Lotus Elan

Help requested for federal brake servo size

PostPost by: sabbot » 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
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PostPost by: rdssdi » Sun May 03, 2020 5:18 pm

LE72696 is he part number for booster, mounting bracket etc. LR17818 booster alone.

1:9 to 1.


http://tr4a.weebly.com/uploads/2/1/9/8/ ... lation.pdf
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PostPost by: GLB » Sun May 03, 2020 6:56 pm

I am in the process of putting boosters back on my +2s, I had one from when I bought the car and was missing the other. Found the second one on Ebay many years ago. Both inop. My understanding is that they are 3-1, My Europa has 2-1. The Europa ones work very well and I like them. I sent my 3-1 boosters to Karps brake service in CA last summer. One was rebuildable and the other not. Both would require some cylinder sleeves but one required a new piston push rod which he did not have. After some months I found that jlsspares in UK had them. Long story short he bought some and was able to repair both of my boosters. They are installed and waiting for me to bleed them and fit vacuum line. Hopefully today or tomorrow. Any way the person I talked to at Karps, presumably the owner, said he had some Girling booster cores he had been unable to repair because of corroded push rods and now he could. You might call him and see if he has one he could sell you. I believe he certainly could repair yours. He also offered as a work around Lockheed booster, available from him. I found out about him from a Jaguar restorer. He has had E type boosters repaired there and was happy. No affiliation to me with either of them and I have not tried the repaired boosters yet but he is easy to talk to. Karps brake service 1 909 985 0800. Gary
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PostPost by: sabbot » Tue May 05, 2020 2:13 am

Thanks for the suggestions and catching that I had accidentally listed the servo kit numbers rather than the servo
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PostPost by: ElanDNA » Tue May 05, 2020 7:53 am

Hi all
The PDF below may be helpful. It's for a singel line braking system.
See under GIRLING ( Interchangeability )
Lotus Elan F H Coupe +2 64049354 LE10117
Urs
Attachments
Bremskraftverst. Lockheed.PDF
(613.39 KiB) Downloaded 106 times
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PostPost by: sabbot » Fri May 08, 2020 4:02 am

Thanks
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PostPost by: alan.barker » Fri May 08, 2020 6:39 am

Hi Sabbot,
a little bit of info. The Servos need to be fitted at an angle so the Valve releases after Brakes have been used. Some owners have added a light spring to help release.
Alan
Alan.b Brittany 1972 elan sprint fhc Lagoon Blue 0460E
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