I have a stange brake problem with my 99 Lightning.

The brake pedal will go further to the floor on the first pump, on the second pump it is bake to normal - hard and only half way to the floor.

Which sounds like I need to bleed the brakes to me?

Here comes the strange part. When I remove the master cylinder cap and replace it, everything is now back to normal. It will take 2 maybe 3 weeks to go back to the 2nd pump required.

What gives?

 

I don't know about the second part of your question, but the pumping the pedal up is indicitive of air in the system (or out of adjustment rear drums, but you probably don't have those).

Try your hunch and bleed the system.

Tom

 

How about this.
the brake calipers are suppost to be self adjusting. As the pads wear down the piston( or pistons) are suppost to move farther out to compensate. if one of the pistons is sticking occasionally your first push on the pedal would include the extra travel needed to pad the pad in contact with the rotor. The second push would not have to compensate for this and would be higher and firmer. Air in brakes would cause a pedal that gradually fades. Wolud also more than likely turn on the brake light( if it was severe enough.
Just a thought

 

Bottom line is you should probably have your brake system looked at or do it yourself .Check the brake pads for wear they may need replacing as you lose material the pedal will have to travel a bit further to make up for the lost material but it should not be that noticable. If the pads have plenty of material I would bleed the system starting at the RR then LR then RF the LF while your at it might as well do a complet flush and get fresh fluid in there I would recomend Castrol GT/LMA it is very good fluid. You may have to ask around but check some of the truck specialty shops they should stock it. NOTE: Be sure to check the Fluid Resivior every two or three pumps to refill it or you will end up getting air in the system and having to start all over.You will need two people to do this and if you do not know how to do it take it to someone that does.

Richard D.

https://www.f150online.com/galleries....cfm?gnum=2479

 

grapeman,

Your master cylinder could be going bad. I was told by one of my co-workers that you will damage the master cylinder on newer Ford's with anti-lock brakes if you retract the caliper pistons the way most people do by using a c-clamp and taking the cap off the fluid reservoir. He has a 97 Ranger that he changed front brakes on that had total brake failure recently (had to pump the pedal and pull it back up before total failure - about 30K after the change). He was told that you need to open the caliper bleed screw to prevent damage to the master cylinder or you will have a failure after 30K to 40K miles on vehicles with anti-lock brakes. He said his fluid level didn't rise when he retracted the pistons on his calipers. I may be in the same boat in about 30K miles with my '01 Supercrew although my fluid level did rise as normally occurs when retracting the pistons.

Are there any Ford mechanics on the boards who know this to be true?

HiO


My Gallery

 

HiO I believe that is true on older ABS sytems. And on vehicles with electronic brake force distribution. In most cases on newer vehicles the old standard of starting with the wheel that is the farthest away from the master no longer works.

However I do believe pestco1 is right on this one. These bosch calipers are very sensitive to dust and dirt and they do get slow and/or stuck which would cause your double pump concern.

I would take each caliper off and clean it and re-lube the slides. (All calipers including the back) and see if this fixes it.

If not get a dealer to flush the system. Stay clear of old fashion independants.

 

Just went thru the entire Brake Repair section of my Ford CD Manual and no mention of not to use a c-clamp and since I have been doing mine that way since i got my truck and also did it that way on my 1988 F150 and it still has the original calipers on it and have also been told by mechanics that is the way to do it then I believe you will be ok( And the 88 F150 had Rear ABS). I would like to suggest that when compressing with a c-calmp DO NOT just crank it down do it slowly applying a little pressure at a time and if you aren't comfortabledoing it that way then open the bleeder screw enough to let the fluid escape but hook up a clear hose to it first so it can drain into a can(I use an old Coffee can for mine) If you have any type of mechanical skills DO NOT take your truck to the shop or dealer to have them Flush your system it is so easy it just requires two people and a bit of common sense. Follow the procedure i posted earlier and you will be fine. As for not starting at the RR That is the way the manula says to do it start at RR then LR the RF then RL. Have someone in truck to push pedal when you open the bleeder screw then close bleeder screw and have person in truck release brake pedal and keep repeating unitl you have clear clean fluuid coming out (MAKING SURE TO CHECK THE FLUID LEVEL IN RESIVIOR EVERY FEW PUMPS AND ADDING AS NEEDED)Repeat this procedure with all four wheels.You have now flushed your system and now have fresh fluid all around and it should be done about every two years or so.I HIGHLY RECOMEND the CASTROL GTLMA DOT 3 Fluid it is great stuff.

Richard D.

https://www.f150online.com/galleries....cfm?gnum=2479

 

Do what makes you feel comfortable. Start at the RR or take it to a shop or not.

If you have a newer truck and have 4 wheel abs there might be other bleeders in the system that WILL get air in them if you do it the OLD Fasion way.

All I am saying is just check to make sure you do not have a distribution box along the frame rail for the rears with a bleeder screw in it.

You can also do this job just as easily by yourself with a one man bleeder kit. They work quite well.

Stay comfortable.