2004 Dodge RAM 3500 Brake Proportioning

[wdk450]

Gang:
2 years ago, I was on a trip in southern California and noticed the front disk brake pads wear warnings start chirping. I went to a Brake Masters chain shop, had the braking system inspected, and was told I needed new front pads, and that the rear drum linings were fine. Fast forward to the Gillette trip over the Bighorn mountains in Wyoming and coming down the East side into Buffalo, Wyoming. I got behind a gasoline tanker with a good Jake brake, I couldn't seem to shift down more, and I ended up with my front brakes pouring smoke out at a pullout 1/2 way down the mountains. (I now realize I should have pulled over earlier, stopped, shifted all the way down, and proceeded slowly). Anyways, I proceeded on to Gillette and got another brake job the next day with new pads, and again the rear linings are O.K. Wednesday I made a 150 mile trip from Sacramento over to Clearlake climbing and descending some heavy duty hills on Highway 20 West, then over to Soda Bay Road on the southern shore of the lake. Although this route is in the campground (Edgewater in Soda Bay) directions on how to get here, the road is about 15 miles of curving climbs and descents. The entrance to the park and down to the office is a steep downgrade from the road down to lake level. All of my friends in my camping group could smell my brakes as I wrangled the 8 tons of Bighorn down that steep hill. I would guess the front pads are gone again.

I had my CalPak exhaust brake looked at for the 3rd time before I left on this trip and was told it was O.K. I am thinking that I am having problems with my brake proportioner, but know nothing much about these on my era of RAM truck. Some online postings and illustrations show a valve on the rear axle area that has a rod that connects to the sprung bed frame with a rod so that more braking is applied to the rear when the bed is fully loaded. If this is what is there, then I wonder if my recent purchase of rear airbags changes this setup?

Anyways, has anyone with a similar truck had similar problems, and what is the answer??

I saw some postings saying that changing out the brake fluid (they say it gets old and compressible , and changing out any rubber rear brake lines (as they ted to swell with applied pressure with age instead passing the brake fluid pressure through.

I have a free week next week while I am staying in this area, and will see what professional help I can get. I found 1 Dodge dealer nearby, too.

Thanks in advance for the help.

 

[danemayer]

Bill, I'm not the automotive expert, but if you've smoked the pads, I'd guess the heat might have warped the rotors, reducing disc brake effectiveness. Maybe someone who knows more will chime in on that point. Also, I'd wonder if the BH brakes are out of adjustment or contaminated. When mine are working well, at 5mph I can cause a pretty hard stop by pressing the brake controller manually.

 

[brianharrison]

Hi Bill, my brother-in-law and I did the redneck removal of the high sensing rear level proportioning valve (on his late model dodge; not sure if it's the same on yours) - removal the rod from the rear axle and zip tie it to the frame in the "up" position (ie loaded) to fool the valve and direct full value to the rear brakes.

Here is the Dodge TSB 05-04-98 which actually talks to removing the valve and replacing with a brake hose for lifted trucks.

One other suggestion I never trust the drum auto adjust feature on larger drum brake systems so I tend to manually adjust with axles on jack stands and turn by hand. EDIT- IGNORE this part 01+ have rear rotors.

Hope this helps.
Brian

EDIT - Brake fluid is better today - however I still change out my fluids with new once every couple of years - especially on systems that get hot - it used to be water intrusion in brake fluid used to be a problem. I still think it is a good idea. Bleeding brakes can be a bit of a PITA (Pain In The A**) however I have a good vacuum brake bleeder (draws fluid to the bleed zerc on the caliper/drum) which makes it easier.

 

[westxsrt10]

Rear drum brakes on the older HD Ram have issues. (not sure the year they went to disks) The self adjusters fail and or just don't work and end up in a pile inside the drums.

 

[wdk450]

Brian and Everyone:
Thanks so much for the info and TSB, although it is labelled for the 2500 NOT 3500. I'm sure it still applies, just if i wave this in front of a Dodge service guy, he probably won't do it for me. I think I will try setting the valve to full rear braking ON (Valve arm up) and see what happens. Actually, I haven't been under the truck to see if that is what I have.

