Weak braking after replacement

[CarlNH]

Due to being in a temporary location without tools, etc. I had a local RV place service my axles. They replaced everything... hubs, bearings, brake assembly. Towed the trailer back and decided to readjust my controller to be sure I had it set properly for the new setup. Well, now I have very weak braking. Not even close to lock up even with controller (P3) at max setting. I checked voltage output as well as current draw from the controller and all is as it should be. So, I'm thinking they did not adjust the shoes. They claim they did and also tested it in their yard with no problem. I'm taking it back Monday morning for them to look at. Wondering if there is anything I may have missed on my end that could cause this? Seems that with good voltage and current draw, I should be good with controller and wiring, right? I am preparing myself for them to say "trailer brakes don't always lock up." Mine, however, did so before they worked on them. Thanks and sorry for the rant :-)

[Ron in BC]

First of all I'm a little shocked that a trailer that new required all those parts to be replaced. They must have had a lot of miles on them. Previous trailers of mine have had lots of miles on them and even after 5 years didn't require that kind of parts replacement.

Secondly, a weak spot in ETI brakes is the electrical connection at the pigtail. I'm presuming that they made a good connection but it should be checked as well as the ground connection to the frame.

If you have doubts that they adjusted the brakes you could just put one wheel at a time on a block and spin the other wheel. You will usually hear a light dragging sound. They also may not have fully seated the brake shoe by tightening the adjuster until the brake locked solid and then backed it off. They may have stopped adjusting when the shoe first started making contact.

Ron

[Rossue]

Yeah, sounds like a royal lube job. Just did same(6 year old trailer with 70K+) and went with auto adjust. Watch Lipperts video on burnishing in new brakes. It definitely took a while, yet they are great now. Even with manual adjust you should burnish in new brakes.

[Patandlinda]

Originally Posted by Rossue

Yeah, sounds like a royal lube job. Just did same(6 year old trailer with 70K+) and went with auto adjust. Watch Lipperts video on burnishing in new brakes. It definitely took a while, yet they are great now. Even with manual adjust you should burnish in new brakes.

I concur Ross ! Also interested in info on auto adjust ? Pat

[CarlNH]

Yeah, a bit of a ripoff for sure but I had limited options. A place with a real good reputation is booked through November and I need to be back on the road in a couple of weeks. Around 30K miles on the trailer. I did pull one wheel previously and found a fair amount of corrosion on all parts of the brake assembly. No substantial wear on the shoes though. Adjusters were corroded and frozen on 2 wheels.

Re. connection to the magnets, if they weren't good, then current draw would be reduced and that does not seem to be the case. 12A with manual triggering of the controller.

Anyway, I'm not going to mess with it until I get it to the service place on Monday. They can pull the wheel then as I watch. I'm going to have them show me how the wheels lock up using their tow vehicle ;-)

Thanks for the comments and suggestions!

[Bill and Earline]

Make sure to check all four wheels. I had one connection that came apart at the crimp connection inboard of the wheels, and thus had no braking at all, for that one.

[rubicon327]

As prep before heading to the shop I would review pages 5-22 of the Dexter Service Manual. Good read on the electric brake system.
https://www.dexteraxle.com/docs/defa...sn=cfe1e328_42

As others have said check the adjustment of shoes (pg. 13), burnish in the new brakes (pg. 16) and then synchronize the brake controller (pg. 12).

A good way to easily check if the brake adjustment is wildly off is to test the breakaway switch which should be done occasionally anyway. Unplug the 7-pin connection at the tow vehicle (very important), then pull the breakaway pin on the trailer. Full voltage of the trailer battery will be applied to the brakes. Then try to pull the trailer. It should be very difficult to pull. This takes the brake controller and vehicle wiring out of the equation and you should be able to hear the magnet at each wheel buzzing so you know you have electrical connection at the wheel.

[CarlNH]

Thanks again folks for your inputs. Just a quick sanity check... your brakes are able to lock up right? Mine always did and I had to keep the P3 controller below 6.5 to preclude locking up. Now, at 14 no lockup and minimal braking.

I did pull the breakaway switch and there was resistance when I pulled the trailer but not what I would deem "very difficult" to move. In could pretty readily pull the trailer though there was clearly resistance.

Anyway, off to the dealer in the morning. Of course, it will be raining and maybe will lock up on the wet pavement....

Cheers!

[CarlNH]

Took the trailer back to the RV place this morning. Tech took everything apart, burnished the linings and drums, checked that mechanisms were all free. Tested it and there was no improvement. He is stumped as am I. He is going to try to chat with Dexter for some input. If no help there, replace everything again. I can't come up with any reason for this... it's not just one wheel that's not grabbing but all 4! And, I need to get back on the road... I'm a full-timer ;-)

Again, any ideas most welcome!

