Abs mwo?

[bizzyboi]

Hello everyone I am getting ready to buy my first M923 and I wanted to know how can you tell if the abs brake problem that was reported by the military (the stalling engine, loss of power steering etc) issue has been resolved on the MV?

 

[Durango_USMC]

As in if an ABS sytem has been installed?

I'd like to say welcome to the site, please let me be the first to say do a search, and read some TM's. You'll learn a lot this way. But in short if I remember correctly an easy indicator to tell if the 939 series truck you're looking at has the ABS retrofit/feature would be the presence of an ABS indicator light in the cab that is marked "ABS".

This may help with some other questions you may have later as well:
http://www.steelsoldiers.com/showthread.php?79228-TM-s-for-the-939-series-trucks

They definitely helped me out a time or two.

 

[bizzyboi]

Thanks for the info and TM's. So if the vehicle has a abs light that means it does not have the issues that caused so many crashes and reduced speed limit mandate? Do you have a idea where I can see a dash blueprint or pic to know where that abs light would or would not be?

 

[Durango_USMC]

http://www.mvcconline.org/catagory3/images/Brett%20Williams/M923-18.JPG is a link to a pic, I can't upload it from this PC. Its not a guarantee that the ABS will be functioning. I dont have a lot of experience with the ABS system in these trucks. But there have been a few people who have had issues with a control box being fried (due to improper tart up or shut down) which disables the ABS system. Just poking around in the 5-ton and up forum here will explain what I'm talking about. If this is your first time with a vehicle this size I strongly advise you to find a member locally who has a 5 ton you can check out. They're not exactly like driving a uhaul

 

[bizzyboi]

Thanks for the pic! So safe to assume these abs buttons will be in the safe location in all m923's? Have you any ideas on repair cost if the system is damaged? I have reached out to a couple members in the area and hope to meet more before I buy one.

 

[GHall]

The ABS module has a diagnostic port that can be troubleshot with a certain reader. I believe the module isn't too expensive. Things that can cause a malfunction in the system are air leaks, stuck brake shoes, bad sensors, not following the startup/shutdown procedure and a probably a few more.

 

[chadande]

Here is a pic of where the ABS light would be on the dash. Like stated above having it installed does not mean it works.
When wathcing a vid of a running truck the light should be off. If it is on while running it indicates a problem with the system.

 

[Durango_USMC]

Thanks for the pic! So safe to assume these abs buttons will be in the safe location in all m923's? Have you any ideas on repair cost if the system is damaged? I have reached out to a couple members in the area and hope to meet more before I buy one.

Have you tried getting ahold of jcappeljr? He's also in PA and might even be able to get you in the divers seat. He has a few for sale as well.

 

[bizzyboi]

Wow thanks chandande! The tip about the vid is priceless info. I appreciate the pic you posted too.

 

[bizzyboi]

Yep I am talking with John too who btw is very helpful and my plan A in regard to getting a truck. Started looking at GL to see if I could catch a deal so now I am just gathering info. Thanks for your help. Also Ghall much appreciated the info you left too.

 

[Kelton VFD]

New to the site ya"ll are great very good info! We have a m-939 5 ton on our VOL. fire Dept. and it's an awsome truck but the problem we are having is the rear brakes locking up also. i have replace the (ABS BRAKES) valve on the front rear axle it's the one with the wiring plug on it. and did not help at all. the ABS light stays on all the time never goes out.
My ? is can i just do away with the abs system altogether. we have thrown money at this truck with no improvement. Like i said it's a fire truck and we have to have it work right every time or the outcome is not good. i am in the texas panhandle and spring time around here gets pretty bad with the grass fires. Any help i could get would be very much app.!!!! THANKS even if you could call me mybe i can explain it a little better. (806)203-0525 Again thanks for you time!!!

 

[juanprado]

Kelton,

You need to download and look at the 2012 tm 23 series. There is a great abs troubleshooting flow chart using the info centre and without. There is a diagnostic connector under the passenger dash to get the abs codes. It is pretty straightforward but you need the machine. A HD repair should also be able to diagnose. Throwing parts at it without knowing the cause won't help you. There are 2 abs valves, 2 electronic solenoids, 2 sensors etc.

It can be tested with out the computer but you will need working knowledge of a test meter.

Follow this post to download the good stuff not posted on here and follow the abs flow chart.

http://www.steelsoldiers.com/showthread.php?104189-Stryker-s-M923a1/page2

 

[PETE BALLARD]

ABS info - the abs pilot lamp on the dash is just an indicator that monitors only the ABS system. It is a good guide to know if you have any operational isses - but it will not tell you if there are foundation issues with the whole brake system ( like worn out brake shoes or brake chambers,ect.) it is a good guide however and you need to know if there is an issue your foundation should operate as a non ABS unit would - helpful to know when you might be driving in adverse conditions because driving techniques are different with each system
On another note any vehicle manufactured with a ABS system or any enhancements CAN NEVER be downgraded to lesser components.Last you must develope some methodical diagnosis skills. I find it helpful to start with checking the wheel end sensors OHM readings and then checking for AC current output by haveing the wheel off the ground and spinning it. When checking the sensors always un plug them for the ECU and run checks thru any cable extension you might have and then moving on to the required corrective action. You might also read about the various thing you can buy as diagnostic tools. Keep in mind most only tell you one code at a time and only go on to the next problem after the first one has been repaired. That is why l like my method - test everything and make your list of TO DO up front. Also keep in mind simple repairs also can remedy the light on condition like cables or plugs being dis-connected so do a good visual check of the entire ABS wiring as well.
Best advise is do not be intimidated by this system. Take one step at a time . Defects usually are broken cable, sensor unplugged or the air gap is too great or tone/exciter ring dirty. Also so many people miss this last one -if you do find a fault with one of the sensors fallow the cable back to the problem because if someone that was working on the system before you did not put the plug in the correct location. You might repair a good sensor and still have a problem. i refer to the diagnostic table the tells you recommended sensor location by plug on the ECU.
Hope this info helps

 

[Kelton VFD]

You guy"s are the best. Thanks for all the help i'll check it out and let you know what i find!

 

[rrrr]

The ecu will actually hold several codes. As explained earlier go through the diagnostic without the haldex box. It is very thorough. Download the TM's. There are two TM's that address ABS. A soldier 'B' is always good to help out because many of these checks require more that two hands.

http://www.steelsoldiers.com/showthread.php?79228-TM-s-for-the-939-series-trucks

Also, use the search there are several threads that talk about the abs that are very good.

Good luck and keep us posted.