I had pads AND rotors ($600) replaced last year in Gillette, and had the Dexter service guy inspect my trailer brakes at the rally. He said they were O.K. I am starting to think I will have to bite the bullet and get disk brakes on the Bighorn while in the Elkhart area, too. I'm pretty sure trailer brake controller is full on.

I will most likely have the brakes checked next week, and will have them change out the fluid.

 

[Speedy]

Bill, When you had new brakes installed were they stock or upgraded versions? You really don't need to upgrade to disc brakes on the trailer to improve braking on your truck. If your are still running stock pads and rotors you may want to look into high performance pads and slotted rotors, new braided stainless steel lines and new brake fluid. You may even want to replace the proportioning valve with a remote adjustable.

 

[wdk450]

Speedy and All:

First of all, my truck is front disk, rear drum.
ON EDIT - I LOOKED UNDER THE REAR AXLE THIS MORNING AND DISCOVERED (!!!!) MY REAR BRAKES ARE DISK, ALSO.

"Bill, When you had new brakes installed were they stock or upgraded versions?" I don't remember being given a choice at Brake Masters, although some time has passed. A year and a half later in Gillette, I found the only tire store that was open on a Saturday that could do the work that day. I also had major transmission problems from the towing trip over the Bighorn mountains, and wanted to get my truck back 100% ASAP, so I took what I was offered in the way of pads and rotors.

"You really don't need to upgrade to disc brakes on the trailer to improve braking on your truck." I only have braking problems when 8 tons of Bighorn is pushing my truck (and me) down steep grades. Many, many posters on this forum have complained about inadequate big 5th wheel braking. Many have also said that disk brakes on the trailer were a vast improvement.

"If your are still running stock pads and rotors you may want to look into high performance pads and slotted rotors, new braided stainless steel lines and new brake fluid. You may even want to replace the proportioning valve with a remote adjustable." Thanks for the advice about the premium braking stuff. I think I will go deeper into this problem, and to do that properly I need to be back at home in Sacramento, with its big city resources and not out here in rural Lake County. I have to go down the hills into the Central Valley on Highway 20, but after that it should be O.K. driving into my next weekend destination of Oroville. I will make that trip on Friday.

The biggest result I want at the moment is to believe that the rear truck brakes are doing something. 3 sets of front pads, and the original set of rear shoes are still O.K., indicates a problem to me.

 

[westxsrt10]

WDK ...We had brake issues with my uncles 2002 2500 Ram near you up at Twin Lakes. I manually adjusted his rear brakes about 20 clicks tighter and saw improvement. (he says he removed his self-adjusters because the rear brakes wore out every 10,000mi.)

 

[DW_Gray]

Interesting. One thing I recommend is weighing your rig if you haven't done so. As I've looked at some of the load ratings for the 2004 Ram, you could very well be exceeding one or more of the load ratings. If you are towing and trying to stop a trailer that's too heavy for your truck, you are going to exceed the capacity the brakes were designed for. As for the exhaust brake, it certainly doesn't seem to be nearly as good as the current stock exhaust brakes on Rams. I rarely have to apply brakes going down hill even with my heavy load.

For more information on load safety and weighing, visit Fifth Wheel St.

 

[hoefler]

Interesting. One thing I recommend is weighing your rig if you haven't done so. As I've looked at some of the load ratings for the 2004 Ram, you could very well be exceeding one or more of the load ratings. If you are towing and trying to stop a trailer that's too heavy for your truck, you are going to exceed the capacity the brakes were designed for. As for the exhaust brake, it certainly doesn't seem to be nearly as good as the current stock exhaust brakes on Rams. I rarely have to apply brakes going down hill even with my heavy load.

For more information on load safety and weighing, visit Fifth Wheel St.

I go for the rear drum brakes adjustment and/or operation. The auto adjusters are not fool proof. And for them to work properly, you need to back up at a fairly good speed and stand on the brake pedal hard to almost lock the front wheels. This needs to be repeated several times to get max adjustment, that is if they are working properly. Don't forget to check the trailer brake adjustment and the brake controller.

