BrakeTandem master cylinder upgrade on S3

[lotus36]

I am looking for info on upgrading a early Elan's brake master cylinder to a tandem circuit master. Any information would be a great help. I don't want to use a late Elan unit as these are so scarce. Has anyone used a Japanese unit? Thanks in advance, Larry

[types26/36]

I dont know if this thread will be of any help although it looks like some images have been removed.
lotus-suspension-f42/can-you-identify-this-master-cylinder-t21951.html#p132296

[UAB807F]

I used one from a Triumph Spitfire, 0.7" bore, part Number GMC 226 and easily available. The bolt pattern is the same but the reservoir is a wedge shape and not really suitable although it will fit at a pinch. On the Spitfire, the m/cyl is fitted at an angle, so it ends up with the correct fluid levels.

It didn't matter as I also wanted a remote reservoir to make monitoring/refilling easier.

Brian

Elan Dual Circuit Brakes002a.jpg (79.35 KiB) Viewed 1575 times

and once in place -

Elan Dual Circuit Brakes003a.jpg (82.97 KiB) Viewed 1575 times

[lotus36]

I will investigate the Triumph MC. What fittings did you use in the master cylinder for the remote fill. The main issue is the overall length. My car is a LHD and the master is tight to the fiberglass. Thank you very much for you imput. Regards, Larry

[UAB807F]

Ah, I overlooked the LHD aspect and it might not be such a good option for you then with the way the outlets are arranged.

The fittings are nothing special. On the reservoir side the rubber grommets are the ones that came with the unit, the 45 degree angle pipes are just typical adapters that you can buy for brake systems. I can't recall what they were from, but they are commonly fitted to a lot of master cylinders - VW, Fiat, etc. I think I bought mine from a Race/Rally shop.

The tubing is reinforced fuel injection lines, definitely over-engineered for the mechanical duty but reassuringly solid. The remote reservoir itself is a typical kit-car unit complete with a low level level indicator, which is wired to bring on the handbrake light on fluid loss.

The only other thing worth noting is that the threads for the brake pipes are metric and not Imperial. So the lines have a metric fitting at the m/cyl and Imperial where they meet the rest of the system.

Brian

[lotus36]

Hi Brian, Thanks for the info. I believe Lotus arranged the brake and clutch masters in a way to give more room to the RHD layout. They just left the same layout for the LHD layout creating a tight situation on the brake master to wheel arch inner. Modifying the wheel well to clear a long master could actually interfere with the left front tire.
I have a pedal ass'y on my bench and I may reverse the pedal action so that the brake master is on the right. This would give much more room. I believe the port location will be ok with a banjo fitting setup. It's all in my head and my head is full. Time to make some good drawings. Thanks again for your imput. Larry

[Galwaylotus]

Here's a thread on that subject: http://www.lotuselan.net/forums/lotus-suspension-f42/tandem-master-cylinder-t19064-30.html. I replaced my single circuit master cylinder with a tandem cylinder of the same bore and removed my servo.

[Elan45]

The Super Safety model installed a Girling dual circuit master cylinder into the S3 body. The inner wing (fender) of the body was modified for the MC to fit. You don't need a MC specifically for Lotus, just a Girling cylinder in the correct diameter. You should be able to deal w/ a British supplier such as Moss. I suppose a Japanese cylinder is also a way out, but I can;t give you a model to look for.

Roger