Wimpy brakes?

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Wimpy brakes?

Post by ScottandGrace on 8/21/2010, 3:36 pm

I just intalled a new P2 in an effort to improve my Cats braking and it's better but it still seems poor. I've adjusted the brakes and made sure all the electrics are working but even when I crank up the power, they don't come close locking up.
Does this sound normal? How well do yours work?

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Re: Wimpy brakes?

Post by Mopar_Earl on 8/21/2010, 3:48 pm

Are you testing this by pedal or by the manual overide?

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Re: Wimpy brakes?

Post by ScottandGrace on 8/21/2010, 3:52 pm

Manual overide.

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Re: Wimpy brakes?

Post by Mopar_Earl on 8/21/2010, 4:12 pm

If your gain is maxed and your not locking or at least whiplashing yourself with the manual control, than something is wrong. Brake adjustment is a major cause of weak brakes. Do you tighten the brake until you feel a drag on the wheel when turned by hand? Maybe you have a magnet or two not working or weak? Have you taken a ohm's reading on the trailer's brake circuit? Is your 7-way ground good on both truck and trailer tested by checking for continuity?

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Re: Wimpy brakes?

Post by ScottandGrace on 8/21/2010, 4:49 pm

I should check the 7 way connector Earl, but I can hear humming and clicking at each brake so I think the electric part is at least trying to work but no, I havent checked it with my meter. I adjusted the brakes so that they turn about 3/4 to 1 revolution with a good spin, which is per the ALKO manual.
Now that I think about it, I have about 25K miles on it so maybe the pads are getting thin. That would kinda surprise me though, I use my exhaust brake extensively and I'm real easy on the brakes but everything wears out someday I guess.

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Re: Wimpy brakes?

Post by Mopar_Earl on 8/21/2010, 5:45 pm

I'd adjust them as if they were automotive drum brakes. I'd adjust them till you can feel a slight drag and try to match that at each wheel. Since you use your exhaust brake maybe the drums are rusty and need a good burn in. Drive down the road 40ish and use your manual control until you feel the brakes grab and do that for a good mile or so. Warm brakes are more aggressive than cold. Sounds like you haven't inspected your brakes in a while. Maybe the wheel seals went and you have grease in the drum and on the shoes? If you're using the easy lube instead of hand packing, there's a good chance of grease in the brakes.

Which exhaust brake are you using? I'm planning to install a Pacbrake PRXB one of these days when I pry the money out of my wallet. lol Is your exhaust brake wired to the ECM (2.5 sec time delay) or with a ECM bypass so there's no delay?

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Re: Wimpy brakes?

Post by ScottandGrace on 8/22/2010, 2:51 am

That sounds like a good idea - the TT's brakes only get used for that last little bit before we stop so Ill warm them up a bit and recheck the adj.
Ok - confession time here; I have never packed the bearings on this TT. Busted
My excuse is that I packed them every year on the last TT and there was never anything wrong with them. We make very short trips and I check the hubs temps every time we stop and so far, they've never been abnormal. I also jack the trailer up every spring and check for play in them but I've never found any. Next spring she'll get a new set of Maxxis and I'll go all through the bearings and inspect the brakes.
I have the Pac and it has worked great for me. It does indeed wire into the ECM but there's an optional kit to add a micro-switch to your throttle pedal if you don't want to go the ECM route. I used the ECM because it was easy enough to do and I need the 2.5 seconds delay so it doesn't engage while I shift gears.
Once you have an exhaust brake you'll never pull again without one!

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Re: Wimpy brakes?

Post by scottz on 8/22/2010, 4:45 am

I would try adjusting them and, at the same time, inspecting for grease.

Also, you might be expecting a little too much. I cannot "lock" my trailer wheels even on max gain, although I do get some serious braking action.

I use my exhaust brake a lot. Mine is simply one of the programs on my DP Tuner that closes the Ford exhaust back pressure valve (the 7.3 Ford has this to help with engine warm ups). It works great.

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Re: Wimpy brakes?

Post by Rich5117 on 8/22/2010, 5:49 am

What brake controller are you using is there a gain adjustment to increase the gain applied to the manual control slide knob. I have the built in system and had to have ford increase the internal gain as I could not lock the brakes on my cat, found this out doing my pull test. My sister works for ford and knew this could be done. Maybe it can be done to installed units.

