TT brakes just don't seem right...

[2partners]

Hi,

Haven't used the AS (2016 30 classic) for awhile. Hooked it up recently to get everything weighed. I tested the brakes manually (Ram integrated controller) on the way out the gravel driveway. I could feel it tug a little although I thought I remembered them skidding on gravel. No skidding and a very gradual, slow stop with trailer brakes only. We usually have the gain set at 4.5, I tried 10. This improved things somewhat but still no skidding. However, and this seems strange, if I start from a dead stop either with the breakaway pin pulled or the manual control fully engaged, the brakes hold solid and the thing won't move. Maybe I remembered wrong and they didn't skid before? Now I'm second guessing myself.

Checked the voltage at the 7 pin and it tops out at 12+ on the TV side. Cleaned the 7 pin and ran a temporary ground from the TV to the TT. No difference.

I doubt this TT has more than 10k miles on these 100k mile Dexter axles and the brakes worked fine when last used, so, I'm wondering if there is something going on outside the axles. Whatever the problem is it seems to be a general problem effecting all wheels.

I think the next thing I want to know is what the total brake amp draw is; apparently it's somewhere around 15 - 16 amps. I'm looking for a tester that that can be installed in line that can take the load. I've looked on line and searched the forums. Not finding one specifically for the purpose. Anyone know of one or have an idea what the problem could be?

Thank you and thank you all of you for your help in the past,

Chris

[Al and Missy]

Measure the current in the blue brake wire. At full power it should be around 3 amps per brake, i.e. 12 amps. This measurement can be made with a multimeter in the amps mode.

https://www.amazon.com/Sinometer-DT6.../dp/B00F68FHM2


The inexpensive clamp on ones do not have sufficient sensitivity or accuracy, particularly for DC. My Tekonsha P3 had a test mode that would actually show the voltage and current. If you are getting 12 amps then the problem, if there is one, is in the brake mechanism. They are prone to collect brake dust, dirt, and rust and should be cleaned and lubricated periodically, along with inspecting the bearings and packing them, if not NevRLube.


That said, I could not find anything wrong with the brakes on my Classic 30. I could not lock the brakes under any circumstances. If the magnets are working correctly and not worn they are attracted to the lug bolt surface of the drum, which pulls on the lever to activate the brakes. If this surface is worn it can be turned if you can find someone with the proper equipment. If is probably more cost effective to just buy new drums. I could have bought new backing plate assemblies and drums and overhauled the brakes and they might have been better and might not. I posted a question on here and got varied responses. Some owners said they could lock their brakes, some said they couldn't. I decided to install disc brakes.


The discs provided about twice as much stopping power as my original brakes, tested by stopping the whole rig from 25 mph with just the trailer brakes. The post of my conversion is here:
http://www.airforums.com/forums/f439...ss-177345.html
The first post presents the test data, post 38 shows the conversion process.


The only disadvantage to the discs is a short lag, on the order of a half second or so, as the hydraulic pressure builds up. Even with this the overall stopping performance is so much better with discs I would never go back.


Edit - I forgot to mention that my 6300# Safari 25 had the same 4 12" electric brakes as my 9100# Classic 30. Stopping the 25, it felt well balanced and the combination stopped about the same as the truck alone. With the Classic, not so much.



Al

[2partners]

Al, Interesting about disc brakes. I didn't know that was an option. Can you recommend a tester for checking the amp draw at the blue wire? Thank you

[2partners]

Originally Posted by Al and Missy

Measure the current in the blue brake wire. At full power it should be around 3 amps per brake, i.e. 12 amps. This measurement can be made with a multimeter in the amps mode.

https://www.amazon.com/Sinometer-DT6.../dp/B00F68FHM2


The inexpensive clamp on ones do not have sufficient sensitivity or accuracy, particularly for DC. My Tekonsha P3 had a test mode that would actually show the voltage and current. If you are getting 12 amps then the problem, if there is one, is in the brake mechanism. They are prone to collect brake dust, dirt, and rust and should be cleaned and lubricated periodically, along with inspecting the bearings and packing them, if not NevRLube.


