Violent Bucking

[rjttam]

I'm wondering if anyone else has experienced the following problem: I'm running with three axles, using elec/hydraulic brakes, and a prodigy brake controller. With brake controller set to a point just before lockup, my truck and probably the 5th wheel, as well, starts bucking violently when I apply the brakes moderately. This only happens occasionally, but when it does, it's scary as all hell. While driving down the WA/OR coast, it happened about 4 or 5 times. Has anyone experienced this problem, and if so, what did you do to correct it? Thanks, rjttam

[RustyJC]

What hitch are you using?

Rusty

[rjttam]

RUSTY, I'm using a TrailerSaver, which is close to being one of the best hitches on the market. Don't think the hitch is the problem, since I used it with my previous 36' MS. It also had hydraulic brakes. Guess I'll just have to keep trying until I find a solution. Thanks for your interest. rjttam

[wannabe]

Does it feel like you have had a blow-out on your truck? If that is how it feels, then make sure you keep your speed under 65 mph. This same thing has happened to us if we hit a pothole or a bridge ridge that is too high then the truck starts bouncing violently like we had a blow-out, or like you've just driven over a ton of small speed bumps put together. We don't brake but slow down and then it smooths out. I have pulled over several times to check for a flat tire.
Someone told me this is the ABS brakes...but we haven't found out the answer yet. We have a Cummins 1-ton dually.

[Hobo]

I'm wondering if anyone else has experienced the following problem: I'm running with three axles, using elec/hydraulic brakes, and a prodigy brake controller. With brake controller set to a point just before lockup, my truck and probably the 5th wheel, as well, starts bucking violently when I apply the brakes moderately. This only happens occasionally, but when it does, it's scary as all hell. While driving down the WA/OR coast, it happened about 4 or 5 times. Has anyone experienced this problem, and if so, what did you do to correct it? Thanks, rjttam

You may want to check and see if your Prodigy controller is compatible with the hydraulic backing system. For one the early CARLISLE HYDRASTAR brake system was not compatible with out a added module.

The problem would cause the hydraulic system to pulsate and over heat.
Do you get any error reading on the Prodigy when it is happening?

[rjttam]

Thanks Wannabe, it sounds like the same or very similar problem. However, speed or bumps don't create my violent bucking, it's only when I apply moderate braking pressure. I have had input from other forums that give me a strong indication that my brake control has probably developed a problem and needs replacing. I will start with that change first, since the one I have now is 4 years old and probably needs to be replaced with a more up-to-date unit. Thanks again for you interest and information. RJM

[rverdlm]

The Prodigy is not recommended for electric over hydraulic disc brakes. The reason is that it is looking for feedback from the brakes based on what would come from regular electric trailer brakes. I have a Prodagy that was purchased at about the same time as the trailer. At that time the hydrologic unit was built to give feed back that was appropriate. An engineer at the company that makes Prodigy told me that if it works OK then good, but it probably wouldn't work with another setup. He also said that the feed back is not needed with electric over hydraulic brakes. They make a controller that is just like the Prodigy that does not have the feed back system. The feed back system is trying to look at the voltage/amperage of 6 brakes and automatically adjust the current flow. I think this is what is causing the bucking.

[bstark]

RJM: JMHO, but I wouldn't throw money at a controller just yet! The Prodigy has the ability to troubleshoot for you and if it isn't showing any fault codes during braking events but rather simply shows the voltage going to your brakes, then it probably is not a controller issue but more than likely a brake hardware issue.

When you say your controller is set just before brake lock-up, that could mean you are set a little too high initial voltage.

I have mine set for boost #2 with about 4 -6 volts max initial feed with stationary trailer and a firm foot application and I only have 2 axles. You may be experiencing all of your axles coming close to lock-up bacause you're just feeding way too much voltage. That can get expensive if you start flat-spotting your tires as they will shake the h--l out of your trailer.

During one of those bucking events, it would be really convenient/helpful if you could eyeball your controller readout to see what's going on vis-a-vis voltage delivery.

[bstark]

Whoops; I posted while Dave was responding to your post and I should attempt to address the points he's raised.

There was a period of early developement of the hydraulic brake units with on-board pumps, there were problems with inertial based controllers. That has, since about mid- 05, not been an issue, at least as far as the Dexter hydraulic braking systems are concerned.

I had a Prodigy controller with our other trailer (02) and contacted Dexter prior to taking delivery of our 05 M/S trailer to enquire as to compatiblity and received assurances from their engineering group that they had addressed that problem and that their current hydraulic pumps were completely compatible with inertia based controllers. In any event a visit with their, or your particular sytems, website should yield a controller compatibility table for verification. I would think it highly unlikely that an 07 Teton would have a braking system that was not compatible with one of the more popular premier controllers out there.

Good luck.

[billr]

I agree with both Dave and Bruce's suggetions to look at the controller and also the setup on the Prodigy.

We have an early 05 unit that has a Dexter brake unit that is not compatible with the Prodigy or even the Ford in dash. We went with the Jordon Research unit that is a direct connect to the brake pedal and works perfectly. I wanted to stick with the Prodigy but couldn't do it.

Like Bruce said, the setting for these hyd brakes needs to be lower initially or they grab severely. I found I had to leave quite a bit of initial slack in the cable and dial back the gain to get a nice even application and not give us whiplash! These brakes work great!

Good luck with the setup!

Cheers,
Bill

[rverdlm]

Going back to what I said about the engineering dept from Prodigy. They said that both the controlers and the brake pumps are constantly being upgraded/improved and that any controller that has a feedback loop is a potential problem. I do agree that these brake don't need to be setup for near lockup. That is no doubt to much brake, especially with 6 of them. One thing I would try is to manually apply the trailer brakes and see if they respond smoothly. That would tend to eliminate the brakes themselves. With six disc brakes they should be able to smoothly stop the whole shebang!

[Burgener_chris]

I would double check that the controller is equipt to handle tri-axle set ups

[Burgener_chris]

hmmmm