 

[DW_Gray]

I'm pretty sure trailer brake controller is full on.

Additional thought: If you're not able to stop the trailer with the brake controller full on and activating the controller without using the truck brakes, then you have a problem between the controller and the trailer brakes. Even at 30 MPH the trailer brakes should stop you comfortably.

 

[wdk450]

Well, I had Dexter rep check all 4 brakes last year at Gillette, and the brake controller shows appropriate braking numeric values, and no error codes. I have been able to stop the rig with just the trailer brakes on a hitch-up test. I haven't done that recently, though.
I'll do that test this morning as I pull out.

Additional thought: If you're not able to stop the trailer with the brake controller full on and activating the controller without using the truck brakes, then you have a problem between the controller and the trailer brakes. Even at 30 MPH the trailer brakes should stop you comfortably.

 

[jnbhobe]

( I am starting to think I will have to bite the bullet and get disk brakes on the Bighorn while in the Elkhart area, too. I'm pretty sure trailer brake controller is full on.)


Make sure your brakes on the trailer are adjusted properly !! There is nothing better than disc brakes on the trailer, If you are thinking about getting them at Mor-Ryde you better be on the phone tomorrow because they are busy, and bring about $2500 with you. I love my disc brakes.

 

[danemayer]

Wild thought...Are you sure it's the brakes that have been smoking, not the tires? I know we've had lots of discussion about how much it matters if payload is exceeded. If you have an SRW, I wonder if the balance of the truck could be the problem.

 

[Bob&Patty]

Bill, one other note. If you are planning on keeping your truck....you might upgrade the front calipers to a 2 piston type. It sounds to me that the rears are not helping much. I bet there is an upgrade to add rear disc's to your truck. Heck I put 4W disc's on my 58 Chebby. Look around and you can find a kit somewhere. Ya never know....maybe a later model dodge with the rear disc's might be a bolt on. You might have to change the proportioning valve though.

 

[wdk450]

Gang:
I had some spare time this morning so I crawled under the rear of the truck to look at the brake lines, and see if I had this proportioner valve with the lever that has been mentioned on Dodge truck forums. I didn't see a valve with a lever, but did see a T block with a 4th rubber tube that went up and over the spare to a plastic endpiece (valve?) with a white cap. Pictures follow. The endpiece cap had a green arrow mark, but I could not change anything about it by rotating the cap in either direction, pushing in on it, pulling out on it, or turning and pulling/pushing together. My first guess this was a port for brake bleeding, as I can't see how changing a setting off of the T would change rear braking pressure.
I sat down and read both the owner's manual and my copy of the Chilton's guide to my truck, and could find no entries on rear brake proportioners, or this endpiece/valve. I DID read in the onwer's manual that dual rear wheel 3500's supposedly have a hydraulic interconnection between the power steering pump and the brake master cylinder. I looked under the hood at the master cylinder and could see no lines going to the power steering (pump or valve).
I will check this out further with Chrysler/Brake professionals this week.

Here are the pics:
The 4 way T block (The line to the right brake is hidden behind the block).


Here is the endpiece (valve?) mounted in place:


Here is the endpiece (valve?) showing the cap with the arrow.


I am beginning to wonder if my rear brakes have ever worked at all.

 

[jnbhobe]

My guess is that its a breather for the rear axel as well as a junction block for the brake lines.

 

[brianharrison]

I didn't see a valve with a lever, but did see a T block with a 4th rubber tube that went up and over the spare to a plastic endpiece (valve?) with a white cap.

I DID read in the onwer's manual that dual rear wheel 3500's supposedly have a hydraulic interconnection between the power steering pump and the brake master cylinder. I looked under the hood at the master cylinder and could see no lines going to the power steering (pump or valve).