That said, I could not find anything wrong with the brakes on my Classic 30. I could not lock the brakes under any circumstances. If the magnets are working correctly and not worn they are attracted to the lug bolt surface of the drum, which pulls on the lever to activate the brakes. If this surface is worn it can be turned if you can find someone with the proper equipment. If is probably more cost effective to just buy new drums. I could have bought new backing plate assemblies and drums and overhauled the brakes and they might have been better and might not. I posted a question on here and got varied responses. Some owners said they could lock their brakes, some said they couldn't. I decided to install disc brakes.


The discs provided about twice as much stopping power as my original brakes, tested by stopping the whole rig from 25 mph with just the trailer brakes. The post of my conversion is here:
http://www.airforums.com/forums/f439...ss-177345.html
The first post presents the test data, post 38 shows the conversion process.


The only disadvantage to the discs is a short lag, on the order of a half second or so, as the hydraulic pressure builds up. Even with this the overall stopping performance is so much better with discs I would never go back.


Edit - I forgot to mention that my 6300# Safari 25 had the same 4 12" electric brakes as my 9100# Classic 30. Stopping the 25, it felt well balanced and the combination stopped about the same as the truck alone. With the Classic, not so much.



Al

I see you did recommend a meter. Missed it somehow. Thanks

[Night owls]

I also have a Ram a 2500 and can't get the trailer brakes to lock up. I've as a precaution taken it to the dealer to have the brake controller inspected and everything checked out fine. They explained that the newer trucks work more on inertia so as to the harder you press your brake pedal the more stopping power your trailer gets but without locking the brakes. Don't know if that is accurate but does seem to be the case. I run mine at a gain of 6 and have never had any issues stopping suddenly. Even if I had it set at 10 I am unable to lock the brakes. And that is also the case with our last SOB trailer previously owned so your situation may be perfectly normal. Let us know how it goes.

[polarlyse]

Haven't seen it mentioned yet so here goes. You didn't say if you had shoe brakes or disc so I'll assume you have shoes since the discs are a high priced option and you'd likely know if you spent that much. So, they need to be adjusted periodically and that's either done manually or through a self adjusting mechanism as part of the brakes. Again, you should either know that one or find out. If they are manual you need to learn how to adjust them or take them and have them adjusted and if they are automatic you need to manually apply them while driving at moderate speed to activate the mechanism that does the adjustment. I suspect that normal low speed applications don't do it very well.

Remember the days of self adjusting shoe brakes on your car ??? You did that while backing. You would aggressively apply the brakes as you drove in reverse. These work differently in that they work while traveling forward.

[2partners]

Originally Posted by polarlyse

Haven't seen it mentioned yet so here goes. You didn't say if you had shoe brakes or disc so I'll assume you have shoes since the discs are a high priced option and you'd likely know if you spent that much. So, they need to be adjusted periodically and that's either done manually or through a self adjusting mechanism as part of the brakes. Again, you should either know that one or find out. If they are manual you need to learn how to adjust them or take them and have them adjusted and if they are automatic you need to manually apply them while driving at moderate speed to activate the mechanism that does the adjustment. I suspect that normal low speed applications don't do it very well.

Remember the days of self adjusting shoe brakes on your car ??? You did that while backing. You would aggressively apply the brakes as you drove in reverse. These work differently in that they work while traveling forward.

Yes, I do remember those days. I was a mechanic then. They are drum brakes and if I have to check them I will. I'm just surprised at the suddenness of the problem. Thanks for your thoughts.

[GCinSC2]

Originally Posted by 2partners

Yes, I do remember those days. I was a mechanic then. They are drum brakes and if I have to check them I will. I'm just surprised at the suddenness of the problem. Thanks for your thoughts.

I checked the crystal ball, I see wheels off and a where are we now brake inspection in your near future.

Amp check is important but will not tell you if brakes are adjusted or mechanical condition only shows condition of electric brake wiring and magnet circuit an important part of the system.

Gary

[2partners]

Originally Posted by Night owls

I also have a Ram a 2500 and can't get the trailer brakes to lock up. I've as a precaution taken it to the dealer to have the brake controller inspected and everything checked out fine. They explained that the newer trucks work more on inertia so as to the harder you press your brake pedal the more stopping power your trailer gets but without locking the brakes. Don't know if that is accurate but does seem to be the case. I run mine at a gain of 6 and have never had any issues stopping suddenly. Even if I had it set at 10 I am unable to lock the brakes. And that is also the case with our last SOB trailer previously owned so your situation may be perfectly normal. Let us know how it goes.

