DodgeTalk Forum banner

1 - 20 of 23 Posts

·
Registered
Joined
·
115 Posts
Discussion Starter #1
I let the brake fluid level go too low so apparently a bit of air got into my brake lines. When I attempted to go to the farthest wheel (back drivers side) I encountered no bleed screw, ..I think. Please see photo below, where's that at?

(The plastic hose near the top is not attached and only in the photo for illustration purposes)
 

Attachments

·
Registered
Joined
·
115 Posts
Discussion Starter #3 (Edited)
That's the hose connection point. Do you think the base of it is the off/on? Edit: If yes, so do I.

Update: Tried backing the 8mm base of the hose connection point out 3 turns and no flow occurred! Also took off the drum thinking it may be on that side. Wheel cylinder appears to be leaking. :( Now I've got a brake job to do also. :(

Update:Just replaced the drivers side rear wheel brake hydraulic since it was apparently leaking (...oil found in and around drum) and since I/we thought it was failing. "Failing" because it would not allow any bleeding of fluid when cracked out just a little or even 4 turns in attempts to open to bleed.

After replacing the drivers side brake cylinder and also now attempting to bleed the rear passenger side and now neither side is allowing of fluid flow. What would keep fluid from getting to the rear break lines?
 

·
Registered
Joined
·
268 Posts
Your "hose connection point" IS the bleeder screw, on every car ever made, that I've ever seen. It's unlikely you'll get any flow out of the wheel cylinder without cycling the pedal, which you have to do anyway. If you're not getting any flow with the screw open and the pedal depressed, then the ABS module is blocking it, and you'll need to release the valve there. Specific procedures are different for different vehicles. It's not a generic procedure.
 

·
Registered
Joined
·
115 Posts
Discussion Starter #5
Yep, pressed brake petal many times and nothing. Haynes Manual also mentions a more complicated method to get this accomplished.

"Bleed the brakes in the following sequence: master cylinder, combination valve, RWAL (rear wheel anti-lock) valve, right rear wheel, left rear wheel, right front then left front".


It also says there exists a 2 wheel and 4 wheel ABS systems types on these 2 gen trucks.

Things are getting more complicated fast. Sounds like I need to figure out which system I have now.
 

·
Registered
Joined
·
115 Posts
Discussion Starter #6 (Edited)
It's a 4 wheel ABS system. Since the fluid hasn't been flushed in it and since I let the reservoir level get too low and replaced the drivers side wheel cylinder, I would like to achieve a good flush. I failed to mention that when the fluid level got too low the ABS and BRAKE dashboard lights came on and are still on despite filling and driving the truck. (slightly "spongy" brakes currently)

That said, I am wondering if the dashboard lights are what's keeping any bleeding of the lines from the back end? It's mentioned above that I would possibly need to "open the valve " at the ABS system. Here's a pic of my system. How does one open the ABS valve? (I tried key on and engine running and that failed to allow fluid flow)

Also, the "FC" port looks like the master cylinder bleeding point. Hynes mentions a "special tool" might be required there.

Quick Update:
On a whim I checked the brake switch. According to the Haynes schematic, both the ABS and Brake warning lights are tied in with the 6 pin switch. Pins 5 and 6 showed open so I installed a replacement. ...Same lights still on dash after replacing. :( Hope ECM turns these off after driving some. Bluetooth Scanner I have can't see either light on the dash.
 

Attachments

·
Registered
Joined
·
4 Posts
Before getting more complex, make sure the bleed screw isn't clogged/rusted etc. There is a pinhole in the side that often gets filled with junk.
 

·
Registered
Joined
·
115 Posts
Discussion Starter #8
Thanks dak,

Are you saying that in the base of the bleed nut there is a pinhole? What purpose would it serve?

Update:
I have given up on getting the dash lights "ABS" and "Brake" to clear ...even after replacing what according to Haynes was a defective brake switch at the brake pedal. I have an appointment with the local dealership this Friday to see if their scan tool can recognize the faults and clear them now that the brake switch has been replaced.

I am also still wondering how to activate the brakes hydraulic switch seen in the photo I have posted above.
 

·
Registered
Joined
·
115 Posts
Discussion Starter #9 (Edited)
Duplicate post. Mods please delete.
 

·
Registered
Joined
·
29 Posts
The bleeder is hollow and the small hole is how the fluid get out when you open the bleeder. Take the bleeder out and see if fluid drips out, don't push the pedal while it is out. If you can't blow though it then it is clogged. That small hole may be hard to see if clogged. It will take a small wire or ice pick to get it open.
 

