HARD BRAKES
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Freshman User
Joined: Oct 2004
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From: Benbrook,Texas
HARD BRAKES
I have an f-250 heavy duty '97 diesel. the brakes are stiff and hard.
is that indicative of a vacuum leak? either thru the lines or the brake booster? i have pulled the vacuum line to the booster and there is some suction and the line doesn't look in bad shape...
any ideas would be appreciated
thanks
KO
is that indicative of a vacuum leak? either thru the lines or the brake booster? i have pulled the vacuum line to the booster and there is some suction and the line doesn't look in bad shape...
any ideas would be appreciated
thanks
KO
Post Fiend
Joined: Jan 2005
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Well, low vacuum may have an effect on the air vents in the cab. However that is going to be the case no matter what the cause.
If you pull the vacuum pipe at the booster and with the engine at idle if you put the palm of your hand over the end of the pipe, it should feel like your hand is being sucked into the pipe, if the pump is good. Best way is with a vacuum gauge.
Usually if the booster is leaking you will hear a hiss when the pedal is pressed.
If you pull the vacuum pipe at the booster and with the engine at idle if you put the palm of your hand over the end of the pipe, it should feel like your hand is being sucked into the pipe, if the pump is good. Best way is with a vacuum gauge.
Usually if the booster is leaking you will hear a hiss when the pedal is pressed.
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From: Benbrook,Texas
oh, ok.. there is a little suction, i certainly wouldn't say it was sucking my hand into the pipe...just enough to pull a little skin...i will locate a vacuum gage and check that out...
thanks
thanks
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Freshman User
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From: Benbrook,Texas
hard brakes
i purchased a vacuum gauge, and checked it at the hose leading to the booster and at a smaller line leading to my climate control... it is barely registering on the scale. if it's supposed to pull into the green at the 20 mark, it's not even to the 1. anything special i should know before i tear into this? it looks pretty straight forward...i noticed on some auto parts website, you can buy components to the vacuum pump... is there just part of it i need to replace?
Post Fiend
Joined: Jan 2005
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Like I said your pump should put up around 20in Hg at idle so it sounds like the pump is bad.
The thing that usually goes in the pump is the diaphram which should be included in a kit.
Nothing special in fitting a vacuum pump.
The thing that usually goes in the pump is the diaphram which should be included in a kit.
Nothing special in fitting a vacuum pump.
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From: Benbrook,Texas
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i ain't rite
Joined: Mar 2005
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From: Marlboro Mental Hospital.
to double check the pump, put the gauge directly on the pump without any other draw.
this will confirm if the pump is bad, or if you have a bad line.
but i will put money on the pump being bad.
this will confirm if the pump is bad, or if you have a bad line.
but i will put money on the pump being bad.
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Freshman User
Joined: Oct 2004
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From: Benbrook,Texas
to all, replaced my vacuum pump saturday; pretty simple, just a wrench and a pulley puller, and wow, i have super brakes... I guess what suprised me the most was that evidently the vacuum pump wore out slowly over time, so that i didn't realize how poorly my brakes were working...because i have not felt brakes like this in quite awhile...they even passed inspection last year...now i can stand that truck on it's nose.
Again, thanks to all that replied, FTE is a great resource.
Again, thanks to all that replied, FTE is a great resource.
i ain't rite
Joined: Mar 2005
Posts: 65,585
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From: Marlboro Mental Hospital.
you are quite welcome.
i never knew my pump was bad until i blew the 5 speed and put a C-6 in my 88. i could not figure out why it would not shift rite. then i did a vacuum test and found the pump was only pulling 9 inches vacuum. you need minimum 17 inches for the C-6 to shift properly. OOPS!!
i never knew my pump was bad until i blew the 5 speed and put a C-6 in my 88. i could not figure out why it would not shift rite. then i did a vacuum test and found the pump was only pulling 9 inches vacuum. you need minimum 17 inches for the C-6 to shift properly. OOPS!!
Postmaster
Joined: Apr 2008
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When my vacuum pump died I was in the middle of Friday evening rush hour hauling a$$ for a trailer place to pick up my brakes controller that I was about to need the next morning - one moment I had awesome brakes, next moment it was as if I was stepping on a brick. Thankfully I do know how a truck with manual brakes behaves, and I was empty too, but still, I learned that day how painfully slow an E4OD is to downshift into 1st. On my way back from the trailer place I stopped by a buddy's place and borrowed his vacuum pump to get me by for a few days, and then at first opportunity converted my truck to hydroboost 
Of course now if the C2 pump fails I'll have neither brakes nor steering, lol
Of course now if the C2 pump fails I'll have neither brakes nor steering, lol
