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Brakes, brake vacuum, ABS module.


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I think it is about that time i dive into the brake systems on this truck. There are a few issues I have and have not addressed. Firstly: My front brake pads seem to be wearing unevenly, unless the previous owner changed one without changing the other... I want to get all new pads and shoes. I also want the brake lines all flushed and bled with new fluid. I do not own any brake tools, at all. What does everyone recommend I do about this? Should I try to tackle the brakes all myself, or should i take it to a flat rate shop?Secondly: I noticed that my ABS module, that runs into the metal lines on the driver-side of the truck, has two wires that currently are NOT connected to anything. When I bought the truck the previous owner had it on a toggle for some reason... I don't know why he would do this but he did. I removed the toggle, the power, the fuse and the ground he had rigged up.I know this pulsates to activate the ABS system in each wheel. And, that is about ALL I know about it. Does anyone know where and how this should be hooked up and what i should do to check to make sure it's operating correctly?And, lastly: My brakes and my A/c were both out awhile back and I finally narrowed it down to the vacuum line underneath the driver side battery, which had been eaten away by battery erosion. I did a temporary fix on the line, that goes into the rubber elbow but I need to know how to properly fix this vacuum line. Any advice? In the process of fixing that I had to T up the 3 vacuum lines that go into the vacuum reservoir, upon putting them back into the reservoir I noticed something didn't look right. Can someone please show me a picture or direct me on how to properly connect the hoses and where they come from and go to, because I feel like mine are not right.

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  • Owner

I think it is about that time i dive into the brake systems on this truck. There are a few issues I have and have not addressed.

Firstly: My front brake pads seem to be wearing unevenly, unless the previous owner changed one without changing the other... I want to get all new pads and shoes. I also want the brake lines all flushed and bled with new fluid. I do not own any brake tools, at all. What does everyone recommend I do about this? Should I try to tackle the brakes all myself, or should i take it to a flat rate shop?

Doing brakes don't require any special tools to do. Just standard sockets and wrenches. As for bleeding you can do that yourself too.

http://mopar.mopar1973man.com/cummins/general/brakes/brakes.htm

Posted Image

Secondly: I noticed that my ABS module, that runs into the metal lines on the driver-side of the truck, has two wires that currently are NOT connected to anything. When I bought the truck the previous owner had it on a toggle for some reason... I don't know why he would do this but he did. I removed the toggle, the power, the fuse and the ground he had rigged up.

I know this pulsates to activate the ABS system in each wheel. And, that is about ALL I know about it. Does anyone know where and how this should be hooked up and what i should do to check to make sure it's operating correctly?

The 2 wire plug into the ABS module under the edge... You'll have to feel for the socket under the edge of the module.

And, lastly: My brakes and my A/c were both out awhile back and I finally narrowed it down to the vacuum line underneath the driver side battery, which had been eaten away by battery erosion. I did a temporary fix on the line, that goes into the rubber elbow but I need to know how to properly fix this vacuum line. Any advice?

In the process of fixing that I had to T up the 3 vacuum lines that go into the vacuum reservoir, upon putting them back into the reservoir I noticed something didn't look right. Can someone please show me a picture or direct me on how to properly connect the hoses and where they come from and go to, because I feel like mine are not right.

As for the vacuum line I would replace the section with a proper size piece of rubber vacuum hose which should withstand the acid a bit better than the plastic tubing.

As for that vacuum line at the firewall...

1. First goes to the vacuum res. under the cowling.

2. Second line takes off and heads into the cab for the HVAC controls.

3. Might be one that leaves this point for the CAD system.

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As for that vacuum line at the firewall... 1. First goes to the vacuum res. under the cowling. 2. Second line takes off and heads into the cab for the HVAC controls. 3. Might be one that leaves this point for the CAD system.

I can't tell what these numbers are referring to. This is a picture of how my setup currently is, I can't tell if these lines were put on correctly or not. Into the vacuum bottle. post-10416-138698170345_thumb.jpg post-10416-138698170351_thumb.jpg
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  • Owner

or cruise control

--- Update to the previous post...

just as ISX pointed out...that guy is quick with a camera:lol:

No kidding... I think he's mastered how to work a wrench in on hand and hold the camera in the other... :stuned:

--- Update to the previous post...

