Question for those with tandem axles

[JasonB]

Earlier this year I tossed my old 3500lb single axle trailer(2400lb dry boat, more like 3200 loaded) with electric brakes for a tandem axle that I restored (camacity 6000lbs). Since it was a complete resto of the trailer, I replaced everything except the axles and frame (coupler, springs, all axle hardware, wheels, tires, equalizers, bushings, etc). I also tossed the original front axle surge brakes taht were too far gone to save, and installed electric drum brakes only on the front axle.<br /><br />The springs and associated hardware were adjusted for me by a very experienced trailer guy.<br /><br />I only towed the trailer <500 miles since, but have noticed that when the brakes apply and the weight shifts, I hear a noise that I suspect is some form of "axle wrap". I believe the weight shift is causing some dumping of weight on the front axle and causing the equalizer and springs to quickly shift and load in that direction. Anyone else experience this?

 

[sangerwaker]

Re: Question for those with tandem axles

I've got a tandem trailer, but my boat is WAY lighter. In fact, the tandem isn't really a necessity on my boat, more of a convenience. I like the tracking of a tandem. <br /><br />Anyways, I have never experienced what you are describing. Are the axles in the right place? There really should be very little "weight shifting" as you describe. How does the tongue weight compare to the total?

 

[JasonB]

Re: Question for those with tandem axles

Tongue weight is about 8% and the axles should be about right. Weight shifting probably isn't a great description. When I apply the brakes, there is a muffled pop, and another when I release. It's not a violent movement, and I don't think it is the brakes themselves. It also doesnt get worse/better at different speeds. It also doesn't seem to add any undue weight to the truck, it's just more of an odd sound. I'm guessing it is only the momentum/weight/??? change that is causing the springs to "pop" against the bolts/bushings and making them work a bit. If I ever add the brakes to the rear axle, I suspect it will go away. I do know that the suspension on this trailer is very "limber" and moves well without binding. Just stepping on the trailer you can see the equalizer bar do its thing.

 

[rwidman]

Re: Question for those with tandem axles

I've got torison axles so my trailer would not behave like yours. A suggestion would be for you to have someone else drive the rig and ride in another vehicle alongside your trailer (let someone else drive this vehicle also), and observe or better yet, video tape the axle under various conditions. Two way radios would be a big help here.

 

[Dunaruna]

Re: Question for those with tandem axles

Does it sound like a 'twang' noise?<br /><br />I had a problem with mine making a noise. It was the spring set carriage (where the spring shackles connect to the frame) flexing when cornering and stressing the frame - it would release the stress as a 'twang'. Extra bracing (and some cracks welded up) fixed the problem.<br /><br />Aldo

 

[dingbat]

Re: Question for those with tandem axles

I'd say you have something wrong in the equalizer system. I've got a 6K trailer with a 4500# boat and it’s certainly doesn’t exhibit these characteristics. I had some equalizer noise at one time but found that a few of the plastic bushings on the spring bolts where shot. I replaced the busing and have not had any since. <br />I’d question the limberness of your equalizer system. I can just about get my rear axle off the ground with a jack before it starts transferring weight to opposite axle. Steeping on the trailer wouldn’t even get the springs to squeak let alone effect the equalizer system.

 

[gspig]

Re: Question for those with tandem axles

If you are experiencing "axle wrap", your load on the trailer is too light. I'll describe axle wrap as: you apply brake, brake on front axle grabs, the axle twists, the twist pivots on the front spring mount forcing the the rear spring mount upwards, the tandem equilizer pulls forward and smacks the boat frame. You need to remove some slack in the spring movement, move the front most spring shackles forward and/or the rear most shackles rearward. Try lighter load springs. The bang may even be loose coupling on the trailer or if you have a removable hitch the hitch bar may be moving.

 

[islandboat]

Re: Question for those with tandem axles

That muffled "pop" may not be the brakes. Could it be slack in the coupler or receiver hitch? The brakes are installed on the front axle, right? Do you have an adjustable brake control unit in your vehicle? Perhaps you might try changing the trailer brake timing or apply force through the electric control unit.

 

[steelespike]

Re: Question for those with tandem axles

Have you tried taking it to a safe place and try some stops without the trailer brakes.

 

[JasonB]

Re: Question for those with tandem axles

Good idea steelspike. I'll give it a shot after she wakes up from hibernation.