• Colin & Valerie Bugler
    6 May 2022 at 14:17 #56019

    I own a 1935 Lg6 and I am looking to improve the braking as I am getting a hard pedal with poor braking performance.
    I have removed the master cylinder and sent for new seals to find that the unit fitted is a later 1950’s commercial unit.
    The unit in question is a Lockheed 1 1/2 inch cylinder part number 27273/2.
    When I search the forum I found that the original should be 1 1/4 inch and the exact symptoms I’m experiencing were described on a post comparing both sizes of cylinder.
    My question is are there any original cylinders available?
    If I sleeve the existing down to 1 1/4 should I be able to achieve the desired result?
    Is there an alternative modern cylinder fix?
    All help gratefully received,
    Regards Paul

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    D R Hine
    30 May 2022 at 11:34 #56831

    This master cylinder should work OK if you fit all new seals and valves
    The main thing is to ensure there is a gap between the pedal plunger and the unit when you release the pedal so that all can return including the mid way piston if one is fitted.
    The 4 slave cylinders may need re sleeving by someone like Past Parts
    kind regards
    David Hine

    L C Hannam
    2 June 2022 at 09:43 #56862

    Your cylinder looks similar to those fitted originally, HOWEVER … there should be a threaded union boss on the side shown, for the outlet to the front brakes. The original is a dual circuit cylinder, which means two independent fluid circuits; if one fails, you still have somebrakes. It may be that yours has the boss on the other side, otherwise, if you have only one outlet, you first need to consider finding an alternative twin circuit master cylinder. You may find HCS or LMB stock something suitable. The larger bore size will give you the wrong ratio of leverage, so, yes, if you stay with that cylinder, have it sleeved to 1 1/4″. You will almost certainly find the slave cylinder bores corroded. I had mine sleeved by Past Parts … but they managed to lose my original nipples through poor return packaging … and then their plater lost the 4 spare nipples I sent! Get it all sleeved in stainless, and use silicone fluid. Standard fluid attracts moisture, which corrodes. Bleeding the system does NOT flush the system out … I’ve proved this with my own LG6. Bled the system comprehensively, then dismantled the slave cylinders … full of crud, and that after having been cleaned out only a few thousand miles previously! Oh, just remembered … I think Ecurie Bertelli can supply newly manufactured correct master cylinders … yes, Aston Martins used the same ones. Aston prices though, I think £1000 plus!

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