johnday in BFE

iTrader: (1)

I had a hard time relating vacuum to pressure. Vacuum is measured in inches/mercury, not psi. Vacuum is not pressure. Useless, but it made the problem hard for me to grasp. LOL
Pressure blows, vacuum sucks.


Agree.

Blue2016XL

Thanks for the clarification John.

joeboy4

The 24 psi is in the line on the side that wasnt replaced. This truck is driving me crazy lol I realize the IWE that doesnt hold vacuum must be bad. But why is there only 8 psi in drivers side line??

joeboy4

sorry meant inches on the vacuum pressure.

Blue2016XL

Starting with the 2009 model year (the years I am most familiar with) both IWEs are run off of the same vacuum line. They connect up close to the check valve. It is also my understanding that it only takes a minimum of 7 pounds (sorry not using correct term probably) to disengage the IWEs. So, if the one IWE isn’t holding vacuum, it will cause the other to not have vacuum either. How are you testing it? Hooking up at each wheel or the line connected to the check valve or solenoid?

So my other question to you is. If the passenger side is not holding pressure, how are you able to get any readings whatsoever? I have one theory and that is the gauge is giving you a false reading because the pressure never tops out as it is always leaking.

johnday in BFE

iTrader: (1)

Only thing I can add, is whichever isn't holding vacuum, is the side I'd be looking at.
First, it's said, passenger, [right side], you can pull 24" of vacuum, then it's said, passenger side isn't holding vacuum, and the driver [left side] holds 8".
Need to have consistent statements here. Maybe it's me.

Let's see if we can clear up the confusion, at least in my simple mind.
I'd hook up the vacuum tester directly to the IWE, make sure you're on the vacuum supply and not the vent side. Pump up the vacuum, does it hold steady? Slowly decay? Or drop right off?
Do the same to both IWEs. If one doesn't hold vacuum, there's the problem child.
If both sides hold vacuum, reconnect the hose for IWEs. Remove the hoses from the T where it splits to either side. Hook tester up there, pump up the vacuum. Which side doesn't hold vacuum, indicates a leak in the hose, bad fitting.

johnday in BFE

iTrader: (1)

I just went to the Mityvac site. I see that hand held pump can be used to supply vacuum, suck, or pressure, blow.
Since joeboy4 keeps referring to pressure, do you have the pump setup correctly for vacuum?
NO, I'm not trying to embarrass, or try to be smarter than anyone, I think it;s a logical question.
If something leaks under pressure, sometimes vacuum will seal the leak.

joeboy4

The 24 in pressure is in the line right at the passenger side IWE. 8 in is in the line at the drivers side IWE. When I connect the mity vac to the IWE drivers side new one and pump it holds in the 20 inch vac range. When I do the same to passenger side I pump and get zero it doesnt bleed off it never has enough vacuum to bleed off. When I look at the lines the all look ok they are in the protective conduit I guess I can pull them out of there.

joeboy4

yes when I remove the line I feel suction when I connect that to the mityvac it goes to 24 on passenger and about 8 on the other.

johnday in BFE

iTrader: (1)

Cool, it sounds like the seal on the IWE is bad on passenger side. Let's concentrate on that side for now.
Might sound funny, but is it cold, slushy, snowy, rainy where you are? There's the possibility that with the bad seal on the pass side, moisture might have been sucked up in to the line and froze? Try disconnecting that line at the IWE, go to the T fitting, and take a suck on the line. If you get vacuum, that would indicate a plug. I don't know how common that is, but it's an easy check.