F150 Brake Feels like no brake for a Second

This is a long shot, but I used to have an old BMW with the exact same system. That car had a "hydroboost" type brake booster instead of the vacuum booster most commonly used, and the problem was that the hydraulic accumulator was shot.

nate

I had a similar problem with my Crown Vic. A new booster fixed it right up.

Lugnut

I had a problem with the MC bypassing. First pedal hit went flat to the floor. Second hit full brakes. It did it twice to me before I went and replaced the MC. I have not heard of it since my 1980 E150 van.

I just wanted to update what I have found so far. Basically I have eliminated the master cylinder and brake booster as the problem. It looks like my ABS was coming on intermittently when the brake is pressed. I disconnected the ABS EBCM so the ABS will not work at all, and my brake issue went away. Now I need to figure out why my ABS would come on intermittently on dry, clear pavement. It is coming on when it should not. I am thinking it may be one of the sensors is bad (I hope because even a rebuilt EBCM is expensive.)

Anyone see either the front or rear sensors go bad to the point where the ABS would activate intermittently when it is not supposed to during braking?

OK...I haven't played/looked at the ABS on my F150, but I had the same problem as you with the ABS on my T-Bird, except that after the first braking and pedal issue, the ABS light would come on detecting a malfunction and deactivate the ABS system. Now in the T-Bird ('93), the setup was a small sensor aimed at basically gear teeth that spun on the hub. The sensor more or less sent info to the computer that determined the speed, and if that wheel was turning based on more or less by how quick the sensors signals were coming back through the gear teeth space as it turned. The computer took the info from all 4 sensors and how much pressure your applying to the brake and made it's calculations. What had apparently happened was that debris or a rock got kicked up into the gear teeth and bent the sensor when it came around so that it wasn't aimed at the gear teeth anymore. All I did was bend it back to where it was supposed to be, by referring to the other sensor on the passenger side and it fixed the problem for $0 and few minutes. I'm sure the truck system is set up different as I'm sure they've improved the ABS system since then (plus I can't imagine that they'd expose the sensors like that of off road vehicles), but I'd pretty much guess it's an issue with one of the sensors.

I'm sorry I can't help too much further other than see what info you can dig up on the sensors....

IYM

"Lee" wrote in message news: snipped-for-privacy@d55g2000hsg.googlegroups.com...