Troubleshooting trailer ground (weak brakes)

[3930dave]

Think of this as "access point" vs. "appropriate amount".

Ex. You access the oil fill point on a engine by taking a cap off. How much do you put in ? 3L, 5L, 14L.... ? Not saying anything about your work/skills, just have seen crankcases, tranis.... overfilled. And... these are cavities that usually have dipsticks (not trying to be funny ).

If the bearings were packed properly to begin with, you'd likely only need a couple of pumps at the most once a year, unless you put on crazy
high mileage.

Even a hand pump grease gun can put out pretty high pressure, and can easily overcome many basic seals on these type of wheels.

I expect a good design from Dexter; they may have taken a design approach that is less susceptible to ove-rgreasing - just saying it may not be immune.

Once the shoes are saturated with grease, you just toss 'em, and have to spend time degreasing most of the mechanical - usually faster to just replace the whole brake assembly. I just had to do this, on an old travel trailer I bought in Dec.


Rgds, D.

 

[CurlyDave]

Well, it's always nice to know the next time I'm bored, I can come up with something to do. At least it's a job I have the skills for (wiring). What's the best way to do those splices? I can pull out a soldering iron if I need to.

I would avoid soldering like the plague.

I used to work for a company that supplied electrical connectors to the auto and truck market. Soldering will always fail in time.

The problem is that the hot solder wicks up the strands of the wire and stiffens it. This produces a stress concentration at the end of the solder wick part of the wire and it will fail under vibration at that point.

The very best connectors are properly applied crimp connectors. In a factory setting a calibrated crimp head will always make a very good connection. This is hard to do in the field, but the closest you can come is to use good quality crimp connectors and one of the crimpers that looks like a pair of pliers.

Avoid the ones that are made out of heavy gauge sheet metal and are combination wire strippers/crimpers.

 

[CurlyDave]

That is where an Amp Clamp is nice. Clamp on amp meter just goes over the wire.

Funny, this post made me think of that. I did not even think to use it a year ago when I had brake issues on my 5th wheel; it was just sitting in the toolbox...

In general, a clamp on ammeter will only work on AC current.

In order to get one that works on DC, like a vehicle has, you need a "Hall Effect Ammeter". These are not easy on the wallet. Even inexpensive ones start at ~$250 and they go up from there.

Essentially, if you have one, you know it and know how to to use it.

 

[3930dave]

Unless you live in Arizona, or some other desert, most connectors (including crimp) will really benefit from a moisture barrier.

Some recent crimp connectors have silicone built into the heatshrink layer. A bit messier solution is to get out a tube of silicone to seal up standard crimps and other connectors - I've done it often.

Marine spec grease is great for repelling water, but even a basic lithium grease liberally applied to electrical connections helps a lot. Corrosion is prevented, and the connections will still be serviceable/useable if you are dealing with removable connectors.

Rgds, D.

 

[jeffsw6]

The very best connectors are properly applied crimp connectors.

I installed my brake controller by putting crimp disconnects on the vehicle's 4 wires under the dash, and the opposite gender crimp disconnects on the fan-out from the TBC connector. The parts were Amphenol and the package said something like "amp disconnect" and a wire gauge. Is that what you mean?

The reason I did the TBC that way was so it would be easy to remove or change in the future.

I have started replacing skotchlok connections on my trailer with solder and heat shrink. I thought this would be the best way. Are you suggesting I do something else? I could buy a box with terminal strips and run everything into it, using crimp-ons on the wires. Will it really last longer? I guess it would be easier to troubleshoot.

 

[joshuabardwell]

The very best connectors are properly applied crimp connectors.

Interesting. Crimped-on wire nuts were what the manufacturer used. Some of them had already fallen off. I twisted the wires together and then heat-shrinked the connection. I checked the other connections. Of the eight such connections on the trailer, two had already fallen off, four came off easily when I pulled on them, and the last two were pretty darn secure, but I pulled them off and heat-shrinked them anyway, because at that point, I had done all the other ones and I was going to do this one too!

Good point about the solder. I never thought of it that way.

 

[RobertN]

Aw, now just go and burst my bubble

The one in the garage is AC...

The one at work is hall effect, and was expensive.

The others at work are hall effect, but are pcboard mounted... Use to measure individual rails going from a PC power supply to the motherboard.

And the other one, is a Tektronix, and goes on an o'scope. It is accurate to a milliamp.

In general, a clamp on ammeter will only work on AC current.

In order to get one that works on DC, like a vehicle has, you need a "Hall Effect Ammeter". These are not easy on the wallet. Even inexpensive ones start at ~$250 and they go up from there.

Essentially, if you have one, you know it and know how to to use it.

 

[CurlyDave]

Interesting. Crimped-on wire nuts were what the manufacturer used. Some of them had already fallen off. I twisted the wires together and then heat-shrinked the connection. I checked the other connections. Of the eight such connections on the trailer, two had already fallen off, four came off easily when I pulled on them, and the last two were pretty darn secure, but I pulled them off and heat-shrinked them anyway, because at that point, I had done all the other ones and I was going to do this one too!

Good point about the solder. I never thought of it that way.

What in the world is a "crimped-on wire nut"?

A wire nut has a spiral spring in it and is wound onto the wire. A crimped connector has the wire inserted straight in and is then crimped on.

I have never seen or heard of a crimped-on wire nut. The spiral spring would resist crimping...

 

[Diamondpilot]

What in the world is a "crimped-on wire nut"?

A wire nut has a spiral spring in it and is wound onto the wire. A crimped connector has the wire inserted straight in and is then crimped on.

I have never seen or heard of a crimped-on wire nut. The spiral spring would resist crimping...

They just look like a wirenut but are crimp on. You simply twist the wires and the put it on like a wire nut and then a crimp to really secure it. If crimped properly they will make a very secure connection. The problem is most do not use a proper set of crimps.

Chris

 

[Travelover]

Interesting. Crimped-on wire nuts were what the manufacturer used. Some of them had already fallen off. I twisted the wires together and then heat-shrinked the connection. I checked the other connections. Of the eight such connections on the trailer, two had already fallen off, four came off easily when I pulled on them, and the last two were pretty darn secure, but I pulled them off and heat-shrinked them anyway, because at that point, I had done all the other ones and I was going to do this one too!

Good point about the solder. I never thought of it that way.

While Dave is right that solder creates a stress concentration at the point where the solder ends, I find it to be a trade off between corrosion (especially where salt is used) and vibration breakage. My method is to solder but to attach the wire in the unsoldered section to the frame with a P shaped stress relief gizmo. I've never had a soldered wire vibrate in two but have had many corrode prior to soldering. My experience, YMMV.