poor brake performance

[tpaulus]

I'm experiencing poor brake performance. When I manually activate the brake controller to 100%, I feel braking but it's mild. No tire lockups, no heavy pulling back.

I checked the brake shoe adjustment, it seems ok. They are self adjusting and it all appears to be working.

Voltage coming out the back of the brake controller seems good, ~11.5 volts (engine not running).

Voltage coming out the vehicle connector seems good, ~11.5 volts.

Voltage drops though at the brake connector (at the back side of the hub), ~8 volts. I cut the brake wire at the front axle and measured voltage there, it's good, ~11.5 volts. If I put wire nuts on and check the voltage again, I'm at 8 volts.

Ran a new wire from the coupler back to the axle and connected it via wire nuts to the brakes, again ~8 volts. If I disconnect each axle and hook them one at a time to the new wire, I get ~10 volts.

Under all of these scenarios, if I measure the voltage coming out the back of the brake controller, it's always the same, ~11.5 volts.

It's all the same with the vehicle running, except perhaps readings are ~.5 volt higher.

Can anyone point me in the right direction?

[Still Kickin]

There are several variables with brakes. Your mention of self adjusting brakes needs addressing. Self adjusting brakes is pretty much a misnomer. They really don't do much of self-adjusting, unless your constantly monitoring the component brake parts (i.e. self-adjuster mechanism) If, as you say, your electronics are in proper working order, than you need to manually adjust your shoes. If you do not feel comfortable doing the adjustment, take it to a shop. Then you should get the desired results your looking for.

[tpaulus]

I'm comfortable that they are adjusted properly. I tightened the two on the right a click or two. Left rear was good, left front was too tight, I actually backed it off a bit.

This problem is electrical. My thought is that if I have ~11.5 volts at the vehicle connector then I should also have ~11.5 at each brake connector. Maybe slightly less due to resistance of the wire and connector but I'm down >30%. Just have no clue why.

[TURBS]

How did you adjust them?

[tpaulus]

Lifted the tire off the ground, tightened the adjustment wheel until I couldn't turn the wheel by hand, then backed off until slight drag. If they are off, they are on the tight side. Like I said, in the end I added one or two clicks on the right side, left rear was good, left front backed off 2 clicks.

Suppose they are adjusted spot on. What else should I check electrical?

My brake controller is very old, purchased in 90's, but it appears to function if you measure the voltage coming out the back and monitor it as you fiddle with the pendulum. Do these things wear out?

[TURBS]

Originally Posted by tpaulus

Lifted the tire off the ground, tightened the adjustment wheel until I couldn't turn the wheel by hand, then backed off until slight drag. If they are off, they are on the tight side. Like I said, in the end I added one or two clicks on the right side, left rear was good, left front backed off 2 clicks.

Suppose they are adjusted spot on. What else should I check electrical?

My brake controller is very old, purchased in 90's, but it appears to function if you measure the voltage coming out the back and monitor it as you fiddle with the pendulum. Do these things wear out?

I'd start with a modern brake controller wether that one is bad or not.
They've come A LONG WAY since the 90's.

I'd have to wonder if it's functioning properly under load.

[tpaulus]

Good news:

So I replaced my controller, got the Tekonsha P3. It's a really nice controller. I'm getting 10.5 volts at the brakes now. Not sure why the old controller couldn't do it but I'm fine with the outcome.

Bad news:

Though braking is better, it's still not enough to lock the wheels with the controller on max power. So I pulled the drums, my seals are blown, grease all over the shoes, drum and magnet. I'm cleaning that up now and will get some new seals in the morning. I'm 36 hours from leaving on a 5000 mile round trip from Atlanta to Yellowstone and vicinity. I'm kicking myself right now for not inspecting this sooner.

Thanks to everyone for your consideration.