Front brakes

[snowpeke]

I did a brake job on my 2002 2500 Dmax. The back brakes on the right rear were down to metal to metal. Put on a new rotor and pads. Now to the front. There were a lot of pad left but changed them any way. Now for a test drive the back brakes were warm but the front were cold. How can I get them to work equally?

[BurbMan]

Grit dog wrote:
What I found was during acceleration, if wheel spin was detected, the car would apply braking force to the rear brakes to control minor wheel spin prior to defaulting to traction and stability control engaging.

Excellent point and trucks do that too when the box is unloaded, ie RWD with no weight over the drive wheels. Similar to my point that proportioning valves that use ride height sensors are overusing rear brakes when they sense that the truck is unloaded.

[Grit_dog]

RoyJ wrote:

Grit dog wrote:
There's a reason that front brakes are never smaller or less capable and generally always larger with more stopping force than rear brakes on ALL vehicles.

On LIGHT vehicles / trucks.

Starting in Class 4 / 5, rear brakes starts to match or slightly exceed the fronts. Ram 5500s have 15.5" rear disks IIRC.

Class 7 and above, single / tandem axle dumps, city buses, hwy coaches, tractors, all have significantly more rear braking power than the front. There's a point where weight transfer can't overcome the much heavier rear axle, especially with long wheelbases.

Yup, 10-4, roger that, I agree. This thread was about a 3/4 ton truck though.
My mistake for using the term “all” without context …

[RoyJ]

Grit dog wrote:
There's a reason that front brakes are never smaller or less capable and generally always larger with more stopping force than rear brakes on ALL vehicles.

On LIGHT vehicles / trucks.

Starting in Class 4 / 5, rear brakes starts to match or slightly exceed the fronts. Ram 5500s have 15.5" rear disks IIRC.

Class 7 and above, single / tandem axle dumps, city buses, hwy coaches, tractors, all have significantly more rear braking power than the front. There's a point where weight transfer can't overcome the much heavier rear axle, especially with long wheelbases.

[Grit_dog]

mkirsch wrote:

Grit dog wrote:

RoyJ wrote:
The front brakes more under HEAVY braking. The proportioning valve assumes enough weight transfer has occurred and send more hydraulic pressure forward. Under light braking, most modern trucks/cars use the rears more.

Now if the fronts are actually cold / lukewarm, there might be a problem.

Have you tried hard (threshold of ABS) braking and then carefully feel the front for increased heat?

scroll up 2 posts. OP said his brakes work fine.

Then why in hell did he ask the question in the first place?

Exactly!
But what I gathered from his cryptic first post was that he slapped now pads on all 4 corners and 1 or 2 new rotors in back. And then drove it around the block once, stuck his finger on each brake and found that the one(s) with the most friction with new rotors were warmer.

[mkirsch]

Grit dog wrote:

mkirsch wrote:
BenK that's all well and good but all that does not stop the adjuster from rusting up and throwing the whole thing on its ear. Who wants to be tearing apart their rear brakes every 6 months to free up/replace the adjusters? That's why they end up the way they end up.

While BenK is reminiscing about his nose bleed brakes, he does have a very good point.
ANTI-SEIZE! Being in the upper rust belt, you should be like the Frank's Red Hots grandma and "Put that on everything!"

Did that. Pulled the adjuster completely apart and gobbed it on like butter on an ear of sweet corn. Still seized up in 6 months. Pull the drum off and there is no evidence of it ever having been applied.

[mkirsch]

Grit dog wrote:

RoyJ wrote:
The front brakes more under HEAVY braking. The proportioning valve assumes enough weight transfer has occurred and send more hydraulic pressure forward. Under light braking, most modern trucks/cars use the rears more.

Now if the fronts are actually cold / lukewarm, there might be a problem.

Have you tried hard (threshold of ABS) braking and then carefully feel the front for increased heat?

scroll up 2 posts. OP said his brakes work fine.

Then why in hell did he ask the question in the first place?

