Vacuum Pump
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Joined: Mar 2004
Posts: 6
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From: Riverside, CA
Vacuum Pump
I have a 86 F250 with a 6.9 during the past few days I noticed that the alternator belt was loose and thighten it, a couple of days later it was loose again but to the point that was within normal range, This morning in my way to work I noticed that the tranny shifted to second gear, thanks God that I was in a traffic jam so the RPM's stayed pretty low. I got aff of the freeway and opened the hood an I noticed that the aternator belt was gone and the vacuum belt was hanging loose. I turned the pulley and noticed that the vac. pump is hard to turn, it goes that way for about 1/2 revolution, then it goes smooth for 1/2 rev then it seems that it is puming air as it becames hard again. Is this condition normal on these pumps or they supposed to be smooth thru its complete cycle?
TIA
Jorge
TIA
Jorge
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Joined: Feb 2004
Posts: 11,697
Likes: 3
From: Marengo, Iowa
Double check your alternator bearing, I just got stung on that , wasn't paying attention, and the bearing was out, had to limp it home on the betteries, luckily there's 2!! I had just tightened the belts the day before, and should have thought to check it. My air conditioning was blowing on the windsheild, as if there was no vacuum, but what had really been happening was the alternator started to bind internally. Without the belt, it seemed ok, but when you put pressure ion it, the internals bound. I had to shut the motor down, and when I restarted the belt started smoking because it was spinning around the pulley, but it wasn't moving. Got hot enough the vacuum pump belt melted. And yes, that is the way the vacuum pump works.
Thread Starter
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New User
Joined: Mar 2004
Posts: 6
Likes: 0
From: Riverside, CA
Vacuum Pump
After been towed back to home, went to get an entire new set of belts, put them on, started the engine, and every thing was working fine. Performed a vacuum test and the pump was puting out 22.5" hg. One thing I noticed even before this happen is that the aternator belt is extremely long and it is necessary to put lots of tension on the belt in order not to have it " jumping" while the ingine is running. Does anyone have seeing this before? Would it be possible to install an idler to solve this problem? and where to get one?. Any Ideas?
TIA
Jorge
TIA
Jorge
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