Surge Brakes

[fitz73222]

Hey guys,

Just have some questions about surge brakes.

I went down to Punta Gorda and picked up my new (very slightly used) Boatmaster drive on trailer. After driving her back about 250 miles I noticed that the brake rotors didn't even have the rust residue removed from them. I did some hard braking on I4 coming back in Orlando traffic so I expected to see some brake lining activity on the rotor. She has Kodiak stainless calipers and what looks like iron rotors. I know the calipers are working because when I engaged the manual emergency brake lever the calipers will grab the rotors. So I was thinking that the trailer weight by itself isn't enough to compress the hydraulic actuator. The master cylinder is full of fluid. I also noticed that I can push the trailer backwards without being hooked up to the truck which I thought needed to be connected to the back up light circuit in order to activate the solenoid to override the master cylinder piston. So is this just a lack of weight issue?

Thanks,

Fitz

[Capt. Bob]

Fitz,

I can't answer with direct knowledge but it seems logical that the system would be fairly passive with little/no load, if for no other reason than to move the trailer around after production and during sale. Probably wrong but just a thought.

[MarshMarlowe196]

It is most likely a lack of weight on the t railer. From my own experience delivering large boats to Florida with a trailer with surge brakes, once the boat  wasn't  on  the trailer the braking effect all but disappeared

[fitz73222]

It is most likely a lack of weight on the t railer. From my own experience delivering large boats to Florida with a trailer with surge brakes, once the boat  wasn't  on  the trailer the braking effect all but disappeared

That makes sense to me also. I can imagine any braking effect on an empty trailer would be difficult to manage without wheel lock up.

[John Jones]

Yep.  All of the above. The solenoid would not come in to play because un-hitched nothing is pushing back on the actuator.

[BTF112989]

Everyone is correct!  I bought an owens & sons aluminum trailer, picked it up from Tampa, and drove it back to Tennessee with no boat on it.  After about 800 miles you could only see a very very slight bit of wear on the brand new rotors.  That was even going through Atlanta stop & go traffic.  As soon as I loaded my 22-2 onto the new trailer at home & drove it 5 miles through town with traffic lights, you could see the brake pads were fully contacting the rotors & the original finish was completely rubbed off.

You just have to put some weight on that thing!

-Ben

[wingtime]

Yup as already mentioned it's a weight thing.  The idea is the heavier the trailer and the faster you stop the harder the actuator pushes on the master cylinder applying the brakes.  If set up correctly you should have a maximum amount that the trailer tries to push on the tow vehicle.   If they are set too "sensitive" then when you stop, the surge brakes would apply hard, the trailer would pull on your tow vehicle, release, then apply again, and so on.  Not a good situation.  The back up solenoid comes into play when backing up a hill, in soft soil, etc etc.   I've pulled trailers with surge brakes without the solenoid and you could not back them up with out turning off a manual valve.

[John Jones]

and you could not back them up with out turning off a manual valve.

or wedging the actuator with a crescent wrench handle.  
I had that problem with a U-haul trying to move a piano for my daughter.  Had to back the trailer up a hill and the surge brakes were locking the wheels.