Brakes are failing at very low speed. Example is like moving up one or two car lengths in stop and go traffic or red light. Pedal feels like ABS shutter. Very scary! Only lasts for a second or two until van stops.

No warning lights, brake light or ABS light on. I checked all fuses inside and engine compartment and they are good! I am going to change and bleed all brake fluid out to see if this fixes issue. Brakes are front disk and rear drum.

Could it be Master Cylinder?

 

We had similar brake issues when we got our van. A new master cylinder fixed it.

Sixto
93 E150 Chateau 5.8 185K miles

 

What's the situation at highway speed, thinking if you had to make a panic stop, some text messaging fool in front of you and no where to avoid rear ending them? What's that like?

This is something you want to fix ASAP as it could be just an early symptom of something larger about to surprise you at the most inopportune of moments.

 

JWA- Actually that just happened to me. I was driving on the freeway and a very slow truck changed lanes quickly and I had to slam on the brakes and steer to change to the left lane going about 70 MPH. Just missed hitting his left rear bed... Brakes performed as they should.

 

Any leaks at the wheel cylinders?

Sixto
93 E150 Chateau 5.8 185K miles

 

I had a similar problem with my '99. the rear brakes would chatter at slow speed just in the morning until they warmed up. turned out the shoes were worn and one had come off it's backing plate. that along with glaze built up on the drums. new shoes and drums took care of it

 

Has this been creeping up on ya or just recently become noticeable?

I gotta go with rear shoes somehow figuring into this but certainly the master cylinder (MC) and entire system needs checked ASAP. It could also be your rotors have worn just enough to simulate low pad pressure, the calipers not able to exert enough pressure on the pads increasing your stopping distances as described.

While the front discs are sufficient to stop given enough distance ahead rear shoes do matter; worn or damaged shoes and/or drums can be the issue there.
I have to think if it were only the MC bypassing fluid around its main piston sitting still and pressing on the brake pedal should have it eventually hit its lower travel limit, almost touching the floor.

Your panic stop was probably more panic than stopping, never a good feeling! Let us know what you find is the problem here---could be helpful to someone else too.

 

IMO never procrastinate when it comes to "braking issues". Your comments run hot & cold speaking of brake failure & normal operation in virtual same breath. Suggest you get a better handle on what is going on, or take it to somebody who understands brakes better w/o delay.

If it were mine I'd check the obvious things like brake fluid level & condition, as well as examining each wheel for signs of fluid/oil leaking/contaminating brakes. I'd drive slowly carefully to a dirt road or grassy area w/no traffic & do a few simple tests. First I'd roll to a stop after not using brakes for a few minutes, get out & feel each wheel to check if any were running hot, a sure sign of dragging. Dirt or grass can be used as a slow speed Skid Pad to visually reveal braking effect at each wheel. At 20 mph or less a panic stop should skid all 4 wheels. If a wheel is pulsing it may be revealed. I'd do several quick stops to heat up the brakes & again get out to feel for excess heat at each wheel. You may find a cold wheel from seized wheel cylinder.

I'd also back up & stop smartly several times to give rear brake adjusters a good chance to take up any slack.

 

Thanks for all of your replies on this issue. This problem started creeping up on me about a month ago.

The first thing I did was check all of the brakes. Front rotors (motorcraft) 50k miles on these now, and second set of pads are all within specs and look good. Back drums and shoes were pretty bad and needed an overhaul so I replaced them with all new parts drums, shoes and hardware. This really firmed up the pedal. however I continued to have issues with the shutter at very low speed.

I bleed all of the lines and changed the brake fluid. Still did not fix the issue. No leaks at the wheel cylinders.

So I went to an old closed kmart with a big smooth parking lot and just started testing the brakes under all different conditions. I got the brakes to shutter at first by replicating....like stopping at a traffic light and then moving up a car length or two. When I would move up a car length or two, brakes would shutter and van would not stop for about 10 ft, even mashing the pedal as hard as I could to the floor. This is all at very slow speed. I was able to do this twice and I couldn't replicate the test anymore and the brakes worked normally. So this told me it only happens when brakes are cold or you first start driving the van.

I also noticed in this testing, that I felt a slight hang up. I felt it in the pedal. Sometime but not all the time, something released a second after I let up the brake pedal after a complete dead stop. I am guessing it was on a caliper. Very slight because I could not tell which side it was coming from and reinspecting the pads and rotors did not provide any clues.

So I replaced both front calipers and bled the system again. I have driven it twice and I think I have solved the problem. If not then I guess I will move on to the master cylinder.

Thanks again for everyone's input..Good advice, I used all of it!

I will keep you posted!

 

Check your emergency or parking brake cables too---those have been known to create problems somewhat similar to yours.

One quick way without dismantling anything is after a drive that didn't include lots of start and stopping or heavy brake usage and feel the rear drums, from inside the wheel if possible. If one or both rear drums are dragging they'll be very warm, almost hot to the touch---good indication something there is amiss. This could be the cause of your slow release issue.

Double check your rear shoe hardware, make sure nothing has popped lose or become misaligned too---never know if a new part has failed.

If this comes down to a new MC I'd suggest a top quality part, maybe OEM or NAPA, anything new or a lifetime guarantee would be my choice. I did this same thing myself due high mileage on an '00 and did use the Ford part.

Let us know your eventual fix---would be helpful to others too I'm sure.

 

I just replaced the MC on my '99 for an unrelated problem. It was 65.00 new at Autozone, which was the same price as a reman. No core charge for the new one

 

I finally got a check engine light to come on after all of the hard practice driving at the closed Kmart. It was a bad ABS module. Hard to find a replacement that matched Ford numbers, however found one close on ebay and swapped it out. Breaks work great now!

Thanks for all the input. I couldn't have fixed this without everyone's help!


Solved the issue in this post: https://www.ford-trucks.com/forums/1...1095-code.html