M923 Brake Question

[TNSS]

Ok I have a m923, it has air brakes I believe. My problem is this the brakes are super sensitive and when I'm just creeping around slow on my farm and touch them the truck stops pretty hard. I will be using this truck for a hay ride and as it is now it will throw people down if they are standing. Is there anyway to make them so they are not so touchy?

 

[R Racing]

Mine are the same way. But I will say if I go down the highway and drive it about 10 to 15 min they are much better at stopping at low speed.

 

[wreckerman893]

If you are not used to air brakes they can be touchy. You have to develop a soft foot since there really isn't a lot of leeway in adjusting the amount of air that is sent to the brake chambers.

If you are going to carry passengers make sure they are seated and restrained, especially if this is a paying event. Hate to break that to you but with a lawyer under every rock you have to cover your bases. I would also look at event liability insurance. It's better than giving somebody the farm. I paid 200 bucks for a one day million dollar liability policy a few years ago.

 

[TNSS]

Ya we have a pretty good ins policy and we are a LLC that "rents" my farm for the use of it which protects the farm. My business partner is a lawyer lol.

 

[armytruck63]

Let me be the first to gently say this: you need to read this manual before you even think of taking your truck on the road.

http://www.steelsoldiers.com/upload/939/TM9-2320-272-10.pdf

It will answer almost all of your operation questions.
We are here to help.

 

[Coffey1]

My suggestion to you is you drive this truck for awhile and get used to all of it's quirks.
Also I think you need to download the operations manual.
I would not let anyone ride in the back until you are proficient in operating this truck because you will hurt someone.
I really don't like to come down on anyone but if you are unsure if this truck has airbrakes then you don't need to be operating it until you know and understand the systems on this truck.

Best of luck to you.
Ken

 

[TNSS]

Thanks for the warnings guys, I assure you I am very proficient at running this truck and machinery far beyond the scope of this little thing lol. I have farmed and ran a vast variety of machinery in my life from farm to excivation to semi. My coment where I said "believe" is I have not messed with this truck in some time and I have really only driven it once when I brought it home. So I was going off memory. My dump trucks all have air brakes as well but are not as touchy as this trucks brakes that is why I wondered if there was some type of adjustment that could be done, all though I do not think there is I figured I would ask just to see. You don't really need to be a rocket scientist to run these trucks lol. And during our Halloween attraction when we will be giving people hay rides with this my driver is a military soldier that runs these trucks every day as his occupation so I think we have that covered. But still I apriciate the warnings as there are some people out there that need all the help they can get there.

 

[Coffey1]

That's great to hear. We can only go by the data given.
And you will get a talking too when you think a truck has a certain type of brake system.
Be safe have fun

 

[hklvette]

In my experience air-brakes can be "grabby" if they aren't used much since surface rust can build up on the drums and make a high-friction spot. Once they smooth out, they become easier to modulate.

 

[randygk]

Just did a 1.5 mile Christmas Parade with the M923A1 and had 12 people in back, all standing. Before we started I gave them the speech about always holding on and being prepared for a sudden stop or acceleration (someone running in front or mechanical issue). The brake pedal has pretty much the same feel as any of my other vehicles, you may have an issue with yours. I even got a compliment on my driving from one of the passengers when the parade was over. Yes, a good liability policy is a must.

 

[74M35A2]

If you have driven a "semi", then this should brake much the same way, as the system is about identical. We can give you benefit of the doubt, and suspect something is wrong, which at that point you will need to start reading through the operation and service manuals or pay to have it diagnosed.

I side with rusty drums, but your driving it back from wherever should have cleared that up. As a reminder, these trucks are designed to stop while carrying a bed load of up to 10 tons (on-road rating). So, on an empty truck, the brakes are going to seem quite overly powerful.

At the same time, I would not label myself as a CDL equipment driving genius, but I am able to drive and stop my M925A2 very smoothly. Point in case would be I can come to a stop with a full McDonald's Coke on the floor (no lid), and not dump it over, if I needed too. So, maybe you do have something wrong. Then again, when a beginner drives my truck and I am passenger, they almost always try to put me through the windshield at almost every stop they make. I would think after the first one they would get it, but they just don't for some reason. People just have to jamb that pedal down. Maybe the size of the vehicle presents an image that they have to be forceful? Not sure.

