I will try to get everything listed here, still kinda tired and cranky cause I have never had problems like this and need my truck!

Ok, here goes.

Replaced pads in my 2001 2wh. anitlock, the pads had fallen apart in the rear, and the left inner pad decided to exit.
(I had a former post titled "Brake pedal hit the floor once, now fine?")

So, I got all 4 rotors turned to just above discard, cleaned up good for the most part. New pads, the most expensive ones from Bumper to Bumper, dunno how they compare to OE, assume that they are equivalent, Wagner pads. Semi-met at least.

I pushed the caliper pistons back into the caliper with a standard tool, but did not open the bleeder screw (as I see I probably shoule have) starting from driver rear, driver front, pass front, pass rear. Cleaned the brackets where the pads slide back and forth, installed the rotors and pads, got the pads on right, they moved freely before I put the caliper on, greased the pins with permatex brake grease (its green grease/green package), installed new pin boots in the rear, both sides lots of grease in all boots, pins slide but not as nicely as they did with the old boots (probably to be expected). Installed everything else, pumped the pedal a few times until resistance not traveling more than 1/2 way, started the truck and headed for home. I live ~14 miles away from where I was working on the truck. As luck would have it, I only have to stop for one stop sign, the stoplights on my way home magically stay green, all 3 of 'em. Anyway, I realize that I need to break in the pads yet so when I approach the turn for my town, I start early, gently depress the pedal and release (it seemed spongy/brakes weak).
I did this 4 times, had to make a turn, did it some more, pressing harder each time, as I was traveling at highway speeds before and after turning. The pedal never got better, still feels kinda spongy and when I press really hard (which I have to do to stop in a decent distance), it will travel about 1/2 way down or more if I push harder, pulls to the left, it really feels like the left front is the only brake that is working. I try a few more times, it never seemed to get better so I hit the gravel road that has a bit of snow on it, idling in 2nd gear (its a 6 speed) I was able to press the brake pedal and stop the truck, but the back tires kept turning, really seemed like there was no pressure getting to the rear pads.

* Definition - Pressing hard = What I would have expected to activate the antilock on dry pavement before I replaced the pads

So, I am stumped and frustrated, I have NEVER had problems like this before on any vehicle.
Did I do something wrong? I had posted this in a different thread and got a response to check to make sure that the pads are not catching the ends where they slide (thanks torquefan) and although I have not looked as of this posting, I don't expect to find that is a problem as the pads moved freely in the holding bracket. That would be too simple for my luck, when things go bad, they go bad...

 

First thought that comes to mine is trying bleeding the brake system. I've seen a few rigs that had moisture in the fluid and cause simular problems. This is fairly cheap to try... Make sure you get fresh fluid out of the system...

Now guessing... Master cylinder???

 

Everything worked fine with the old pads, I am skeptical that the master cylinder would need to be replaced...

 

Over the years a few vehicles that i have done with disks on all 4 corners have needed some time for all the caliper pistons to come back out to their normal place. I usuallt like to really pump the pedal alot before i take it out for the first drive.

 

I have found that the most expensive, lifetime warranty pads, are to hard. they dont work worth a darn. I have better results if I use a softer pad that actually grabs. The softer pads may not last as long, but the truck stops alot better.

 

I agree with Whazzup. We used to get brakes from the aftermarket and I experienced this a few times with them. Mopar came out with the "V line" series which put the factory parts back in a price range that would compete with the local brake shops and I have had excellent results using them.

 

I appreciate the info about the pads, in the future I will just go with OEM.
But, to reiterate, my biggest problem right now is the spongy pedal/general suckiness of the brakes.
From 60 MPH I bet it takes 2x longer with about 4-5 times the foot pressure to stop the truck.

I called the dealer to get some ideas, they asked if I opened the cap on the master cylinder, I didn't.
They said that this can cause the rear seal to blow when pushing the pistons back in some cases.
(so perhaps mopar1973man is right...)

I hope not.

I will post more details when I get them.

In the mean time, other ideas/comments are still needed...

 

Dealer is sort of right, forcing the caliper back can damage seals. Always better to open a bleed screw, never heard of opening the cap though.

 

Perosnally, I would disagree with the dealer about the seal blown out by pushing the piston's in. The seals have to withstand pressures in to the 1,000 PSI range! I seriously doubt push a piston back would cause a seal in the master cylinder to fail.

If so I would of blown out the brake system on every rig I've owned or worked on...

If the seal did fail under such small amount of pressure be glad... It might of scared you later when you really need the brakes!

Is there any brake fluid leaking out of the master cylinder too? If so then the master cylinder has failed for sure...

Do the brake fluid change first... Give that a try... You suppose to change the brake fluid every 30K anyways... If the fluid is bad it will make everything work spongey...

Matter of fact my brake fluid is coming due to be changed. It will get very dark like gear lube color almost.

 

The problem with the pedal sponginess didn't start until I put the new pads in. Before that, everything was working fine.
(except that the pad fell off the backing plate on the rear driver side inner pad, but you couldn't tell that when using the brakes.)

This is not a snipe or anything, just want to keep the thread from drifting too far.

So, quick summary:
Pads bad, replaced, pedal spongy and SEEMS like the driver front is the only brake working correctly as there is severe pull to left when applying the brakes hard, which is required to get any stopping action at all at highway speeds...

 

Big difference is when applying the brakes the force is only in the forward direction, releasing the brakes only a very slight amount of fluid flows backwards since the pads for all practical purposes remain touching the rotors. The only way to send a large amount of fluid in reverse is to manually compress the caliper.
Believe me, it can cause seal damage as some of the seals in the master cylinder are designed for pressure in only one direction. If the fluid had a free flow back to the master the pads would eventually retract back away from the rotors and you would have to pump the brakes stop. That's why when compressing these cylinders a tool like a clamp is necessary, with a bleed screw open you can compress them with your hands.

 

Well....Iff forceing the pads back well hurt anything....dont think so least not in my case seince 1960 somthin.........so two things left....some how air got in there-from what you describe you fit the discription ,,next master cyl is hemoraging inside itself (internal leak leaves nothing on the grd.) I would bleed the system and see what happens.

 

I think your problem will go away with a brake bleed.
You can take your wheels off and check that the pads are against the rotors. If they aren't then you have a groove on the inside of the caliper and the pistons are binding.
I have been doing brake jobs for 20+ years and have never seen a master cylinder damaged from compressing the caliper piston. The seal is what holds the piston close to the rotor. The fluid must have an unrestricted path back to the master cylinder or else after you applied the brakes or when the fluid heated up and expanded they would drag severely. Let us know what you discover.

 

I agree with HotRodJim, if you lost a pad and probably some fluid?, it sucked air back into the system. May be just in the rears, but after driving it very much the air will circulate around and cause the spongy pedal. Try bleeding them before spending any money on other parts.....Most of the time spongy pedal =air in the system somewhere......Hard pedal could be several other things........

 

I also agree with HotRodJim. As long as the pedal is not depressed, there should be a port open allowing brake fluid to flow back to the Reservoir, which prevents the brakes from pumping up when they get hot (like a closed system mountain bike brake setup).

I would also try bleeding the system first.

I'm no expert/pro, but my second guess would be the wheel calipers. At least with motorcycles, I've seen corrosion happen on the caliper piston, which doesn't cause a problem until new pads are installed.

The corroded part of the piston gets pushed through the seal when the pistons are pushed back in the caliper, and if that doesn't damage the seal, with the new thicker pads the caliper seal can end up trying to seal on the corroded part of the piston...

Let us know what you find.