Does your trailer 'clunk ... ?

C

Casey

New member
Ok, I know this may be a silly question, but: Does your trailer 'clunk when you start-up from a stop?

We have a dual axle trailer with surge activated disk brakes. It tows fine (and we've done a LOT of towing). But whenever we come to a stop, when we restart, there is a momentary 'clunk (excuse the overly technical description), Every time.

I'm pretty sure it's only the surge actuator on the coupler shifting to its "drive" position, but I'm not sure. Should I try adjusting the mechanism? (Aside from the 'clunk, the trailer is working fine*, so I'm not inclined to mess-with-it.)

Best,
Clunky&Mary
PS: Now that the boat is in temporary storage we actually miss the clunking while driving the truck!
*Now that I think about it, at towing speeds over 90mph there does seem to be a slight reduction in gas mileage. Should I get the tires rebalanced? **
** RELAX ... I was only kidding about towing over 90mph. (no reduction in gas mileage) :-)
 
Yes they can clunk and everyone I have had does from time to time. They work like this: As you stop your truck, the trailer brakes are applied by using the weight of the trailer/boat to move the actuator - it is like a brake pedal. The faster you stop your truck, the harder your trailer ball pushed on the actuator mechanism. The actuator mechanism does have a small spring that returns it to the normal position, but now there is some wiggle room forward and aft because the actuator had to move to apply the brakes. When you take off from the stop, the trailer ball moves back to it's old position when you were towing and you hear that clunk in the begining. Keeping everything lubed up helps a lot with this and I suspect it would probably go away, or at least nearly completely go away if you greased your ball. If your ball it all beat up, it wouldn't hurt to get a new one. While you are at it, it wouldn't hurt to check how smoothly your actuator is working too and grease it as needed.
 
My surge brake trailer has been clunking away for 15 years and almost 70,000 miles. Seems to do so more when the actuator needs a bit of cleanup and lube. I try to keep the actuator sliding back and forth easily with lots of that sort of TLC. If it's particularly gummed up with road grit etc the trailer brakes don't start working as easily, sometimes needing more agressive braking from the truck to engage them. The brakes don't release as easily when I start after a stop either, resulting in a louder clunk.
 
Surge brakes will give a little clunk normally...but if it is excessive it can mean the brakes need to be bled. There should be a small amount of travel in the actuater...but if the travel is approaching 100% it will really clunk...and the remedy is to bleed the brakes.
 
Chris":2n9t0pll said:
Surge brakes will give a little clunk normally...but if it is excessive it can mean the brakes need to be bled. There should be a small amount of travel in the actuater...but if the travel is approaching 100% it will really clunk...and the remedy is to bleed the brakes.
Click to expand...

Good point....that is if there is even any fluid in it at all! Hey, it is happened to me - had a leak....and a clunk.....and fortunatley was towing with an F-350 CC 4x4 dually at the time and those have huge brakes. I didn't even notice the boat had no brakes until I checked the fluid at the end of the season.
 
I have observed the slightest clunk even pulling trailers without surge brakes. It does not matter which truck I am pulling with or which trailer I am pulling. Sure it is more pronounced on some but there on all. The draw bar is fairly tight but can be felt to have a little play. My assumption has always been that the draw bar rocks or moves slightly as the load is applied. Maybe you are hearing something louder tan I am but it is always there.
 
Yes they can clunk and make other noises from the brake system but check your trailer out. Mine was making a noise on starts and stops that turned out to be that I had two loose bolts holding the coupler on the main frame. Could have been a helluva mess had I not caught them.
 
Some of the clunking can come from the receiver at the draw bar. You can get receivers with dampers built in. I did this and it got rid of most of the clunking on my setup. Before this there would be clunking when starting and when going over bumps in the road.
 
ssobol":b9oq19hw said:
You can get receivers with dampers built in. I did this and it got rid of most of the clunking on my setup.
Click to expand...

Another option is locking down the drawbar. There are two types I've used. Both have eliminated the clunk I've encountered on every receiver hitch setup I've owned.

The J-pin type requires a receiver with a smaller set of holes next to the hitch pin holes. The j-pin hooks into the smaller hole on one side, and is tightened down on the other with the included wrench. Couldn't find a pic of a hitch with this setup, but I believe all the Draw-Tite models use them. Here's a hitch extension with the same config, along with a locking J-pin:

wTEsRxN.jpg

c7LLs3E.jpg


Quite frankly, I hate this setup. You have to use the spanner wrench it includes, as the nut you are tightening is too far down the shaft for a deep socket. On most setups, you can't use a standard open end or crescent wrench due to space limitations - so misplace the spanner wrench and you're hosed. And invariably, these space limitations make using the included wrench a total PITA - something always seems to interfere in the tight confines of where the nut resides, requiring many small turns to get things cinched up. If you rarely remove your drawbar, it works fine - but getting it on/off is a pain in the butt.

The other method I have works just as well - don't have a picture, but it's easy to explain and can be retrofit onto any receiver. Simply drill a hole of adequate size for a large bolt on the receiver tube, and weld a nut to the outside of it. Install the bolt after the drawbar is installed and tighten down on it. This simpler method allow you to use a standard socket on the bolt, works just as well and allows you to get the drawbar on/off in seconds with standard tools.
 
Agree with all; part of a pre trip inspection for us, involves checking the brake fluid level in the coupler brake reservoir. A way to check the brakes is to back up with the lock out solenoid detached--again a good thing to do before starting a trip. If you have good brakes, then you will feel the resistance to rearward movement.

We also check the tire pressure, walk around the frame, check all fittings,springs, bunks, and put the motor in the trailering position--in the Caracal we have a "Transom saver"--the C Dory 22 a hard rubber block. We also make sure the motor is centered and that it is chocked to keep it from stressing the hydraulics as we do down the road.

The wheel bearings are greased before every major trip.

I just did all of the above, since we leave for the Keys in the AM.
 
I have surge brakes on the tandem trailer under my 22, with disc brakes on both axles. If I stop more "firmly" than usual (say a stale light changes and catches me), and then perhaps accelerate more quickly than usual, I can get a slight clunk from the coupler. However, under my usual driving conditions any clunk is either not there or nearly unnoticeable.

I can't remember for sure, but I think there was supposed to be something in my coupler to "dampen" the action. If so I guess it must be working. So it seems as if it is possible to have surge brakes with no major clunking.
 
Glad to know that I'm normal. I get the occasional clunking. It is quite loud from inside the truck. I will try some suggestions found here to reduce its occurrence.
 
On my Pacific Trailer, (tandem axle with Surge brakes) there is a bit of a clunk on startup after a stop. It is the actuator releasing and going into tow mode. There is a small fiber/rubber washer in there that helps to dampen that clunk. If it is missing, there will be much more clunk volume. I don't think greasing the ball will have much affect on the clunking one way or the other. I have kept mine greased, still have some clunk. If your hitch is set up right there should be very little play between the ball and the socket, (less than 1/16 inch.) If there is play there, things could get nasty and then you will get a chance to see how good your safety chains work. :shock: :twisted:

Harvey
SleepyC :moon
 
Plenty of "clanks" in our Caracal trailer, which does not have brakes. Just play in the coupling. So don't assume that any clunk has anything to do with the brakes.
 
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