Thanks for this Night Owls. I wasn't aware of the inertia braking and will see if ours (2010) has this. I am VERY aware however of the highway (74) being closed though. Noticed you are in Hemet. Sure is taking a long time...

[Al and Missy]

Originally Posted by Night owls

I also have a Ram a 2500 and can't get the trailer brakes to lock up. I've as a precaution taken it to the dealer to have the brake controller inspected and everything checked out fine. They explained that the newer trucks work more on inertia so as to the harder you press your brake pedal the more stopping power your trailer gets but without locking the brakes. Don't know if that is accurate but does seem to be the case. I run mine at a gain of 6 and have never had any issues stopping suddenly. Even if I had it set at 10 I am unable to lock the brakes. And that is also the case with our last SOB trailer previously owned so your situation may be perfectly normal. Let us know how it goes.

The newer trucks use the brake line pressure, not deceleration, to help decide how much energy to apply to trailer brakes. At least my Ram does. My Tekonsha P3 had a deceleration sensor it it, but I don’t think my truck does. Either way you can use the braking lever to apply full braking power while sitting still or at slow speeds. While you don’t want the brakes to lock under normal use, you do want them to be just before locking up in a hard stop. If you can’t lock them when testing you don’t know what fraction of full braking power you are getting in normal use. In my case it was about half. Stopping my trailer in a hurry was scary. I had two panic stops after the disc conversion where I am totally convinced I would have hit the car in front of me if I hadn’t had the disc brakes. I drive to avoid those cases but sometimes they can’t be avoided.

Al

[2partners]

Originally Posted by GCinSC2

I checked the crystal ball, I see wheels off and a where are we now brake inspection in your near future.

Amp check is important but will not tell you if brakes are adjusted or mechanical condition only shows condition of electric brake wiring and magnet circuit an important part of the system.

Gary

Looks like your crystal ball and mine are similar, although, the image in mine isn't quite clear yet. Certainly, I'll do what is necessary. There's just something about solving the mystery in the fewest, least labor intensive steps. I understand what you are saying about condition etc. and I appreciate it. Thank you

[2partners]

Originally Posted by Al and Missy

The newer trucks use the brake line pressure, not deceleration, to help decide how much energy to apply to trailer brakes. At least my Ram does. My Tekonsha P3 had a deceleration sensor it it, but I don’t think my truck does. Either way you can use the braking lever to apply full braking power while sitting still or at slow speeds. While you don’t want the brakes to lock under normal use, you do want them to be just before locking up in a hard stop. If you can’t lock them when testing you don’t know what fraction of full braking power you are getting in normal use. In my case it was about half. Stopping my trailer in a hurry was scary. I had two panic stops after the disc conversion where I am totally convinced I would have hit the car in front of me if I hadn’t had the disc brakes. I drive to avoid those cases but sometimes they can’t be avoided.

Al

"If you can’t lock them when testing you don’t know what fraction of full braking power you are getting in normal use." This is what my gauge for testing brakes is. I got to the point of manually operating the brakes and could tell their effectiveness by how much and how quickly they slowed the TV without skidding, or at least with very little skidding. Since our driveway is gravel this was always done on gravel. Never tried it on pavement. From the responses it looks like some have been able to skid and others haven't. I think I'll call Dexter or AS and see if they can shed some light and let you know. Thanks!

[uncle_bob]

Hi

Be a bit careful about just how much braking you ultimately *do* use. You can indeed destroy the brakes on your trailer .....

The brake circuit is independent of the other pins on the 7 pin connector. They run from the brake wire to ground. To verify what's going on, you need to be sure you are on the brake wire.

If indeed the tires lock up when you pull the breakaway plug / manual application, then the issue is not in the trailer. You likely have a problem with the 7 pin it's self, the cable, the truck wiring, or the controller.

Bob

[guskmg]

If your brakes have been unused for a while rust builds up on the drums and it will take a few high speed stop applications to clean them off. On the disc brakes, there is no lag if you use Airstream’s DirecLink controller, it plug into the OBII port and detects the slightest pedal application. That feature and a proper gain adjustment and lag is eliminated. DirecLink also has a trailer brake anti skid option. I don’t have that option, but the system itself, really works smoothly. Their customer service is excellent. The firm name is Tuson.

