Really Low Brake Pedal... Just WEIRD!

[uglytruk]

I removed my LF axle to change the u-joint last nite, and retracted the caliper piston a bit. Pads were so-so. Up until then the pedal was real nice and high and firm.
Now it's low and the hydro boost squeals. The fluid was very low, so I topped it and checked for leaks, none. It's a mostly rust-free Oregon TEERUK, so no rust on lines. The pedal DOESN'T sink like a weak master, and responds to pumping it up.
I locked up the left front and rear tires on snow, so at least the left side brakes work.
Usuallly when the caliper is retracted, a couple of pumps, and all is well. I just moved the piston less than 1/4", and the wheel locks, so it's working, but the pedal is REAL low!
I installed new pads on the right side a couple thou back, weird that the rite was down to the rivets, but left not quite 1/2 worn... the rotors are as new...

 

[GNERGY]

Put the other new pads on the left and see if it makes any difference. If it doesn't just bleed your brakes and that should solve your problem.
Tarey

 

[toomany]

I installed new pads on the right side a couple thou back, weird that the rite was down to the rivets, but left not quite 1/2 worn... the rotors are as new...

If one side is wearing more than the other, then that caliper isn't sliding freely or the piston is getting stuck. Check the pins/bolts that hold the caliper to the backing plate. Put a little grease on them. Or replace them if they have notches worn in them.

 

[4X4HIGH]

Or the brake hose on that wheel is bad.

 

[toomany]

Or the brake hose on that wheel is bad.

Oh yeah I forgot about that too. When I bought my 82 Z28 it had a bad brake hose. Lets just say driving it home wasn't such a good idea. Everytime I touched the bake pedal, the left front tire locked up. But it was one of those I need it gone now, who's got the cash deals.

 

[gmx4x4lover]

and check to see if it got twisted when you put the caliper back on

 

[chulisohombre]

i vote for bad caliper.if rust gets inside the rubber seal on the piston it will rust up and it sounds like it is not retracting after you let up on the pedal.that is why the pads are wearing so bad on that side.and not the other.the caliper itself isnt working right.pinched brakeline will have the same effect.

 

[uglytruk]

It's below zero here now. when it gets "normal", I'll try my Mity Vac. Just weird that nothing seemed worn on the caliper, and the rubber orings were nice, zero rust. LF wheels lock easily on snow... Maybe the master was empty, getting sucked into the booster... Just coincidence that I touched the caliper and it lost pedal...

I'm thinking the caliper,but that wheel DOES lock up.... Hmmmm... But It's too cold...

Thermometer last nite, and 7:00 AM Thursday

 

[dbabicky]

It's below zero here now. when it gets "normal", I'll try my Mity Vac. Just weird that nothing seemed worn on the caliper, and the rubber orings were nice, zero rust. LF wheels lock easily on snow... Maybe the master was empty, getting sucked into the booster... Just coincidence that I touched the caliper and it lost pedal...

I'm thinking the caliper,but that wheel DOES lock up.... Hmmmm... But It's too cold...

Thermometer last nite, and 7:00 AM Thursday

It's that cold here too, with a -35 wind chill. Frick that, I am not venturing outside either. Can't blame you !!!

 

[uglytruk]

Back on topic... After all speculating, I bled the front brakes. That hadn't been opened in 4ever. there was rust/dirt in the bleeders that I had ta remove with a little drill bit. Both calipers had air, and the pedal is hi and hard, just like it was a day before. Go figure...

 

[chulisohombre]

thats good.glad you figured it out.sometimes its just that the brakes have heated up from overuse and created air bubbles.

 

[uglytruk]

Hmmm, heated up in the cold COLD snap we've had??? It's air that's been there for a long time, but why the hi pedal sunk when I tinkered with the bearing, and removed the caliper without touching the line? That's the MYSTYERY

 

[chulisohombre]

if the brake fluid is heated up to a boiling point,the air that is created by the boil gets trapped in the brake lines.i believe this is what happened in my car before when racing it around town.my caliper froze and kept constant pressure on my rotor.never in my blazer as of yet.it does take a lot but if the brake fluid is old it will start to break down and it is easier to heat up and boil.most brake fluid i believe boils at around 400 degrees.so if this happens it will usually burn thru the brake pads pretty quick also.as was said ive seen it happen on my old 91 celica.i dont know if this happens alot but i have seen it happen personnally.maybe it was just my bad luck.i dono.it is very weird but stranger things have happened when messing with our trucks.either way glad u figured it out.

 

[uglytruk]

Weird is rite. Based on what I found, it should have ALWAYS been low... I drive like a granny... And only in winter... Thx fer looking...

 

[chulisohombre]

Weird is rite. Based on what I found, it should have ALWAYS been low... I drive like a granny... And only in winter... Thx fer looking...

no prob man.it usually happens on heavy duty braking like race cars.but i dont know your driving habits.maybe you live in the mountains where coming downhill with oversize tires it will overheat the brakes alot.pedal goes almost to the floor with brake fade.i have to worry about this alot with my 18 wheeler if i have a heavy load coming down hill.at a certain point you will have no brakes at all no matter how hard you put it to the floor if the brakes are overheated

 

[uglytruk]

There are some mountains around here, but I've been driving real conservative... Just in denial, I guess