Dexter trailer brakes problem...

[Gary - K7GLD]

I have Dexter axles on my '88 24 foot Kit fiver - and since new, brakes have been LOUSY! Towing other rigs with my truck, their brakes put mine to shame... I've carefully checked all brake adjustments and internal magnets and such for proper condition and adjustment, and disassembled wiring and carefully soldered everything for maximum current flow. I get VERY poor stopping power - and when my controller is set on max, if the brakes DO start to function with any degree of power, usually results in one wheel or axle sliding before the others - actually ruined a new set of tires on one axle that way.



About the only way I get decent and noticeable stopping power is at low speed in city traffic - out on the road, you can usually barely notice any brake function from the trailer. On dirt/gravel, it is easily possible to slide all 4 wheels - 1n fact, that is usually what happens when going from the road onto some parks gravel driveways...



I've checked for voltage and current, all wheels are showing 3 amps each at max activation, and will immediately stop spinning if spun up on a jack and brakes applied. I usually set the brake shoes for a slight but noticeable drag when up on a jack - but have tried other adjustments within reason, with no improvement...



Any ideas?

 

[Whitmore]

Gary

Magnetic brake set ups are famous for what you describe, my recomendation would be to get with Dexter and find out if you can convert it over to another system that they may provide, this will give you alot better tire wear as well as reliability... ... ... ... ... . Kevin

 

[Gary - K7GLD]

PERHAPS - but the older Road Ranger 5er of my parents, and the 33' Alpenlite of my friend's both stop EXCELLENTLY with the same magnetic setup when hitched up to MY truck - as do hundreds of thousands of others on the road for other users - my suspicion is that there may be something specifically wrong with the 3500 lb. rated axles supplied by Dexter in the late 80's, and maybe SOMEONE has had and corrected whatever it might be...

 

[rwitt]

Gary,

Try running a separate ground wire to the brakes and see if it makes a difference. If you've checked everything at the wheels then maybe the problem is between the truck/trailer connector and the brakes. As I'm sure you know a poor ground can cause some really strange problems.

Rich

 

[Gary - K7GLD]

That might be a good idea Rich - even tho' I seem to be getting the right current reading at each wheel, it wouldn't take much loss back thru a long wiring lead to drop efficiency - thanks for the idea...

 

[Paychk]

From experience learned long ago, some people (even some manufactures) try to save a little money by grounding the trailer through the coupler ball. I work at one of the best RV shops in Eugene, Ore during the late 70's and we fab'ed up a jumper cable from 8 gage wire and clamped it between the trailer / vehicle frame. It was unbelievable how well all the electrical systems behaved with a proper ground. With that in mind, when trouble shooting electrical anything, I always go to the ground and verify that first.



PS Not saying you don't have a ground, starting there might just turn out to be the best expenditure of your time... ... GOOD LUCK!

 

[Roger Ledbetter]

Voltage drop?

Gary, I have the same complaint about my 32 ft Prowler 5th wheel. My other trailers I could always get the brakes to lock up at 20 mph. This one forget it. I upgraded to a prodigy controller and things are a little better but some questions maybe one of the experts can answer will help us out.



OK I called Fleetwood and yes they say about 3 amps per brake is correct. My controller is proportional but here is the confusion I have... it is by voltage not current. Does that mean each brake will always draw 3 amps regardless of the voltage? Seems so. If that is the case then Gary I would say check your voltage at the wheel and compare the same with your friends trailer. The ground could be a likely problem if you have a major voltage drop, but other things like the proper gauge wire up to the controller can also factor in. I should do the same test but I do not have anyone else to refference against.



Maybe someone can chime in here who has checked how much voltage drop is normal between the controller and the brakes they are sending the voltage to. I would guess maybe no more than 1 or 2 volts for a normal 12 amp run going less than 20 feet.



Prodigy made refference about running a separate ground wire from the controller direct to the battery... just another possibility.



You should not have to run oversized wire Gary, but don't skimp when you wire up that ALS -500 ! Hi.

