Brake Replacement Issue (need help/advice asap)

[nubiannupe]

So, my wife decided that I need to change the brakes on the Pathy this weekend. Seeing that I've done brake pad replacements on many other cars (including my Maxima) in the past, I figured this would be a piece of cake - I'm thinking an hour and a half, tops. Hoping that someone can give me some advice or point me in the right direction, because how much more wrong could I have been on that assessment!!

 

Just to give you a little history on the Pathy at this point, the truck's brakes have been really loose lately. By 'loose', I mean that the pedal travel was waaay farther than it normally had been up to this point. Almost to the floor. And as of the past week or so, the 'brake' and 'anti-lock lights in the dash would come on intermittently. So I got everything that I needed, took the Pathy to my friend's garage (I stay in an apartment, so no garage of my own), and got to work. Here's a rundown of how I got to where I'm at (and keep in mind that some of the wording is from a 1994 FSM) :

• Blocked off rear wheels (because I decided to do JUST the front brakes)
  
• E-brake on (just in case...)
  
• Removed driver front tire
  
• Verified that the reservoir was full
  
• Opened air bleeder valve
  
• Removed the two torque member fixing bolts from behind the caliper
  
• Disconnected the union bolt holding the brake hose to the caliper (two copper washers came off as well)
  
• Pulled the entire caliper assembly away from the rotor
  
• Popped the old brake pads off from the caliper assembly
  
• Pressed the pistons back into the caliper assembly by hand, since I did not have a c-clamp
  
• Installed the new brake pads
  
• Put the caliper assembly back onto the rotor and seated it
  
• Replaced the union bolt and brake hose, along with the copper washers
  
• Reconnected the two torque member fixing bolts
  
• Closed the air bleeder valve
  

I repeated this procedure with the passenger-side front tire, as well. After I put everything back together, I once again made sure that the reservoir was full-up and proceeded to bleed the entire brake system starting with the passenger rear, driver rear, passenger front, driver front. No ABS, so that was not an issue. Here's where the issue came up. Back brakes bled fine. Got to the Passenger front, but no fluid came out of the bleeder valve. Went through the bleeding procedure at least 5-7 times, but still nothing came out. My friend suggested that the caliper may have frozen, but I wasn't gonna give up on it just yet. Removed the brake hose from the caliper and verified that fluid was coming out of the hose (which it was). Also checked that both the holes on the union bolt as well as the aire bleeder valve holes were not obstructed. Did this for both front calipers. Re-bled the entire system again, but the same thing was happening - no fluid coming out of the air bleeder valves up front after pumping the brake pedal a few times and holding it down.

 

Just on the off chance that my friend was right, I went ahead and bought a new caliper for the passenger front side. I installed it, and re-bled the entire system, but still have the same results as before. Is there something I missed or failed to do (or not do)? Frankly, I'm stumped at this point, and unsure what to do next. But I know I have to do something, as this is my family's only means of transportation to school/work. So, in a word... HELP!

[TerranoNZ]

If the pedal was going to the floor-ish before you started and you can't get fluid out of the front. I'd guess the master cylinder (The seal inside is bypassing)

I'd hate for you to replace it and still have the problem though...

 

Have you ever locked up the rear brakes only?

 

Did they stop ok before?

EDIT : Can you see any "KINKS" in the steel lines?

Does the pedal feel firm(Stops at a point)?

No visable leaks anywhere?

 

 

 

Good luck

Edited April 14, 2008 by TerranoNZ

[GhostPath]

You may have airlocked the master cylinder primary circuit. Try bleeding the master cylinder.

[nubiannupe]

TerranoNZ - Hmm... master cylinder wasn't something that I considered being an issue, since the brakes seemed to gradually get softer (normally associated with wear-and-tear). But to answer your questions, I've never locked up the rear brakes. Come to think of it, I've pretty much never slammed on the brakes at all. As for stopping ok before, I'd have to say no. But that's only because of the progressive brake failure I mentioned before from normal wear and tear. If memory serves me, we haven't had a brake change in close to two years (when we purchased the Pathy). There's no kinks in any of the lines that I can see. There's no visible leaks that I can see (other than a leaky power steering reservoir - but that's an entirely different post. LOL), and the pedal doesn't necessarily feel firm at all.

 

GhostPath - Master cylinder, huh? I'll try bleeding it and see what happens.

 

Thanks for the input, fellas. I'll break out the wrenches again and update with what is happening.

[Simon]

The other thing it could be is the proportioning valve needs bleeding. IT's located on the passenger side framerail, about halfway down the truck. Do that after bleeding the rears, but before bleeding the front.

[94extreme]

i'll say you need new hoses and the calliper for the other side; never do just one.

 

you said you check to dee if there was fluid coming from the hose, was it dripping? did you depress the pedal? how did you check this?

[msavides]

My best guess is when you removed the caliper the hose was left dripping and it drained the entire front brake lines. This created an air lock in the brake lines and probably in the mater cylinder. Best way to remedy it would be to get a hand vacuum pump (mighty vac) and a brake bleeding reservoir. Hook it up to your front calipers bleed screw then open up the screw and pump until you see no air bubbles in the clear tube. repeat the other caliper. This should remove all air from your master and valve and lines.

 

Mark