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1985 Bronco 5.0 EFI manual transmission
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Engine Electrical wiring Wire Automotive engine part Fuel line

I’m about to dive into the vacuum leak/hose replacement hole.
Quick question on a test I ran. The round canister on the left tested that it holds vacuum tight. The one on the right (supplies the bank of vacuum solenoids), when pumped to 10in hg, leaked empty over course of 4-5 minutes. Is this normal? Does such leakage constitute a vacuum leak in an of itself that can show up in engine performance issues?
Many thanks.
 

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Charlie don't surf..
'92 Ford Bronco XLT
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Not sure how much bleed off is considered normal, but if you're talking over the course of 4 to 5 minutes, I'd call that good. no system is going to be 100% sealed.
 

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Yo mrbuckfast,
The Emission/power brake booster, etc Vacuum Reservoir ("Coffee Can") stores vacuum and provides "muscle" vacuum. It prevents rapid fluctuations or sudden drops in a vacuum signal such as those seen during an acceleration period.
View attachment 171149
or;


"Apply initial vacuum of 15 to 20".
Vacuum loss should not exceed 0.5" in 60 seconds.

If it does, replace the reservoir."
They usually rust on bottom side.
Also:
View attachment 171150 View attachment 171151

Finally 💤😎
Overview; "...The vacuum is an energy that is used as a power source to operate different emission controls and accessories like the controls for the ventilation system. There are times that an engine does not create a good supply of vacuum. Because of this the vehicle manufacturers install reservoirs to store vacuum. The hose from the engine or the reservoir itself will have a check valve that blocks the loss of vacuum back to the engine. Why is this? When accelerating, the amount of vacuum created by the engine drops to a level that will no longer power any emission controls or provide for control of the ventilation system. The reservoir is designed to hold enough vacuum in storage to maintain control under most driving conditions. If the check valve fails the vacuum reservoir will lose vacuum so quickly that there will be none left in reserve. The result? A loss of control of vacuum operated devices.You can make your own as SigEp did but for the Emission stuff..."
Source: by miesk5 at FSB😎
 
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