Tow vehicle question

thebottomfish · #1 06-08-2018, 10:36 AM

Sorry if this is in the wrong section, couldn't really find a better place to put it...if it needs to be moved I apologize.

I was towing my V20 down to my Marina with a single axle trailer, no trailer brakes, with my 99 Durango.
The Durango is well equipt and has a tow rating of 7,650 so no worries there.
It has 4 wheel anti lock brakes, disks up front drums in the rear. Now to be brutally honest, the brakes are probably nearing the end of their life at all 4 corners, maybe another 5-7k miles in them.
I towed from exit 168 to 132 to stop at the rest stop and when I got out I smelled the brakes roasting.
Check tire pressure, all within range, all the same, trailer tires good as well.
Took an IR gun and read temps of 90 degrees at the disks, 95 degrees on the trailer hubs and 180 and 160(passenger and driver side respectively) on the drums. Ambient temperature about 70 degrees.
After letting them cool down, and checking to make sure they weren't sticking I ran down to the rest stop at 100 and when I got out drums now showed 90 degrees each side, so success? When I got to my marina in brick the drums were hot again, at 160ish. But no burning smell this time.
Ran home without boat and pulled into the driveway with the drums at 80 degrees each side.

My question is, is there so much pressure(weight) on the rear brakes while towing that they could heat up that much? Or do you think it was the brakes dragging sporadically. I definitely used the brakes more on the first leg and third leg of the trip and that's when they showed the highest readings. It's my first vehicle with drums and I'm not sure if I can expect this is normal from the rears.
I know my Grand Cherokee front and rear disks get about 15 degrees warmer when towing but it's pretty even between axles.
Regardless I'll be changing the brakes, but more curiosity than anything else.

Any insight?

bradford · #2 06-08-2018, 11:57 AM

Emergency brake partially engaged?

thebottomfish · #3 06-08-2018, 12:56 PM

Thought of that as well, didn't seem to be, I also never used the ebrake, but I set it and released it quite a few times to rule that out.

SkunkBoat · #4 06-08-2018, 03:12 PM

drums hold heat much longer and can build up heat.

Possible they were staying on while towing.

Rear drums tend to not really do much on a vehicle with front discs under normal weight.

You were on the Parkway...stop & go or steady pace?
Under 50 MPH?

Much as I hate trailer brakes, if you are going to make that kind of trip regularly, you should probably get them.

thebottomfish · #5 06-08-2018, 04:45 PM

I make the trip to Brick once in May/June and it stays in a slip, comes back out in November. I'll run to seawarren in April and May once or twice, so I don't trailer it all that much. But point taken with trailer brakes, certainly couldn't hurt.
Kept a pretty steady pace of 55-60mph the whole way, little traffic on the first leg of the trip when the brakes showed the hottest. Couple traffic lights off the parkway on the last leg of the trip when the drums were hot as well.
The run from 132 to 100 I don't even think I touched the brakes so I've been chocking it up to they just run hot when towing because of the added weight on the rear, maybe the disks aren't handling the stopping well and the drums are getting more of a work out to make up for the fronts? I'm not sure. Just figured someone on here might say it's relatively normal or no something is drastically wrong.

thebottomfish · #6 06-08-2018, 04:47 PM

Also just realized you sold your V20 skunkboat! Was hoping I'd get to see more of it this year, but I'm sure that Grady is a nice upgrade

Destroyer · #7 06-10-2018, 12:10 AM

Like Skunk said, drums tend to hold their heat more than disks. However, the weight of the tow should NOT effect the brakes while towing. The only time you should be generating heat is when your brakes are actually being used. If you were not riding your brake pedal then I would look into dragging brakes not releasing properly (weak/broken springs or sticking slave cylinder(s)) or your emergency brake is adjusted too tightly causing them to drag. When braking your rear brakes should come on first to prevent fishtailing, but your front brakes really do most (up to 75%) of the actual stopping of your vehicle. (That's the main reason why, when you stop your vehicle, the nose tends to dip).

And yes, trailer brakes are ALWAYS a good idea. Just remember to wash them thoroughly after they have been dunked into the ocean.