Vacuum pump
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MIDNIGHT RIDER
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A good in-cab mounted vacuum GAUGE is almost as important as good mechanical temperature and pressure gauges.
Along with that, a decent hand-held vacuum gauge can be stuck in isolated lines, narrowing down the problem.
First, check vacuum straight into the pump, with no other lines attached; this will tell whether it is the pump, or a big leak somewhere else.
These pumps are pretty much bullet-proof and many get tossed when nothing is wrong with them.
Along with that, a decent hand-held vacuum gauge can be stuck in isolated lines, narrowing down the problem.
First, check vacuum straight into the pump, with no other lines attached; this will tell whether it is the pump, or a big leak somewhere else.
These pumps are pretty much bullet-proof and many get tossed when nothing is wrong with them.
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MIDNIGHT RIDER
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There. Fixed it for ya.
I read that thing the forth time, before I caught what you "fixed".
Thanks.
The main reason I ask is that it seems that the pump turn over way too easy, alot easier than it did 4 years ago. The brakes work ok but if I hit the brakes 2 times real close together the pedal gets real hard.
oregon-mike
Registered User
******,
That's the exact symptoms my truck had when the vacuum pump went out. I found a vacuum test online somewhere....Here's what I did:
Pulled a plug from the vacuum manifold on the driver's fender.
Plumbed my vacuum gauge into that port.
Fired up the truck. Vacuum, about 19" (should be 21" if I remember right).
Went into the cab, hit the brakes twice. Went back out and looked at the gauge. It was down to 5" or so, took it almost a minute to get back to 19".
Turned the truck off, it held the 19" for 15 minutes (that's all I left the gauge plugged in for) so I knew it wasn't a leak.
Bought a brand new vacuum pump from Napa ($130ish), pulley remover from HoboFreight for $10ish and went to town. Found out that the pulley on there was bent, got a new one from Ford ($30ish), reassembled and back in business.
Since then I've heard from a few folk who never mess with the pulley. Too easy to bend and they just replace them when they do the pump. My local International parts shop had the pump with pulley for about $175 if I remember correctly. Next time I'll go that route.
Mike
That's the exact symptoms my truck had when the vacuum pump went out. I found a vacuum test online somewhere....Here's what I did:
Pulled a plug from the vacuum manifold on the driver's fender.
Plumbed my vacuum gauge into that port.
Fired up the truck. Vacuum, about 19" (should be 21" if I remember right).
Went into the cab, hit the brakes twice. Went back out and looked at the gauge. It was down to 5" or so, took it almost a minute to get back to 19".
Turned the truck off, it held the 19" for 15 minutes (that's all I left the gauge plugged in for) so I knew it wasn't a leak.
Bought a brand new vacuum pump from Napa ($130ish), pulley remover from HoboFreight for $10ish and went to town. Found out that the pulley on there was bent, got a new one from Ford ($30ish), reassembled and back in business.
Since then I've heard from a few folk who never mess with the pulley. Too easy to bend and they just replace them when they do the pump. My local International parts shop had the pump with pulley for about $175 if I remember correctly. Next time I'll go that route.
Mike
It is the volume of air, not the amount of vacuum that usually fails first, hence the gauge in the cab is more usefull than a gauge under the hood, as you will have grown accustomed to how much the needle moves for any given circumstance, where as if you only use it during diagnostics you will see that it draws down to 19 or 21 inches and think "oh, it must be good." This is why it brakes fine on that first press, but goes downhill after that. If you have vacuum operated cruise control, you will see it failing there also.
h2odrx
Anti-O
does anybody have a repair kit for these?
Alex S
Jeoff
drop in a hydro-boost and toss the pump ;-)
LCAM-01XA
Full Access Member
Yeah, kinda what I wanna do myself, hydroboost - all my steel lines and rubber hoses are new so they will handle the pressure just fine, just gotta find a suitable hydroboost donor truck.
h2odrx
Anti-O
I may do this on mine but just wanted to know?
Mr_Roboto
Full Access Member
The pulleys won't bend if you use the right tool. Trying to use a jaw puller will ruin them instantly.
The diaphram is what usually goes bad. I've replaced two vacuum pumps so far out of four Ford IDI's. The International uses hydroboost.
The diaphram is what usually goes bad. I've replaced two vacuum pumps so far out of four Ford IDI's. The International uses hydroboost.
still need vacuum for the heater controls---and like roboto--ive replaced two on three diff trucks--they damn well aint bulletproof--and no one makes a kit to repair them--as youd have to have a can opener type assm to peel the diaphragm lid apart!!!!!!!!!!!!!!!
Alex S
Jeoff
im sure its not a direct replacement but if was easy to fit in my scout but 90s GMC astro and chevy safari van are full of them.
all i had to do was drill 4 holes in my fire wall, shorten the pedel to booster push rod and do the hoses and that was it, but i did also use the chevy MC as well
