Well I am new here, i own a ranger myself but my dad has a 98 f150 with the 4.6l, 4x4, extended cab, etc...

The braking has gone from bad to worse.

First off the pedal just seems way to soft and you have to really push it down.
The braking is so erratic(sp?) sometimes they work fine, other times not at all, and more often the rear brakes just lock up!

We put a new master cylinder on it a while ago, and the front brakes have not been replaced in a while but the pads are still good and so are the rotors. maybe 6 months ago we went through and changed the rear pads and wheel cylinders, new springs and such. the braking worked great for about 4 months now its just getting worse and worse every day.

It has 150k on the clock and needs some serious attention in many places which we would like to get done.

any help on the braking situation would be great!


I dont have a picture of my f150 but here is a picture of my ranger

 

Nice Ranger First I would bleed the brakes all the way around and on a F150 it can take 3 times to get all the air out, so buy the big bottle of fluid. I would spray the bleeder screws with penetrating fluid and use a flarenut wrench/line wrench to keep from messing up the bleeder screws.

 

X2, but I think air in the system would of happened sooner, who knows. Maybe the ABS module? Sometimes they act screwey. Nice pics of the Ranger, by location it would appear you are from Windsor too, no?

 

thanks guys. we bled the brakes when we put in the new wheel cylinders, but air does make sense. we are going to give that a shot. the rear axle needs a complete rebuild.

how would i know if its the abs module?

and Blue20004x4 I was in Windsor a month ago for a big ranger meet. I am from Indiana.

 

You may want to check the soft lines at the wheels. They can become weak and stretched, causing them to collapse under pressure.

 

When you say "really push it down"... do you mean push hard, or it has a longer travel? I assume by the "soft" comment you mean long travel, but I want to be sure.

If you have ABS - one way to check if that is causing the problem is to pull the fuse for the ABS module. (don't do this in the rain or snow!). This way you can drive it without any ABS events and see if the issues duplicate.

However, ABS problems won't cause long travel / soft brakes. (unless there are leaks at the module) The ABS functions by shutting valves to stop the brake fluid from getting to the wheels / pumping fluid back to the cylinder. It is a closed system so there are no places for the fluid to go.

You say the rear brakes lock up - This truck (are we talking about the 98 F150) probably has a proportioning valve on the rear brakes. Maybe even a load sensing proportioning valve. That could be the issue, if the prop valve was not working correctly it could dump too much pressure to the rear brakes and they would lock up. The ABS might be trying to compensate and this could be causing some of the "erratic" behavior.

This is another good thing to check, although the flex lines will stretch, not collapse. If you have done a thorough bleeding and the brakes are still soft, there is a good chance that there is either a small leak somewhere or the flex lines at the wheels stretching. That said - have you checked all the fittings for brake fluid dripping?

Where did you get the new MC from? Is it the same MC as the stock one... or some sort of "upgrade master cylinder"??? The occasional soft brakes could also be an issue with one of the seals.