Brake Upgrade

[stevemorris]

our new to us 15 yr old 3000 lb tt has very feeble braking action. it has dexter 2200 lb axles with 7 inch brakes

despite a total check and setting up(brake lube, adjustments)and a very thorough check over of the electrical system, braking is very poor. with the trailer on jackstands, the breakaway will lock all 4 wheels, on the road, virtually nothing

our previous tt with dexters and 10 inch brakes would lock up all 4 wheels easily on the road(manually) and the brake controller would give nice braking action at 30-35% power. this tt does almost nothing at 100% output

so I'm thinking the brakes are too small. up grading to 10 or even 12 inch brakes looks fairly simple, spindles, bearings, wheels look identical

comments?

sources for the total package?

[stevemorris]

an updte, I'm chasing down voltage drops through the system, after all 7 inch brakes are going to take a lot more electrical power for the same braking action

with the brake controller fully applied I had 8 volts at the "last" brake, 12.6 volts at the truck battery

so I started at the rear of the trailer and replaced the brake feeds with twin two wire cables 14 ga, one down each side of the trailer, then added a new 14 ga from the battery via the breakaway and a new ground. the new wiring goes into the junction box under the trailer where all brake connections have soldered ring terminals and are bolted together, the ground right to the box, the hot leads on an insulated stud mounted on the box.

the brake and ground leads from the 7 pin were also wired to those studs

I also replaced the wiring for the brake controller from the truck battery, brake controller all the way to the 7 pin. went from 16 ga to 10 ga with a ground wire all the way back. I used a 10-3 cable, the third conductor is used for the 12 volt feed to the trailer and also feeds an outlet in the truck bed where we have a 12v fridge

it surprises me how much voltage drop there was in 30 feet of 16ga, 2-2.5 volts at 16 amps plus all the mickey mouse connectors, corroded ends etc etc. its easy to measure voltage drop over a section, a vom with a sharp probe and a ground connection soon shows the "bad" spots

braking action is better, but not like our previous trailer with 10 inch brakes

[stevemorris]

I believe dexter welds the spindles on to the swing arm

[Acdii]

So there is no option to replace the spindle? You would think you could undo 4 bolts and replace it. I see spindles at Farm and Fleet all the time, along with full brake kits.

[stevemorris]

an slight update. after 100 km or so of driving applying the tt brakes manually lots to seat in the shoes, there's a very minor improvement. but I can still pull the tt easily with the breakaway pulled out. on gravel the wheels skid very slightly but still turn

I spoke to our local dealer's mechanic and dexter, both agreed that 7 inch brakes should never have been used.

so a conversion to 10 inch is in the works

10 inch brakes are not available for the 2200 axles, so some research is needed.

it turns out that the 2200 drum/hub uses 2 identical bearings, cant remember the number but the id is 1 1/16 (1.0625) inches

10 inch brake/hubs use the same bearing on the outer end and a larger inner bearing and seal, typically 1 3/16 id but other sizes are available

so my local bearing guy says that a compatible bearing and seal should be available, ie fits both the hub and the smaller spindle, the other option is get a bushing, also commonly available.

where is a good place to order the brake assemblies and drum/hubs? prices in Canada are astronomical compared to etrailer.com for example. crossing th border to pu the parts is easy, port huron mi is 10 minutes away from us

[stevemorris]

another try at posting!!

nothing is really changed, a local well respected rv dealer and his mechanic suspects the brakes are simply too small, dexter agrees

fully serviced, lubed, new wiring and I can pull the trailer almost normally with the breakaway pulled out. with the trailer jacked up, I cant turn the wheels with the breakaway pulled

I even went for a drive (100 km or so) actuating the brakes manually lots, still very little braking action with the controller set at 100% output

so my next step is get a used 10 inch backing plate and drum from the dealer and see what the difference is. I suspect bearing id but the spindles "look" the same as our previous tt with 10 inch brakes. if I can, i'll mount the used 10 inch and try it

[stevemorris]

I'm having trouble posting an update, wrote a new long reply and it disappeared

nothings changed

[westend]

Keep us updated, I think the wiring will definitely help.

[stevemorris]

Griz14 wrote:
Just curious, have you had someone else with a known good brake controller in their tow vehicle test your trailer's braking? You might have a bad controller in you tow vehicle.

we did the reverse!
tried another trailer, truck/brake controller are fine

so now I have new 12 ga wires down both sides of the frame from the junction box, new ground from the battery to junction box, new ground to the plug etc etc.

test drive today!

[rbpru]

My problem is the reverse, my 7 inch PUP tires will lock up, my 10 inch TT will not. Both can be adjusted to provide smooth braking on the road.

[Griz14]

Just curious, have you had someone else with a known good brake controller in their tow vehicle test your trailer's braking? You might have a bad controller in you tow vehicle.

[stevemorris]

well dexter 3500 ales are way off the budget, so I'm stuck with optimizing the 7 inch brakes. or finding a bearing that will fit between the spindle and the 10 inch drum/hub

funny thing is that the manufacturers' brochure says that the tt came with 10 inch brakes

[Lynnmor]

I've had snowmobile and camping trailers with the 7" brakes for 39 years. They are nothing but trouble. One issue that has been the most frequent is the clip that holds the magnet comes off. While you would think that there is not enough room for the magnet to come off the post, they will. My solution was to silver solder the clip in place. To do this, place a large washer over the magnet to protect it, and push the magnet back exposing the clip.

I had adjusters where the teeth would just crumble and those parts are no longer sold separately. I made my own adjusters from stainless steel. Lube the threads with anti-seize.

I have tried brands other than Dexter, but had magnet wires break off first trip. There is no good answer that I have found. Over 30 years ago, the brake shoes had riveted linings and generally were made better. They worked well, but there was only 1/32 of lining above the rivets and needed replaced every time you looked at them.

[stevemorris]

well a new update, one of the magnets wasn't doing anything, vom shows infinite resistence, so its burnt out

got a new magnet, wired it up with new cable from the junction box. now both brakes on the drivers side have a good solid connection and I get a solid "clunk" when I power the breakaway system with two brakes energized

so now I have both driver's side brakes fed by a new 12 ga cable, now I'm going to run a new cable from the junction box to the curb side brakes

I'm stripping and soldering all splices, i'll cover them with heat shrink stuff when its done, ive also added a return wire from every wheel, this will eliminate any grounding issues

[stevemorris]

ive had the entire system apart, right down to the shoes off the backing plates.

10 inch brake/drums use a different spindle than the 7 inch so bearings are not compatible