Weak front brakes bled

[Jerry phillion]

my 87 r10 2wd Silverado's weak front brakes can't lock up the front tires no matter how hard I
Push the pedal. So l had the rotors turned and installed new pads, had brakes bled,
And rear brakes adjusted. Still can't lock up wheels. Pedal feels solid, but I think I'll
Try to break in the new pads further before I try again. Any other Suggs.

 

[Jerry phillion]

Sorry, I should have mentioned that a couple weeks ago, I had to
Hit the brakes hard, and they didn't stop very well no matter how
Hard I pushed the pedal. So, I did the above. Will let you know
Results later.

 

[1987 GMC Jimmy]

Any leaks? Are you loosing fluid out of the rear portion of the master cylinder?

 

[Jerry phillion]

No leaks at all. What started it all is if I had to hit brakes hard,
The front end would shudder coming to a stop. So l had rotors turned and put new pads on. I don't know that much about trucks, so Maybe there brakes were designed so you could not
lock up Front wheels. Now I have to break in new pads. Any info will help.

 

[MikeB]

Typically you don't have to do anything special to break-in new pads, unless they are high performance compound or the pad manufacturer says otherwise.

If the truck now stops well, I wouldn't worry about it. My 82 C10 has manual brakes that work very well with my new rotors, calipers, and Wagner MX55 semi-metallic pads. But I'm not sure I could lockup the fronts (255-70x15). What size are your tires? Locking up a 255-70 is lot harder than an original equipment 205-75, or even 225-75.

On another note, when I did my front brakes a few months ago, I noticed the brake fluid passages in the banjo bolts were probably 50% clogged by corrosion. That would definitely slow down the volume of fluid to the caliper. In fact, if you haven't done it already, consider replacing the hoses, front and rear. Old ones can start to "bloom" under pressure, which reduces pad-to-rotor clamping force.

 

[1987 GMC Jimmy]

Hmm... It'd be a clear cut answer if you had a leaky brake hose, wheel cylinder, or otherwise. Also, if the MC was loosing fluid with no discernible leaks, there could be a seal failure in there, but if you're not loosing any fluid, that's a tough one. Are you sure all the air bubbles got out when you bled the brakes? I might take Mike's suggestion on the brake lines, especially the fronts and especially if they look bad.

 

[Jerry phillion]

Mike--- my new pads are also semi-metallic. My new front tires
Are 225/75/15. I can't remember, but the rears are wider but
Same diameter. It does stop pretty good now though.

Jesse--- had brakes bled professionaly. Getting hard for me to get up and down.

Note! If you ever have trouble bleeding the rear brakes, and getting no fluid to rears,
Check or change rear flex line. Had this problem with my sons 67 Camaro. It was the
Rear flex line. Took it apart and it was collapsed.

 

[MikeB]

You can certainly have braking issues w/o any fluid leaks. In addition to old hoses and clogged banjo bolts, I once had an old car that had a crimp in a rear hard line bend which had been done by some PO. Sure, fluid eventually made it through the obstruction to the wheel cylinders, but I think an increase in volume to the wheel cylinders did not occur fast enough to rapidly force the shoes out against the drums. It's like funneling down a garden hose from 1/2" to 1/4". Lots of pressure but it takes longer to fill a bucket.