View Full Version : Trailer brakes

11-02-2009, 01:01 PM
I have a 19 ft searay that i take to the lake on a shorelander trailer with drum surge brakes . The brakes work fine with the boat on the trailer . When the trailer is empty and i try to backup the trailer brakes lockup i can pull forward and they release but when i try to back up they lock again .

11-02-2009, 01:08 PM
t bachtel
There should be a lock out on the surge control on the trailer that allows you to lock out the piston from engaging when backing up. Maybe too much weight on the trailer with the boat there for the wheels to lock.

11-02-2009, 08:31 PM
"If your trailer wire hook up is 5 or more wire, then it is as Bert says."

11-02-2009, 08:43 PM
"If your trailer is old (er) it may be the hydraulic actuator, It may not be releasing all the way and the brake pads are not returning to there "home" position so when you back up they are making more contact than normal.
I had the same problem, boat on trailer all was fine, no boat and one wheel would lock up. Actuator was bad.

Also have you adjusted them lately?"

11-03-2009, 08:46 AM
"Thanks for the help, the trailer is a 2001 and has the flat 4 pin connector. I did clean and adjust the brakes back in the spring they worked ok all summer and the last 3 times i was out i had the problem .It sounds like the hydraulic actuator maybe the direction i need to go .Kghost where did you get your parts ?"

11-03-2009, 10:09 AM
"look at your manual, if you don't have one you can usually go on line to your trailer mfg. and get one,(download)
would check adjustment,pad contamination,( grease seal leaking and grease every where?)should also tell you how to check actuator and part number for it. my drum brake trailers always had to put the reversal lock out pin in them to go backwards with out boat on?"

11-03-2009, 11:39 AM
I purchased mine from a local marine business.

Look at the one on your trailer actuator.
The manufacturer and part number should be STAMPED into it. Do a google search for that part number.

11-03-2009, 12:17 PM
"t bachtel
Do a Google search on Hydraulic Surge Brakes and you'll find loads of information on this subject. If you think about it for a minute, when you apply your vehicle brakes the trailer wants to keep coming at you. The surge brake detects this movement and applies rearward pressure to the piston which pressurizes the hydraulic system which expands the brake shoes. When reversing the same thing is happening, rearward pressure is being applied to the piston. Thus the lock out lever on surge brakes. In fact one can buy an electric lockout valve that shuts off the hydraulic pressure being sent to the wheel cylinders with a flip of the switch on the dash. On my boat trailer I just inserted a ball valve in the line for when I backed up.

11-03-2009, 02:27 PM

Some, mine included do not have a mechanical or electrical lock out at or near the actuator.

The forward brake pad in the drums has a special design that allows the pad to cam over and "tuck in" when the drum turns backwards so as not to apply pressure on the leading or forward shoe when backing up.

If he has that type of drum brake system (it is easy to tell as the forward brake shoe pivots near the center.

One more thing here.....you say you adjusted them?

How did you do this?

Boat trailers do not always adjust like auto drum brakes.

My original said to adjust to drag and back off TEN clicks. My new actuator says 2-4 clicks.

Maybe you should try loosening them a bit say 3-4 clicks first before spending any money........."

11-03-2009, 03:53 PM
Sounds like we're talking apples and oranges here. The brakes I had were normal drum type.

11-04-2009, 08:22 AM
When i boat the boat the brakes didnt work . I found a leak at the brake cylinder and repaired it added new brake fluid and bled the system . The brakes still did not seem to be working so i pulled the drums and found alot of grease the shoes still had plenty of pad i cleaned everthing up and turned the adjustment wheel for shoes about 1/4 of a turn . When i installed the drums there did not seem to be any drag on them but the brakes are working . Do these style of brakes self adjust like automotive style /

11-04-2009, 09:45 AM
"not usually, and the sign of excessive grease tells me the grease seal is leaking,may need to check the bearings also. down load a manual and it should tell you maint. procedures. all the brakes I have adjusted were 10 clicks,KGhost has a set that says 2-4 clicks, so the brakes are specific.mine are from tiedown engineering and says it right on the coupler.

http://www.sschapterpsa.com/ramblings/Boat%20Trailer_brakes.htm ("")"

11-04-2009, 02:39 PM
"I would go with Kghost on this one. I just rebuilt my brakes on a similar sized boat trailer for $300 (new actuator, drums with pads, and lines). No lock out as drums are able to reverse with out maximum braking unless they were installed backwards. The bigger shoe should always point forward. Discs usually have a lock out. If your brakes are 8 years old it's probably time for a new actuator. trailerpartsdepot.com is agood one. Ebay is good too for new parts."

11-05-2009, 09:53 AM
"Thanks for everyones help , i pulled the drums again and the brakes are the type Kghost described .All was clean i think the grease i cleaned in the spring was fromm the previuos owner getting a liitle to happy with grease gun on the bearing buddys. Im looking at trailer depot for parts"

11-05-2009, 02:28 PM
"Here is a very rough drawing with some more explanation. Hope this helps.......


11-05-2009, 05:12 PM
"Glad to here all is going well.I'm in PA and require yearly trailer safety inspections, nothing like failing one for bad brakes."