·
Registered
Joined
·
268 Posts
The bleeder is hollow and the small hole is how the fluid get out when you open the bleeder. Take the bleeder out and see if fluid drips out, don't push the pedal while it is out. If you can't blow though it then it is clogged. That small hole may be hard to see if clogged. It will take a small wire or ice pick to get it open.
He said earlier that he screwed it out several turns with no results. His problem is that he has air in the ABS module, and gravity alone will not pull brake fluid out, it's going to require a pressure bleeding system, more than likely.
 

·
Registered
Joined
·
268 Posts
It's a 4 wheel ABS system. Since the fluid hasn't been flushed in it and since I let the reservoir level get too low and replaced the drivers side wheel cylinder, I would like to achieve a good flush. I failed to mention that when the fluid level got too low the ABS and BRAKE dashboard lights came on and are still on despite filling and driving the truck. (slightly "spongy" brakes currently)

That said, I am wondering if the dashboard lights are what's keeping any bleeding of the lines from the back end? It's mentioned above that I would possibly need to "open the valve " at the ABS system. Here's a pic of my system. How does one open the ABS valve? (I tried key on and engine running and that failed to allow fluid flow)

Also, the "FC" port looks like the master cylinder bleeding point. Hynes mentions a "special tool" might be required there.

Quick Update:
On a whim I checked the brake switch. According to the Haynes schematic, both the ABS and Brake warning lights are tied in with the 6 pin switch. Pins 5 and 6 showed open so I installed a replacement. ...Same lights still on dash after replacing. :( Hope ECM turns these off after driving some. Bluetooth Scanner I have can't see either light on the dash.
Without making it sound like I'm belittling you, it's clear you don't fully understand how this works. The ABS/Brake lights are not the result of a P-code, so they will not reset using a generic scan tool that resets a "check engine" light. Clearing brake/ABS codes requires a scan tool with more bi-directional capability. If the condition causing the fault indication is persistent, the warning lights will not turn off anyway. The "brake" light is indicating a generic brake system fault, the "ABS" light is indicating that the ABS system has been disabled due to a detected error state. It's not unusual for them to appear together. These lights are activated via the PCM which drives your dash display, they are in no way connected to anything in the brake system itself. It's possible on your vehicle that bleeding the brakes will require a bi-directional scan tool to activate the ABS module, most later model vehicles require this now. There is an ABS bleeding subroutine that is activated this way. Unfortunately I can't tell you which tools will or will not do this. Some manufacturers don't even release this functionality to the aftermarket.
 

·
Registered
Joined
·
29 Posts
I saw that he screwed it out several turns, if it is clogged it has to be removed to clean it. Below is the procedure from the Chrysler data. Also a place to get a DRB scan tool emulator.
www.aetools.us/products/drb-iii-emulator/
ABS system bleeding requires conventional bleeding methods plus use of the DRB scan tool. The procedure involves performing a base brake bleeding, followed by use of the scan tool to cycle and bleed the HCU pump and solenoids. A second base brake bleeding procedure is then required to remove any air remaining in the system.

1. Perform base brake bleeding.
3. Select ANTILOCK BRAKES, followed by MISCELLANEOUS, then ABS BRAKES. Follow the instructions displayed. When scan tool displays TEST COMPLETE, disconnect scan tool and proceed.
4. Perform base brake bleeding a second time.
5. Top off master cylinder fluid level and verify proper brake operation before moving vehicle.
I have been in the auto/truck repair business 54 years.
 

·
Registered
Joined
·
115 Posts
Discussion Starter #14 (Edited)
Update:
I now understand the smaller hole in the bleed screws that I did not realize prior. (Sorry, I am a tad slow at times!) I also understand it's purpose. (Allowing fluid flow without needing to completely remove the screw) Thanks for pointing this out! I will attempt to completely remove the screw from the brand new hydraulic wheel brake pusher I installed when time allows, ...tomorrow, I hope.

I took the truck to the dealership up the road since they said they would check/clear codes for no charge! He was required to retrieve an older type scanner to look at the dash lights issue. "Code 78 Foundation Brakes" is what was displayed and could not be cleared because the brake switch I replaced was not the issue, (...despite Hyanes Manual saying pins 5 and 6 reading open indicate a bad switch.)

