Hey i just bought my first vehicle yesterday and its a 1993 Ford F250. The truck has a 7.3L Diesel and 5 Speed. The only problem with the truck is the brakes. When im driving and i come up to a red light the first time i apply the brakes they work very well and grab really good. But if i take my foot off the brakes and put them on again...i get nothing...the brakes dont want to grab no matter how hard i push the pedal. Say im driving down the road and somebody pulls out infront of me and i slam the brakes they grab well and work...but again if i take my foot of the pedal and apply the brakes i get nothing. The guy i bought the truck off of says he was told that it could be a problem with the pump on the front of the motor that produces the vacuum. That pump connects to the brake booster. I was wondering if anybody knows whats wrong with my brakes or what i can do to fix it. Thanks.

 

yup. sounds like the vacuum pump is bad.

 

what could i do to check the vacuum pump?

 

pull a vacuum hose off, and put a gauge on. you need a minimum of 17 inches of vacuum for everything to work properly. i would venture to guess you only have around 8-9 inches of vacuum now.

 

What do you mean by "I get nothing"? Does the pedal go to the floor or is it hard as a rock and you need to stand on it to make the pedal move?

My vacuum pump went out and did the latter of those two symptoms. I put a $4 Harbor Freight vacuum gauge on a spare fitting on the driver's side inner fender. Supposed to be 21" or thereabouts. Mine was 19" or so and took a few minutes to go back to that after applying the brakes.

You can google: cdnsarguy vacuum test

You'll find his vacuum test. I can never remember where he's got it stashed but it'll step you through testing the vacuum system. Even gives you the NAPA part # for the pulley puller if I recall.

If it goes to the floor, that's usually a master cylinder/RABS valve/bulging hose somewhere.

Mike

 

no the pedal doesnt go to the floor...its very hard and no matter how hard i push it doesnt seem like my brakes are working.

i just talked to my neighbour who is a mechanic and he has a vacuum tester and he is going to help me test the vacuum when he gets home. if im getting low vacuum i assume i need to replace the pump...how much does a pump cost?

 

yep your pump is heading south, 50-150 for a new one

 

yeah my neighbour just tested the vacuum...he said its very low and its definately the pump that is shot. he said a new pump will be around $70. so im just going to call some of the local parts stores and check some prices. he also said i might need a special puller to take off the pulley...so im going to have to find one of those too...

 

i normally just buy a new pulley from the ford dealer when i do a pump. it only cost $22 the last time i did one 3 months ago.

 

I think I paid about $120 for a pump from NAPA. Had to buy the pulley puller set ($15ish from Harbor Freight). Old pulley was warped somewhat. Ended up buying another pulley from Ford for $20ish. I have an International dealer in town and checked with them on pricing. They wanted $150ish for a new pump with pulley. Next time I'll go that route instead of dealing with the pulley.

Mike

 

well i thought the vac pump was out on mine after i changed my brakes with new ones and new lines well i started the truck cut the truck and pull the vac hose off the booster and it was holding vacuum, so to me that tells me the vac pump was okay, well i got the bleeding order and i bleed the brakes in the correct order and the brakes works perfect. you have to bleed the back first then the brake block on the frame 5/16 bleeder screw then the front in that order any other way no brakes i fought for 3 days on the brakes,

by the way i got my truck on ebay for sale ends less then a day

 

I’m no expert to this but let me try, 'coz I have encountered an almost similar problem with my jeep brakes...--I think you have a low brake pedal, it can result if shoe adjusters on drum brakes stick and fail to compensate for normal lining wear. Adjusting them may restore a full pedal, but unless the adjusters are cleaned or replaced the problem will return as the linings wear. Other causes include worn brake linings or a fluid leak…Try to check it out and let me know the result…Good luck…<o></o>

 

Easy test for a bad vacuum pump or a bad vacuum leak.

The heater will only blow air out of the defrost vents.

Defrost is the default position so you can see what you are going to run into when the brakes quite working.

LMAO

 

i have a friend whos mom works for NAPA. Shes pretty high up in the company so she gets a pretty good discount. Im getting my vacuum pump through her for 90$CDN. Im getting it tomorrow. But today i borrow a pulley puller and took off the pulley from the old pump. And when i get the new pump tomorrow im going to install the old pulley on the pump...get the pump installed and hopefully my brake problems are solved. and then maybe ill be able to finally drive the truck i just bought...i cant wait!

 

I need some help!.. i got my new pump...started to install it tonight. Its all done except for that black bracket that is held on by 2 of the 3 bolts on the pump...i cant remeber how that bracket goes. can someone please show me a picture of it or explain it to me so i can finally get my truck on the road tomorrow?. Thanks