help, brakes

[DBANDGB]

89 grand marquis, prob. bad left front caliper. i just replaced both front calipers,gravity bled one at a time after installing. bled both twice. driving on the grass & pedal is not as high as it was before. drove out my driveway about 12 mph, stepped on the brakes & rear wheels lock up skidding on the blacktop. rebled fronts & tried again, same problem.i was very careful in taking apart & didnt loose any excess fluid, master cyl. still had more than enough fluid. what do i need to do???
thanks, gary

[HATNINJA]

Im not sure if boxes have them but thier may be an issue with the proportioning valve.

[Lincolnmania]

i'll bet the prop valve is stuck......slam your foot on the brake pedal real hard a few times.....that usually frees them up

[HATNINJA]

So they do have them are they part of the master cyl or external.

[1990LTD]

i don't believe 90-91 have normal prop valves

[HATNINJA]

where are they i have a 91 gmq?

[gadget73]

Have you had someone work the brake pedal while you bled the brakes? Gravity bleeding doesn't always work right on these cars. I usually bleed all 4 wheels just to flush the fluid out, but having someone work the pedal while you work the bleeder seems to do a better job.

[91waggin]

Bleed them properly with a second person pumping the brake pedal, and then adjust the rear brakes up so that they are just a smidge off dragging.

[85crownHPP]

Might need to bleed the rear to reset the valve, if they work like the older ones

[85crownHPP]

where are they i have a 91 gmq?

all '88 up have is the doodle in-line with the rear brakes, attached to the master cylinder

[gadget73]

yeah, if there is no block on the frame down below the master cylinder with lines going in and out, you don't have the old style shuttle valve stuff. No fears of the later model screw into the side of the MC prop valve sticking.