LsxMatt

iTrader: (4)

I recently swapped to ls1 front brakes on my 86. My complete setup is the stock brake booster, rebuilt thirdgen master cylinder, thirdgen stock rear disk combination valve, ls1 front brakes with thirdgen hoses, and 1997 rear disks with hawks swap parking brake cables.

The issue ive been having lately is the brake pedal seems to get stuck halfway down. It seems to happen alot when i do high rpm pulls, then when i go to brake, the pedal is very hard, then immediatly drops to normal travel when the engine comes back down to idle. Im thinking its the brake booster, but im not sure. The one way valve on the booster is good, and there are no vacuum leaks. The pedal pumps up hard when not running, and drops when started so it seems like the booster is alright.

Yesterday after doing a high rpm pull, the pedal was stiff for the rest of the day, even after turning the motor off. The parking brake also had alot less resistance pulling up until about half way. If i sit in the car pumping the pedal for a few minutes, eventually the pedal becomes unstuck, and drops down to the normal travel distance. If i do some hard braking, with the pedal "stuck" halfway up, it start smelling brakes, almost like the rears arent doing anything and im overheating the fronts. Any info would be great. Not sure where to start. Thanks

86White_T/A305

Just my opinion but id look at that "rebuilt" master cylinder.Ive had issues similar where they were not the right cylinder or built to spec and didnt always release with the brake pedal causing the brakes to drag on.I would have to pump them a few times to release.Ive also had the front brakes lines cause my brakes to pull to either side due to their age and not allowing fluid to return to the master.

But with your pedal feeling like it gets stuck..seems like a master/booster issue and Id guess more the master.When it comes to braking..I learn to buy new and not rebuilt..cant worry about cheaping out when it comes to stopping!

scoflaw

iTrader: (2)

I'd say master as well, had a similar issue. An LS1 master is a direct bolt on for your application to your 3rd gen booster. I'd try that 1st

LsxMatt

iTrader: (4)

The pedal isn't actually getting stuck as in dragging, what i meant to say was it stops halfway down. Like it gets much more firm than normal, and the travel gets limited to 1/4 to halfway down. Then eventually it snaps out of it and the pedal drops more to where it normally is. It almost feels like it only has half the booster pressure. It did it a half hour ago driving home, right after hard acceleration in 1st. Feels like i loose most of the booster assistance, then it goes back to normal after a few blocks of slow driving.

86White_T/A305

And your certain there are no vacuum leaks in the entire system? Did this only start happening after swapping to ls1 front brakes?