Front Axle Hub temperature higher than rear axle

I never use the EZ lube systems on any of my dexter axles so equipped. It is a lazy man's stupid idea.

I finally took it to the horse trailer place that upgraded my entire axle, brake and tire assembly last October.

They found grease on rear axle brakes was the final problem. Due to my over-lubing and blowing out the rear axle seals. Not sure what was the first problem, but there were multiple things learned here by me:

1. I used my "Trailer Aid" to easily lift one tire at a time so I could adjust the brakes and lube the axle.


2. I lubed the axles before adjusting the brakes (Dexter EZ lube system). But apparently I pumped the grease too hard on the rear axle and the axle seals came loose according to the trailer repair shop. Looks like I'm not the first one to do this. Lots of posts on dexter ez lube blowing out seals.

3. the 10 gauge wire definitely eliminated the voltage drop, but I don't know if it made any difference. I did the over-greasing before upgrading the wire.

My guess is one or more of these were contributing to the problem:
- voltage drop from front to rear axle
- rear axle needed adjustment more than front axle
- grease on rear brakes (after over-greasing rear axle).

Ed

eb145 wrote:
I ran 10 gauge wire (both hot and ground wire) from front of trailer to both axles. No more voltage drop.

But the rear axle still is not doing much braking. I unhooked the front axle wire and did some testing of my rear axle brakes. They barely do anything. They gradually slow the trailer down but aren't very useful for braking.

I adjusted them after replacing with 10 gauge wire and no luck.

I haven't taken the drum off yet - there might be some obvious mechanical problem. Maybe tomorrow.

Ed

Good call on the 10 ga wire. Do you have easy-lube axles? Maybe you have grease on the pads. I had one dead brake on my new 5th and turned out to be a combination of being very loose to begin with, not seated/worn in as much as the othe brakes once I did adjust them, plus I had to wipe down the pads several times with solvent before they came clean. Now it is slowly getting better and is nearly as hot as the other 3. In addition, it will now lock on gravel. When I started, it was ice cold.

When you pull the drum check the actuator arm pivot at the top they should swing freely. I have seen these freeze up and render the brakes inoperable.

I ran 10 gauge wire (both hot and ground wire) from front of trailer to both axles. No more voltage drop.

But the rear axle still is not doing much braking. I unhooked the front axle wire and did some testing of my rear axle brakes. They barely do anything. They gradually slow the trailer down but aren't very useful for braking.

I adjusted them after replacing with 10 gauge wire and no luck.

I haven't taken the drum off yet - there might be some obvious mechanical problem. Maybe tomorrow.

Ed

I just went through modifying the wiring on our 5th. I was getting less than 9 volts at the axles. This is a result of using 30-35 feet of 12 ga supply wire. When the total magnet resistance in parallel is only around 1 ohm, a small resistance in the main feed wires(which are in series to the magnets) has a significant effect. The resistance of the wires that drop to the axles is less significant while the wires that cross the axle are least important to getting peak performance.

Based on the work I did, your 10 volts at the axles seems reasonable. I could only get 10 volts after a few mods. The only way you can do better is to run 10 or 8 ga wire the whole way back, along with heavier wire in the tow vehicle and a heavier 7-pin harness on the trailer.

I got to do some work today on the trailer.

I greased all 4 sets of axle bearings with the Dexter EZ Lube process. Old grease looked fine, less than a year old.

I did a drag test on the brakes - where you lock the trailer brakes manually at a full stop on gravel. Then pull the trailer a couple feet. Surprise - only the front brakes lock up. The rear brakes do not lock up.

I adjusted the brakes according to Dexter instructions. No change, rear axle still won't lock up.

I did some voltage checks while holding the brake controller to manual "full on":
- 12 V at the back of the TV when measured at the 7-pin. (trailer unplugged)
- with trailer plugged in, something like 10 volts at the front brake and somewhat lower voltage at the rear brake.

I went for a test drive and the front brakes are running much hotter than the rear brakes.

So it looks like the wiring from the trailer 7-pin cable to the trailer brakes is at fault.

I need to check the connectors and isolate the voltage drop. Hopefully just a bad connection somewhere.

Ed

Thanks for all the helpful comments.

I have weighed the TT several times and the weights were all OK - but I did not weigh the rear axles separately from the front axles. Next time I hit the scales I'll weigh them separately.

My TT does not have torsion axles.

I need to check the brakes to make sure they are configured correctly.

And I need to check the grease on the axle bearings.

It might take a couple weeks to get these done, but I'll report back what I find.

Thanks,
Ed

Also weigh it at a scale.

One other thought is, the torque of the nuts holding the bearings and hub on. Too tight or too loose will cause temp variations however I think it may just be brakes aren't working on rear. Lay under it and have someone apply them and see. You can hear them.