 

[C Schomer]

Maybe check the plug and recepticle connections and contacts. You should have at least 14 ga. wire for 4 brakes. Dexter sells the backplate complete with shoes, hardware and magnets for about $65. Full current on mine (manual brake pulled all the way) is 13. 1 amps. I also have two 3500 lb axles. 4 brakes should be 12-14 amps. Your 3 amps is low but you said other trailers are fine with your truck. I wonder what the full amp draw is with your truck and other trailers. You should have good grounding thru the neg wire in the plug - regardless of ball ground or anything else. Have you ever tried ohmming your trailer brake wiring and magnets and someone elses. I'm thinking if you ohm between the frame and the brake contact in the plug on yours and another 4 brake trailer, they should be close to the same. That may help narrow things down. Craig

 

[T-Ricky]

Did you buy this trailer new? Has anyone else serviced the hubs? Does it have easy lub hubs? The reason I ask these questions is my dealer injected a lot of grease into my hubs and ruined the shoes. They wiped them nice and clean but the brakes worked as you described until I changed shoes. Then they lasted another 90,000 miles. I found it cheaper to change the entire axle ( from Southwest Wheel) than rebuild the old brakes and bearings because the armature was shot on the wheel this time around.



Good troubleshooting.

Rick T. KC5EQU

 

[mobilescout]

The quality of wire is also important. Needs to be heavy enough to carry the amperage to the magnets. My brother was having similar brake problems and discovered the wire, near the fifth wheel pin, was damaged. It only had 6 strands of wire left. This was not enough to carry the full load to the brakes. Once he repaired it, the brakes worked as they should.

 

[Blakers]

Gary,



Perhaps your brakes just aren't big enough for your trailer.



Next time you drive it, use the brakes on a pretty good hill or some other means of making them work, then get out and see if all the drums are warm or hot. If they aren't, then they're not doing their job.



If some are cold, they're the ones that need attention. Check the lining for wear or grease contamination.



Blake

 

[Gary - K7GLD]

Lots og good info - thanks guys...



Bought the trailer new - the 3 amps per wheel is what Dexter specs - drums, brake shoes and magnets are fine as far as cleanliness is concerned - as is the magnet plate the magnets drag on. It appears that all primary system grounding occurs at a central point - and all other trailer lights and functions seem fine...



BUT, I do NOT get equal braking on all wheels or axles, as can be seen when adjusting on loose surfaces, where one wheel, or both wheels on one axle (usually the front one) will drag the tires much sooner than the others - and on a good surface, ONE wheel does MUCH more work than the others, and get lots hotter after a stop.



It seems obvious that in spite of equal amp draw at each wheel and axle, I am NOT getting equal braking - and I don't know WHY!



Due to the age and mileage on the trailer, and the fact it's getting about time to replace some wheel/brake elements anyway - as well as the need to swap axles to below the springs because of my new '02 Dodge, I'm almost temped to just buy 2 NEW complete axle/wheel sets - except that if it IS an electrical problem, my basic problem will remain...

 

[rwitt]

Gary,

Does your trailer sit level when hitched to the truck? If it's higher in the front then theres going to be less weight on the front axle of the trailer causing the tires to lock up even with equal power to both axles. If it is level I'd still try to get a ground wire from the brakes that goes directly to the frame and make sure the trailer connector to truck is good.

Rich

 

[Roger Ledbetter]

Another possibility...

I like the idea of checking the resistance with an ohm meter at the plug, Very easy to tell if there is a problem that way. I am going to check mine this weekend. If others with dexters can check and report we will all know what is normal.



Gary, it is possible if you had too much drag when you adjusted your brakes they will heat up and distort the drum. I had that happen to my rear brakes on the truck after new shoes and drums were turned. The brakes grabbed and would lock up after the drum was toast. New shoes and another clean up turning of the drums solved it. I have never adjusted my brakes on the trailer, it has always been done for me but I do not think any sort of drag is a good thing.