[Grit_dog]

mkirsch wrote:
BenK that's all well and good but all that does not stop the adjuster from rusting up and throwing the whole thing on its ear. Who wants to be tearing apart their rear brakes every 6 months to free up/replace the adjusters? That's why they end up the way they end up.

While BenK is reminiscing about his nose bleed brakes, he does have a very good point.
ANTI-SEIZE! Being in the upper rust belt, you should be like the Frank's Red Hots grandma and "Put that on everything!"

[frankwp]

My 2003 2500HD had the rear brakes done at about 200,000 km & the fronts were worn out about 30,000 km later. Most of the driving was done unloaded.

[mkirsch]

BenK that's all well and good but all that does not stop the adjuster from rusting up and throwing the whole thing on its ear. Who wants to be tearing apart their rear brakes every 6 months to free up/replace the adjusters? That's why they end up the way they end up.

[BenK]

mkirsch, agree...but drum/shoe setup can be super tuned to be pretty good...still not as good as disc

Supper tune has to start when they are brand new. Once the slider wears a groove in the backing plate, they will never be able to be super tuned.

Part of that super tune is to liberally coat the adjustment assembly with anti-seize grease. Inside the dead-end hole, the rod that pokes into that hole, star wheel side, etc....but...not so much as to have it migrate to the friction material

Then the backing plate where the shoe edge rides on. I rub in (burnish) anti-seize and not so much to have the grease get onto the friction material.

There is a reason all shoes edges have that V or Z bent, and it is to increase the surface area & to NOT wear a groove into the backing plate because the 'swept' area is larger

Also grease the self-adjuster cable routing

Back when was a partner in a SUV/Suburban forum, many complained about poor rear braking performance. Even went out and helped a few and all of them had almost brand new rear shoes when they took it apart (just supervised their hands on, as won't hands on personally). One guy had over 100K miles and his shoes were brand new)

Too many variables to have one size fits all regarding front vs rear braking.

Back on the OP's question/situation...since they didn't notice until the rear went metal to metal, doubt if they will now know the difference with brand-new friction materials on all four. Guessing a repeat to find metal to metal down the road...unless their mechanic found and fixed whatever was the 'real' problem

[Grit_dog]

time2roll wrote:

snowpeke wrote:
Thanks for the advice just took a one dayn RV trip and they stop the truck and trailer fine.

If the rears are wearing substantially faster than the front.... I believe the brakes are not working properly or were poorly designed.

What part of "Thanks for the advice just took a one dayn RV trip and they stop the truck and trailer fine." didn't register with you?

Also, the OP never said the rears wore out faster than the fronts. All he said was the rears were done for and the fronts had some pad left.
Truck is 20 years old. Could have been on orig brakes all around, could be on it's 4th set of fronts and original rears. Could be somewhere in-between, maybe the OP bought it last week and has no idea when the brakes were done last.

And where does the "poorly designed" comment come from? When is the last time you heard of an OEM vehicle brake system that wasn't at least adequate up to industry standards. And especially on a HD truck?
I'll add, I've had the same truck as the OP and driven many others similar, probably with the same brake part numbers and there was nothing wrong with the design of the brakes. Not that it's pertinent, but just to confirm that truck doesn't have poorly designed brakes.

It is always more accurate and objective to not read into the story just use the info given until that info changes.
Not unlike the other multitude of responses telling the OP his front brakes weren't working right, when that was never said, or even implied.

[Grit_dog]

mkirsch wrote:

Drove trucks with rear drum brakes for many years. Rear brakes almost never worked because they were drums, the adjusters would rust up, and they'd wear out of adjustment quickly. Rear brakes were always in GREAT shape when it came time for brakes because they were out of adjustment and not doing anything. Not once, ever, did the truck ever try to swap ends because only the front brakes were working.

