why does it feel as tho i lost braking power when i switched to the ls1 master? im almost tempted to go back to my stock master. any body else having this problem and why? btw i still have my drum prop valve. i know it doesn't bring the full potential but it doesn't feel like my fronts bite like they should. input appreciated.

 

Check post #26 for another opinion:

https://www.thirdgen.org/forums/brak...upgrade-2.html

JamesC

 

While I don't know the math/science behind it, all I CAN tell you is I noticed a dramatic reduction in braking force. The pedal seems to travel farther as well.

One thing I have looked at is the actuator rod that goes into the MC from the booster - The LS1 style is a "coned-mushroom" style, whereas the original 3rdgen is a single dome-ended rod. IIRC, the 3rdgen rod is shorter than the LS1 style; The reduction in braking force may simply be that the 3rdgen actuator rod isn't pushing far enough into the LS1 M/C. I can include some pics, but it'll take me a couple days to get 'em uploaded.

 

The LS1 M/C has a larger bore then your stock M/C. Hence less line pressure for the same foot pressure. Although do make sure that it is fully bled.

RBob.

 

Rbob is correct, the bore size is different, though i thought the ls1 was smaller?

I've looked into the pushrod shape differences, and they are both the same length and sit in the same spot, ahd swapping the two will make no difference in braking, been there, done that

anywho, i have the ls1 on my 86 and my 92, while i havent driven the 92 with this yet, i noticed no difference in performance on my 86 between the stock one and the ls1 master, using 13" c5 fronts and 4th gen 12" rears.

make sure you bench bleed the master properly before install, and bleed the brakes properly before driving. a little air will make the brakes suck.

 

No problems here. I found away of gaining some extra pedal. Take the factory sound deadener off the firewall were the booster and pedal assembly sandwich it. You'll need to make a mod to the brake light switch since it sticks to far out. The factory style clip nut sucks *** anyways, i trim one of the nuts down and then jam nutted the switch in-place.

 

one thing i have noticed is that its only low sometimes. some days the pedal is right there and some days i have to really get into it to stop. i did bench bleed it and i have bled the lines 3 times. i do have all new lines {stock}. im a mechanic for a living so i work on other peoples cars all day and really don't have the time to track down this slight complaint. all parts of the system are new or fairly new except the booster but ive only seen the pedal go rock solid when they fail. so far thanks for the tips, i know the wealth of knowledge here will bring me to the answer i seek.

 

LS1 M/C is 1" bore. The late 3rd gen M/C is a 0.945" bore, 12% smaller cross sectional area.

What confuses people is the 3rd gen M/C is a quick take-up design. This larger bore area is used to get a large slug of fluid to the calipers. This is done to reduce pedal travel, and adds/subtracts nothing to pedal effort.

But it is confusing as it makes it look like the 3rd gen M/C has a larger bore then the LS1 M/C, when it doesn't.

RBob.

 

thanks for the info, but its 10.5 percent smaller