electric trailer brake question

[Ray]

Can brake magnets get weak? I've got one set of dual wheels on my gooseneck trailer that will smoke the tires pretty easy. Adjusting the brakes didn't help. I'm wondering if it maybe has a stronger magnet or for some reason or is getting more voltage than the others.

 

[old]

There are a number of things that can cause that. Poor ground or poor connection some place or yes the magnet can get weak due to what it does and can have the magnet coil start to short out and also simple rust can cause the braking action to be weak

 

[Ray]

I had new brakes put on last fall and they haven't worked right since. They installed new shoes and said everything looked good. Another place took it apart last week and said everything looked like new. Normal braking is about 3.5 on my controller, at about 4 one set of dual wheels will lock up. I adjusted the brakes on that axle,but it still does the same thing. Each axle brake is grounded to the frame. I guess I cold run a new ground wire from all 4 duals to the truck.

 

[old]

A little bit of rust or a corroded hook up at the frame can cause that problem. I have run into where the ground wire hooks to the frame that it has a bad connection.

 

[Geo-TH,In]

I replaced just one magnet. It was stronger than the old ones. So it may be possible one magnet is stronger if they weren't all replaced.

 

[rrlund]

I did the exact same thing. New brake shoes on the stock trailer and they haven't been right since. Royse was here with a meter and checked everything. We never did get it figured out.

 

[Steve@Advance]

A number of causes for that...

There are different magnets for different size brakes. I don't know if they will interchange, but this is interesting:
https://www.etrailer.com/question-8117.html

One common cause is too small wire, wired first to one magnet, then the next, then the next... The first one in line gets the most voltage, not a lot of difference, but can be enough to cause problems. Best method is to wire down the middle, tee off to each wheel, try to keep the leads the same length, use #12 wire. Soldering the connections is best, heat shrink and liquid tape make a good water proofing. If there are any of the little blue fold over connectors, they need to be removed, horrible way to wire anything, especially something subject to water and shock vibration!

As with any brake system, a little bit of grease can cause a lot of problems. Any leaking grease seals need to be fixed and the grease cleaned or shoes replaced.
Another factor is suspension geometry, or differentials in weight on a particular axle or wheel. Be sure the trailer is riding level, all the spring linkage is in order and moving freely.


As with any brake, a tiny amount of grease will create big problems. If there is any seal leakage it needs to be corrected, cleaned up, or shoes replaced.

 

[Anonymous-0]

In the seven pin connector there is a provision for a ground connection. There should be a wire ran from the truck receptacle direct to the battery negative post.

The corresponding terminal on the trailer plug should have a wire run and tapped to each wheel on the trailer just the same as the hot feed.

Both the trailer plug terminals and the truck receptacle terminals should always be liberaly coated with a water repelling grease.

Relying on frame ground connections, whether on the truck or the trailer, is trouble waiting to happen.

Depending on the hitch ball ground connection is an exercise in stupidity.

 

[Anonymous-0]

EDIT EDIT EDIT EDIT EDIT EDIT EDIT EDIT EDIT EDIT EDIT

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Why can't we edit our posts here???

An edit to my previous post....[b:18f2ac1224]12 gauge wire is highly reccomended. [/b:18f2ac1224]

 

[John T]

Ray, I didnt see an answer to your question "Can brake magnets get weak?"

NOT much as they are an electromagnet NOT a permanent magnet.

HOWEVER their current induced electromagnetic field strength can be weak due to a bad/resistive connection or a bad/resistive ground or a bad/resistive connector because less current flows through them. More current = more electromagnetic field while less current = low field and less brakes.

Got it??? Typical causes are poor grounds or corroded or loose connections. Crimp or pinch connections get loose and corroded and develop resistance and allow for voltage drop, if you solder then seal connections and grounds you are better off

John T

 

[Geo-TH,In]

John, My brake magnet changed magnetism after it rubbed brake drum, wore out the metal core, then shorted out the windings.

I also discovered that previous owner has replaced some of the electromagnets. The replacements had different internal resistance, used different currents and had different magnetic strengths.

If I recall, aren't there manual break adjustors? So you may think the there is something wrong with magnet when brakes are out of adjustment. geo

 

[David G]

I have seen people put the long shoe on the front, that makes them grabby.

 

[Determined]

(quoted from post at 16:09:42 04/14/16) Can brake magnets get weak? I've got one set of dual wheels on my gooseneck trailer that will smoke the tires pretty easy. Adjusting the brakes didn't help. I'm wondering if it maybe has a stronger magnet or for some reason or is getting more voltage than the others.

Although under certain circumstances when things seize, bind or are incorrectly installed you may experience one wheel or axle locking up.
In general brakes do not suddenly develop super powers.
If one side is locking up it is likely because the others are not doing there job and need adjustment or attention.

Front brakes lock up when the backs are not contributing.
And visa versa when the fronts are not working properly.

 

[jon f mn]

Most comercial trailers bring the power wire back along one rail to the front wheel, then branch off to the other wheels. This causes the first wheel to get the most power with each wheel further away getting less. If the sliding wheel is the first in the system then nothing is wrong except sloppy wiring. If you decide to re-wire it then buy 50' of 2 wire extention cord to do the job, I've found that works best. Bring the wire to the center of the axles and branch off from there giving each wheel an equal length of wire and all wheels will then work equally. If the sliding wheel is not first then you have another problem, likely poor ground to 1 or more of the other wheels leaving the most power going to the sliding wheel. Again the solution is to re-wire properly.

 

[buickanddeere]

Heat will ruin magnets

 

[T in NE]

I figure you can't have too many grounds.

When I wired a trailer I ran a ground to all lights
and brakes, tied the ground to the trailer frame at
the rear and at the hitch as well. Provided a
secondary ground if a wire other than the one from
the hitch to the plug got damaged.