Leyland glow plug and head gasket replacement

When I first purchased the Leyland it was impossible to start without using easy start, not ideal! However after some testing with a multimeter it turned out that all the glow plugs had failed open circuit, this should have been a simple job, but when I removed the plugs from the head I was greeted by this motley crew;

The tractor had been run with dead plugs for so long that carbon had built up solidly round the tips and caused them to break off when the body of the plugs were un-screwed, the only way to remove the stubs was going to be lifting the head…

Once the head was on the bench the next challenge was to knock out the combustion chambers, eventually achieved using a specially curved rod inserted through the injector hole and hit with a hammer;

Once the stubs from the injector were punched out, the remaning carbon deposits were cleaned out using a 11/64 drill, and the head was de-coked and refitted with a new gasket.

Since then cold starting has not been a problem, no easy start required.

5 thoughts on “Leyland glow plug and head gasket replacement

  1. Hello Michael,

    Thank you for sharing your experience with replaceing plugs. We are faceing the same situation and without your excellent post, we would still have major problems.

    Two of our plugs also broke off when unscrewed and we have removed the combustion chambers for these plugs.
    The problem we have is:
    How do you remove the remaining parts of the plugs that are stuck in the head? Our workshop manual for Leyland 154 does not describe this type of mishaps…

    We would be very grateful for some support in this matter!

    Thank you and best regards,


    • Take a small parallel punch and hammer and gently tap them out. They will be stuck in with carbon deposits which are not too tough. Once you have the broken bits of the plugs out drill through as per the original posts to clear any remaining carbon.

      Glad to be of help! Any more questions please ask!


  2. Mike,

    Thank you for a very Swift reply.
    We managed to remove the remaining parts of the plugs. Now the motor is back in place and after we have checked the fuel system I am sure we are up running again!

    Godo luck with future projekts.


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