circuit servo - hugely expensive but remarkably effective.
Now at last all plumbed in and working a treat - lovely pedal feel, great peace of mind.

I am not running a standard set up and have a deep alloy rad between the vac lifters. I found space on the passenger side for the servo which needs access for bleeding on both sides.

Was it worth it? I did achieve dual circuitry from the master all the way through. However - it was quite an effort and very expensive. It does stop well - but it did before (the 4 pots on the front help a lot there).

I don't think I'd go there again. Next time (is he mad?) I might just split the circuitry from the servo and take a risk.

Anyway, I thought I'd share my experiences with you just in case anyone needs putting off!

All I need to do now is get rid of the fuel smell on right handers - floats and tank breather I suspect.

Never a dull moment - ho hum
Gavin

[ElliottN]

Interesting experience. I am about to overhaul my brake master and was thinking of replacing with a dual master instead. I think I'll stick with the original.

Did say you used copper pipe for the reworked brake hydraulics? If so I'd recommend a change to correct bundy piping some time. Sooner or later copper will give under the pressures generated under brake loads. Proper brake hydraulic piping is typically made from cold rolled steel (it may be copper coated) and will handle pressures well in excess of anything drivers and/or boosters can generate.

[RotoFlexible]

I have experienced three brake failures on my single-circuit, unassisted S2 - all my fault in one way or another. The last one resulted in a low-speed crash and a new front clip. From experience, I can recommend two ways to avoid brake problems:

1. Make sure the hairpin clips that hold in the brake pad retainer pins are snug.
2. Don't leave brake lines angled out so that the edge of a wheel can nick them.

I was planning to replace the single MC with a dual MC I have on the shelf, without boosters, but a review of this article at the GCLC site gives me pause. If I read it correctly, the author ditched the dual MC, boosted system in his +2 in favor of a single MC, unboosted system using the Elan MC to achieve acceptable pedal pressure. Perhaps I'll stick with the single MC and just make sure the plumbing is sound.

[Foxie]

Gavin,

I'm very interested in the details of your 4 pot conversion. What caliper/disc are you using ? Is this on the standard Lotus hub, or maybe the Sierra hub ?

Sean Murray

[/quote]
Was it worth it? I did achieve dual circuitry from the master all the way through. However - it was quite an effort and very expensive. It does stop well - but it did before (the 4 pots on the front help a lot there).


Never a dull moment - ho hum
Gavin[/quote]