Question : Is 1st Gen W body Master cylinder weak?

[packardbell]

Did a complete brake job on my cutlass supreme this weekend. Replaced all four rotors, four calipers and pads. New fresh brake fluid since I replaced the four calipers it needed to be bled as well. Break in the pads and now when I slam on the brakes it does not lock up the wheels. Why? The brake pedal is firm but it seems that the brakes do not grab hard enough to lock up even the front wheels.
I am not using R comp tires and using General Tire Altimax HP 225/60/16 tires.

[robertisaar]

Break in the pads and now when I slam on the brakes it does not lock up the wheels. Why? The brake pedal is firm but it seems that the brakes grab hard enough to lock up even the front wheels.

...... so it does or does not cause wheel lockup? those two statements seem to contradict each other.

what kind of pads? what kind of rotors? has the booster gotten weak but not completely failed?(Schurkey has experience/info with this)

with ABS disabled, the MC(with its "ancient" rear drums) can lock the rear wheels at pretty much any speed from 30+ if you jump on the pedal hard enough. fronts are a bit more difficult to do so due to weight transfer while braking.

[packardbell]

...... so it does or does not cause wheel lockup? those two statements seem to contradict each other.

what kind of pads? what kind of rotors? has the booster gotten weak but not completely failed?(Schurkey has experience/info with this)

with ABS disabled, the MC(with its "ancient" rear drums) can lock the rear wheels at pretty much any speed from 30+ if you jump on the pedal hard enough. fronts are a bit more difficult to do so due to weight transfer while braking.

fixed, it was does not lock up.
My cutlass does not come with ABS and there is no drums in the rears as well. Fronts or rears do not lock up at all.
Maybe I need to drive it some more since the brakes are still fairly new?

[robertisaar]

depending on the pad material and rotor surface, you may not be able to get a wheel to lockup even with a good booster and master cylinder on dry pavement. i know i've bought pads before that have made that impossible for me. a lot of the "organic" pads seem to do that and ceramic seem to be finicky about rotor surface. the semi-metallics are hit and miss.

[packardbell]

depending on the pad material and rotor surface, you may not be able to get a wheel to lockup even with a good booster and master cylinder on dry pavement. i know i've bought pads before that have made that impossible for me. a lot of the "organic" pads seem to do that and ceramic seem to be finicky about rotor surface. the semi-metallics are hit and miss.

I just got Wagner Thermo Quiet pads and Aimco rotors for the fronts, for the rears I got Raybestos Sure stops and ATE premium one rotors.

[SappySE107]

You need the 96 grand prix brake setup. You wont get it to lock up and its gonna feel like shit in a year. GM improved the rears in 94 and the 96 has the largest fronts. I forget if the rears changed again for 96 but I know the fronts did.

[packardbell]

You need the 96 grand prix brake setup. You wont get it to lock up and its gonna feel like shit in a year. GM improved the rears in 94 and the 96 has the largest fronts. I forget if the rears changed again for 96 but I know the fronts did.

could it be the master cylinder is just not big enough to supply more than adequate pressure to squeeze them calipers?

[1988GTU]

Did you replace the soft whip hoses at the same time as calipers? If not, do that and it should at least give you a better chance at skid stopping on broken gravel or sandy ashphalt.

[packardbell]

Did you replace the soft whip hoses at the same time as calipers? If not, do that and it should at least give you a better chance at skid stopping on broken gravel or sandy ashphalt.

nope I didn't replace those soft hoses. Well I am going to bleed the lines again and test it out tomorrow and see if anything improves. I will also order some replacement hoses from rockauto.

[SappySE107]

You want stainless braided hoses if you want better braking. Master cylinder does just fine with larger brakes, but you could try to upgrade it and see if that helps any.

[robertisaar]

I forget if the rears changed again for 96 but I know the fronts did.

late 95 and all 96+ 1/1.5 gen cars got the 11.25" front rotors. all of the 94+ rear(except 94 lumina, IIRC) disk setups for the 1/1.5 cars should be the same as well.