Vacuum line integrity

1
Hi ALL,

A question please on what is normal/abnormal vacuum line pressure or seal or resistance.

At the vacuum line tube next to the difflock vacuum storage bottle, if I blow back up the tube, I'm querying which is the normal state ... no loss of pressure or a slowish loss of pressure? In other words, should I experience total seal of the vacuum line or only partial? At the moment my blowing back up the vacuum tube is resulting in only partial i.e., partial resistance, not total. Any thoughts please anyone. TIA.

Cheers.

Ken

2
Ken.There is a small one way valve[looks a bit like a fuel filter] on that line near the vacuum resevoir. If you remove it noting which way it is oriented and blow through it the direction of resistance will be revealed. My diff lock wasn't holding vacuum and this valve was leaking when i blew through it or sucked through it. Replaced the valve and now diff lock works fine. Bill

--- In Syncro_.
3
Hi Bill,
Sorry, my query was garbled, let me try and rework it.

My query has arisen following on from my recent investigation, checking on all vacuum lines integrity for better difflock and decoupler functionality. 

Scenario is for my query, I've removed the one way valve you referred to from the "upstream" side of the vacuum line, i.e., now I'm addressing only the vacuum line heading towards the motor. This line routes rearwards down the side of the van until it terminates at the motor. So when applying mouth pressure into the open end of this upstream end vacuum line, I found only partial pressure resistance, not full resistance as would occur in a sealed length of tube. So my query is ... applying mouth pressure to this vacuum line, what should be normal for correct vacuum line functionality? Should it be either a full seal (full resistance) or some leakage (partial resistance)? If it should be a full seal (full resistance), then I need to investigate whether or not a leak is occurring at some point in the line and/or at its end connection at the motor. Any thoughts please either way would be appreciated.  
Cheers.
Ken

To: Syncro_T3_Australia@yahoogroups.com
From: marg_bill@westnet.com.au
Date: Wed, 28 Nov 2012 07:48:24 +0000
Subject: [Syncro_T3_Australia] Re: Vacuum line integrity

 
Ken.There is a small one way valve[looks a bit like a fuel filter] on that line near the vacuum resevoir. If you remove it noting which way it is oriented and blow through it the direction of resistance will be revealed. My diff lock wasn't holding vacuum and this valve was leaking when i blew through it or sucked through it. Replaced the valve and now diff lock works fine. Bill

--- In Syncro_.


4
Ken this line is connected to the inlet manifold. Without the engine running you will not be able to check the viability of any component from this end. The correct method is to fit a mighty vac (hand vacuum pump with gauge) at the motor end and check for leaks down stream. If you don't have a mighty vac you can just get under the bus soon after turning of the engine and check for leaks. A good system will hold residual vacuum for a long time, as the one way valve will seal off the engine and the reservoir will store capacity. I think they did this to give you one or two diff lock operations after stalling an engine. The easy check is to pull the "off" vacuum line from your rear diff lock some time after turning off the engine (hours, days), if there is still vacuum you have a good system. Greg E

From: Ken Garratt <unclekenz@hotmail.com>
To: _T3_Australia forum Syncro <syncro_t3_australia@yahoogroups.com>
Sent: Thursday, 29 November 2012 12:15 AM
Subject: RE: [Syncro_T3_Australia] Re: Vacuum line integrity
 
Hi Bill,
Sorry, my query was garbled, let me try and rework it.

My query has arisen following on from my recent investigation, checking on all vacuum lines integrity for better difflock and decoupler functionality. 

Scenario is for my query, I've removed the one way valve you referred to from the "upstream" side of the vacuum line, i.e., now I'm addressing only the vacuum line heading towards the motor. This line routes rearwards down the side of the van until it terminates at the motor. So when applying mouth pressure into the open end of this upstream end vacuum line, I found only partial pressure resistance, not full resistance as would occur in a sealed length of tube. So my query is ... applying mouth pressure to this vacuum line, what should be normal for correct vacuum line functionality? Should it be either a full seal (full resistance) or some leakage (partial resistance)? If it should be a full seal (full resistance), then I need to investigate whether or not a leak is occurring at some point in the line and/or at its end connection at the motor. Any thoughts please either way would be appreciated.  
Cheers.
Ken

To: Syncro_T3_Australia@yahoogroups.com From: marg_bill@westnet.com.au Date: Wed, 28 Nov 2012 07:48:24 +0000 Subject: [Syncro_T3_Australia] Re: Vacuum line integrity  
Ken.There is a small one way valve[looks a bit like a fuel filter] on that line near the vacuum resevoir. If you remove it noting which way it is oriented and blow through it the direction of resistance will be revealed. My diff lock wasn't holding vacuum and this valve was leaking when i blew through it or sucked through it. Replaced the valve and now diff lock works fine. Bill --- In Syncro_.
 
