Tech Alert-Brake fluid flushing

abittenbinder

Doktor A (864-623-9110)
There have been numerous posts regarding the importance of regular 2 year brake fluid flushing intervals as part of routine maintenance.

Brake fluid slowly absorbs moisture and the long term result is a lower fluid boiling point which can cause entrained bubbles and a low/soft (or non existent!) pedal at very high brake operating temps.

Another consequence of excess fluid moisture contamination is damage to costly brake system components, in particular ABS/ESP components which are extremely expensive.

ALL '02-'06 Sprinters (with standard ABS and standard traction control, regardless of ESP option) utilize a 4-channel Bosch 5.3/5.7 ABS unit.

Because of the 'X' brake pipe circuit configuration (RFront-LRear, LFront-RRear) and standard traction control (ASR), non ESP Sprinters feature the same 12 solenoid valves as ESP equipped Sprinters in the ABS hydraulic modulator.

Each of the 2 hydraulic modulator circuits in the 'X' pipe configuration has 2 inlet valves, 2 outlet valves, a high pressure switching valve and a switchover valve, for a grand total of 12 valves. Each circuit also has a pump element and low pressure reservoir using the shared electric pump.

When flushing/bleeding the brake system using ONLYthe conventional pressure or suction methods, the 2 high pressure switching valves and the 2 switchover valves as well as the fluid return pumps and all their related hydraulic paths, ARE NOT FLUSHED OR BLED. This can cause deterioration of the expensive hydraulic modulator.

If flushed properly using the factory DRBIII (along with pressure or suction devices) these 4 valves as well as the 2 pump elements are DRBIII remotely activated and also purged of old fluid.

DIY brake fluid flushing will replace fluid at the calipers, master cylinder and 8 of the 12 internal valves in the ABS hydraulic modulator, but not the 4 valves and 2 return pumps critical to ABS, ESP and ASR operation. Doktor A
 
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abittenbinder

Doktor A (864-623-9110)
What would be a fair price to pay for this complete flush at a dealership? Thanks paul
Any DRBIII equipped Sprinter technician can perform this 'complete flush' procedure-it doesn't necessarily have to be the dealer.

The DRBIII activation does require a second tech or helper for this procedure and obviously the use of the DRBIII's time and use so I suspect this will add marginally to the flush cost compared to a 'conventional' flush. Doktor A
 

maxextz

Rollin Rollin Rollin.....
There have been numerous posts regarding the importance of regular 2 year brake fluid flushing intervals as part of routine maintenance.

Brake fluid slowly absorbs moisture and the long term result is a lower fluid boiling point which can cause entrained bubbles and a low/soft (or non existent!) pedal at very high brake operating temps.

Another consequence of excess fluid moisture contamination is damage to costly brake system components, in particular ABS/ESP components which are extremely expensive.

ALL '02-'06 Sprinters (with standard ABS and standard traction control, regardless of ESP option) utilize a 4-channel Bosch 5.3/5.7 ABS unit.

Because of the 'X' brake pipe circuit configuration (RFront-LRear, LFront-RRear) and standard traction control (ASR), non ESP Sprinters feature the same 12 solenoid valves as ESP equipped Sprinters in the ABS hydraulic modulator.

Each of the 2 hydraulic modulator circuits in the 'X' pipe configuration has 2 inlet valves, 2 outlet valves, a high pressure switching valve and a switchover valve, for a grand total of 12 valves. Each circuit also has a pump element and low pressure reservoir using the shared electric pump.

When flushing/bleeding the brake system using ONLYthe conventional pressure or suction methods, the 2 high pressure switching valves and the 2 switchover valves as well as the fluid return pumps and all their related hydraulic paths, ARE NOT FLUSHED OR BLED. This can cause deterioration of the expensive hydraulic modulator.

If flushed properly using the factory DRBIII (along with pressure or suction devices) these 4 valves as well as the 2 pump elements are DRBIII remotely activated and also purged of old fluid.

DIY brake fluid flushing will replace fluid at the calipers, master cylinder and 8 of the 12 internal valves in the ABS hydraulic modulator, but not the 4 valves and 2 return pumps critical to ABS, ESP and ASR operation. Doktor A
its probably best to let the dealer do this then, thats the worst thing about modern vehicles nearly anything you want to do you need a computer:censored:
 

poiuytrewq

New member
Im located in canada, there are no dodge dealerships that can competently service my 2005 sprinter. They are truly clueless. There is no question that they would screw up the procedure, damage some other component and try to cover their asses. I had an idea about this brake fluid flushing. What if i have the brake fluid flushed conventionally. Then drive on one of the back roads, put 2 wheels on the gravel and stop hard so i can hear the abs kick in, then do the same to the other 2 wheels- then repeat the process 10 times or so. Looking at the abs device , it is small so i imagine the valves internally are small, would this not push the old fluid out of the valves into the fresh fluid? And thereby bring in fresh fluid to the valves in question.
 

abittenbinder

Doktor A (864-623-9110)
Im located in canada, there are no dodge dealerships that can competently service my 2005 sprinter. They are truly clueless. There is no question that they would screw up the procedure, damage some other component and try to cover their asses. I had an idea about this brake fluid flushing. What if i have the brake fluid flushed conventionally. Then drive on one of the back roads, put 2 wheels on the gravel and stop hard so i can hear the abs kick in, then do the same to the other 2 wheels- then repeat the process 10 times or so. Looking at the abs device , it is small so i imagine the valves internally are small, would this not push the old fluid out of the valves into the fresh fluid? And thereby bring in fresh fluid to the valves in question.
One of the big advantages of living on the arctic circle. Yes, your DIY activation of the ABS's hydraulic modulator should accomplish an effective flush.

