berry72

I recently installed a new master cyclinder, brake pads - front and back, all new rotors and cleaned out the entire system with fresh fluid. The brakes are still mushy. The pedal goes almost to the floor before it will hit rock bottom hard pedal. The brakes are good enough to stop the car but are not stopping on the dime as they should. There are no leaks in the brake system and the booster is holding vacuum. I am thinking I should replace the calipers??? I noticed that when I pull the emergency brake the back brakes barely hold. I have adjusted the cable but it makes no diffrence. I am over looking anything? I just purchased the car a few weeks ago and the previous owner left the car sitting a lot without running it and I've already had to replace all the fluids and several other hoses, etc. due to dry rotting so I think the calipers may just be sticking a bit due the dirty fluid I removed. However, I didn't have any trouble or find any leaks with I was installing new brake pads. I don't have ABS on the car but was curious to as when they started putting ABS breaks on the corvettes?

Thanks,

Matt

BADDUCK

May have some air left in the lines.
When you get a chance fill out your profile.

89vert

Did you bench bleed the master before putting it on the car? I just put a master on my car and it took a while to get all the air out of the master while I was bench bleeding it. Also my '89 has ABS. Check the compartment behind the drivers seat. The ABS pump will be there.

CentralCoaster

Sponginess means you still have air in the lines.

If there is much pedal movement even before it gets spongy, then you probably have to adjust the brake booster pushrod. You unscrew it to lengthen it before installing the master cylinder. It should be just barely not touching the master cylinder piston when it's at rest.

Also be sure to verify the brake bleed with the car not running, otherwise the booster will make it harder to tell. I recommend buying speedbleeders to simplify the process. And as mentioned, if the master cylinder isn't bench bled it will take forever to bleed the system.

berry72

Yes - I did bench bleed the master cyclinder before I installed it. I also used a vacuum mighty pump to bleed the brakes. I will check the ABS pump and try to bleed again. So no one thinks it could possible be the calipers? I just thought I would try that as well.

Thanks,

Matt

Aardwolf

It could be sure, check them out to. Let us know!

CentralCoaster

No. Unless you forgot to install the rotors or bleeders.

Check the booster pushrod. How much movement is there with the car shut off?

berry72

The booster push rod has very little play with the car shut off. It appears that there is very little room between the push rod and MC - it hard to tell when your bolting up the MC but from what I can tell push rod is barely touch the MC. Is there another way for me to measure the distance?

Could this have anything to do w/the ABS? What I if I just unplug the ABS all together? The light on the dash isn't working anyways but the fuse is good. I got a feeling the previous owner took out the bulb in the dash but I will not know until I remove the dash and see what is going on.

Aardwolf

Once you start the car, and move around 5 MPH the ABS makes a whirrling sound. Can you hear that? It will also make the noise when you brake very hard or if your in mud or snow and the front tires lock up while the backs are still moving.

berry72

No - the ABS doesn't make a sound.