m925 brake issue

[thunderechief83]

Ladies and Gentlemen I am having an issue with the brakes on my m925, abs light goes on and off like it is suppose to, brakes fine when slowing down but right before I come to a dead stop the brakes grab hard enough to jar your teeth out!!! any ideas what is going on?

 

[doghead]

Are you sure it's not the transmission downshifting to 1'st?

 

[Coffey1]

They hit really hard from the shift 2nd to first.

 

[thunderechief83]

interesting didn't think about that! so thats a normal issue for the transmission to downshift that hard?

 

[Coffey1]

Yes and mine the longer I drive it tends to soften out a little

 

[thunderechief83]

Yes and mine the longer I drive it tends to soften out a little

funny you say that! the previous owner told me the same thing but he thought it was the brakes too.

 

[thunderechief83]

I think I will start floating through the stop signs! I don't think anyone will get in my way! LoL

 

[R Racing]

When my m923a1 is cold at low speed my brakes grab bad. It will lock the tires up. But once the truck has been driving a bit they get better and don't lock up.

 

[74M35A2]

http://www.steelsoldiers.com/showthread.php?131016-M923-hard-downshift

Post #5.

I disagree that it is normal. The transmission should not be shocking the driveline that hard. Lubricate the modulator cable and make sure its spring return is working correctly. Also lubricate the accelerator pedal and linkage mechanism well.

My 925A2 went through this recently, and after I lubricated the modulator cable very well and worked it in, the harsh 2-1 downshift turned butter smooth.

 

[Artisan]

I have an M925A1

The tranny is a MONSTER, you are driving it empty, it will shutter downshifting like a punk rocker
in a mosh pit when empty. Put 6K in the back and drive it again...you will see what
I mean.

I pulled 7 trucks up and down hills for about 150 miles or so, it barely took
the edge off the tranny. 10K in the back and a 15K trailer is what it will
haul, think about that.


These are tachtical trucks, NOT Chevys..NOT Fords...nothing nice or comfy
about them at all, they even leak water when raining, trust me on that! HA!

 

[Artisan]

http://www.steelsoldiers.com/showthread.php?131016-M923-hard-downshift

Post #5.

I disagree that it is normal. The transmission should not be shocking the driveline that hard. Lubricate the modulator cable and make sure its spring return is working correctly. Also lubricate the accelerator pedal and linkage mechanism well.

My 925A2 went through this recently, and after I lubricated the modulator cable very well and worked it in, the harsh 2-1 downshift turned butter smooth.

I am open to new things. Is there a pictorial on how to do this?

 

[R Racing]

My m925 A1 shifts a bit ruff but not like you guys are discribing. My m923a1 shifts like my f350 Smooth as silk. It's a recent rebuilt truck. I did have to lube the linkage on the m925 as it was sticking badly. The m923 linkage is all new and smooth.

 

[Ford Mechanic]

Yeah they tend to shift a little hard at the 1-2. I found it was worse when I coasted to a stop easily. If you brake a little harder instead of coasting under 15mph it was it's not nearly as bad. Mine would toss my dog off the passenger seat.

 

[74M35A2]

I am open to new things. Is there a pictorial on how to do this?

Sorry, no I didn't do a pictorial. Mine changed overnight after an off-road adventure, so I knew it was not normal. Mine was butter smooth to begin with. After off-roading, it would slam on the 2-1 at about 7mph. I carefully observed the trans modulator cable, and saw it is spring loaded (on the trans end under an external cover with anti-tamper screws in it), and wasn't fully returning. This is all observed at the injection pump accelerator arm. I pulled the cable seal back and sprayed WD-40 with a straw down the cable, and worked it in by pulling on the cable core and letting it snap back to its home position. I did this over 40 times, while kept spraying. It is a 15 year old cable and probably has never been lubed. Immediately after on the first test drive, the harsh shifting was gone and it was back to being relatively smooth again. Several others have since done so and had similar results. Try to push your cable in further. If it can be pushed further toward the trans before it bottoms out, then that is likely your issue also, as it was mine. Mine now fully seats on its own, and it did not when I had the U-joint breaking 2-1 downshift.

I could easily have a full McDonald's Coke sitting on my floor board with the lid off while slowing down, and it would not tip over or even spill out when coming to a stop. I can't find a better way to describe how mine downshifts. Guy I bought it from did say it was one of the best shifting trans he has seen, and he pedals a few of these trucks per year.

All I can say is try it, a 15 year old cable likely needs to be lubed anyway.

 

[gimpyrobb]

I have found if a 939 series truck has braking issues, you just need to bleed the brakes and it will clear right up!

 

[Ford Mechanic]

I have found if a 939 series truck has braking issues, you just need to bleed the brakes and it will clear right up!

Hmmm. I didn't know you could bleed air brakes. Are you talking about any water in the tanks or water in the lines? Or was this sarcastic humor? I find it hard to tell online which it is sometimes.

 

[doghead]

He must have recently red about the guy asking about greasing his brakes(bleeders)