How much is a trailer supposed to (if at all) knock against the hitch ball when the brake actuator extends when accelerating after having made a complete stop, like at a red light? <BR> <BR>Our old 96 trailer did it some, but we just assumed that the shock absorber was worn (I think the actuators have one?). The new one on our X2 trailer does it quite a bit. Is this normal? Stopping is smooth. <BR> <BR>Thanks. <BR>

Make sure it is full of brake fluid so it has something to compress smoothly...

Make sure it is not the receiver in your truck that is moving, often there is some play where the pin slides through &amp; that will cause the same thing. I have never towed anything that hasn't made some noise from the ball area, probably not a big deal. Just check to be safe.

Pretty sure it is not the receiver pin. There is some play in there, but not much. The knocking is quite substantial. It's more than a noise, and it jerks the whole truck... <BR> <BR>Brad, wouldn't it also knock when stopping if brake fluid is too low?

My Dhm trailer also does the same thing when starting up after stopping. I called Dhm and they said this was normal for there trailers. I got one of those ball mounts that have the rubber in them and the clunk is almost gone. These hitch ball mounts that fit in the reciever on your truck are made for trailers with surge brakes they also help save your ujoint on the drive shaft, they cost about 40 bucks.

I have had a couple of trailers with surge brakes, the last two seem to have been the worst with that noise. I am 99% sure it is normal. The sound/feeling you are experiencing is when you stop completely the boat compresses the surge brakes (you can actually put the truck in park and go look to see if they are compressed) and when you take off the brakes are on on the trailer so the truck takes off before the the trailer and after only about a few inches or less of travel the trailer has to start moving since the truck is pulling it... basically the truck is taking the slack out, or uncompressing the surge brakes. The faster you take off the worse it is. I have gotten pretty good at a real slow start and then nailing it after the thump. I don't think it hurts anything either way, just sounds/feels funny. I don't think it has much to do with brake fluid either, mine is full and still does it. You can also check to make sure the brakes are working well by trying to back up after you come to a complete stop like that. (make sure you don't have the electronic release) and just try and back up... you shouldn't be able to.

Unless you have the drum brakes. Backing up I mean.

Mine did thesame thing. I had air in my brake lines. Once I got all the air out the slamming went away. Just becasue it's new doesn't mean that all the air is outof the lines.

I was having the same problem on my DHM trailer. I found out that the master cylinder on the Attwood actuator had gone out and needed to be replaced. I was able to replace it myself and once the brake lines were bled, I no longer heard the clunk when starting off. My suggestion would be to bleed the brake line again as it sounds like there might be air still in the lines.

Some sound is normal (which is reflective of what DHM told Tom). But a loud "clunk" is not normal and indicates a problem with your system. On a trailer I previously owned, the problem was a worn-out master cylinder. But it can also be air in the lines or poorly-adjusted brakes (both of which will cause the actuator to move too much/too rapidly and "clunk"). <BR> <BR>In any event, if it is loud, I would not ignore it. <BR> <BR> <BR> <BR>(Message edited by jrichard on April 14, 2003)

You may also want to check the size of the ball on your hitch. Make sure you have the right size ball or if you can, tighten the trailer toung to fit tighter on your current ball. I had this problem with my old boat and found out I was using too small of a ball.

I had the same problem on my '95 CC trailer, the knock and jerk were horrible. I could never keep air out of the lines. Turns out the master cylinder was shot and I assume that the dampner was also. I replaced the stock DICO actuater assembly with a Tie-Down Engineering Assembly. It's shock absorber is incorporated into the master-cyclinder. It works great! No knock or jerk at all. And it has a reverse lock out.

My MC trailer has done it since day one (2002) and the dealer trailered it and said it was normal even though it seemed a bit excessive to me. Fluid levels were normal, but they didn't mention the possibility of air in the lines or the master cylinder failing. <BR>How do I know if either one of these is the case?? It is very annoying and seems quite excessive and unnecessary!

We had a pretty good clunk on our Ramlin trailer for the boat before this one. I found that the bolts/nuts that hold the braking unit to the actual trailer were loose. Luckily they were lock nuts so they didn't fall off, but once I tightened them up the clunk was gone. <BR> <BR>We don't have the clunk with our current trailer (Prestige).

David, I have an '02 MC tandem and it does not make any clunking sounds (or, if it does, it is minor and not noticeable). I'd like a dollar for every time a dealer told me, "Oh, that's normal..."! <BR> <BR>You could bleed the lines to make sure you don't have air in them. But, if your master cylinder is bad, you will likely soon have more air pumped into the fluid. I don't know a good way to test the master cylinder as I've always had a trailer-specialty shop look at mine if I've suspected that it's a problem. <BR> <BR>One other option is to have your dealer let you "test pull" another MC trailer (with boat) from his lot so that you can compare the level of "clunk." If your "clunking" is louder, it might push your dealer to investigate further.

Picked up the boat from being de-winterized last night. I had them check the brakes because I was getting the “clunk” sound last season. They added brake fluid and bled the system. No clunks on the way home from the launch. I also noticed I have to put in the locking pit to back up the small hill into the drive way to the shop. I guess that means my brakes are working better. I could also feel a difference when driving… the trailer brakes were responding faster so if was stopping at a light I would not feel a push from the trailer.

i am getting the clunk sound too. what about "pulsating" when slowing down. about half of the time, sometimes worse than other times, my whole car and trailer pulsate. thats the best word i know how to describe it. my dealer said they checked out the trailer and everything was fine.

Thanks a bunch for all the input. With the better understanding based on all your info, I called the actuator manufacturer. <BR> <BR>They said that there should be little to no knocking and that if it was stopping smoothly, but knocking when accelerating, it may be a bad cylinder. <BR> <BR>Their guess was that it was not just air in the lines since it was stopping smooothly. But it sounds like to me that checking this is a good place to start looking. If that doesn't help, I suppose we'll have to take a trip to the dealer... <BR> <BR>If we get rid of the problem, I would be happy to post a follow up in case anyone with the same issue would be interested. <BR> <BR>/Fredrik <BR>