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Re: Wimpy brakes?

Post by MountainMan on 8/22/2010, 6:34 am

I think I'd be inspecting for wear and grease first then go from there. Its real simple and takes very little time to take a look.

I have a good strong trailer brake but they will not lock on the pavement. Personally, I don't want them to have the ability to lock on pavement either.

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Re: Wimpy brakes?

Post by ScottandGrace on 8/22/2010, 2:42 pm

Rich, it's Prodigy P2 and not a built in unit (I wish it was though!).
I'll check them for grease and wear but as far as adjusting them, the manual is very clear and I believe correct. I also asked a long time mechanic buddy of mine who has done hundreds of brake jobs on trailers of all kinds. He said it a wide spread misconception that brakes should only slightly drag and agreed with what Alko wrote as that was what he was told in college and thats what he has found in his experience. He went on to explain how he has fixed brake jobs done by novices and that adj. was the most common cause of poor perfomance after these folks had serviced the brakes themselves. Adjusted as I described, they will not get warm or suffer any negative affects but effectiveness will be maximized.

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Re: Wimpy brakes?

Post by Mopar_Earl on 8/22/2010, 4:15 pm

Can't speak for trailer axles but in the automotive world, slight drag is what is in all service manuals and what I've been taught at school, by old timers and by the State (have my state inspection license). After that the automatic brake adjusters take over. I adjust my trailer brakes the same way and them babies work great with no problems and they do lock up if wanted. Disc brakes also have a slight drag with no human involvement. The method you use is a little tighter than I use and that doesn't change anything other than your brakes would be slightly more responsive cause they're in more contact with the drum.

Do let us know what you find. Also if your brakes are shot, upgrade to automatic adjusting brakes. Dexter makes them http://dexteraxle.com/inc/sdetail/27395

I do agree that brake adjustment is a major player in good braking. Everytime I adjust my brakes, I need to lower my controller gain as the brakes are more responsive. When my units brakes wear out, I'll be upgrading to Dexter brakes with automatic adjusters so I don't have to screw around with brake adjustments. http://dexteraxle.com/inc/sdetail/27395

Copied from Lippert axle service manual http://www.lippertcomponents.com/OwnersManuals/Trailer-Axle/8-3-10-Trailer%20Axle-Web.pdf

1. Jack up trailer and secure on adequate capacity jack

stands. Follow trailer manufacturer’s recommendations for

lifting and supporting the unit. Make sure the wheel and

drum rotates freely.

2. Remove the adjusting hole cover from the adjusting slot on

the bottom of the brake backing plate.

3. With a screwdriver or standard adjusting tool, rotate the

starwheel of the adjuster assembly to expand the brake

shoes. Adjust the brake shoes out until the pressure of the

linings against the drum makes the wheel very difficult to

turn.

4. Then rotate the starwheel in the opposite direction until the

wheel turns freely with a slight lining drag.

5. Replace the adjusting hole cover and lower the wheel to the

ground.

6. Repeat the above procedure on all brakes. For best results,

the brakes should all be set at the same clearance.



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Re: Wimpy brakes?

Post by ScottandGrace on 8/22/2010, 4:41 pm

The difference is in the assumed meaning of "slight" I guess. Alko defines it more specifically as 3/4's to one turn.

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Re: Wimpy brakes?

Post by Mopar_Earl on 8/22/2010, 5:01 pm

ScottandGrace wrote:The difference is in the assumed meaning of "slight" I guess. Alko defines it more specifically as 3/4's to one turn.


It's a different method that's for sure. But depends how hard and or fast a person spins the wheel as to how fast it'll stop. I agree, one persons slight could be barely turn the wheel to another where there is no drag at all cause they're hearing the magnet rubbing on the drum and not going by feel. lol The real key is making all 4 wheels the same for equal braking. Dexter's method is different as well. They state to crank the brakes till the wheel is hard to turn, than back off 6 clicks. Manual slacks on air brakes you crank tight than back off a turn and double check your slack stroke is within DOT's specs. I think an inch. Been 14 years since I've done air brake adjustments. lol

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