Apparently the bottom line is that unless I buy another scan tool and the required "Special Tools" I will not be able to perform the level of bleeding needed to clear the dash lights. For my sanity however, I intend to determine why I can have brakes functional but no fluid flow when backing out a new screw and 2 others a few days ago! I am also wondering if I can bleed the master valve by pressing the little ball "FC" down?

Update 9/29: While checking the tire psi's I noticed the front 2 rims where hot to the touch after doing a bit of city driving. I am wondering no if the reason I had no fluid to even a brand new bleed valve at the back wheel is because the Code 78 has the rear wheel braking disabled? (Son took the truck so I won't have access to it for a week.
 

·
Registered
Joined
·
268 Posts
I'm perplexed why you're allowing someone to drive a vehicle with part of the brake system disabled? This seems reckless, to say the least. I'm also curious why a so-called Chrysler dealer doesn't know how to bleed brakes on a Dodge pickup? Code 78 is an ABS controller code implying that the proportioning valve is out of position, which would explain a lot of things.
 

·
Registered
Joined
·
115 Posts
Discussion Starter #16
guy,
No need to be perplexed. Son had a run in with an SUV at gas station parking lot last sun-day and was left without a functional car and needing to get back to college 200 miles away! Now I am stuck with fixing his Scion front end and my 99 Ram when he gets back here! No need to fret about being "reckless". I've been driving it around town here and it still stops on a dime just fine! (Cautioned him about minimal brake use until he gets back. Hopefully we can all 3 rest assured he will get back here in one piece! :)

So you would agree that no fluid from the bleed valves in back and front wheels getting hot when braking frequently indicates air in my braking system is causing my no bleeding issue at the back wheels which WE were trying to get diagnosed?

According to the 20 year tech at the Dodge dealership the code 78 on his scanner indicated "Base Braking Fault". Either way I think at this point I/we can assume air at the proportional valve/...and possibly elsewhere is causing issues.

I don't intend on taking the 99 Ram to a garage, ...yet. Therefore the question remains. Can I bleed the prop valve by pressing "FC" down and pressing on the brake petal while keeping fluid reservoir full?
 

·
Registered
Joined
·
268 Posts
We've already explained that bleeding the brakes requires a scan tool. The "problem" has already been diagnosed. If you choose not to believe us, that's your privilege. My question centered around why the guy at the shop with the scan tool and 20 years experience didn't just bleed the brakes?
 

·
Registered
Joined
·
115 Posts
Discussion Starter #18
Not sure what you are saying I don't "believe" or whom you are calling "we"? Air, above describes a method BUT it requires a "base bleeding" to begin with and that is not possible until the pressure difference in what is erroneously called the proportional valve is corrected. Hence my question about enabling bleeding the back wheels line 1st by bleeding "FC" is what I am attempting to find out here.

If that fails I will attempt re-balancing the pressure reduction valve by pressing "FC" in while pressing the brakes. If that fails disassembly will likely be my next step. (...when my Ram gets back here)

The tech at the shop was not asked/authorized to attempt brake bleeding the truck. Only to see if replacing the brake/abs switch would clear the 2 faults showing.
 

·
Registered
Joined
·
222 Posts
The front brakes will still get plenty of heat into them even if the rears are working...

Was there any heat in the rears? If none, that's a different story. But remember that about 85% of the braking happens at the front wheels.
 

·
Registered
Joined
·
115 Posts
Discussion Starter #20 (Edited)
The FIX is in!

I got discouraged attempting to figure this out so I took the truck to a local shop for a diagnosis. Tech on site said he has seen this before and is normally able to fix it by opening both back bleeder screws and slamming on the brake a few times to get the pressure reducing valve (...aka: proportioning valve) to open. This failed so he said he felt replacing it would help.

Sure enough, once I had it off the truck it dawned on me to check the ohms of the 2 wire connection point. (see pic) I compared it to one that I procured from a local salvage yard. (see pic) Installed the new (...used but nice) valve and without turning the key on fluid flow to the rear wheels returned!

A normal brake bleeding sequence was completed. Started the truck and the BRAKE warning light went out. Great!

Now I am left thinking that when the fluid in the reservoir got too low, the valve went into emergency mode and stopped allowing fluid to the back wheels where the leak had developed. At the same time the circuit within the valve opened causing the dash light, "BRAKE" and NOT "ABS BRAKE". (Hence the "base brake" fault the dealership scanner saw) My conclusion: The Dodge engineering design is a one time failure of the Prop Valve if a wheel cylinder failure occurs.
 

Attachments

1 - 20 of 23 Posts
Top