Hello, i have a 1992 F250 with a 7.3 idi and a E4OD transmission 2wd, and since i have the truck (almost a year now) i find that it doesn’t brake hard, brake fluid has been changed, the hard lines on the rear diff too, front calipers work as they should and no leaks, also no air, brake light is off, but i hear a small hiss when pressing the brake pedal, since i have the truck too, tought it was normal, if you have an idea what can be the problem i’ll gladly listen!
Almost no braking power
- Thread starter UslAura1
- Start date
IDIBOBS
Registered User
Have you tested your vacuum? System needs no leaks and MIN of 16” should be more like 20plus of vacuum. Also check your check valve.
If that’s ok then I’d say booster with the hissing.
Also make sure your rears are adjusted right. Auto adjusters may not be working. But that has nothing to do with the hiss
If that’s ok then I’d say booster with the hissing.
Also make sure your rears are adjusted right. Auto adjusters may not be working. But that has nothing to do with the hiss
IDIBRONCO
IDIBRONCO
About the only way to truly test your vacuum pump is with a vacuum gauge.
IDIBRONCO
IDIBRONCO
It should work for checking for leaks, but not for testing how much vacuum your vacuum pump makes.
well the booster works, when i unplug the hose when stopping the truck i can hear it sucking, saw that test on another thread, so i don’t think it’s booster related, where do you plug the vacuum gauge when you install it?
IDIBRONCO
IDIBRONCO
Anywhere in the vacuum lines that's easy for you.
IDIBOBS
Registered User
Can always borrow a vacuum gauge from auto parts store. As for the booster my money is still in a bad booster. That’s pretty much the only place you will here a hiss from.
IDIBRONCO
IDIBRONCO
I agree.
Old Goat
Full Access Member
I put my money on a bad Booster.
Mine was hissing when pushing down on the Peddle, and not stopping very well. Later you will get one brake application,
and then almost nothing on the 2nd one. Loose Vacuum = lose Brakes.
I was at NAPA talking to the guys and one said the hissing was normal, I didn`t think so..
Bought one at O`Really`s, and stopped so good almost hit the Windshield...JK.
I agree get a vacuum gauge, Harbor Freight has then for not too much.
You are in Canada, you have an equivalent up there.
A vacuum gauge should be installed on all these trucks, on the Dash some where for safety. It should be around 22HG.
Also show`s how quickly the Vacuum Pump builds the Vac back up.
Goat
Mine was hissing when pushing down on the Peddle, and not stopping very well. Later you will get one brake application,
and then almost nothing on the 2nd one. Loose Vacuum = lose Brakes.
I was at NAPA talking to the guys and one said the hissing was normal, I didn`t think so..
Bought one at O`Really`s, and stopped so good almost hit the Windshield...JK.
I agree get a vacuum gauge, Harbor Freight has then for not too much.
You are in Canada, you have an equivalent up there.
A vacuum gauge should be installed on all these trucks, on the Dash some where for safety. It should be around 22HG.
Also show`s how quickly the Vacuum Pump builds the Vac back up.
Goat
Don’t forget to adjust/tighten rear drums too
WrenchWhore
Full Access Member
If it makes you feel better you're not alone. I've already put in a new booster, master cylinder, and two vacuum pumps on my truck and i've had it for maybe 3 years.
