Hello...

I have a Primus brake controller installed in my F250 and I tow a Cherolee Tomahawk 4H. The problem that I have is that the "let down" is very severe...i.e. the brakes work fine when applied, but when you release them they suddenly let go, causing the trailer to jerk. This is especially bad when driving in town (very jerky on stop starts) and when on long decents when you are on and off the brakes quite a lot. I have to constantly adjust the controller while driving.

I follewed the set up instructions to the T...I have also adjusted the trailer brakes....

This is really irritating and uncomfortable.... an of you know how I can fix this problem....

Cheers for now

Alot of the time adjusting the "Sensor positioning Arm" will take care of the jerky stops/starts.

http://www.tekonsha.com/primusintro.html

http://www.tekonsha.com/instructions/Primus8.5x116909Rev.A-FINAL.pdf

Hey Retento

I have adjusted and adjusted and adjusted but nothing helps.

It is not jerky when you apply brakes, it is only when you release the brakes that it lets go so suddenly...it is like there is no ease off....if you know what I mean...

It is seriously uncomfortable.

That big old clunk when you let off the pedal, it snaps like a steel trap!!.... You know, that just may be an ALKO thing... My Cherokee tends to do that and according to what paperwork I recieved with the trailer, it has 8000# ALKO axles....Not, 8000# Dexter the axles as I was lead to believe it to have. May just be the nature of the beast..

Now you got me wondering...

http://www.al-kousa.com/

http://www.al-kousa.com/prod_rubsus.htm

http://www.al-kousa.com/prod_bhd.htm

Retento

It doesnt make a noise at all - it just lets go so suddenly. Kind of the same feeling you get when you come to a stop street and you keep the same pressure on the pedal till you have stoped, without easing off....it kind of kicks you back in your seat...

It is not nice

I have done the adjustment on the actual brake shoes (they are manually adjusted) ....I do understand that when you cut the power to the magnets it will let go.....but I just feel that the reaction is so sudden...I cannot believe that it is normal. In my mind the controller should ease off the voltage - not simply cut it.... Hey I might be wrong - and mayby you guys are used to it... but in my mind it is actually not safe for the horses....

Do all magnetic brakes let go like this --- or do I have a problem...it is so difficult for me to say, cos I do not have anything to compare it to - other than my old trailer which was smooth...

Surely the electrical bofins have enough savvy to design a controler to ease off....

Now I am actually lost....but still believe that it is not right...

You are correct, what you describe is not proper function of the electric brakes.  The Primus is a proportional brake controller and should not "snap" off the brakes.

What is the volt reading on your Primus when the truck is at a complete stop and your foot on the brake pedal? 

What is the power limit you have set with the adjustment dial?

The problem you are describing sounds similar to problems some truck/trailer combos have with the Prodigy and its Boost settings.  This type of problem is more easily remedied on the Prodigy due to its Boost feature.  I.E. one may choose to use Boost 2 on the highway for more powerful braking, but may select Boost 1 in town to make the stops "smoother".

Chadsalt

I will hook up my trailer today and see what the settings are....although I have tried so many different ones....I will let you know as soon as I have hooked it up.

Thanks for your input