Violentl vibration

[okiejoe]

I was leaving Branson Friday morning and as I left the campsite got on the highway and came to one of the down grades in the Missouri hills around Branson and stepped on brake as I decended down the grade and felt this violent vibration and immediately took foot off brake and it stopped, reapplied braked and again it happened. It did this on about 3 grades then I pulled over checked everything and saw nothing. Now I know the brakes need adjustment and my gain was up to 8.5 because of them being so in need of adjustment but just hadn't had time to get that done and this was just a short trip from home. Now I'm getting them checked out next week and in fact going to just have the axles serviced but going to have the Tech check it out real close but what do you all think happened. Now it wasn't the truck but the shaking was so bad it radiated into the truck. Give me your thoughts. Never had this happen before.

[allen8106]

Same thing happened to me in the Arizona mountains. I had forgot to turn on my exhaust break. Once I did that the vibration/shudder went away.

[lee_worsdell]

Same thing happened to me last week coming home from Bristol.But this was my truck it shook so bad steering wheel went 6 inchs side to side. Shop thinks it could have been abs malfunction of some sort. Only did it once.

[rickeoni]

ETCrockett wrote:
Ok, I have to ask a newbie question. What is exhaust brake? Is that the same as Tow Haul mode for the transmission?

Most modern trucks have VVT (variable vane turbos) so the close the turbo vanes up for retarding horse power. Trucks of your vintage do not have a separate control for this, it works in combination with transmission braking when the tow haul switch is activated.

Very few pickups use an actual Jake Brake.

[okiejoe]

Not the truck, it stops nice and smooth, I'm going to service axles and adjust brakes and inspect wiring and magnets etc. but again not rotors on trailer, drum brakes

[GoPackGo]

If you felt the vibration through the steering wheel, I'll bet it's one of the truck's front rotors.

[richardcoxid]

A number of years ago I had a cyclic brake problem, whenever I applied the brakes they cycled "on" and "off". Took it to a shop in Tucson and had it fixed!

One of the brake wires inside one of the drums had been rubbing on thr brake magnet arm had its insulation rubbed off. On brake application current flowed and the brakes worked, as the brake magnet arm moved it contacted the insulated spot and shorted the magnet effectively denergized it. As soon as the magnet deactivating it and removing the "short" it reapplied the brakes etc.

They rewired the magnet and placed the wires in a way that it would not rub the insulation off.

[jay5er]

I would be willing to bet you have warped front brake rotors but they may need to be replaced. Depending on the miles on your tow vehicle, they may be turnable but may need to be replaced....

[okiejoe]

Vette Racer, now that you mention it that morning was very humid and a fog in the air and in fact all week in Branson was wet and humid to the point of a foggy haze of humidity in the mountains there. That's a very good point, moisture cupola have been the problem. I'm taking it in next week for a complete axle service and brake adjustment so I'll make sure they give it a real good look at everything including wiring and grounds. I WII GIVE A FOLLOW UP.

[Vette_Racer]

I bet it was moisture in the drums causing a chattering of the brake shoes, did it go away after a few uses or continue until you got home, that would tell you for sure. If it went away it was moisture, if it continued then its something in one of the drums more than likely unless it really is a bad controller.

[Pauljdav]

Warped drum. Since it is only when hooked to the trailer try activating the brake controller. If that causes the vibration it is a warped trailer drum.


I recently had warped a drum on the truck. It shook violently. It was a recent full brake job the shop over adjusted the rear drum.

[tinstartrvlr]

My first thought was that if you were braking hard maybe the antilock brake system on the truck kicked in; it creates a shuddering, but you said it was the trailer. x2 what MEMTB said.

[memtb]

Just to be certain....go down a grade and apply trailer brakes only! This will isolate the unit causing problem, then address!

[oldbird1965]

After you hear this noise try stopping and shoot the hubs-wheels with a inferred heat reading sensor. The highest reading will probably be your trouble spot.

[Dave_H_M]

That one should be easy to find when the drums on the trailer are pulled (assuming you have drum brakes).

BTW, i usually have my gain set around the 8 setting on my 10K trailer. since it has always been that it doesn't indicate much to me.

BTW, I would appreciate a follow up.

Good info post here.