Brakes completely locked up!!!

[angelfly]

Please help brakes wont release!

First let me start by saying I have a 1998 Mercury Mountaineer with the 5.0L V8 with the 5R55W trans, and 8.8rear with 3.73gears an LSD, and ABS...

My problem happen when I was just driving along earlier today and the next thing I know i feel pressure in the brake pedal... Shortly after I ended up parking and turning my rig completely off, when i turned it back on the brake pedal was rock hard and all 4 brakes were completely locked up! I know for a fact the e-brake is working properly, I just installed a new master cylinder about 6weeks ago, 4-6weeks prior to that i did the front and rear brake pads along with ebc rotors in the front and had the rears resurfaced! Just recently i bought a replacement booster valve and when I installed that, it ended up leakin air causing me to have little to no pressure in my pedal... But it would come and go and so I ran it like that for 2-3days before FINALLY FINDING the stock 1 and putting it back in, that was about 10days ago....

So WTF would cause this??? Any and all help is VERY MUCH APPRECIATED!!!

 

[Andy D]

just a wild guess, the push rod between the brake pedal is too long. This would cause the MC not to release pressure . Is the firewall bent toward the pedal.

 

[Mark_88]

Flex lines could be damaged causing them to lock fluid in the calipers...

Air introduced into the master when installing...

 

[angelfly]

just a wild guess, the push rod between the brake pedal is too long. This would cause the MC not to release pressure . Is the firewall bent toward the pedal.

It's not like this is a new setup or anything... It's been driving like it is right now for the last 5,000+miles! So I don't see how the rod could be too long now when it wasn't before....????

As soon as I start the motor after a few secs you can feel the brake pedal building up pressure and the brakes slowly locking up.... I HAVE NEVER SEEN THIS HAPPEN BEFORE PLEASE HELP!!!

 

[enjr44]

My guess would be the power brake booster is malfunctioning and applying the brakes.

I'd go to your favorite yard, get one and give it a try.

 

[angelfly]

My guess would be the power brake booster is malfunctioning and applying the brakes.

I'd go to your favorite yard, get one and give it a try.

Ok cool, that was the only thing I could think of also, so thank you will give it a try!

 

[enjr44]

One question I forgot to ask. Do they release if you pull the vacuum hose off the booster with the engine off? If not I would think about the master cylinder not releasing, they can hang. New no longer means good. And rebuilt (unless you do it yourself) don't seem to be very good anymore.

 

[gandrimp]

Does the brakes release if you loosen a line at the master cylinder?

 

[angelfly]

So when the brakes were locked up i tried pulling the hose off the booster while the engine was running and it had 0 effect on the brakes...

I didn't try loosening 1 of the 2 hardlines coming off the master....

To make it all even that more confusing the next day when I went out to try and sort out the problem and get it fixed.... All of sudden the brakes were working again and have since not given me a single issue (knock of Mother F***ING WOOD!!!). I am just praying that everything holds together and no further issues arise until the 29th of this month.... It is my B-Day and will be starting the Straight axle swap!!! So fingers crossed, if the problem reoccurs I will post back up... However if no issues arise I will be posting my build thread around New Years Eve, and will if all goes as planned have the straight axle in and my rig back on all 4's no later then the 2nd of January!!!

Thanx for all the help and the replies!!! If anyone has any further input or questions please ask away and post up!!!

 

[kimcrwbr1]

Is it possible the brake pedal was just stuck down? When it happened did you try lifting up on the pedal? Possible the pedal was sticking or the pin was binding going into the master. What color is the fluid in the reservoir? I would at least flush out the old fluid brakes are way too important to hope they fixed themselves.

 

[enjr44]

IMHO, master is hanging and will do it again (or not, I guess).

 

[Andy D]

Flex lines could be damaged causing them to lock fluid in the calipers...

Air introduced into the master when installing...

A hose could degrade internally. Acts like a check valve. I had it happen on a bug that 20 yrs old at the time. I replaced the hoses on the Rat because they looked so bad on the outside. 20$ a hose more or less it greatly simplified R+R'ing the front calipers. Sa-nip! In these climes, if the brake hoses need replacing, chances are you'll destroy the lines

 

[angelfly]

Is it possible the brake pedal was just stuck down? When it happened did you try lifting up on the pedal? Possible the pedal was sticking or the pin was binding going into the master. What color is the fluid in the reservoir? I would at least flush out the old fluid brakes are way too important to hope they fixed themselves.

That's what's super weird about it, was that the pedal was stiff as all hell! Like when you push on your brake pedal with the vehicle shut off and the pedal builds up pressure and is completely solid until u restart the vehicle... Well that's how it felt. I could literally stand on the ****er with all my 195lbs and the pedal wouldn't move more then 1/8of an inch....

 

[angelfly]

Is it possible the brake pedal was just stuck down? When it happened did you try lifting up on the pedal? Possible the pedal was sticking or the pin was binding going into the master. What color is the fluid in the reservoir? I would at least flush out the old fluid brakes are way too important to hope they fixed themselves.

Oh the 1 thing I have done since all this happened was have all the fluid flushed completely out and replaced with brand new fluid.... I had a shop do it so I know it was done right... They said when I picked it up that they kinda felt bad doing it cause it was obvious that the fluid was brand fricken new... But they flushed the system and refilled it....

And this problem wasn't a situation like the pushrod getting stuck because it gradually built up pressure. It wasn't like 1 second I could push the pedal all the way down and the next second I couldn't.... Slowly the pressure built up in the pedal to the point I couldn't push it down whatsoever and the brakes were completely locked up as if I had my foot slammed on the brake pedal.... Very weird i gotta say...

DOES ANYBODY BY CHANCE HAVE A LINK THEY COULD GIVE ME THAT DETAILS HOW TO REMOVE THE ABS SOLENOID AND ALL THAT BS??? Would very much appreciate it! Thanx

 

[Mark_88]

Don't have a link as such...but the ABS (on my 96) for the RABS rather, is located just under the driver side foot well. What many people do is to simply get a line connector and pull the lines off the RABS and join them together with the line connector...remove the fuse and it will be a done deal...

If you have all ABS (front and rear) then it's just a matter of connecting the front lines to the front lines and back lines to back lines to bypass...not hard at all...

Much easier than a rear end swap...although you'd have to bleed the lines again...