Good Luck!



BTW my drives a big rig and said that pulsing brakes or modulating them is not good for the drums. Much better to apply a steady preasure for slowing down. He claims that the drums/rotors will heat up evenly that way and less likely to get a hot spot. Never heard of that before but it makes sense.

\

 

[Gary - K7GLD]

Well, completely re-did ALL the crimp-on connectors from the trailer umbilical cord to the trailer wiring using soldered connections - found one that was suspicious, but it wasn't one specific to trailer brakes - also ran a dedicated ground wire from the junction of the brake's ground connection back at the axles directly to the trailer frame - all connections securely soldered... Maybe take the trailer out tomorrow for a test run...



Along the lines of what Rich suggests, an Email directly to Dexter on the issue some time back resulted in a recommendation from them to provide a resistor (they have them for sale - so it must be a fairly common complaint!) to the front axle brakes only (to reduce voltage/current to the front brakes, forcing the rears to do more of the braking), since they claim this style axle suspension creates a situation where heavy braking causes the front axles to "lift", and forces the rear axles into heavier road contact - and then causes the potential for the front wheels to slide since they now have less road contact in relation to the rears... The resistor they recommend is on the order of 6 ohms at 50 watts... I happened to have a 6 ohm rheostat in that wattage value, so installed it a while back - pretty well eliminated the unequal braking between axles, but did nothing for overall system braking, or the one wheel brake that seems more aggressive than the others...



As far as brake adjustment is concerned, I've tried everything from a fairly firm drag, to completely backed off, with no perceptible improvement...



We'll see what tomorrow brings...

 

[Gary - K7GLD]

WELL, the results are in - after all the electrical re-do, absolutely NO braking improvement!



SOOOooo, guess that if I really wanna get braking improvement, I'm gonna hafta consider a new set of complete axles... Maybe not all that bad an idea, since the old brakes, drums and bearings would all be upgraded at the same time, and I would hafta completely remove the old axles anyway, to re-set them under the springs for added clearance with my new truck... .

 

[Oxjockey]

Don't the backing plates just bolt on? You could probably get new backing plates & brakes as a compleye setup.



Bryan

 

[Gary - K7GLD]

A few years back, a failed wheel bearing severely damaged one of the trailer wheels - completely destroyed the brakes, magnets, and did serious damage to the spindle... I replaced the complete backing plate/brake assembly - as well as all bearings and seals - that wheel , with the new backing plate designed for it and the axle, is no better at stopping than the others - and I still worry about the damaged spindle, and constantly check it out on the road - the only way the spindle can be replaced, is to replace the complete axle...



OTHERWISE, your idea might be a good one - if higher capacity backing plates WOULD mount to my current axles, that would be an easier and cheaper way to go - hafta check into it!

 

[pkennedy]

The only thing nobody mentioned is the mechanical shoe adjustment, if the shoes are set to loose or unequal so will performance. Shoes should be set so that the shoe and drum run freely(no drag) but excess movement will result in lower grabbing capability despite magnet performance. PK

 

[RThompson]

Gary,

I have been down that same road with a 1988 FW with 3500 lb Dexter axles. Dexter products of that era are a bad joke.

We ordered a 2003 model trailer with Standen axles, http://www.standens.com/index2.htm

A couple of other problems I discovered with the Dexter's is, the axle bearing nut is so crude that getting a good adjustment is diffficult without having an assortment of nuts or taking the time to face some of the inner side of the nut. Also, the brake hold down springs break if they get to much heat and end up tearing up the lining.

I used a compass or stud finder to check the magnet operation on a regular basis when we were traveling. Since buying the Jordan controller I can see the total ampere load of the magnets and know if one is failing.

Another problem that occured on regular basis was bearing adjustment getting loose. Previous owner was also a truck mechanic and we never could resolve that issue. ( the cups were seated)

3500 lb rating on these Dexter axles was kind of a joke also. I straightened the axles several times and the axles never had 6K on them.

Good luck