[padlin]

Did he check the grounding wire Ron mentioned above?

[Rossue]

How were the brakes burnished? Lippert video shows two ways to do it. First one is to make about 50 stops from 25 mph with time for brakes to cool in between. Second method is to go 60-65 mph then apply full brake controller while driving for one minute. The drums should get to 375 degrees to allow real burnishing to occur.

Was sure there was something wrong and magnets not getting full voltage yet they did come around. Also- even though I opted for self-adjusting I did do a manual adjustment after initial burnishing did not seem to fully address soft braking. It gradually improved and is great now.

[Rossue]

Originally Posted by Patandlinda

I concur Ross ! Also interested in info on auto adjust ? Pat

Hi Pat- been out running around; got the brakes from Redneck Trailer (Redline) and drums from Amazon(Lippert). $400 for eveything- hardest part was removing old backing plates due to corrosion so blast the bolts good first.

[CarlNH]

Thanks for the additional suggestions! Got a call from the RV place and they had been in touch with Dexter. They will be replacing all the magnets. So, hoping that is the final resolution. Not sure what they did for "burnishing" but they mentioned they used the "machine" to prep the linings and drums. Might have just been a wire brush or something. In any event, they had only seen a case like this a few years ago on a brand new trailer. Hoping for the best with the new magnets.

They did confirm full voltage at each magnet so suspect the ground is OK.

Cheers!

[alanmalk]

Originally Posted by CarlNH

...
They did confirm full voltage at each magnet so suspect the ground is OK.

Cheers!

That statement makes me a bit nervous. "Full voltage" at the magnet does not necessarily mean the ground is good. It could actually mean the ground is poor or missing. There are two ways to measure a "good ground". 1 - check the amperage flowing through the magnets, one at a time, and compare the numbers to the specifications. If there is a poor ground then not much current will flow. 2 - Use a multimeter to check the resistance from the magnet connection - on the ground side - back to the vehicle battery. Or in other words, the total path the current travels after flowing through the magnet on the return trip.


It's easier to use a diagram to illustrate what could go wrong with ground connections than it is to use a keyboard.


--
Alan

[CarlNH]

Originally Posted by alanmalk

1 - check the amperage flowing through the magnets, one at a time, and compare the numbers to the specifications. If there is a poor ground then not much current will flow. 2 - Use a multimeter to check the resistance from the magnet connection - on the ground side - back to the vehicle battery. Or in other words, the total path the current travels after flowing through the magnet on the return trip

--
Alan

Thanks Alan! Actually, I had previously measured the total current delivered from my controller to the braking system. It was 12 amps which is correct as each magnet is spec'd at 3A. Also, just prior to bringing the trailer in for the work, brakes were locking up when controller set above 7 so I'm thinking the chassis ground is OK. But guess it wouldn't hurt to give it a quick check. I'll let them know to have a look.

Carl

[alanmalk]

Originally Posted by CarlNH

Thanks Alan! Actually, I had previously measured the total current delivered from my controller to the braking system. It was 12 amps which is correct as each magnet is spec'd at 3A. Also, just prior to bringing the trailer in for the work, brakes were locking up when controller set above 7 so I'm thinking the chassis ground is OK. But guess it wouldn't hurt to give it a quick check. I'll let them know to have a look.

Carl

Can't find any issue with those electrical specs - essentially perfect. I'll leave the mechanicals to the experts in that field.
--
Alan

[CarlNH]

Originally Posted by alanmalk

Can't find any issue with those electrical specs - essentially perfect. I'll leave the mechanicals to the experts in that field.
--
Alan

Yup, me too! Thanks!

[Brian B-P]

Originally Posted by CarlNH

Tech took everything apart, burnished the linings and drums, checked that mechanisms were all free.

This description didn't include adjusting the mechanism. Even if you have the self-adjusting version, that's just to compensate for wear, and they probably still need an initial manual adjustment.

[Tom&Joan]

Originally Posted by Brian B-P

This description didn't include adjusting the mechanism. Even if you have the self-adjusting version, that's just to compensate for wear, and they probably still need an initial manual adjustment.

^^^ What Brian said.

[rubicon327]

Originally Posted by Brian B-P

This description didn't include adjusting the mechanism. Even if you have the self-adjusting version, that's just to compensate for wear, and they probably still need an initial manual adjustment.

Originally Posted by Tom&Joan

^^^ What Brian said.

Completely agree. I don't care how comprehensive you think a shop was with your brakes. It is well worth it to jack the trailer up and make sure each wheel has brake shoes with close contact to the drum. Then (after ensuring the 7-pin is not connected tow vehicle) pull the breakaway pin and there is no way you will be able to turn the wheel if everything is working properly. This is a time where a Trailer-Aid ramp comes in real handy if you have tandem axles.

https://www.amazon.com/Trailer-Aid-l..._ob_title_auto