93 Brake Problems

[agobbie]

Hi Again !

I am having problems with my front brakes on my 93. Heres whats goin on.
when braking the pedal pulsates, vibrates alot. Thought it may be the rotors, so did a full brake job, rotaors, pads etc ......... Problem went away and then came back after about a Month. Pulled the rotors off again and had them machined, for piece of mind - went away and came back again !! Am I missing here or is this normal ????

Also if you travel on the brake pedal, sitting in traffic and dont lift off all the way, the pedal goes flat to the floor and ya have to pump it to get back to normal ???

Thanks in advanve for all yer Help !!!

 

[quicklook2]

are you sure your bleeding the brakes the correct way with the abs?

 

[agobbie]

are you sure your bleeding the brakes the correct way with the abs?

Not sure - is it differnant with ABS ?

 

[Anime]

Is the pedal vibration/pulsation like the pedal is kicking back? If so, it may be the ABS randomly engaging. Might need to check the ABS sensors. Some models have 2 wheel ABS (front wheels only), some have ABS on all 4 wheels.

If the pedal goes flat to the floor, I'd say it's the master cylinder. Might try to bleed the whole system to see if it makes any difference, but I'd say just go for a new/rebuilt one, might solve all issues in one swoop.

 

[mikeinri]

agobbie,

In case this isn't obvious, the symptoms you are describing are most definitely NOT normal...

Mike

 

[trucku]

If your going to the floor then you have a master cylinder that in need of replacement or rebuild.

If your wheels get over torqued you can warp your good rotors. I think 100ftlbs is max.

Change that master cylinder first and go from there. Do a complete brake fluid flush. Bleed out all the old fluid from all the wheels and keep filling the reservoir.

 

[ricco750]

I was having similar problems on my Ex last Fall...I did a COMPLETE rebuild of my brakes...I'm talking rotors, drums, pads, shoes, calipers, cylinders, master cylinder (new, not a reman), and booster...pressure bled the system...then took to Ford to have them bleed the ABS module. No more problems!

 

[msmith65]

This is just a guess. Your master cylinder is all messed up. Because of that, you're not getting any rear braking action, so the fronts are doing all the work and overheating, causing the warpage.

 

[mikeinri]

Warped rotors are bad...

Another possibility, although somewhat remote in your case, is that the rotors were not seated properly, and/or the axle nut was installed too loose. This would allow excess play which would eventually cause rotor warpage. This happened to my truck, but my symptoms were the pulsating only, I didn't have low/no pedal.

Mike

 

[agobbie]

Update

I went thru the barke system and found a bad/leaky wheel cylinder - replaced it and bleed the brakes - no air in the lines at all. But still have the spongy brake pedal. before I relace the master cylinder is it possibe that just going to ford and having the ABS bleed will fix the problem ?

Also, according to the haynes book, The master "should not be done at home", is this true or can i repalce the master, bleed the lines and then drive to ford for the abs to done ??

Thank ya all

 

[trucku]

Did you bleed all of the brakes lines out or just the one you worked on?

If just the one, Bleed them all out completely with new fluid and maybe you will get rid of the soft pedal.

 

[agobbie]

Bled all four w/ same results

 

[trucku]

Must be the master cylinder. Its not holding pressure. You can probably buy a rebuild kit and do it yourself or just replace it.

 

[mikeinri]

As for the Haynes advice, all I can say is there are plenty of posts here from people that have done it themselves. It's possible that Haynes doesn't want the responsibility if it goes badly. If you screw up one brake, you have three others. If you screw up the master, you have no backup (other than the e-brake, which is usually a joke).

The big thing is, be sure to bench bleed the new master before installing into the truck.

I've done millions of brake jobs over the years (OK, at least 10-20), but I would personally not attempt this job, mainly because I haven't ever done one before and don't have anyone nearby that could watch me do it. If you're more comfortable with your skills for this repair, by all means go for it.

Hope this helps.

Mike