5
Hi Greg,
I don't have a problem on the downstream side of the one way valve. Just curious about the up stream side appearing to not hold pressure, your explanation clarifies it. Having a look at the vacuum line in the engine bay, is that a one-way valve located in the vacuum line just before it passes through the firewall? If so, might it be suspect?
Cheers.
Ken

To: Syncro_T3_Australia@yahoogroups.com
From: gregespo73@yahoo.com
Date: Wed, 28 Nov 2012 12:44:13 -0800
Subject: Re: [Syncro_T3_Australia] Re: Vacuum line integrity

 

Ken this line is connected to the inlet manifold. Without the engine running you will not be able to check the viability of any component from this end. The correct method is to fit a mighty vac (hand vacuum pump with gauge) at the motor end and check for leaks down stream. If you don't have a mighty vac you can just get under the bus soon after turning of the engine and check for leaks. A good system will hold residual vacuum for a long time, as the one way valve will seal off the engine and the reservoir will store capacity. I think they did this to give you one or two diff lock operations after stalling an engine. The easy check is to pull the "off" vacuum line from your rear diff lock some time after turning off the engine (hours, days), if there is still vacuum you have a good system. Greg E

From: Ken Garratt <unclekenz@hotmail.com>
To: _T3_Australia forum Syncro <syncro_t3_australia@yahoogroups.com>
Sent: Thursday, 29 November 2012 12:15 AM
Subject: RE: [Syncro_T3_Australia] Re: Vacuum line integrity
 
Hi Bill,
Sorry, my query was garbled, let me try and rework it.

My query has arisen following on from my recent investigation, checking on all vacuum lines integrity for better difflock and decoupler functionality. 

Scenario is for my query, I've removed the one way valve you referred to from the "upstream" side of the vacuum line, i.e., now I'm addressing only the vacuum line heading towards the motor. This line routes rearwards down the side of the van until it terminates at the motor. So when applying mouth pressure into the open end of this upstream end vacuum line, I found only partial pressure resistance, not full resistance as would occur in a sealed length of tube. So my query is ... applying mouth pressure to this vacuum line, what should be normal for correct vacuum line functionality? Should it be either a full seal (full resistance) or some leakage (partial resistance)? If it should be a full seal (full resistance), then I need to investigate whether or not a leak is occurring at some point in the line and/or at its end connection at the motor. Any thoughts please either way would be appreciated.  
Cheers.
Ken

To: Syncro_T3_Australia@yahoogroups.com From: marg_bill@westnet.com.au Date: Wed, 28 Nov 2012 07:48:24 +0000 Subject: [Syncro_T3_Australia] Re: Vacuum line integrity  
Ken.There is a small one way valve[looks a bit like a fuel filter] on that line near the vacuum resevoir. If you remove it noting which way it is oriented and blow through it the direction of resistance will be revealed. My diff lock wasn't holding vacuum and this valve was leaking when i blew through it or sucked through it. Replaced the valve and now diff lock works fine. Bill --- In Syncro_.
 

6
No, you are basically sucking and blowing into the inlet manifold. The manifold is open to atmosphere - normal.

From: Ken Garratt <unclekenz@hotmail.com>
To: _T3_Australia forum Syncro <syncro_t3_australia@yahoogroups.com>
Sent: Thursday, 29 November 2012 10:29 PM
Subject: RE: [Syncro_T3_Australia] Re: Vacuum line integrity
 
Hi Greg,
I don't have a problem on the downstream side of the one way valve. Just curious about the up stream side appearing to not hold pressure, your explanation clarifies it. Having a look at the vacuum line in the engine bay, is that a one-way valve located in the vacuum line just before it passes through the firewall? If so, might it be suspect?
Cheers.
Ken
To: Syncro_T3_Australia@yahoogroups.com From: gregespo73@yahoo.com Date: Wed, 28 Nov 2012 12:44:13 -0800 Subject: Re: [Syncro_T3_Australia] Re: Vacuum line integrity  
Ken this line is connected to the inlet manifold. Without the engine running you will not be able to check the viability of any component from this end. The correct method is to fit a mighty vac (hand vacuum pump with gauge) at the motor end and check for leaks down stream. If you don't have a mighty vac you can just get under the bus soon after turning of the engine and check for leaks. A good system will hold residual vacuum for a long time, as the one way valve will seal off the engine and the reservoir will store capacity. I think they did this to give you one or two diff lock operations after stalling an engine. The easy check is to pull the "off" vacuum line from your rear diff lock some time after turning off the engine (hours, days), if there is still vacuum you have a good system. Greg E

From: Ken Garratt <unclekenz@hotmail.com>
To: _T3_Australia forum Syncro <syncro_t3_australia@yahoogroups.com>
Sent: Thursday, 29 November 2012 12:15 AM
Subject: RE: [Syncro_T3_Australia] Re: Vacuum line integrity
 
Hi Bill,
Sorry, my query was garbled, let me try and rework it.

My query has arisen following on from my recent investigation, checking on all vacuum lines integrity for better difflock and decoupler functionality. 

Scenario is for my query, I've removed the one way valve you referred to from the "upstream" side of the vacuum line, i.e., now I'm addressing only the vacuum line heading towards the motor. This line routes rearwards down the side of the van until it terminates at the motor. So when applying mouth pressure into the open end of this upstream end vacuum line, I found only partial pressure resistance, not full resistance as would occur in a sealed length of tube. So my query is ... applying mouth pressure to this vacuum line, what should be normal for correct vacuum line functionality? Should it be either a full seal (full resistance) or some leakage (partial resistance)? If it should be a full seal (full resistance), then I need to investigate whether or not a leak is occurring at some point in the line and/or at its end connection at the motor. Any thoughts please either way would be appreciated.  
Cheers.
Ken

To: Syncro_T3_Australia@yahoogroups.com From: marg_bill@westnet.com.au Date: Wed, 28 Nov 2012 07:48:24 +0000 Subject: [Syncro_T3_Australia] Re: Vacuum line integrity  
Ken.There is a small one way valve[looks a bit like a fuel filter] on that line near the vacuum resevoir. If you remove it noting which way it is oriented and blow through it the direction of resistance will be revealed. My diff lock wasn't holding vacuum and this valve was leaking when i blew through it or sucked through it. Replaced the valve and now diff lock works fine. Bill --- In Syncro_.