Brakes locking up?

[dewyg]

When I back up my back tires on my dual axe trailer are locking up. The trailer lights all work. Any suggestions?

[FisHn2DMax]

If you have disc brakes, this is normal if the back-up lock-out selenoid wiring is not working. If you have drum brakes, they too will engage when backing up and pressure is applied to the surge mechanism, however, the way the drum brake is designed going in reverse, they usually do not lock-up the wheels.

I suspect you have disc brakes and the back-up selenoid is not working or wired / not hooked up. There is a selenoid that prevents the surge brake from actuating the brakes when the back-up light is on. Verify the 5 wire plug is hooked up right to the tow vehicle. I've seen this happen with my brothers boat trailer ( disc brakes) when he bought a 5 wire to 4 inline converter. All was well until he tried to back up. On his trailer, we found a manual lever / switch that allowed the trailer to back-up. He changed his tow vehicle plug to the proper one and no more problems when backing up.

If you have drum brakes, they may not be adjusted correctly which may also cause this condition. Many of the smaller tandem boat trailers do not have brakes on all four wheels, just the rears.

[dewyg]

I have disc brakes/ How do I fix the solenoid? I have a flat five, and all my lights etc.. are working.

[perchjerker]

make sure your reverse lights on your vehicle are working properly for starters

[FisHn2DMax]

Make sure your back-up lights are working on the tow vehicle. If the back-up lights are working ,check the 5 wire plug to the trailer. The back-up selenoid is up near the surge brake acutator and in-line with the brake line going to the rear brakes on the trailer (usually mounted on the tongue of the trailer).

With vehicle engine turn off, key on, and in reverse ( back-up lights on), check with a voltage meter or test probe to verify the selenoid is getting 12 Volts ( single wire going to selenoid). If it is, and your brakes are still locking up, its either the selenoid has gone bad or there is too much residual pressure in the brake line. This can happen if your trying to back the boat up a steep incline. Here is a link to more information on how to solve this: http://www.championtrailers.com/Solenoid%20Valves.pdf

I would start with the easy stuff ( blown back-up fuse in the tow vehicle) and work back to the trailer brakes.

Good luck

[alanexpup]

Hi. I always check the electrical connector first from the trailer to thetruck. those pins can get dirty and not make a good connection.:cheers:

[Blackmacs]

Dewyg, what kind of a vehicle do you have? If it's a '97 to '03 Ford F150 you need to add a relay to the fuse block.

[dewyg]

I have a 2005 dodge 1500 4x4. I'm currently locking out the brakes manually with a pin. Has anyone heard of a flat five tester that you plug in to the harness to test the system? I can find a flat 4 tester but not the five.

[Hot Runr Guy]

If you don't own one already, every boater should have a simple, digital multimeter like this: http://www.radioshack.com/product/index.jsp?productId=2103174&cp=2032058.2032235.2032305&pg=1&allCount=10&fbn=Price%2F%2410.00+-+%2449.99&searchSort=TRUE&fbc=1&y=6&retainProdsInSession=1&fr=StorePrice%2FRSK%2F00001000%2F00004999&x=22&s=A-StorePrice-RSK&parentPage=family

for $20, at Radio Shack, Home Depot, Lowes, Farm & Fleet. Personally, I like alligator clips rather than probes, but set the meter to read DC volts, the black test lead goes to the white ground pin, the red test lead goes to the 5th (blue) pin on the flat-5 connector. You should read at least 12volts when the back-up lights are on, which is usually what triggers the brake-lockout solenoid on the trailer.
HRG

[dewyg]

I was looking at buying one of these http://www.myboatsgear.com/mbg/product.asp?prodID=989

[Hot Runr Guy]

I was looking at buying one of these http://www.myboatsgear.com/mbg/product.asp?prodID=989
That'll certainly do the job. But you'll get a lot more use out of a multimeter, checking batteries, fuses, AC outlets, etc. Remember, any day that you acquire tools is a good day!
HRG