I bought a 93 f-250/350 about 6 weeks ago. Initially it was working fine but very recently two things started acting up. The brakes have started getting stiffer, that is the brake pedal - to the point now where you really have to push to get brakes, then it will click, and all at once the brakes will be full on. In order to get the pedal back up i have to lift it with my foot. When it started doing this a couple of weeks ago it was intermittent, and after the truck had been driven until warm, then shut down and restarted it seemed to completely subside. Now its constant and more severe. Is this definitely the brake vacuum booster, or is there anything else which could cause this?

This is the IDI 7.3 Turbo diesel, and just today after shutting down, when I went to restart the engine acted like it had lost its prime - idling fine for a second then rough then stalling. It took 7-8 seconds of cranking to restart - then seemed to run fine until I had to shut down and restart.... when I did same thing except I gave it more fuel to keep from stalling. I don't have any leaks to speak of - that I could see anyways - and I looked near the injectors and main fuel lead and filter, anyone have thoughts on what could cause the vehicle to lose its prime?

 

First off you'll get better responses if you separate your questions into different threads ... Different people know different areas.

For the starting issue.
let it set, longer the better (over night or all day is best), then pull the fuel filter, is the fuel filter completely full??
If not, Install a Injector Installation Kit

Many, including me prefer to toss the o-rings in the kit and use these Viton Return O-Rings - McMaster-Carr Item 9464K24, Viton is impervious to Diesel.

For the Injector Installation Kit installation You can follow Starmilts Humorous Fuel Return Replacement Procedure, I like to cut the 6 pieces between the Injectors to 4-1/16", Use a sharp razor blade to cut the hose and Vaseline to lubricate the o-rings.

For proper fuel system bleeding you can use steps 1 through 4 and 13 through 15 of the Fuel Filter Replacement.

Just because you don't see any fuel leaks doesn't mean there is no air leaks, Air molecules are smaller then diesel molecules.

-Enjoy
fh : )_~

 

Since Festus answered your starting question so well, I'll chime in on your brake issue. It sounds like you're loosing the boost on your brakes. Could be one of two things, the booster itself, or the vacuum pump. Pull the hose from the vacuum pump off, and you should have a definite suction on your finger. If you have one, you can put a vacuum gauge on to check it of course.

If the vacuum seems okay, likely the booster has died. Personally, whenever I replace a brake booster now, I replace the master cylinder with it. Seems like if I try one or the other, something goes on that I end up replacing the other one soon after anyway.

Make sure you bench bleed your master cylinder before installing, and other than some contortions for us bigger guys working in under the dash, it's not a bad job to do.

 

dang i always late ya i am 100% with greywynd sounds excatly like when my vac pump went out

 

How is your heater vents working, when your vacuum pump gets weak it will only work on defrost no matter where you set it.

 

Many thanks for the helpful tips, I'll check the operation of blower and then also check the vacuum pump at the source to double-check.

As far as the engine prime issue, the day it was acting up it was the middle of the day and it was 95+ degrees. I'm wondering if that had anything to do with it, because it has been fine the last 5 times I've started it since then - and it's been 15 degrees cooler outside. Ahhh, intermittent problems.

 

Sever heat can make the return tees expand just enough that they let air in where they normally don't.

But if the extra heat is the cause, you probably will be replacing the return lines/ O rings shortly anyway, they are on their last legs.

 

"Severe heat can make the return tees expand just enough that they let air in where they normally don't.

But if the extra heat is the cause, you probably will be replacing the return lines/ O rings shortly anyway, they are on their last legs."

The problem hasn't re-occurred since its been cooler. So the area of suspect is the small gauge return line in between the injectors, and in between the injectors and the fuel filter?



I installed a new vacuum brake booster and master cylinder yesterday and the brakes are working perfectly now. Thanks for the help figuring it out.

 

The small hoses from filter head to Injectors, Injection Pump to Injectors are return hoses, where they attach to the Injectors are plastic tees with o-rings between the Injectors and tees.

You need to replace the hose, the tees, the o-rings, It is called an Injector Installation Kit as stated in post #2.
And use the spring clamps, not worm gear clamps!

If you do not do the complete return system you will be chasing your tail over air leaks!
Once you do the Injector Installation Kit DO NOT DISTURB the return lines and tees!

-Enjoy
fh : )_~

 

How do i know that the engine and brakes are in good condition and how it was tested without putting it on engine for the safety of the People who handle it. Trash Trucks

 

I think you need to explain your question(s) a little better?

Brakes can be visually inspected, by pulling wheels etc off, but final result actually is you don't know for sure they are 100% without a road test of some sort. Of course, you only want people that know what they are doing with that test, as if there is a problem with, or no brakes, it can be very dangerous.

Beyond that, I'm not sure what you are 'putting it on engine'?