Brake shoe wear question

[MVA]

Forum,

We greased the wheel bearings and inspected the brakes today. Perhaps oddly, the front axle brakes on our E19 indicated higher shoe wear (wear was uniform) that the rear axle brake shoes. Any thoughts?

[Iowa Dave]

Back brakes are not adjusted as close to the drums as the front ones. Other guesses will follow. Any or all may be valid. Voltage to the magnets may not be even due to connections. M that’s my second guess.
Iowa Dave

[Ron in BC]

Originally Posted by Iowa Dave

Voltage to the magnets may not be even due to connections.

Iowa Dave

Probably a possibility given that the grounds for each axle are separately grounded to the frame. In the past I've found less than ideal situations with the brake wiring.

Ron

[MVA]

Originally Posted by Iowa Dave

Back brakes are not adjusted as close to the drums as the front ones. Other guesses will follow. Any or all may be valid. Voltage to the magnets may not be even due to connections. M that’s my second guess.
Iowa Dave

Interesting thought. I did replace the front axle so I did the front axle electrical connections. Perhaps they were better than OEM?

[MVA]

I will need to get some "through insulation" probes for my multimeter to measure the voltage.

[Iowa Dave]

Originally Posted by MVA

I will need to get some "through insulation" probes for my multimeter to measure the voltage.

I never know what other folks know about a system. Sometimes nothing, sometimes ten times what I do (or more). So I’m never trying to be a hotshot or to make people feel their knowledge is lacking.
So if you know this I’m sorry. If not I might save you some time.
Coming out of the backing plate on your brakes is a pair of wires. One green one white I think.
They are inside of a split piece of flexible plastic. About ten inches to a foot up the wire is the connection to the power coming to the trailer for the brakes. Peel that split plastic off to see the connection. I have personally found bad connections at that junction where the person at the trailer manufacturing factory “missed the crimp”. You should be able to check the voltage there. Then, where the wire goes through the backing plate make sure it’s not cracked or worn through and “grounding out”. And finally inside of the assembly where the wires connect to the magnet. You’ll want to make sure those connections are good.

When I change my brakes out, I buy the whole assembly not just the magnet and the shoes. At the brakes to trailer connection, I solder the wires, crimp the butt connector carefully, apply heat to the shrink connector and finally put a few wraps of Scotch 33 electrical tape around the connector. Keeping moisture out reduces corrosion especially if the trailer encounters salty water on the road.

I’m not nuts about using the probe to violate the insulation covering when looking for a short. I think it can cause problems later.
All my best
Hope you figure it out.
Iowa Dave

[MVA]

I appreciate the advice greatly. Our trailer has undercarriage foam and I do not remember to what degree the foam is encasing the loom tubing. When I replaced the front axle, I cannot remember how the wiring was run and where the connection from the wire from the 7-pin box to the front axle is that proceeds to the back axle; that I can figure out tomorrow. I agree with you on piercing probes. I did not want to be cutting wires to measure voltages down the wire path to diagnose the problem (voltage issues, magnet issues, brake adjust issues).

thanks again

[alanmalk]

In my boating days it was an absolute must to keep salt water out of wires. If violated, the salt corrosion would migrate many feet up the entire wire. To that end, if a connection was necessary I would: solder, cover with adhesive lined heat shrink, then cover all with a rubber product called "Liquid Electric Tape".

[Ron in BC]

Originally Posted by Iowa Dave

Coming out of the backing plate on your brakes is a pair of wires. One green one white I think.
I have personally found bad connections at that junction where the person at the trailer manufacturing factory “missed the crimp”. You should be able to check the voltage there. Then, where the wire goes through the backing plate make sure it’s not cracked or worn through and “grounding out”.

I solder the wires, crimp the butt connector carefully, apply heat to the shrink connector and finally put a few wraps of Scotch 33 electrical tape around the connector.

Iowa Dave

I agree, along with the frame ground that connection point is also a potential problem point.

I also like to solder and heat shrink connections.

I recently replaced the axle on my 21 and it looks like the connections were done with a bit more care than they were on my old 19.

Ron

[MVA]

Alan - thanks for the advice. I have not used a liquid electrical tape. Looks quite functional. I have ordered a jar.

[MVA]

Originally Posted by Ron in BC

I agree, along with the frame ground that connection point is also a potential problem point.

I also like to solder and heat shrink connections.

I recently replaced the axle on my 21 and it looks like the connections were done with a bit more care than they were on my old 19.

Ron

Ron,

I have previously examined the "ends" of the brake wiring system; at the individual brakes which has two wires (power and ground) from the electromagnet are and at the 7-pin junction box for the hot lead for the brakes. Do you know where the brake ground wires from the individual brakes terminate and are connected to the frame?

thanks,
Steve

BTW - those old butt splice connections look terrible!

[Ron in BC]

Yes, they're connected to the frame on the driver's side very close to the axle.

Mine were corroded so I cleaned them up and added a common ground up to a newly installed ground stud connected to both the frame and the battery -.

Ron

[MVA]

Ron - thanks for the picture - it is exceedingly difficult to see through the foam.

--Steve

[MVA]

Adjusted brake shoes yesterday and measured voltage at individual brakes today. Iowa Dave's' original suspicion appears to be correct. The voltage at the breaks was nearly the same. Apparently I must have not adjusted the brakes the same last summer.

I have some liquid electrical tape arriving tomorrow to seal the wires on the probe holes.

Thanks all.

p.s. - BTW on my F150, the "gain" setting on the OEM brake controller is actually the maximum output voltage on the brake circuit. Hence, a gain setting of 8.5 will result in 8.5V at the brakes when the max output level is squeezed. Perhaps obvious to others.

[Roger C H]

If you have the trailer not level when hooked up to the tow and there is more weight on the front axle, that could cause uneven wear.