Losing Vacuum. Where To Start Looking?

[Grey2003]

Hey folks. On my '95 Bronco I loose my vacuum pretty quick when I shut it off or any sort of hill over 15 secs of climb. I notice this because I lose the vent setting on the HVAC in a hurry. If i shut the truck off, the vent actuator looses it's position very quickly and then it takes maybe five or more seconds to move the actuator back to it's setting.

So where should I look first? I have been poking under the hood and thought that I had found it when I noticed a rubbed brake boost line. I probably should replace it anyhow. Any other ideas where to look? Is the actuator itself a common culprit?

Thanks.

 

[Seabronc]

Check the vacuum line to the A/C controls. It goes from your Main vacuum tree to the vacuum reservoir and then to the A/C control. You will probably find a broken line or the vacuum reservoir has a hole in it. The Defroster is the default position for safety purposes in the event you lose vacuum.

Good luck,

>-

 

[Grey2003]

Check the vacuum line to the A/C controls. It goes from your Main vacuum tree to the vacuum reservoir and then to the A/C control. You will probably find a broken line or the vacuum reservoir has a hole in it. The Defroster is the default position for safety purposes in the event you lose vacuum.
Good luck,

>-

Great. Now don't laugh but where is the main vacuum tank and tree? Remember don't laugh.

 

[Seabronc]

Great. Now don't laugh but where is the main vacuum tank and tree? Remember don't laugh.

The Main vacuum tree (distribution block) is near the rear of the intake manifold. You will see several vacuum lines connected to it. The Vacuum reservoir is located on the passenger side wheel well. On your truck it probably is a red line running from the distribution block to the reservoir with black line to the A/C control. That arrangement varies with year, sometimes it is a large plastic tank with a check valve built into it and some times is a separate tank with a vacuum check valve in the middle of the line someplace on the passenger side as shown in the diagram I included in the last post.

Good luck,

>-

 

[BroncoJoe19]

Here is a pic you might find helpful

I circled the vacuum tree, the MAP sensor (on the firewall) and the vacuum canister in RED.

I put little yellow dots on some of the vacuum lines that I could make out in the picture.

Including the tree the map sensor the EGR the brake booster, maybe the cruise control.

 

[Grey2003]

Awesome and thanks guys. I had just found the tree a little bit ago and I am going to get some vacuum line for the brake booster. You can see in that picture that it was laying against the wiper motor and it has worn throught the outer layer. Might as well get one. Thanks again.

 

[Grey2003]

Here is a pic you might find helpfulI circled the vacuum tree, the MAP sensor (on the firewall) and the vacuum canister in RED.

I put little yellow dots on some of the vacuum lines that I could make out in the picture.

Including the tree the map sensor the EGR the brake booster, maybe the cruise control.

Okay the vacuum canister. All I see is wires no vacuum lines. I'll keep looking. Thanks

 

[BroncoJoe19]

I don't have my truck here to compare, or to take a look, but I am pretty sure that canister that looks like an old juice can is just a holding tank. If you see something that goes into it that looks like a wire, it is probably a vacuum hose.