I can't tell what these numbers are referring to.

This is a picture of how my setup currently is, I can't tell if these lines were put on correctly or not. Into the vacuum bottle.

[ATTACH=CONFIG]1820[/ATTACH]

[ATTACH=CONFIG]1821[/ATTACH]

In you pics there I've never seen that can before??? :shrug:

Ok...

So 1 line from the vane pump drives the vacuum brake booster.

There should be another line that is smaller that passes through the firewall...

Then somewhere there is a tee and a another line should head down for the CAD switch (transfer case).

As for my numbers they have no bearing... (Sorry)

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No kidding... I think he's mastered how to work a wrench in on hand and hold the camera in the other... :stuned:

--- Update to the previous post...

In you pics there I've never seen that can before??? :shrug:

Ok...

So 1 line from the vane pump drives the vacuum brake booster.

There should be another line that is smaller that passes through the firewall...

Then somewhere there is a tee and a another line should head down for the CAD switch (transfer case).

As for my numbers they have no bearing... (Sorry)

Ah, well I am not sure what to do, because I'm pretty sure that can just hold up vacuum so that when the A/C is on and I hit the brakes my brakes wont be hard, as a rock, to push. The vacuum is supplied for my CAD, Cruise, Brakes and HVAC.

But, to be honest this is just what I was told by another 2nd gen owner/mechanic, I cannot say anything for sure. The vacuum works fine the way it is now, but the brake pedal tends to get hard like there is not enough vacuum and I have had some close calls, even STANDING on the pedal, once the vacuum builds the wheels lock though.

And, as for the numbers thing I wasn't sure if you tried uploading a pic and maybe it wasn't showing on my computer or what. That's why I posted those pictures to see if those numbers were in relation to the lines I had showing in the pic.

Thanks for keepin up on this so far guys! :thumbup2:

--- Update to the previous post...

I wonder if that is some sort of auxiliary vacuum pump.. Does it have anything else running to it or just the lines we can see from the pics?

I'm pretty sure it stores vacuum, It is bolted to the fender wall and has only vacuum lines run to it.

The one's Ted up in the picture were all attached to the fittings on top the bottle.

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Well for one, the brakes have nothing to do with the vacuum.. The vacuum and power steering pump connect to each other to share a common shaft but are not related to each other. The power steering pump is what assists your braking. I would bleed your brakes though, they sound like they have air in them if you can stand on it and nothing happens. Your pads might also be done for.

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Well for one, the brakes have nothing to do with the vacuum.. The vacuum and power steering pump connect to each other to share a common shaft but are not related to each other. The power steering pump is what assists your braking. I would bleed your brakes though, they sound like they have air in them if you can stand on it and nothing happens. Your pads might also be done for.

Ah, I see. I am going to do a full brake job on the pads and shoes, and take the calipers apart to replace any worn piston seals or get rid of any residue; I think on one side the caliper piston maybe be sticking. Does anyone have a picture of a 95 under hood, what is in place of that can then?
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Ah, I see. I am going to do a full brake job on the pads and shoes, and take the calipers apart to replace any worn piston seals or get rid of any residue; I think on one side the caliper piston maybe be sticking. Does anyone have a picture of a 95 under hood, what is in place of that can then?

On mine, there is absolutely nothing there. That is why there was room for the can lol. There is NO reservoir for the vacuum in a stock setup, just the vacuum hoses, nothing more.
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Well I can only see part of the picture. Stock it goes from the vacuum pump to a "T" on the cowl, I'm not sure where it breaks off to go to the CAD but one will go to the cruise control (under battery) and one will go to the HVAC (goes through firewall over by the ECM/Downpipe. If you have met those requirements, I don't see why it won't work. If your vents will go to something other than defrost and the cruise control works, you probably did it right. If your 4wd light on the CAD works and turns on and off with the transfer case shifter, then you have fed all the vacuum ran components and everything will work.

