Any Leyland 4/98 NV experts who can identify a part?

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jeff mann
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Any Leyland 4/98 NV experts who can identify a part?

Post #1 by jeff mann » Mon Apr 03, 2017 5:11 pm

Hi all
i have a boat with a jcb leyland thorneycroft 4/98 NV normally aspirated engine..
just forward of the DPA pump is a box that appear to be some kind of diaphragm ,and it has a threaded hole below one of the nuts that is sucking in air ..my question is ..what is it (see pictures attached , ? should it be blanked off with a plug (it is threaded) and if i put my thumb over it it is sucking quiet vigourously but nothing seems to happen to engine speed or sound??? anyone know what this thing is for please?..
my pics are at the bottom of this post (i think)
HAS ANYONE ANY IDEA WHAT THIS IS??
Thanks gentlemen
Jeff




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jeff mann
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Re: Any Leyland 4/98 NV experts who can identify a part?

Post #2 by jeff mann » Tue Apr 04, 2017 3:33 pm

Hi all
i have a boat with a jcb leyland thorneycroft 4/98 NV normally aspirated engine..
just forward of the DPA pump is a box that appear to be some kind of diaphragm ,and it has a threaded hole below one of the nuts that is sucking in air ..my question is ..what is it (see pictures attached , ? should it be blanked off with a plug (it is threaded) and if i put my thumb over it it is sucking quiet vigourously but nothing seems to happen to engine speed or sound??? anyone know what this thing is for please?..
my pics are at the bottom of this post (i think)
HAS ANYONE ANY IDEA WHAT THIS IS??
Thanks gentlemen
Jeff
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Mrsmackpaul
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Re: Any Leyland 4/98 NV experts who can identify a part?

Post #3 by Mrsmackpaul » Tue Apr 04, 2017 9:01 pm

nope sorry I have no idea

Paul
Your better to die trying than live on your knees begging

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FOWLER MAN
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Re: Any Leyland 4/98 NV experts who can identify a part?

Post #4 by FOWLER MAN » Wed Apr 05, 2017 1:56 am

Hi Jeff,
I reckon that's an exhauster, (vacuum pump).
Be interesting to know what it says on the small plate riveted to the pump flange in the pic., (Possibly Clayton Dewandre).

Your engine was obviously fitted to something with servo assisted brakes or controls at one time. The exhausters usually provided about 25 lbs. of vacuum to a vacuum storage tank which provided assistance to servo brakes or operated hydrovac brakes.

I converted ex. BRS Leyland Octopuses' from servo to the more efficient hydrovac system back in the days before air brakes were the universal standard. The vacuum brakes were still used on smaller trucks well into the 1970s and possibly later.
Fred


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Re: Any Leyland 4/98 NV experts who can identify a part?

Post #5 by jeff mann » Wed Apr 05, 2017 9:13 am

Thanks Fred
What you say makes perfect sense ....so it doesn't matter if its blocked off or left open sucking air in as there are no brakes on the boat
I will go today to see what is on the plate and will let you know
Thanks again
Jeff


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