Surge brake "Clunk" when starting off. Normal?

[Todd157k]

ya, I know... "another" Surge brake thread. Not really. I searched several of them and no one has brought up the thing I'm looking for. This is my first trailer with surge brakes. They work fine and do a pretty good job of slowing me down, specially when I hit the brakes hard. They don't stick, it's just the master cylinder traveling back to it's "pull" position. It's a free travel and then CLUNK.. and I'm pulling again. I try to take off as easily as possible but it still doesn't seem like it should do that.
The question is... is the trailer supposed to "clunk" back into position when I start from a stop? There doesn't seem to be any 'cushion' when starting off. Is that correct?

 

[Maclin]

Re: Surge brake "Clunk" when starting off. Normal?

I think it is "mostly" normal depending on the brand of the surge unit, unless it is really violent. Sometimes adjusting the brakes will minimize that free travel distance. Your adjusted takeoff technique should minimize any potential damage to hitching components.

 

[Philster]

Re: Surge brake "Clunk" when starting off. Normal?

My older trailers did it very distinctly. Clunk.

My new disk brake trailer: You can feel it just a little bit. It's there, just not as strongly or abruptly as the older drum brake trailers I had. Also, the bigger loads really did it more abruptly -clunk- and were more noticeable for sure.

It made me think, "Good, the brakes were grabbing on that stop."

 

[R Socey]

Re: Surge brake "Clunk" when starting off. Normal?

Mine did it, but not violently.

 

[Thalasso]

Re: Surge brake "Clunk" when starting off. Normal?

First of all. Is it drum brakes? If so the clunking is a good indicator of poorly adjusted brakes unless you have a bad master cyl. As you adjust the brakes spin them in a forward rotation. Drum brake are free backing so if you spin them in reverse you won't get them adjusted. What is happening is the master cyl. is bottoming out on the stops and when you go forward you take up the slack and get the bang.When they are adjusted right the unit can't bottom out.

 

[UncleWillie]

Re: Surge brake "Clunk" when starting off. Normal?

To see what is really going on.
Have someone you trust pull the loaded trailer forward up to about 10 mph on a quiet side street.
Wait at a predetermined spot and have them come to a moderate/aggressive stop and hold the tow vehicles brakes until you can get a look at the surge coupler.
It should not slide back past halfway in the slot.
Some couplers have a spring and mini-shock absorber built in to softly reset the coupler after a stop.
Be ready to observe the coupler immediately as/after the trailer stops.

Mine used to clunk until I found out the Master cylinder was almost empty.
Bleeding the brakes quieted them right up.

 

[foodfisher]

Re: Surge brake "Clunk" when starting off. Normal?

Is it the brakes? How about a ball to small for the receiver. 1 7/8" ball will clunk in a 2" receiver.

 

[Thalasso]

Re: Surge brake "Clunk" when starting off. Normal?

Is it the brakes? How about a ball to small for the receiver. 1 7/8" ball will clunk in a 2" receiver.

It also will come off.

 

[QC]

Re: Surge brake "Clunk" when starting off. Normal?

I have had drum and disc surge brakes. Sounds absolutely perfectly normal to me. Both had this style coupler:

One way to minimize the clunk is to "two foot" your take offs. Left foot on your brakes for just a second or two as you apply throttle.

Edit: and I have also found, depending on the grade I am stopped on (flat). That simply taking my foot off the brakes for a second or two before I hit the throttle will take up the slack. This method is not 100% depending on how hard I, the grade, etc.