21 cummins megacab 2500 - brake goes to floor

[jhr4tx2]

Ok … go easy on me. This is my first post.

I have had a ‘14 1500 and an ‘18 1500. The brakes on those were just like any other vehicle I’ve driven …. Firm (hard) on startup and very responsive when driving. Fast forward to my first diesel truck. ‘21 2500 cummins 6.7 used with 25k when i bought it in 05/23. From the first day when you step on the brake to start it the brake goes 100pct to the floor and then immediately pressures up on start, but is still way mushier than any other vehicle I’ve driven. Its a heavier vehicle than I’ve ever owned so no surprise stopping distance is longer … but this is way longer … to the point where I use the smart airbrake around town to help. I’ve been ti the dealer 3x and they say “nothing wrong here” (shocking), but when i ask the direct question “is it normal for the pedal to go to the floor?” They will not give a direct answer. I’m looking for a “yes, 100 pct normal” or “no, not supposed to be that way” answer and I cant get one. Thoughts? Anyone have the same issue? Is this just a diesel thing? I’d love to hear if you have the same setup and know if yours does the same or the pedal is firm before you start it.

 

[vincentw56]

Ok … go easy on me. This is my first post.

I have had a ‘14 1500 and an ‘18 1500. The brakes on those were just like any other vehicle I’ve driven …. Firm (hard) on startup and very responsive when driving. Fast forward to my first diesel truck. ‘21 2500 cummins 6.7 used with 25k when i bought it in 05/23. From the first day when you step on the brake to start it the brake goes 100pct to the floor and then immediately pressures up on start, but is still way mushier than any other vehicle I’ve driven. Its a heavier vehicle than I’ve ever owned so no surprise stopping distance is longer … but this is way longer … to the point where I use the smart airbrake around town to help. I’ve been ti the dealer 3x and they say “nothing wrong here” (shocking), but when i ask the direct question “is it normal for the pedal to go to the floor?” They will not give a direct answer. I’m looking for a “yes, 100 pct normal” or “no, not supposed to be that way” answer and I cant get one. Thoughts? Anyone have the same issue? Is this just a diesel thing? I’d love to hear if you have the same setup and know if yours does the same or the pedal is firm before you start it.

You might have better luck in the Homepage - HD Rams forum. This is the 5th Gen 1500 Rams site.

 

[Richard320]

I agree with Vincentw56. I'm pretty sure you have a hydroboost for your brakes, not vacuum like a gas engine has. They will feel different. Ask over at hdrams.

 

[Brutal_HO]

Soft Brakes - weak brakes - sponge brakes 2021 3500 - merged threads

I now have 600miles on my new 2021 3500 HO Long Bed. In general I'm extremely happy BUT the brakes seem a bit soft? i.e. have to push the peddle approx. halfway to start feeling any action. The brakes in my previous 2008 3500 SO Short bed seemed more aggressive. Is this normal for the new...

hdrams.com

They're "speed sensitive" relative to the speed of your foot.

@Richard320 is correct, they're hydroboost, fed by the PS pump.

If you have ACC, that will "pre-fill" and raise the line pressure via the ABS pump to position the pads closer to the rotors and improve brake feel but at the expense of pad wear.

I've never had any trouble in a panic stop with the braking distance of my 9000 lb truck.

P.S. "smart airbrake" is an exhaust brake. It uses a VGT (variable geometry turbo) setup to restrict exhaust flow when engaged, using vanes on a sliding assembly to produce an engine compression braking effect. While not a true "jake brake," it's the most effective exhaust brake among the big 3. There's also 2 settings "Full On" that engages whenever you lift your foot off the accelerator, and "Auto" that has more to do with cruise setting and/or foot brake/speed maintenance. Bottom line, yes this is all best discussed over on hdrams where all the hefty duty folks are.