Help requested for federal brake servo size
Posted: Sat May 02, 2020 7:47 pm
Hi,
I’m in the middle of rebuilding the brakes on my 1972 federal +2, which has never had its brake servos fitted. However in my boxes of parts from other lotus I happen to have two brake servos; an original girling mk2b servo (5.5” diaphragm) and a Lockheed 3232656C servo (6” diaphragm).
I want to fit two identical servos (the federal +2 have dual circuit brakes) and obtaining another girling mk2b unit seems nigh on impossible.
My questions are does anybody know what the correct Lockheed servo is when fitting two of them to a +2? Also does Lockheed part 3232656C equal LE10117 or LE 27696 or some other part?
Moss motors lists two different parts for Lockheed servos and doesn’t list the diameter of the diaphragm but from other sites it seems as though they are both are 7” and the Lockheed servo I already have is definitely 6”.
According to moss motors Lockheed part LE10117 was fitted to the +2 but doesn’t indicate whether it was for single or duel circuit brakes but does list the servo as having a power assistance ratio of 3:1 and 5/8 cylinder bore
Also According to moss Lockheed part LE27696 was fitted to the elan S4, with a power assistance ratio of 1.9:1 and has a 11/16 bore
My gut feel tells me that fitting two servos with a power assistance ratio of 3:1 will be overkill and I assume the higher power assistance level is obtained by using a larger diameter / area diaphragm but I don’t know for sure that the LE27696 has a 6” diaphragm and is the equivalent of the 3232656C unit that I already have.
Any advice would be appreciated - thanks
I’m in the middle of rebuilding the brakes on my 1972 federal +2, which has never had its brake servos fitted. However in my boxes of parts from other lotus I happen to have two brake servos; an original girling mk2b servo (5.5” diaphragm) and a Lockheed 3232656C servo (6” diaphragm).
I want to fit two identical servos (the federal +2 have dual circuit brakes) and obtaining another girling mk2b unit seems nigh on impossible.
My questions are does anybody know what the correct Lockheed servo is when fitting two of them to a +2? Also does Lockheed part 3232656C equal LE10117 or LE 27696 or some other part?
Moss motors lists two different parts for Lockheed servos and doesn’t list the diameter of the diaphragm but from other sites it seems as though they are both are 7” and the Lockheed servo I already have is definitely 6”.
According to moss motors Lockheed part LE10117 was fitted to the +2 but doesn’t indicate whether it was for single or duel circuit brakes but does list the servo as having a power assistance ratio of 3:1 and 5/8 cylinder bore
Also According to moss Lockheed part LE27696 was fitted to the elan S4, with a power assistance ratio of 1.9:1 and has a 11/16 bore
My gut feel tells me that fitting two servos with a power assistance ratio of 3:1 will be overkill and I assume the higher power assistance level is obtained by using a larger diameter / area diaphragm but I don’t know for sure that the LE27696 has a 6” diaphragm and is the equivalent of the 3232656C unit that I already have.
Any advice would be appreciated - thanks