However, ASR or ESP (if present) activation would be required, as well. This is because ABS operation involves pressure REDUCTION via the hyd modulator's outlet valves whereas ASR/ESP involves pressure BUILD-UP via the high pressure switching valves and associated pump elements. Doktor A
 
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mackconsult

New member
Doktor A,

So I don't know that my sprinter has ever had the brakes flushed. It has 78k on it, and now I am concerned. I have the the DAD, and I am sure the capability to do it. But in my searches on this forum I just couldn't put together the "complete" process on how to do this. I have adjustable compressor and a vacumm pump from my WVO filtration.

Any help greatly appreciated.
 
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NBB

Active member
I'd figure it's just like any normal flush while the DAD is agitating the ABS.
I don't have specific experience with the Sprinter, but I have flushed ABS in the past via a scan tool. There was a very specific sequence of which actuators to fire, which wheels to do first, etc, based on which ports fead into the others. I'd think you'd want to look into that.

The other thing I do recall is that they didn't actually recommend you attempt to flush the ABS motor and they laid out reasons I have since forgotten. Just a conventional flush was the recommendation. This was the factory's point of view for a particular Bendix motor. My personal view is more along the lines of changing fluids often. I like the original color of a fluid.
 

scubanw3

New member
There is a specific procedure for the Exceptional Bleeding Program. When running the program via a factory scan tool (or the SDA aka DAD), you activate each ABS circuit individually starting with the right rear, moving to the front left, then the left rear and the front right. During activation you manually pump the brake pedal for the specified amount of time controlled by the program. During the bleeding process, the ABS pump is continually activating and pumping fluid through the ABS control unit. BTW, you get a great foot massage out of the deal! Hope this helps.

Thank you, John
Sprinter Store
http://sprinterstore.com/
A division of Upscale Automotive, Inc.
19460 SW 89th Ave.
Tualatin, OR 97062
503-692-0846
 

stroud_omnibus

New member
After reading the original post, I have had mine done at my local dealer about a month ago. I think it took about half an hour and cost £65. It hadn't been done in my ownership an that is now two years. Personally, I don't think it had been done properly before.
 

kkanuck

LUV my T1N
Has Anyone used the DAD to do the proper DIY Brake flush yet?
 

kkanuck

LUV my T1N
Yes, but only the ABS circuit showed up when I went to agitate the valves. ESP was MIA on DAD.

Is there a sequence to agitate the ABS? When does one perform it, at what stage of the flushing, etc?


Cheers
 

shortshort

Dis member
Instruction are in the service manual and the DAD manual but basically:

1) get a presure bleeder from Pro-Motion

http://store.motiveproducts.com/european-bleeder--0100-p34.aspx

2) get a quart of ATE Super Blue and a quart of something yellow in color and within spec. If the lack of MB numbers on the Super Blue can has your rectum all aquiver, try a muscle relaxant. Sheeesh.

3) suck the reservoir dry with your vacuum pump, refill to about 2/3 capacity with super blue, then pour the rest of the quart into the bleeder tank.

4) download the service manual

5) bleed per the manual, when the blue stuff comes through you know you are done with each circuit. It doesn't hold much so let it run a bit more for peace of mind

6) suck out the blue from the res and put in the yellow, ditto for the bleeder tank.

7) do the ABS bleed routine, for this you need another pair of feet. Instructions are in the DAD manual under Special Functions section 5. This time, obviously, you are looking for the yellow to replace the blue in the exiting fluid.

Absent a DAD, you can just pressure bleed twice with joyride on a gravel road between sessions :)
 

jcolvin

New member
I had a heck of a time getting the local Mercedes sprinter dealer to do this. They said it was completely un-necessary and useless for T1N sprinters. When I insisted I wanted it done they pulled up the Mercedes service manual which said it "must only be done if air remains in system after several bleeds"; ie DON'T DO IT unless you need to. They also said they could find nothing in the Chrysler manuals at all. I did get them to do it anyway, but it was like pulling teeth.
 

jdcaples

Not Suitable w/220v Gen
I had a heck of a time getting the local Mercedes sprinter dealer to do this. They said it was completely un-necessary and useless for T1N sprinters. <snip>

They also said they could find nothing in the Chrysler manuals at all. I did get them to do it anyway, but it was like pulling teeth.
They don't have access to the "Chrysler manuals," unless they downloaded them some non-MB computer - from somewhere outside the MB field of authorization - and charged you for the time it took to download & read them.
 

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