Sinking brake pedal

[indept]

Why the abs, sounds like a bad master cylinder to me. When you press the brake pedal the master cylinder pushes fluid through the lines if it's good then the pedal will be solid. If it's going to the floor then the brake fluid is going somewhere it shouldn't. So it's either leaking past the master cylinder piston seals back to the reservoir or it's leaking out of the system whick you would see fluid somewhere under the truck and the reservoir would be low.

 

[Burla]

Why the abs, sounds like a bad master cylinder to me. When you press the brake pedal the master cylinder pushes fluid through the lines if it's good then the pedal will be solid. If it's going to the floor then the brake fluid is going somewhere it shouldn't. So it's either leaking past the master cylinder piston seals back to the reservoir or it's leaking out of the system whick you would see fluid somewhere under the truck and the reservoir would be low.

I don't know, just going off wagner instead of personal experience, this from wagner...

Vehicles equipped with ABS have a hydraulic assembly also called an ABS modulator. This assembly contains multiple internal solenoids and valves. An internal failure, corrosion or debris in the brake fluid can cause a valve not to operate properly, resulting in a low or spongy pedal.

I did get air in my wife's brakes when I changed her caliper last year, and when I pressed the brakes I would have to go all the way down to get it to stop. My mechanic said it was from abs, said I would even need to clear codes or reset something, I can't remember exactly the deal, but it ended up just a flush fixed it for me.

 

[averageguy]

I appreciate your offer, can you do a bit better?

I will go $2600.00 if you put the Red Line brake fluid in it.

 

[McBroom]

I will go $2600.00 if you put the Red Line brake fluid in it.

Surely you can do $3K. Its a great truck and OP needs a gen5 to ride in.

Black 20 Ram

 

[averageguy]

Surely you can do $3K. Its a great truck and OP needs a gen5 to ride in.

Black 20 Ram

I wish I could but with the brake issues I just can't do it.

 

[McBroom]

I wish I could but with the brake issues I just can't do it.

I was jus messing with ya. Lol

Black 20 Ram

 

[Arth]

My vote is the master cylinder. My 2014 did something similar. Pedal would travel to the floor every time with light pressure. Sounds like fluid is leaking past the plunger that is pressed in the master cylinder just like mine. Replaced it and no issues till I sold it.

 

[don340-4]

Brake problem fixed, I installed a new master cylinder (Rock Auto), and a used ABS pump W/module (EBay), flushed and bled system, problem solved, solid pedal, but I do have an ABS and Anti Skid light, hoping they will go away on there own after driving a hundred miles or so, don't want to visit the dealer if I don't have to. Appreciate any comments.

 

[NJMOPAR]

Buy a cheap scanner that can clear codes and try that. I got mine at Harbor Freight.

 

[skirider]

Question.

Somewhat related. My pedal is firm but will eventually go to the floor with constant preassure.

Is that normal?

Like truck stops fine but if i keep pressing hard on pedal. It will slowly go to floor

Is this normal?

 

[Arth]

Question.

Somewhat related. My pedal is firm but will eventually go to the floor with constant preassure.

Is that normal?

Like truck stops fine but if i keep pressing hard on pedal. It will slowly go to floor

Is this normal?

Not normal.

 

[don340-4]

NJMOPAR thanks I have a H F real close I'll pick one up. skirider mine acted a little different, on the first depression of the pedal it just went right to the floor with no resistance, let the pedal up depressed again then had good pedal. Got tired of messing with it just replaced everything, now brakes are like when truck was new.

 

[skirider]

Not normal.

I just tried in work van a same thing

Try it

If you keep forcing pedel. It. Bottoms out wirh excessive force.

If not normal. Whats the cause.

Brakes all new and fluid flushed

 

[Sherman Bird]

I need to get some information before I take my truck to the dealer, I have a 2012 Ram 1500 R/T purchased it new has 25000 miles on it, great condition always garaged, for the last couple months it has been scaring the hell out of me, first depression of the brake pedal it will sink to the floor with no resistance, pedal comes up depress again got brakes with a solid pedal. I am really considering getting rid of it, I am an old guy and retired, was hoping this truck would last me the rest of my life, even if the dealer works on it and charges me a bundle I don't think I will ever trust the brakes again. Hey guys anyone have any ideas? Brake fluid is full, pads are original like new, no mods to this truck whatsoever.

Several things come to mind, being as how the truck IS 8 years old. Low mileage means it sees very limited use. I'd suspect bypass in the master cylinder first. I'd expect the brake fluid to be contaminated and look like coffee. My second suspicion would be valve bypass in the ABS hydraulic unit. My 3rd suspicion would be a wheel hub bearing gone bad and the rotor having lateral play, thereby causing the piston in the brake caliper to be pushed in, causing the pedal to go down a long ways on initial application to pump the piston back out, then the second brake pedal thrust would be firm.

If you have valve bypass in the ABS hydraulic unit caused by a sticky valve, a flush and an automated bleed with a scanner will possibly free up that pesky valve... or, if you're the venturous type, take the truck out to a slick blacktop street and slam the brakes on to force ABS function, thereby "exercising" the ABS hydraulic unit.

My final thought would go to if you have rear drum brakes that are out of adjustment!

 

[Arth]

I just tried in work van a same thing

Try it

If you keep forcing pedel. It. Bottoms out wirh excessive force.

If not normal. Whats the cause.

Brakes all new and fluid flushed

You changed the game here.

First post you said constant pressure it would sink to the floor. That's not normal. You should be able to apply constant but steady pressure and it will stop the truck without you needing to apply more or sinking to the floor.

Now in your second post you said excessive force it goes to the floor. OF COURSE IT WILL IF YOU ARE FORCING IT.

 

[Syazoo]

Did you get any closer to correction of this problem? I am having some issues partly of which sound like yours.

 

[don340-4]

See post #28, problem solved

 

[indept]

Buy a cheap scanner that can clear codes and try that. I got mine at Harbor Freight.

Just make sure it says it will read & erase ABS codes. The real cheap ones don't.