2005 Dodge RAM 2500.
Had this truck for 2 years. Always has had a soft brake pedal.
Rear calipers were sticking so I decided to overhaul the entire system.
New master cylinder, new/rebuilt calipers all around, new pads, new rotors, all new Stainless Steel brake lines from Inline Tube, new brake hoses.
Bled 7 quarts of brake fliud through it via vacuum canister, pedal and hold and ABS bleed via scanner trying to evac air.

​​​​​​Did the floor it and stomp as hard as you can on the brake pedal to engage ABS.
Truck stops fine and straight and ABS works. No lock up of tires.
No ABS lights. No codes whatsoever.
Bled again. No air. Just fluid. Bubble free fluid!

Went to junkyard, got a same model/year Booster just to eliminate it as a cause. Nope, booster is fine.

But the pedal still has sponge in it.
You can feel the brakes grab high in the pedal travel. Inch or less travel. So everything is there like it should be.
But the pedal is too soft. And it travels down too much, compressing air.

The other day, had a helper work the pedal for me while I bled the master cylinder in the truck. Got good streams of fluid with no air.
Did the same at the ABS. Good streams with pedal bleed followed by ABS scanner bleed.
Still sponge!I know these Kelsey Hayes 4WAL systems have given people fits trying to bleed them. Well, I am living it brothers and sisters!

My next attempt is use the three factory brake lines that I removed from the ABS. Cut them into nipple length and use my vacuum canister to pull a vacuum and try to suck out the bit of air that has to be in that darn Kelsey Hayes wonderful piece of engineering!

I will use the ABS scanner bleed while drawing the vacuum right at the ABS.
If this does not evac the air, what are my options?

Live with it? C4 and run?
​​​​​​
Any help would be most appreciated!

Jake

 

Grab your warm body again, have them pump up the brakes and HOLD THE PRESSURE while you crack open a bleeder valve. Do that several times at each wheel. See if that doesn't improve its attitude.

 

I have been using the truck as is. The vehicle stops fine as stated above. I had a couple of 1,200 pound, long distance loads to deliver before the end of the year. All went well. So now, I hope to improve the soft pedal feel. I have cut the original (3) ABS brake lines to nipple length.(see below) My idea is to install these one at a time at the ABS module and connect my vacuum canister. Pull a heavy vacuum and see if any air will come out. Will run the ABS motor via scan tool while pulling the vacuum. My hope is that the vacuum pulling hard on the line will evacuate the stubborn air that is trapped in the ABS or maybe reset the valves. This suction is normally not there under normal braking.
So hopefully, this added assist will get it where it needs to be. Then hook the three brake lines back up and run a standard 4 corner bleed.
If that does not get it right, the only other thing I can try is to put the original master cylinder back into the truck. I have it cleaned out and bench bled. But it's an 18 year old unit and this problem existed when it was installed.

After these last two attempts, I will just have to live with it if not to my satisfaction. There will be nothing left to be done!

One other thing:
Is this pedal feel just the nature of the beast?
This 2500 HD truck. Is it meant to have a softer pedal due to the large calipers and rotors? So not to be too "Touch em and go thru the windshield" type brakes?


Original ABS brake lines. Cut to nipple length.

 

I would be more tempted to pic up the service manual for your truck, if you don't already have one.... There should be a bleed procedure in there for the abs and the rest of the brake system.....

Barring that, to get the last bit of air out of the abs controller, I usually just find a nice dirt road, and exercise the abs 3 or 4 times, then go home and finish bleeding the brakes. I live on a dirt road though, so, it's a pretty short drive home.

 

I appreciate the help. I have a copy of the 05 Dodge Ram Shop Manual. No joy there. Also, did the dirt road, slam on the brakes procedure followed by a another ABS bleed and conventional bleed.
This has been a frustrating situation. I am almost 100% sure the previous owner of the truck gave up on it because of this problem. Someone was chasing this issue when I bought the truck. Had some new components. I have since replaced every brake system part. Everything! Truck stops fine and ABS works but the pedal is not right. This era of Rams do not have an adjustable push rod for the brake pedal. Its all engineered into the machined pushrod in the booster. No threaded brake pedal rod to adjust.

I am surprised there are not more folks on here that have run into this problem. To me, the problem is definitely in that Kelsey-Hayes ABS. But both units work with no codes. Both the original and the junkyard replacement which is same model, year and numbers matching.

And to be clear. The truck stops fine. Does not pull under braking. And the ABS engages and works like it should. The tires never lock up and you can feel the pulsing in the pedal. The pads also catch high in the pedal travel. Inch or less when depressed. But the pedal is soft and travels too much to make a full stop. Not to the floor. You can slide your left foot under the brake pedal when stopped. But you can also feel the spongey, air compressing in the hydraulic brake system. All brake components are new, tight and leak free. 7 quarts of brake fluid have been sucked and pushed through all the bleeders.
Master Cylinder changed and bled numerous times. ABS bled at fittings and via scanner multiple times. Every brake line replaced. Every brake hose replaced. Booster swapped out. ABS swapped out. All new Calipers, Rotors and Pads.

 

Is that 4 wheel disk brakes?

 

Yes, 4 Wheel disk brakes.
Also, adjusted the rear parking brakes.
E-brake holds back the HEMI in gear at 1,500 RPM.

Thanks!

 

Hhhmmm..... That's kinda strange. Generally, pedal height is controlled by the rear brakes, but, that applies to rear drums. Rear disc should be self adjusting.... (more so than drum.... less complicated) Soft lines can also contribute to a spongy pedal.... the lines expand under pressure, hence, why some folks go with the braided stainless soft lines.... (did wonders for the brakes on my brothers WRX....)

Have you driven another, similar truck? Might wander around the used car lots in your area, see if you can find a similar truck, take it for a test drive, see how the brakes feel on that one.

 

Good idea on the test drive of another similar truck.
These HD trucks were (and still are?) made in the RAM Truck Plant in Mexico. So it would be nice to find one similarly equipped from 2005. Most of these trucks are in the junkyard around here now.
My truck is a survivor. A small home remodel carpenter owned it and it only had 100k on the clock when I got it in 2021. I believe he shop/garage parked it. It's still a very serviceable truck. And for my purposes, it's perfect. And paid for! 😁

I sacrificed some prebent master cylinder lines that I had from a previous 2005 Ram. I made them into bench bleed lines. Used them on the original MC that is still clampped in the bench vice.

I may just try to install these into the replacement MC in the truck and do the "endless loop" bleed of the MC. Just to be 1000% 🤦 sure that there is not air in the MC or something nutty going on.

So, more brake fluid! Prestone loves me!

I will report back on this matter.

Thanks!

 

Since you replaced all the calipers, know that they will mechanically fit on the wrong side just fine. But the truck will never bled all the air out, because when the wrong side it installed - the bleeder is not at the top of the caliper. Double check where your bleeders are, they have to be at the top.

This actually happens often, I've seen many threads where the OP made that mistake.