A Special Builder's Notes


The Special Builder's Breakfast Club

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26 August 2014

Going And Stopping.

On closer examination of the front brake shoes I discovered that one of the ends was half the thickness of the rest and in consequence that shoe wasn't contributing at all. I can't think why I missed that in the assembly but I've since built it up with a steel plate welded to the shoe and, because the linings were a touch thin, I've introduced a 1mm saddle to the operating cam.

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That gives me enough extra diameter to get the shoes to just touch the drum at the minimum adjustment. What it hasn't done is improve the pedal travel. Besides the air in the system, my next discovery was that the master cylinder wasn't 7/8" bore as I supposed, but 3/4". Hence the slaves at 7/8", are bigger than the master - not helpful in my efforts to reduce the pedal travel. I've ordered a 1" master cylinder with the same mounting holes and, at the same time, a modern plastic reservoir that will take a pressure (rather than a vacuum) bleeding system. Everyone seems to have a different opinion on how to reduce the pedal travel but the advice to look at the simpler things first before getting into deep water seems logical; I shall first do the pressure bleeding and secondly look at the position of the actuating rod on the foot pedal and see where that takes me. I've got reasonably effective brakes - no worse than they were originally - but what I've learnt is that simple though hydraulics may appear in theory, their application is more complex. If they look right, they may not necessarily fly right; you've got to do the maths. As breakfast in Holt was on the cards, I clamped each of the pistons at the bottom of their respective cylinders and then re-bled the brakes. The results of this exercise were encouraging enough to proclaim the car roadworthy.


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We met up with Awkward and his Avon Special at Mundford at 7.15 on a chilly Saturday morning but by the time we got to Holt the sun was out and we managed to park right outside the cafe.

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There I discovered that a certain amount of the diff oil had worked its way down the half-shaft casing and was dripping out of the drain hole provided for just such an event. That was the only snag on the trip and on the way back we bowled along happily at an indicated 50-55mph stopping briefly at Awkward's workshop to have a quick look at the diff oil. We drained out what was there (only just enough) and then added the same quantity of engine oil as a get-us-home gesture which revealed that the diff oil might have been too thick in the first place and, after being flung about by the crown wheel and pinion, wasn't falling back to the bottom of the diff casing. There hasn't been any sign of a leak since.

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Breakfast in Holt brought the total mileage to 313 with a slight improvement in mpg at 16.8. Some more tweaking is called for and I must get down to the rolling road. The Morris Six returned at least 24mpg and this prompted me to get Counsel to come and help with the calcs again. We determined the following:

In top gear (1:1) 1000rpm equates to 19.2mph. 2000rpm gives 38.4mph, 3000rpm, 57.6mph and 4000rpm, a heady 76.8mph. That's fast enough for me.









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next post A Curious Conundrum.


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