 

[TNSS]

In my experience air-brakes can be "grabby" if they aren't used much since surface rust can build up on the drums and make a high-friction spot. Once they smooth out, they become easier to modulate.

Now that you say this I bet this may be the issue as the truck had sat for a while. I'll drive it for a bit and see if it smooths up. It needs to just warm up some so its easier to start. I should have thought ahead when i parked it so it would be close to my shop. I really don't like using ether, I learned the hard way with my allis dozer. I used ether to start it all the time in the winter and now it won't even start when it's warm with out it. It's a addict lol.

 

[TNSS]

If you have driven a "semi", then this should brake much the same way, as the system is about identical. We can give you benefit of the doubt, and suspect something is wrong, which at that point you will need to start reading through the operation and service manuals or pay to have it diagnosed.

I side with rusty drums, but your driving it back from wherever should have cleared that up. As a reminder, these trucks are designed to stop while carrying a bed load of up to 10 tons (on-road rating). So, on an empty truck, the brakes are going to seem quite overly powerful.

At the same time, I would not label myself as a CDL equipment driving genius, but I am able to drive and stop my M925A2 very smoothly. Point in case would be I can come to a stop with a full McDonald's Coke on the floor (no lid), and not dump it over, if I needed too. So, maybe you do have something wrong. Then again, when a beginner drives my truck and I am passenger, they almost always try to put me through the windshield at almost every stop they make. I would think after the first one they would get it, but they just don't for some reason. People just have to jamb that pedal down. Maybe the size of the vehicle presents an image that they have to be forceful? Not sure.

The brakes were smooth on the trip home no issues at all. The truck sat for a while and was then moved back on the farm that was when they were "grabby". It wasn't driven enough to clean any rust off I didn't even think about that. My dump truck sits for long periods of time and they don't seem "grabby" like this trucks but I usually jump right on the road with it so they probably clean up fast.

 

[Floridianson]

Does the dump truck have wedge brakes or S cam?

 

[74M35A2]

Does the dump truck have wedge brakes or S cam?

I hate wedgies !!!!

 

[TNSS]

The dump truck has cams we run it all over the farm and wedge brakes will load up with dirt and have to take extra care to keep them clean when running it off road. I'm a little lazy so don't want to have to worry about that all the time.

I am in no way a mechanic but in pretty handy, I have a very good mechanic when it comes to the bigger jobs but if it's something I can tweak I will attempt it myself before calling him. He is the one that taught me to stay away from the wedge brakes when we were looking for this truck.

How does that affect the issue im having with my m923?

 

[Floridianson]

Mine is a 1982 M925A1 with Stopmaster II wedge. Did they switch from wedge on the A2's?

 

[TNSS]

Mine is a 1982 M925A1 with Stopmaster II wedge. Did they switch from wedge on the A2's?

Sorry you asked about my dump truck and in my mind I was thinking about my "bruin tractor, Detroit diesel baby lol" as that is the dump truck I have lol. The M923 I have is not a dump truck it's just the flat bed with flip down sides. I have not looked at the brakes on it so im not sure it's parked in a field. It's cold and I'm trying to do some research before hand that way when it warms up I have a game plan on where to start with it.

 

[Floridianson]

The point is if the M939 series all have wedge stopmaster II which I think they have then your dump truck with S cam will act/feel different. Yes they are both air brakes.

 

[TNSS]

The point is if the M939 series all have wedge stopmaster II which I think they have then your dump truck with S cam will act/feel different. Yes they are both air brakes.

True but the brakes on the m923 should not be as grabby as they are. At least I don't think they should. When I drove it home there was no issues with them stopped fine but after it has set a while they are super grabby. I didn't think about surface rust like some of the other guys mentioned I really think that may be the whole issue I just need to run it a bit and see if it clears up. Thanks for the help guys