Coming from the midwest rust belt, I always hated drum brakes as well.
Now, moving out west, my opinion is decidedly different about drums. Still more parts and pieces and more complicated than discs, but the bulk of the issue with drums, IMO is a lack of regular maintenance and RUST. Have a 1974 Jeep drums on all 4 corners. Purchased in New Mexico going on 20 years ago now. Been garaged 95% of the time I've had it. Doesn't get driven alot, but drives good.
The FIRST time I even removed a wheel on it was 2 years ago, to replace the 25 year old dry rotted tires and refresh the front wheel bearings and locking hubs. That little Jeep stops PERFECTLY. Has since the day I bought it. It will almost do a stoppie! And I can hammer the brakes at 50mph no hand on the wheel and it is straight as an arrow.
God knows how old the brake fluid was when I bought it. I've done a few redneck brake fluid flushes to it over the years (empty the master cyl and refill with fresh fluid), but that is it. Had to manually back of the adjusters to get the front drums off for the hub work. Figured for sure they'd be froze up. Nope, smooth as butter and since I lubed the adjusters, they will probably not even stick when my grandkids inherit it and my own kids aren't even adults yet!
And my 86 GMC, Eastern Oregon truck. Granted the rear brakes were all brand new when I bought it couple years ago. Everything down to the nails and springs. But the rear brakes on that truck flat out WORK and work well. Even moreso, when I set the little GM rear bias valve to the loaded position. (Which for Burbmans edification, is intended to INCREASE rear brake pressure when loaded and decrease it when unloaded. You know, to keep the vehicle from swapping ends)
Common theme from someone who used to cuss out drum brakes? NO rust = good drum brakes!

[Grit_dog]

mkirsch wrote:

BurbMan wrote:
The brakes are working as designed. The front brakes are bigger and designed to do most of the stopping when the truck is loaded. If the front brakes went to work with the box empty the truck would go sideways in an instant, especially on a wet road. The proportioning valve is set to have the rears do most of the work when the truck is unloaded to keep it in a straight line.

Drove trucks with rear drum brakes for many years. Rear brakes almost never worked because they were drums, the adjusters would rust up, and they'd wear out of adjustment quickly. Rear brakes were always in GREAT shape when it came time for brakes because they were out of adjustment and not doing anything. Not once, ever, did the truck ever try to swap ends because only the front brakes were working.

Didn't want to be the first to make this comment, but I agree.
There's a reason that front brakes are never smaller or less capable and generally always larger with more stopping force than rear brakes on ALL vehicles. (keeping it to disc brakes at all 4 corners, as comparing disc to drum would be far more complicated).
Has nothing to do with pickup trucks and their ability to carry large amounts of cargo. It's just simple physics. When a vehicle is moving forward and brakes are applied, weight bias and correspondingly traction is INCREASED on the front wheels. Doesn't matter if it's a pickup with a 4000lb payload or a sports car with perfect 50/50 weight static weight bias.
The only vehicle(s) that I've seen that used up rear brakes faster than front brakes are my wife's SRT8s. And I was stumped by how a set of rear pads, same brand/model, replaced at the same time as front pads, same rotors was wearing the rear pads down faster. What I found was during acceleration, if wheel spin was detected, the car would apply braking force to the rear brakes to control minor wheel spin prior to defaulting to traction and stability control engaging.
Given that the car(s) are 450-500hp rwd and driven frequently in the rain, the car was likely applying rear brakes to some extent alot of the time when taking off from a stop on wet roads. (Also explained why the car appeared to get better wet traction than it felt like it should have)
New SRT8, generally parked during the wet months here, hasn't shown the same wear, compared to the old one that was a daily driver all year around.

[mkirsch]

BurbMan wrote:
The brakes are working as designed. The front brakes are bigger and designed to do most of the stopping when the truck is loaded. If the front brakes went to work with the box empty the truck would go sideways in an instant, especially on a wet road. The proportioning valve is set to have the rears do most of the work when the truck is unloaded to keep it in a straight line.

Drove trucks with rear drum brakes for many years. Rear brakes almost never worked because they were drums, the adjusters would rust up, and they'd wear out of adjustment quickly. Rear brakes were always in GREAT shape when it came time for brakes because they were out of adjustment and not doing anything. Not once, ever, did the truck ever try to swap ends because only the front brakes were working.