Hi!

Since I bought the Blazer it's brakes are horrible! The pedal feels very spongy, so I tried this things:

new Brake Pads for the Drumbrake
new Brakepads and Discs
new master cylinder
new brake tubes front and rear
new brake combination valve instead of the ABS-valve, because here in Germany nobody has this obd-computer to bleed the abs

And I bleeded the System 3 times with an adapter that gets the brakefluid under pressure in the master cylinder...

Nothing changed! Any ideas? Could the power brake be "a little bit broken"? I mean, you feel a great difference when the motor runs, so I think the power brake is ok. But when I brake I feel a little crack in the pedal, but there ist no backlash/play in the pedal.

 

try starting the truck and then hold the brake pedal. If it stops then slowly sinks to the floor its your master cylinder

 

Using quality brake pads and shoes with a higher mettalic content make a big difference over using the inexpensive low quality parts.
I have used some cheap brake parts before to save money and the truck almost would not stop. I changed to more expensive pads and shoes and the truck stopped very well.
To check the brake master cylinder, with the engine turned off pump the brakes a few times until the pedal is hard to push, then while holding the brake pedal start the engine and the pedal should go down a little. If it does then the brake booster is working.

 

Does the truck stop good?Just the pedal feels spongy?

I know my Blazer isn't the firmest brake system I've driven... But it is a little on the spongy side, pedal wise, at least...

Find a wide open area and do some brake tests... unplug the ABS fuse and see if you can lock 'em up...

Granted, I'm sure that's not the safest or most professional way of testing them, but you can be going 50km/h or less and still lock 'em up, lol

 

The master cylinder is brand new!

The pads and discs are from Raybesto, this is standart quality, or not?

No, when it would stop good than I would live with it. I have to brake very strong to stop the blazer and I'm not sure if it would lock up at 50km/h...

 

Does the pedal vibrate like ABS is working, when stopping normally?

 

what exactly is the pedal doing besides feeling spongy how far down do you have to press before you feel the brakes engaging for you to stop?

 

No vibrations.

There is no point where you can feel, that the brakes start braking. I drove a chevy Astro Van, same modellyear (95) with an servooil-powerbrake and you feel the point, when the pads "bites" into the discs. And it's no Problem to lock up the brakes from the Astro Van!

 

ok with abs on your vehicle it prevents lock ups when pressing the brakes hard. so on to spongy brakes lets see here you changed just about everything bled them 3 times and still spongy well i would still have to say i believe you still have air somewhere in the system thats what i can think of that is still causing them to be spongy unless someone else has a better idea, sorry i couldn't be more help other than that someone will think of what im not i know brakes pretty well and this one actually has me pretty stumped.

 

Did you bleed the brakes at the calipers?

That's the method I've used for bleeding brakes... Usually a two person job, unless you've got a stick that can press the pedal down far enough when wedged against the seat, lol.