M&G brake system problem

[heybc]

We tow a Jeep Wrangler with a DP and use the M & G brake system. Have used the M & G for 11 years and two Wranglers with no problems. Yesterday while towing the brakes locked up. A passing car signaled us that we had a problem and we pulled over on the shoulder. The left front was hot enough to be smoking. Disconnected the toad and after the brakes cooled I drove while my wife followed in the Coach. Brakes worked OK and I stopped twice to check wheel temps. No sign of lockup or overheat. Hooked back up and towed the rest of the way with out the air line connected. Has anyone experienced a brake lockup while using M & G? Any trouble shooting advice would be appreciated. Currently traveling around FLorida and won't hook up the brake system until I figure out what is going on.

[stuhly]

I suspect that the adjusting rod did not get Lock tite on the threads when it was installed. Over time it will come out of adjustment. Dismount the M&G unit and readjust and use locktite on the threads. Happened on my Tahoe.

[BobGed]

I would suggest a call to M&G.

[palehorse89]

One more suggestion, I took a pressure gauge and screwed a air chuck fitting on it so you can put in on the air chuck on the rear of the coach to see what is going on with the air pressure, just for a test and peace of mind, most likely, as mentioned, the rod has wen out of adjustment. Have you noticed the braking to be any different when driving it? A call to them would be first in order:
Toll-free: 1-800-817-7698

[wa8yxm]

The design of the M&G suggests something else happened.

Do you have the Break--a-way kit installed. From the sounds of it that activated, why I do not know, but once it activates what you describe happens.. I can think of no other way.

The thought about the activating rod adjustment does not fit the symptoms.. You see, if that were the problem,, Disconnecting and driving the Jeep would have also caused the problem..

But the break away tripping, that would cause exactly the symptoms you cited including no problems driving independent due to no pressure in the break-a-way tank.

[hypoxia]

Originally Posted by wa8yxm

The design of the M&G suggests something else happened.

Do you have the Break--a-way kit installed. From the sounds of it that activated, why I do not know, but once it activates what you describe happens.. I can think of no other way.

The thought about the activating rod adjustment does not fit the symptoms.. You see, if that were the problem,, Disconnecting and driving the Jeep would have also caused the problem..

But the break away tripping, that would cause exactly the symptoms you cited including no problems driving independent due to no pressure in the break-a-way tank.

[FIRE UP]

Originally Posted by wa8yxm

The design of the M&G suggests something else happened.

Do you have the Break--a-way kit installed. From the sounds of it that activated, why I do not know, but once it activates what you describe happens.. I can think of no other way.

The thought about the activating rod adjustment does not fit the symptoms.. You see, if that were the problem,, Disconnecting and driving the Jeep would have also caused the problem..

But the break away tripping, that would cause exactly the symptoms you cited including no problems driving independent due to no pressure in the break-a-way tank.

I kind-a have to agree with this analysis. But, I also have a theory about maybe the M & G unit just simply STUCK one time in the application position. Then, for whatever reason, it self released and went back to its "at rest" position. Yes, if either of those TWO adjustment sections of the M & G unit were to start to back off of the original adjustment, then, based on the fact that it pushes on the master brake cylinder piston, which, applies basically the same amount of brake pressure to ALL FOUR WHEELS, then why would only the one be extra hot and not the rest?

What about a theory that one of the Jeeps brake calipers STUCK in the ON position for a short while?

You could call M & G and get an opinion of what "could" have happened or, a simple move would be to simply remove the unit and see if either of the adjustment sections are loose. And, while it's off, you can actually move the diaphragm and test it's action(s) to see just how free it moves. It's a very simple mechanism so, some simple tests will reveal if, and or what, if anything is wrong with it.
Scott

[Bigd9]

When the M&G applies the brakes it does so exactly like you stepping on the Jeep brake pedal. So having the "left front" hot and the others not so hot kind of points me to a problem with the Jeep system.

However a call to M&G should give you some answers. And please share with the rest of us what they say, and what you find is the problem.

[dpinvidic]

The OP should reconnect the air line and try it again in the parking lot.
Since front brakes do most of the stopping, if the M & G applied a little brake pressure, the fronts may get hotter than the rears.
Not sure if the OP checked both front brakes for temperature.

Something may have pulled the emergency break away switch as another poster suggested.

Regardless, he should confirm if it is a hard problem, or intermittent.

Regards,

Dan

[wa8yxm]

Now that you folks mentioned it.. That happened to me on a different type of vehicle, only it was the right front,, Brake line (hose part) turned into a check valve so when I applied the brakes it bound, but did not release (Slang for brakes: Binders, which is exactly how they work). What happened after that was expensive (new brake cylinder, hose, pads, rotor, tire) OUCH.

[palehorse89]

Our 2011 Sahara has been towed 20k miles with a M & G System, not one problem. Maybe a caliper is sticking.........
What year is the JK in question?

[walt2137]

Originally Posted by wa8yxm

Now that you folks mentioned it.. That happened to me on a different type of vehicle, only it was the right front,, Brake line (hose part) turned into a check valve so when I applied the brakes it bound, but did not release (Slang for brakes: Binders, which is exactly how they work). What happened after that was expensive (new brake cylinder, hose, pads, rotor, tire) OUCH.

I would agree and I have also had this to problem on a vehicle, I can't see any other reason for only one wheel brake to lock up, i would change the brake line to that caliper.

[heybc]

All the brakes were hot. It was just that the left front was smoking. After they cooled off, I drove the jeep for fifty miles with normal braking and no excessive heat. I will call M&G and see what they say. Currently traveling until the middle of next month, so cannot do any trouble shooting until I return home. Florida is pretty flat and will just allow for more stopping distance rather than chance a repea. Had the brakes checked at a reputable shop and they found no problems.

[heybc]

Did not think about the breakaway activating as the pin was still intact. I will check that out when I have a chance.