Lotus Elan Master & Slave Cylinders

[@richardcooper9417]

My experience suggests that the problem usually lies with the rubber seal in the slave cylinder; if you look at it, it is situated next to the exhaust pipe, and suffers a lot of thermal stress. That is the first bit I would replace. Cheap enough too!

[@peterlumsden5248]

Nice one Paul. Going though the same thing now. Cheers.

[@seanchapman5731]

Paul, thanks for the video. I am about to replace the brake master cylinder seals in my Elan +2. Some years ago my clutch pedal went straight to the floor with no resistance. The non return valve was the culprit - the one with little spring washer in your video. In my case there was rust inside the cylinder from long term storage, and I think some muck was stopping the valve closing. I was very careful with the brake master cylinder, which has the same single point of failure but which in that case could lead to lots of pain. Do you know if there's a master cylinder out there that avoids this? It's the one thing that I am really nervous of with the Elan, but it's the same on any car with that type of master cylinder. Regards. Sean.

[@PaulH_S2_Elan]

Glad you like the video. It might be worth looking into a dual circuit master cylinder, where two wheels (opposite corners) are on each circuit. I'm not certain it gets rid of the valve problem, but looking a cross section diagrams it may well do so. I'm sure if you ask on lotuselan.net someone will know the answer.

[@frankhoward7645]

Another great video from Paul. Been rebuilding British hydraulics since 1970. Never took the time to understand what the non-return spring was for. Thanks for explaining it. I remember the master cylinder caps on my first car, a 1964 TR-4. They said "Use Girling Crimson Fluid Only". I thought it was nothing but an advertisement for Castrol so I ignored them. Found out a few months later when my car began leaking brake fluid from both calipers and both wheel cylinders that the warning was not an advertisement, but a legitimate warning. Apparently, the seals were made of pure rubber which regular brake fluid attacked and turned into chewing gum. Because Castrol Girling was plant based, it wouldn't dissolve the rubber. I would guess that since that time, the seals supplied in kits are made of neoprene which is not affected but I'm still paranoid about using anything but Castrol. Do you think I can put my concerns to rest and use anything off the shelf?

[@PaulH_S2_Elan]

I've used Universal Brake Fluid DOT 4 which I happened to buy from Millers when I bought engine oil from them. I imagine any supplier of DOT 4 brake fluid will be fine.

[@alro2434]

Girling Rubber Grease for the piston & seal will make it last A LOT longer, brake fluid, even Crimson, isn't that good a lubricant, especially for those very soft seals. Also, the old wives tale of any other then Girling Crimson will kill the seals is partly true only if the fluid is not DOT 3 or 4, or some shite from a 7/11 that lies! Also, also, remove the clutch fork's return spring, the release bearing is more then good enough to last forever while lightly rubbing continuously with no real load, and now the clutch is SELF ADJUSTING!

[@PaulH_S2_Elan]

OK, interesting. I'll have to investigate.