Trucker Cap
Troublemaker
can i remove the Vaccum storage tank (coffee can) and bypass it if my air conditioning is allready ripped out?
can i remove the Vaccum storage tank (coffee can) and bypass it?
- Thread starter Trucker Cap
- Start date
rhkcommander
Full Access Member
Mine isn't hooked up. It has nothing to do with A/C as far as I recall its an "oh crap" device to give you some braking power when the vacuum pump fails before it loses vacuum. But I could be wrong.
theguruat12
Certified Tinkerer
I BELIEVE that the coffee can is mostly for the cruise control, since that vacuum servo that actuates the cruise throttle cable eats up a ton of vacuum when it needs to accelerate. Don't hold me to that 100%. Mine was bad when I got my truck and I don't remember noticing anything wrong.
icanfixall
Official GMM hand model
I too feel that can is to supply vacuum to the cruise control. They do get moisture in them and that settles to the bottom where it rots the tin. Mine was rotted out so I removed it and applied some RTV. That was about 14 years ago. Still holding fine. No real braking need for the vacuum on my rig. We have hydroboost brakes and very happy with the more than double the braking line pressure availability.
Michael Fowler
Registered User
Check out old Mercedes Diesel in the pick n pay yards. Their reservoirs are plastic, and don't rust. In a W126 model ( the BIG mercedes from '80-mid 90s--the ones that the evil white guy/ drug dealers drive in the movies) its in the spare tire well in the trunk--looks like a bunch of plastic balls all stuck together. Other older diesels have them under the hood as a single sphere.
The coffee can on the pass side was for the HVAC controls on the GAS trucks. On a gas truck when you start pulling a hill and open the throttle up, you lose vacuum. So the vacuum supply line from the engine ran over to the pass side, through a check valve, and then a tee, one leg to the reservoir and the other leg went through the firewall. The coffee can supplied the HVAC controls vacuum when the engine vacuum dropped, keeping the heat from going to defrost when you are pulling a grade with a gas engine.
The diesel doesn't have this problem, the vacuum pump keeps pumping. So I don't know why they are on a diesel truck, except it might have been a standard install operation on the assembly line for all trucks. I will have to look again, but I thought my truck had another reservoir for the cruise.
The diesel doesn't have this problem, the vacuum pump keeps pumping. So I don't know why they are on a diesel truck, except it might have been a standard install operation on the assembly line for all trucks. I will have to look again, but I thought my truck had another reservoir for the cruise.
theguruat12
Certified Tinkerer
Our trucks should have two reservoirs actually: the coffee can one on the driver's side, inline between the cruise servo and the vacuum block on the passenger's side firewall IIRC, and a spherical plastic one with only one connection on the passenger's fender near the low-vacuum switch and voltage regulator.
OLDBULL8
Good Morning Ya'll.
That vacuum can "reservoir" is strictly for the cruise control, nothing else.
I just looked under the hood of my truck and the above is true. I have no can on the pass side, I do have a large can on the driver's side inner fender and it does go to the cruise system.
OLDBULL8
Good Morning Ya'll.
That vacuum can "reservoir" is strictly for the cruise control, nothing else.
The one on the pass side is the drier and for the AC.
theguruat12
Certified Tinkerer
Wait wait wait, even though it only has ONE vacuum line going to it and nothing else? I'll see if I can find a picture of what I mean.
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