OEM rear trailer brakes not working

[Canyonlight]

The front axel will slide first because of the geometry in the spring hangers. When the brakes are applied there is rotational force on the axels which make the axel push down on the front of the springs and up on the rear of the springs. This makes the triangular spring hanger between the springs (some I think are referring to as an equalizer but I have known as center shackle) swing toward the front of the trailer which lifts on the rear end of the front springs and pushes down on the front of the rear springs. Weight transfers to the rear tires so the rear tires have more traction, thus the front tires will slide first.

Great easy to understand explanation of something I have not even wondered about but once again, I learned more factual information from the forum !

Thanks, for sharing this !

Dan

[MidwestCamper]

Well this makes for a good case to not be towing at 80 mph. As the brakes are being applied with heavy force, the rear axle will torque/rotate over from the apposing forces from the brakes. Since the equalizer will allow this rotation, the equalizer shifts more force on the rear axle and lifts the front axle that cannot rotate due to the front spring hanger. I remembered this video but did not study it until the subject came up and wow! We are much better off keeping our distance and to have plenty of time for braking. The more severe the application, the less potential there is to stop. This may be a case to move to an independent suspension.

[MidwestCamper]

Wondering how much more weight is being applied to the rear tires versus the front on heavy braking? Are most tire failures on the rear axle?

[andrewssteve]

So, as hinted at the start of this thread, we're on the road from Minnesota and are now in New Mexico (with off and on internet service). I'm now caught up on the discussion, and its been interesting.

One fact that seems to have been overlooked in all the theories of explanation: My front brakes locked and the rear rolled from an initial breaking speed of not much more than 5 mph. Not much 'momentum' happening at such low speed.

An aside in praise of 1-ton pickups with engine brakes: I hardly touch the truck or trailer brakes going down anything in the Rockies. The engine brake holds me back even on a 10% grade. Really impresses me a lot. Still worried about the emergency stop, but I am pleased with my rig for normal situations.

[andrewssteve]

One other note regarding trailer orientation: The Solitude front end doesn't give me nearly as much turning freedom as my old Keystone Laredo had. I'm pulling with a B&W Companion hitch, and for the Solitude, I've adjusted the hitch as far aft as it will go. That moved the king-pin about an inch behind the truck's rear axle, giving me an extra 4" of turning clearance.

So, regarding @jkwilson 's thought about being nose-high, I'm not. The new hitch position has me level or maybe a tad low.

[powerscol]

I may not be correct on this, but would increasing the wire size help in this issue, especially from the front to rear axle as it can be a long run through the axle tubes?

[MidwestCamper]

I may not be correct on this, but would increasing the wire size help in this issue, especially from the front to rear axle as it can be a long run through the axle tubes?

There could always be reasons behind brakes not functioning properly. Adjustment, wiring, greased brakes, and so on. But the physics cannot be denied. The torque from the rear axle will pivot the equalizer and raise the front spring to reduce traction on the front axle on heavy braking. The only way to avoid this is to not do panic stops to reduce this torque, or move to an independent suspension system.