pulsating brake pedal?

[FastOrange]

the brake pedal in my 1989 4x4 is pulsating when i press the pedal down, feels just like when rotors are screwed, replaced rotors and pads (which looked perfect to start with) and it STILL does it.

any ideas? master cylinder?

 

[squeaky3]

wheel bearings, ball joints, tie rod ends, all other suspension parts good?

unless you got some crappy rotors or warped them by braking extremely hard after you put them on

 

[dirtridinz71]

My 92 has been doing the same thing from time to time, seems like started after changing a rear wheel cylinder. Never looked into it too much but was thinking it was related to the real brakes. Actually as I think more about it i did unplug real under the hood and havent had the problem as of late.

 

[RHamill]

Could be as simple as a little brake fluid on the rotor causing the pad to grab when brakes are pressed, or it could be some bad rotors like previously stated.

 

[FastOrange]

well im gonna pull rear wheels and drums tomorrow and look there. see if anything is up

 

[FastOrange]

Could be as simple as a little brake fluid on the rotor causing the pad to grab when brakes are pressed, or it could be some bad rotors like previously stated.

Has brand new rotors!

 

[DRAGGIN95]

I have seen that happen on several 88-94's when the rear abs valve stops working correctly, I would try bypassing it.

 

[FastOrange]

I have seen that happen on several 88-94's when the rear abs valve stops working correctly, I would try bypassing it.

how do i do that?

 

[DRAGGIN95]

Here you go, I posted how about half way down the page. http://www.gmt400.com/forum/showthread.php?7849-rear-abs-module-delete&highlight=abs+delete

 

[RHamill]

Has brand new rotors!

That doesnt mean a thing when it comes to pulsation, ive put brand new rotors on at work that were way warped out of the box. Measure them rotors in 8-10 spots with a micrometer, or use a dial indicator while spinning the rotor.