[Vwdiesel] Fw: Crankcase ventilation / rotary vacuum pump

[mark shepherd]

----- Original Message ----- 
From: "mark shepherd" <mark at shepher.fsnet.co.uk>
To: "Craig Osborn" <cosborn at epix.net>
Sent: Thursday, July 02, 2009 11:27 PM
Subject: Re: [Vwdiesel] Crankcase ventilation / rotary vacuum pump


> Blank off the sump ventilation and ventilate from the cam cover only. Only 
> the brake servo/booster should attach to the vacc line [maybe some small 
> control lines too eg a/c...]
>
> Mark
> ----- Original Message ----- 
> From: "Craig Osborn" <cosborn at epix.net>
> To: <vwdiesel at vwfans.com>
> Sent: Thursday, July 02, 2009 11:11 PM
> Subject: [Vwdiesel] Crankcase ventilation / rotary vacuum pump
>
>
>>
>> I recently purchased a rotary vacuum pump that was advertised as a bolt 
>> on
>> replacement for my old diaphragm type vacuum pump on my 1981 PU.
>> When I started to install the pump I noticed that it only had one hose
>> fitting whereas the old diaphragm pump had two hose fittings (one on the 
>> top
>> that went to the brake servo, and one on the side that went to the
>> crankcase).
>> I took the car around the block after hooking up the vacuum hose to the 
>> top
>> fitting without attaching the crankcase hose to anything and I had the 
>> best
>> braking power that I have had in years.
>> I then called "Parts Place" to ask what to do about the crankcase
>> ventilation hose and they said that many of their customers were putting 
>> a
>> T-fitting on the top and attaching both hoses this way.  When I did this, 
>> my
>> braking power decreased markedly.
>> I then took my old diaphragm pump and spun the gear and noticed that it
>> pulled a vacuum in the top hose fitting but put positive pressure out of 
>> the
>> bottom fitting where the hose would attach that would go to the 
>> crankcase.
>> Given this discovery, it seems as though the recommended T fitting would 
>> not
>> be the proper thing to do.
>> Can anyone help me retrofit this pump properly on to my 1981?  Maybe 
>> someone
>> with a 1984 (when they started factory installing the rotary pumps) can
>> explain how their ventilation system is set up.
>>
>> Craig
>>
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>>
>