My daughter has a 2007 Ford Fusion with brake issues. Brakes are squishy after the car is “jarred” (i.e. hits a bump or pothole). The brakes go almost all the way to the floor and return to normal after a driving for a while. All the work described below has been performed by Ford dealers (at great expense): Master Cylinder replaced, all brake pads replaced. Brakes have been bled numerous times. When we bring it in they bleed it and say it’s fine, next “bump” and the problem comes back. We’re really at our wits end, the car is, at many times, scary to drive.
You need to take your vehicle in for a second opinion or a third if necessary. Seek out a good independent mechanic and stay away from the dealerships. I think the mechanics working at your particular dealership have no idea what they are doing. You don’t want to second guess your brakes at any time. It’s critical that they work properly all the time.
There are a few maybes
1 - Try slamming on the brakes and holding them down on a wet or gravel straight road.
2 - A mechanic with a good scan tool bleed the ABS.
3 - Replace ABS unit.
There are a few options. The new master cylinder might be defective. there might be an issue with brake lines or hoses. Also the booster might be on its way out. I agree that you need a 2nd opinion. Brakes should not be that difficult to figure. They have had the same basic principles for many years.
go to another mechanic.
Pull the fuse for the ABS and then drive the vehicle.
If the braking problem goes away there’s a problem with the ABS.
ABS problems are sometimes hard to diagnose. I had an ABS problem on a 1990 Ford Aerostar. When I applied the brakes hard enough to kick in the ABS, the rear wheels would lock up (the Aerostar only had ABS on the rear wheels). The Ford dealer worked on it several times without success. A technician at my independent tire dealer who was a brake specialist tracked it down to a sticking valve in the ABS.
The hard impact might be causing one or more of the caliper pistons to be retracted abnormally far…A bad wheel bearing or otherwise loose hub or caliper mounting might be at fault…The next stop or maybe two, the pedal travel would be greater than normal but a couple of quick pumps on the brake would restore order…Otherwise, focus on the ABS …
Hmmm… Abs unit?
Anywho, it seems if we had electric brakes alot of these expensive problems might be eliminated.
“Anywho, it seems if we had electric brakes alot of these expensive problems might be eliminated”
Better yet, let’s go back to the mechanical brakes of the pre-1939 Fords. All you had to do was keep the rods in adjustment.
You’re assuming that electric brakes would not bring problems unique to electric brakes. That’s a big assumption.
Thank you for the input - it helps us zero in on the real issues. We have to take it elsewhere to find out what is wrong…
that s what some of us suggested…