DON'T KNOW WHAT TO DO. MY HUSBAND IS ON THE INTERSTATE ON HIS WAY HOME FROM WORK. HIS BRAKES WENT OUT, COMPLETELY!!! NO E-BRAKE EITHER! HE REPLACED MASTER CYLINDER ABOUT A MONTH AGO, BRAKES WORKED OK FOR ABOUT A WEEK AND STARTED MESSING UP AGAIN. NOW HE HAS NO BRAKES WHAT-SO-EVER... IS THERE ANYTHING HE CAN DO TO GET HOME SAFELY? I BELIEVE HE HAS HYDROBOOST UNIT.. HE MENTIONED BEFORE A TINY LEAK FROM PS PUMP... NEED HELP, ADVICE, ANYTHING... BRAKE PEDAL GOES ALL THE WAY TO FLOOR... NO STOPPING.. CAN HE RIG SOMETHING UP TO GET HOME WITHOUT WRECKING? WHAT COULD BE CAUSING THIS PROBLEM AGAIN?
TIA

 

He needs a roll back and his truck on it. It is too dangerous to try jury rigging brakes.

 

Agreed. Hook it home and fix it right.

 

Really needs to have it towed, but if that is not an option then he should be looking for a place where the fluid may have leaked out of. Then he might be able to repair the leak and refill with fluid. That might get him home depending on how the repair and refill goes, but hard to say from here.

The truck should not be driven in its current state. Do you have AAA, Good Sam, etc? Where are you located?

 

Thank you all for the quick replies. The truck is home now.. Next, is to FIND and FIX the problem. Since he has a new master cylinder on it, could it be the PS pump or the hydroboost? and how can we find out what is causing the problem? Would the tiny leak on the PS pump cause problems with the hydroboost and cause the brakes to go out a second time? Where would a good starting point be?

 

Someone else with a much better understanding of how the system works will be along shortly, but I would start with checking for fluid under the vehicle. I would check the rubber brake hoses, PS fittings, everything. Get a good flash light for him and go out with him to help or keep company while you look from the top side while he rolls around on the ground looking underneath.

Glad he made it home safe though, good luck and make sure to let us know what you find.

 

Also, to add in there, the truck is a 99.5 F250 Lariat ext cab. I've read on some other forums that the PS pumps and hydroboost seemed to be a common problem with the 99.5... don't know how true that is but I know we're having that problem...lol... I'm just trying to help my husband online while he does the mechanic part. He's worked on PSDs for years and not once came across this problem.. so any helpful advice would be welcome! Thanks!!

 

Ha, you know it's funny you say that... me getting out there helping him.. I think the PSD is one thing we actually do together.. and get along... anyway, all hoses are good. There's a tiny, very tiny, leak from a fitting(I believe).. would that be enough to cause problems with the hydroboost? After 6 years of working on Fords, this is literally the first time we've come across this...
If it is a fitting leak, would that call for a whole new pump? Like I said this is the first time I came across this type of problem...

 

I'll jump in here. A leak from the power steering pump is a disaster in the making. It powers your steering and your brakes. If you have a leak on the intake hose, this creates a situation where it leaks more in the driveway than it does on the road, but it's injecting air into your power steering pump and Hydroboost - very bad juju. Air in the pump creates cavitation, which diminishes (or eliminates) its ability to build pressure. Air in Hydroboost won't allow the hydraulics to work because you spend all your leg (brakes) and arm (steering) movement compensating for the air compressing before the hydraulics build any real force on the steering gearbox or brakes.

There is no "emergency brake" per se. It is a parking brake that is manually activated with your leg muscles - no hydraulics involved. The normal brakes are rotor and caliper (disc type), but the parking break is the old-style shoe and drum in the rear axle only. OK for holding the truck still (just barely) when the system is 100%, but woefully over-matched when addressing 8000 pounds at 65 MPH. Now... take an ignored parking brake and try to use it for the first time in an emergency, and you get more heart leaping out of the chest than truck screeching to a halt.







Don't even contemplate messing around with this - and I'm not kidding. What's the ability to stop on the freeway worth to you? New parts likely cost far less than fixing old parts.

 

I'm thinking the month old master cylinder is defective. While a leaking power steering pump or hydro boost is not good and needs to be fixed, it normally wouldn't be a "pedal going to the floor" issue. It would be a hard pedal if I'm not mistaken.

 

I'll let him know last night about the PS pump and hydroboost... I may be wrong, since I don't know quite how this system works, but even though the master cylinder is new, if the PS is leaking wouldn't it cause the master cylinder to not work right? I apologize for not knowing a lot about this.. I've just learned here and there... he knows a lot about it, but this was something he was not sure about. I'm sure he'll be on here next instead of me, able to give more in depth info. But if we replace the PS pump, then wouldn't that fix problem with the hydroboost.
Yes, the brakes go all the way to the floor. He said the ONLY way he can stop is if he slams the pedal and it feels like it flings your heart out of your chest. :/ He's done a lot of work on 7.3 and 6.0s, even complete rebuilds but this just puzzled us. We thought the master cylinder would fix it, but it didn't. I'll get him on here this evening when he gets in from work and hopefully we can get this fixed... Thank you for all the help. I really appreciate it.

 

New parts can be defective out of the box, so re-test this 'new master cylinder' and be sure it can be eliminated as part of the problem.

 

My brake line blew from rust along the frame rail behind the fuel tank. I'd put fluid in it and find the leak if its empty. It's gotta go somewhere!


I had just picked up our camper at 5 o clock on a Friday evening when mine blew.