[2partners]

Originally Posted by uncle_bob

Hi

Be a bit careful about just how much braking you ultimately *do* use. You can indeed destroy the brakes on your trailer .....

The brake circuit is independent of the other pins on the 7 pin connector. They run from the brake wire to ground. To verify what's going on, you need to be sure you are on the brake wire.

If indeed the tires lock up when you pull the breakaway plug / manual application, then the issue is not in the trailer. You likely have a problem with the 7 pin it's self, the cable, the truck wiring, or the controller.

Bob

Bob, I've been on the forums for a year or so now and always enjoy reading your take on things. My rule of thumb when it comes to brakes is when applying the brakes, if the pedal feels about the same as it does when the TT is not attached and there is no push and maybe a slight tug -- then that's pretty good. Do you think this is accurate? Please clarify something when you talk about the 7 pin. I'm not sure what you mean by, "They run from the brake wire to ground."? Thank you

[2partners]

Originally Posted by guskmg

If your brakes have been unused for a while rust builds up on the drums and it will take a few high speed stop applications to clean them off. On the disc brakes, there is no lag if you use Airstream’s DirecLink controller, it plug into the OBII port and detects the slightest pedal application. That feature and a proper gain adjustment and lag is eliminated. DirecLink also has a trailer brake anti skid option. I don’t have that option, but the system itself, really works smoothly. Their customer service is excellent. The firm name is Tuson.

Thank you for this. I hope Al reads it. Sounds like this is just what he needs to solve his slight lag problem. I thought about rust and this could have something to do with it. I'm going to work on the problem more this weekend now that I've got some more ideas. Thanks again.

[kb7our]

Interested in this thread as we also have a Ram but no issues and it works great. What brake type in the settings is being selected? Not sure I saw that from the OP or may have missed it.

[uncle_bob]

Originally Posted by 2partners

Bob, I've been on the forums for a year or so now and always enjoy reading your take on things. My rule of thumb when it comes to brakes is when applying the brakes, if the pedal feels about the same as it does when the TT is not attached and there is no push and maybe a slight tug -- then that's pretty good. Do you think this is accurate? Please clarify something when you talk about the 7 pin. I'm not sure what you mean by, "They run from the brake wire to ground."? Thank you

Hi

The brake circuit is wired so that 12V feeds in on the brake wire. The way the level of braking is controlled is that less than 12V is feed when less than full braking is required. You might read 6V on the brake wire on a very normal / properly working system as a result.

The other side of the brake system is the ground wire on the 7 pin connector. It's all that is in "common" between the brakes and the rest of the 7 pin wiring. If you have a flakey ground, you will notice the brakes having issues. You also should see weird stuff going on with the lights. Since ground can also happen via the hitch, ground issues are "interesting" to track down.

======

You need the trailer brakes to keep the trailer behind you . With no brakes at all, there is a risk of a jackknife and that's not a good thing at all. With absolutely zero information on trailer wrecks, there is no way to know how common jackknife (as opposed to sway) disasters are. None the less "zero braking" is indeed a bad thing.

Just how much braking you need / want / get / have is tough to judge. You *can* detect wheels locking up. The gotcha is ... that's to much braking. It is very much unclear what an easy measure is.

At lest to me, if you have the trailer brakes cranked up to the point that the trailer is doing most of the braking, that is to much on the trailer. They just aren't as big brakes as what you have on the typical TV. Toss in the whole disk / drum controversy and the TV wins to an even bigger degree.

What you can judge is stopping distance. You also can judge how the trailer behaves in a hard stop. Both are experience based and are not easy to quantify.

Ideally you would like to know how much "tension" is on the hitch during the entire stop. If the trailer keeps the hitch in tension the entire time, then the trailer brakes are being used to stop the TV (the trailer is pulling back on the TV). The more the hitch is in tension, the more the trailer is doing the stopping.

The other side of the setting range is the hitch never being in tension the TV is stopping the trailer. That's not really ideal either. What you want is a bit of tension, but not a whole lot. Without some pretty fancy gear, I don't know of a really good way to calibrate all that.

So in the real world, you likely are either going to be on the "not quite enough" or the "a bit to much" side of things. As long as we are talking about a little bit, it's not a big deal either way. What I'm really suggesting is that people get a bit to excited about cranking up the gain. They overheat the trailer brakes and when they need them ... they aren't there.

Bob