In search of the best 5/8" tandem brake master cylinder

[h20hamelan]

260-14241-BK - Wilwood

mounted sideways?

[2cams70]

I doubt a race car setup with independent master cylinders will be legal for the road. I think the regulatory requirement is that there is feedback through a sudden increase in pedal travel to indicate that a circuit has failed. You want that feedback before the car swaps ends on you!

[h20hamelan]

Interesting, did not consider that.
The Elan circuits I believe are set up as front drivers as one. The passenger and rear as another.
As I dont think anyone on here has donated an Elan to you as of yet 2cams70, for your excellent contributions.

[mikealdren]

Not sure if has changed but from my days running Vauxhall's brake testing at Millbrook in years gone by, the requirement was that secondary braking performance could be achieved with a single circuit failure. Typically the split was front/rear and either failure should immediately be obvious to the driver. With rear circuit only, the braking performance would be significantly reduced but also, potentially locking the rear wheels reduces the car's stability in an emergency. For earlier cars with single circuit brakes, the handbrake provided the secondary braking!

I'm still considering using the twin circuit M/C from the late model Triumph Spitfire. It looks to fit easily but the output would need to run under/over the cylinder and the sloping reservoir would need replacing for horizontal mounting. I think they are 11/16".

[h20hamelan]

I would like to get a dual circuit for my early car too.
Does look like the Mk4 Spitfire should work!

[mbell]

I'm still considering using the twin circuit M/C from the late model Triumph Spitfire.

There may be a few version of the master. I bought one to fit to my +2 but found it too long to physically fit due to its length. It might just fit on a LHD +2 due to slightly more space between peddle box and bulkhead. Not sure about a Elan.

It would fit the +2 RHD if mounted as per the Spitfire mounting angle but that requires modifying the peddle box or coming up with adapter to mount it.

mounted sideways?

I think its more you need to find a way to mount the to the car.

[snowyelan]

Some discussion in the link below. For what its worth I have the Datsun M/C in my S4. Fits just fine but as of yet untested. It has a 11/16" bore (.688").

I may be wrong but didn't the servoed cars have a .75" bore and the un-servoed a .70"? The OP mentioned .625" which I think won't work or would have an extremely long pedal travel?

viewtopic.php?f=42&t=38002&hilit=datsun

[h20hamelan]

For what its worth I have the Datsun M/C in my S4. Fits just fine but as of yet untested. It has a 11/16" bore (.688").

Is this the 1200, and I am guessing you replaced the reservoir?
Also, no interference at the bottom where the lines come out?

As long as it fits, should work!

[mbell]

I may be wrong but didn't the servoed cars have a .75" bore and the un-servoed a .70"? The OP mentioned .625" which I think won't work or would have an extremely long pedal travel?

I am the Op there . I am currently running a 5/8" (0.625) single master on my car. The pedal isn't short but I wouldn't describe it as long, brake engagement is around level with accelerator pedal from memory. There again I've no experience with the standard setup.

I think a 5/8, 11/16 or 7/10 would likely be ok with no servo.

As long as it fits, should work!

It won't fit a +2 as lower protrusions will hit the pedal box, unless you significantly modify it. I think they'll fit a Elan fine thou.

Can't remember if you have an Elan or +2...

[h20hamelan]

2 +2’s, one elan

viewtopic.php?f=42&t=38002&hilit=datsun&start=30

[snowyelan]

The casting looks the same, different reservoirs. It fits. I haven't plumbed it yet but see no issues. Worst case is a banjo off the forward port but I think a standard fitting will do. I did modify the check springs to be reduced from 10psi to 2. The cylinder is meant for a 4 drum setup which needs higher residual pressure. Simply cut the springs shorter. It is close at the forward end but clears the fiberglass.

Its a Centric cylinder, p/n 130.42001. Prof. Google shows it with 2 variations of the reservoirs and lids.

[h20hamelan]

ac delco 18m1072
Is the new part number, as centric is not being made.

[h20hamelan]

It won't fit a +2 as lower protrusions will hit the pedal box, unless you significantly modify it...

I am on the hunt for the +2

[mbell]

I am on the hunt for the +2

The spitfire one should fit if its LHD.On RHD it fouls the corner of the engine bay with the rear outlet. LHD should have slightly more clearance and the outlet will point to the center of the car making it easier to connect the fittings.

[Sea Ranch]

Greetings. Lots of new discussion on this old thread. Nice

Just an update from me: I fitted a Girling brake master, 5/8" bore, with fat reservoir, and plumbed the car (1970 Plus 2S) as single circuit.

My experience: yes, there is some pedal travel but not enough to bother me at all. What I like is the moderate pedal effort. The smaller bore master, combined with high friction pads (currently Porterfield pads in their R-4S compound) makes for very nice braking. And I can lock up the wheels on dry pavement (did it a couple weeks ago while behind someone pulling a u-turn in front of me )

I also fitted a Sovy unit ("customized" a spare Girling aluminum master cap) so that I have a nice bright warning light on the dash if ever the fluid level in the master drops at all (I set it up and run the fluid level so that the light will wink at me around a very hard corner). My feeling is that the Sovy will give me enough warning to allow one good braking effort if I have a slow to moderate system leak/failure.

In any case, been on the road for two and a half years now, including trip down coast to LA and back. Thing brakes fine, and with rebuilt calipers, new rotors, new cunifer lines, et cetera, I'm feeling pretty safe. For now.

Regards to you all . . .

Randy