Ok everything on the brake system has been replaced...Green pads, Earls lines..New back Calipers, rebuilt front Calipers, and master Cylinder....Car still does not stop good..The rear is out of a 1986 IROC...Have the right Prop Valve for that rear...Brakes still push to far, and the car does not stop as it should...I have bled it, till i'm bleeding...I think it was better with rear drums...We did have a hell of a time with that emergency brake adjuster.... ..Any ideas guys?????Thanks, Tom

 

The delco 10.5 brakes are some of the most lacking brakes from a performance standpoint. I did away with them in favor of the 12" c4 brakes. For what it's worth, you are running basically the same brakes, size wise, on all 4 corners, if the brakes are stock 86 stuff. I would invest in some brackets and get some 89-97 PBR calipers for the rear, you will be much happier with this combo. I tried the same thing you did, bought nice rotors, rebuilt my calipers, new master, new prop valve, new pads, and it just wouldn't stop like I had expected. After screwing around, I bit the bullet and installed new front brakes, never looked back!

Will

 

did you bench bleed the new master? does the booster hold vacuum?

 

Did bench bleed the master, but do not know about the booster...Never thought of that at all...How would the booster effect the brake performance???..Might look into the PBR stuff...Its a shame my 89 did not come with them....I am disappointed to say the least, I was expecting a change for the better...Thanks for the replies......Tom

 

If so, here's a link that will provide info that you might find helpful:

https://www.thirdgen.org/forums/faq-...iscs-89-a.html

JamesC

 

Thank you very much..........Tom

 

without the booster working properly, you will have no power assist, the pedal will get really hard pretty quick and the brakes will suck. A simple vaccume leak in the vacuum line feeding the booster will make brakes suck.

 

two weeks ago I replaced my master cylinder.
if I am going 30 mph and I press the brakes, I have push the pedal all the way to the floor to come to a full stop. my breaks squeak when the brakes are applied.
my brakes lock up when pushed to all the way the floor and squeak.

 

From: http://autorepair.about.com/od/troub...s_brakes_2.htm

Brake Pedal Goes To Floor. If you step on the brake pedal and it has little to no pressure and goes all the way to the floor, especially if you're getting no braking:
Low Brake Fluid Level: Check your brake fluid. If it's low, top it off to the mark on the side of the reservoir.
Air in the Brake Fluid: Even though your brakes operate in a closed system, contaminants can still work there way into the works. Air can enter the system through the smallest hole. There's not really any way to check for this, but bleeding your brakes will remove the air and replace it with new fluid.
Master Cylinder Bad: A bad master cylinder will cause your brakes to have no pressure. Master cylinders cannot be repaired and will need to be replaced.

Brakes Squealing or Whining. Brakes make those high pitched noises for a few reasons, some of which are no big deal at all:
Worn Brake Pads: When your brakes are worn and need replacing, they are designed to let you know by giving you some loud squeaks when you apply the brakes. Replace your brake pads.
Brake Pads Vibrating: Your brake pads are installed with a little metal gasket between the brake pad and the piston. This gasket absorbs the vibrations that can increase in frequency to the point of squealing. If they are missing, replace them. There are also special anti-squeal lubricants you can apply to shut them up.


JamesC

 

the master cyl. reservoir is on full mark

the brake pedal does have pressure but feels weak

the KARR does slow down if I press the brake pedal but not enough for city driving.

the brake pads and rotors look good
my karr need an alignment and the wheel bearings need to be repacked

i think it could be brake fade or air in the system

 

Since you've replaced the master, air is the easy answer. Did you bench bleed the new master?

JamesC

 

yes

 

Do you mean PBR's for the front, or the back.??? What did you do master cylinder wise when you went to PBR's...??....I do believe you are right, I was just expecting way to much out of this system......with all the work done on the front end, the car handles well..it has a fair amount of power, but the stopping is just plain poor...Thanks much for taking the time to respond...Tommy Shaw

 

I rebleed the brakes the squealing is gone and the brakes are a litttle bit firmer. But the break pedal still feels a bit weak.
I think there is still air in the system

 

the brakes are still squealing and but they dont lock up any more. The brake pedal is a litttle bit firmer, but the break pedal is still weak.
I think there is still air in the system and I now hear a gushing noise when I push the brake pedal to the floor

 

Bad power brake booster, I had the same sounds/symptoms, replace part, problem solved...

 

How do I test the Power Brake Booster?

 

the sound of air being released under the dash shows that the diaphragm inside the booster is bad, the booster is only about 80 dollars and is easily replaced, you don't even have to open the master cylinder. just remove the 4 bolts inside the car under the dash, and the cotter pin from the brake pedal, then take the 3? nuts attaching it to the master cylinder off and slide it out from the firewall and the m. cylinder, the slide the new one in. and reverse process. takes about 20 minutes.

 

Hell, I might do it, just so everything will be new...they seem a little better, but I was just hoping they would really haul her down...Thanks to all for the replys....tom

 

I have a similar problem after I just replaced my prop valve. I have rear PBRs. My car stops worse after getting a disc/disc prop valve. The brakes feel ok but it takes everything I have to stop it (40 mph) and the pedal gets real stiff past half way. Everything worked fine before replacing the valve so I doubt its the booster.