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Well I can only see part of the picture. Stock it goes from the vacuum pump to a "T" on the cowl, I'm not sure where it breaks off to go to the CAD but one will go to the cruise control (under battery) and one will go to the HVAC (goes through firewall over by the ECM/Downpipe. If you have met those requirements, I don't see why it won't work. If your vents will go to something other than defrost and the cruise control works, you probably did it right. If your 4wd light on the CAD works and turns on and off with the transfer case shifter, then you have fed all the vacuum ran components and everything will work.

Huh. I don't understand why they added the can then. Maybe it was because, when I first got the truck, the A/C only worked if the RPMs were climbing. I knew there was some sort of vacuum leak. I followed the vacuum line that goes under the battery for the cruise and found that the line was eaten away, that fixed all vacuum leak as far as I know and the A/C has worked ice cold and perfect since. I just ran a universal T to fit all those lines, I will try to find the actual part for it soon and trim up those lines. Now the cruise control does NOT work. I am pretty positive it is a busted clock spring and I'm sure it is also the cause for the Airbag light, and the fact that the horn and cruise do not work. That is another thread tho I spose haha.
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The vacuum line does this for each thing:

HVAC-Controls vent setting (floor, head, etc.) when there is no vacuum it defaults to defrost.

Cruise Control-Is used to pull the throttle back

CAD 4x4-Is used to engage the axle http://forum.mopar1973man.com/showthread.php/2472-4x4-CAD-System

My cruise control is a piece of crap. You go down a hill and it relieves all the vacuum and when you start going back up the hill, it is still collecting vacuum and after it has lost 5mph it will have enough vacuum and instantly floor it. This might be one of the reasons the can is there, not sure if it would be a vacuum pump capacity issue or a hose diameter issue (since they are tiny stock). The HVAC doesn't take much vacuum to work. I put a check valve on mine and that makes it work perfect.

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  • Owner

Personally if you increase the size of the tubing it would be capable of pulling a vacuum on the cruise motor faster. But you can only suck so much vacuum through that tiny tube... I'm thinking of chucking out that lame 1/8" tubing on Mom's 96 because of the very same problem. I changed a few fitting around so everything has access to the vacuum reservoir but on long uphill runs the vacuum runs out of the can too quickly... Hence same problem... :banghead:

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Personally if you increase the size of the tubing it would be capable of pulling a vacuum on the cruise motor faster. But you can only suck so much vacuum through that tiny tube... I'm thinking of chucking out that lame 1/8" tubing on Mom's 96 because of the very same problem. I changed a few fitting around so everything has access to the vacuum reservoir but on long uphill runs the vacuum runs out of the can too quickly... Hence same problem... :banghead:

You can see his setup uses those huge lines, then that vacuum reservoir... I'm thinking that would fix those issues. I just wonder if the bottleneck going into the cruise unit would keep it unchanged. I do think it is partially the vacuum pumps fault though so it couldn't hurt. I might have to try a reservoir on mine and see what happens. My "T" has a spot for another line anyways.
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Yeah I am familiar with what the vacuum lines are sent to and what they activate. I actually found out today that my cruise control DOES work, the light on the dash however does NOT work. I have a feeling the only wires cut under my dash (blk with orange stripe) have something to do with this. They are hanging by my fuse box from behind the fuse panel. I am pretty sure my ABS is causing my rear brakes to engage more or first. This was noticeable more than ever, when I was painting my frame, and drove the truck around with no bed in the rain. I am gonna have to have my drums heat checked. And, also think that if my ABS is NOT working correctly it will only increase the problem once I redo my brakes. I need to find the source of this problem. This article has a good post by someone who found an article of the actual ABS system used in our trucks. http://www.cumminsforum.com/forum/94-98-powertrain/135570-abs-brake-problems.html#post3402664 Kelsey Hayes ABS. I cannot stand not having good if not, decent brakes.

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Does anyone know where and how the green vacuum line that runs all the way from the engine bay to the transfer case and is paired with the red/blk vacuum lines for CAD?

It seems to be "hanging" around under hood. I can't figure out where it attaches.

Oh, also check this out...

Posted Image

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The green one should run straight down to the switch on top of the transfer case, along with 3 other lines. Two of the lines (red/black) run to the CAD unit. I assume the green one T's into 2. These are pics of an 01' so it might be different.

post-45-138698170458_thumb.jpg

post-45-138698170465_thumb.jpg

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