The "T-block" on the axle is a distribution block for the brakes hydraulic lines - one in and two out, one to each drum. It is held on to the top of the axle by the vent nipple which extends through the distribution block and into the rear axle. Hence the low pressure vent hose which is on top the block, extends up and above the spare tire - the vent plug on the top of the hose will have some means on venting out any pressure build up in the axle, passing through the hose. Two separate functions. The low pressure vent nipple and the high pressure brake fluid are separate systems and do not interconnect.

The "hydro-boost" brake systems - using high pressure power steering pump fluid to "assist braking" can be found on some heavy duty one tons and larger trucks, This was more frequent on engines that could not sustain high vacuum to provide assist on vacuum boost style of brake systems. I have one on a 1978 Chev 454 dually. Sounds like you do not have this - you more than likely have a large, round vacuum "chamber" behind the master cylinder (vacuum assisted power brakes).

If you follow the brake like back from the distribution block, along the frame rail and towards the front of the truck - you should see any other proportioning valves, if there are any. If not, the line should tie into the distribution block in the engine compartment, which itself may have some proportioning action built in. Somewhere the brake system has the proportioning function, to distribute brake fluid force to the front and rear brakes.

Hope this helps.
Brian

PS - one day while you pull, brake hard coming into a rest area - get out and feel the rear drums on your truck - if both are warm/hot, your rear brakes are working. If not - no brakes.

 

[Bob&Patty]

Bill, your truck must have a "hydro boost" set up of some kind. You have a Cummins engine and they dont have enough vacumn to run a "normal" vacumn booster like a car has. On a GM truck, the lines run from the P/S pump to the Hydro boost that bolts to the firewall. All the brake lines run from that to where ever. Your proportioning valve could be bolted on the booster and the lines for the rear brakes will be there. Normally you will have 2 lines that go to the front brakes and only one that goes to the rear brakes. Each front caliper has its own line from the proportionong valve. These line should all be hard lines....not rubber. Is there a brass block with a wire on it bolted (or on a bracket) on the booster with hard lines coming to and out of it?? If so, that is the proportioning valve. The wire is the warning lite wire for the dash for low brake fluid.

 

[wdk450]

Gang:
For the information of all interested in this thread, I received the following information in an e-mail from Brian Harrison this morning:


2004 Dodge Ram 3500

BRAKES - ABS
DESCRIPTION
The antilock brake system (ABS) is an electronically operated, three channel brake control system.The vehicle has Electronic Variable Brake Proportioning(EVBP) designed into the system which eliminates the combination/proportioning valve.The system is designed to prevent wheel lockup and maintain steering control during braking. Preventing lockup is accomplished by modulating fluid pressure to the wheel brake units.

The hydraulic system is a three channel design. The front wheel brakes are controlled individually and the rear wheel brakes in tandem. The ABS electrical
system is separate from other electrical circuits in the vehicle. A specially programmed controller antilock brake unit operates the system components.

ABS system major components include:
Controller Antilock Brakes (CAB)
Hydraulic Control Unit (HCU)
Wheel Speed Sensors (WSS)
ABS Warning Light

OPERATION
Battery voltage is supplied to the CAB. The CAB performs a system initialization procedure at start up. A check of the ABS motor is performed at 15
miles per hour. Initialization consists of a static and dynamic self check of system electrical components. The static and dynamic checks occurs at ignition
start up. During the dynamic check, the CAB briefly cycles solenoids to verify operation. An audible noise may be heard during this self check. This noise
should be considered normal. The ABS motor and pump are then checked at a speed of 15 mile per
hour. If an ABS component exhibits a fault during initialization, the CAB illuminates the amber warning light and registers a fault code in the microprocessor
memory. The CAB monitors wheel speed sensor inputs continuously while the vehicle is in motion. However, the CAB will not activate any ABS components as
long as sensor inputs indicate normal braking. During normal braking, the master cylinder, power booster and wheel brake units all function as they
would in a vehicle without ABS. The HCU components are not activated. The purpose of the antilock system is to prevent wheel lockup. Preventing lockup helps maintain vehicle braking action and steering control. The antilock CAB activates the system whenever sensor signals indicate periods of wheel slip.
The antilock system prevents lockup during a wheel slip condition by modulating fluid apply pressure to the wheel brake units.