Trouble with surge brakes going downhill

[sunbyrned]

I was mainly trying to get a idea of height of the truck. I pull my 21ft with a f150 . I use a 0 drop hitch, meaning its level coming out of the hitch receiver. I also use a stiffer shock in the rear. A fox 2.0 shock, this helps with sag a lot. I don't know about Nissans shocks but fords are horrible. The fox shock is difficult to compress, the ford shock was so easy. With a 24 footer, I would probably look at something like that as well. It will tighten up the back end a lot, in the f150 it takes the bed hop away.

I gotcha. Next time I hook it up I’ll measure the height before and after and let you know. Shocks is something I haven’t considered either bu probably should. This thing is so bouncy everyone gets car sick. They blame it on my driving but perhaps it’s the shocks.

 

[djetok]

I gotcha. Next time I hook it up I’ll measure the height before and after and let you know. Shocks is something I haven’t considered either bu probably should. This thing is so bouncy everyone gets car sick. They blame it on my driving but perhaps it’s the shocks.

a quick search for a armada does not show a fox shock is available. Not knowing the year, I put in 2017, it does show a Bilstein 5100 available for the rear. You might want to look at a air bag setup if flipping it doesn't help enough. Keep in mind though, you could always try a bigger drop flipped as well, at some point though it might interfere with the rear gate opening. It looks like you are using a 2inch drop hitch now.

 

[swatski]

I gotcha. Next time I hook it up I’ll measure the height before and after and let you know. Shocks is something I haven’t considered either bu probably should. This thing is so bouncy everyone gets car sick. They blame it on my driving but perhaps it’s the shocks.

I totally agree with @djetok. I tow with a similar vehicle to your Armada, my squat was not bad maybe 1” when sitting but aftermarket air coils inflated to 25psi helped a lot with my towing comfort especially with dynamic loads when moving.

—

 

[sunbyrned]

a quick search for a armada does not show a fox shock is available. Not knowing the year, I put in 2017, it does show a Bilstein 5100 available for the rear. You might want to look at a air bag setup if flipping it doesn't help enough. Keep in mind though, you could always try a bigger drop flipped as well, at some point though it might interfere with the rear gate opening. It looks like you are using a 2inch drop hitch now.

It’s a 2012. All good suggestions. One of the reasons why I love this forum. I’ll experiment with flipping the hitch first and go from there.

 

[djetok]

I gotcha. Next time I hook it up I’ll measure the height before and after and let you know. Shocks is something I haven’t considered either bu probably should. This thing is so bouncy everyone gets car sick. They blame it on my driving but perhaps it’s the shocks.

put a level on the tongue, this will be your best indicator. Then you can look at tongue weight and moving the post of the trailer to get in the ballpark if your over on your tongue weight. Towing a trailer that is weighted and towed at the proper height is something that once you have it right you will enjoy.

 

[2kwik4u]

A @sunbyrned Which lake? I'm local and know a few, just curious which is causing you the problems. I remember the decent into a few of Cumberlands marina's being sketchy at best.

To address some of the other comments above (as if someone asked me), the angle created by the tongue being downhill due to a low ball height will create no change in the horizontal force dictated by the stopping motion of the trailer. Just because something is angled down, does not mean the direction of the force changes. Put a trailer on flat pavement. Lower the tongue jack until it's as low as it can go. Does the trailer suddenly start moving forward? The reaction force INTO the trailer from the ground will change angle in relation to the trailer frame, but not in relation to the ground. The hitch is the ground in this case. A level trailer is best for a myriad of reasons, but this is not the culprit here. I'll be happy to draw the free body diagrams for anyone interested. I just scribbled them myself before posting to make sure what I had in my head was correct.

*edit*.......this is a quick edit, I can see how the force into the actuator from the hitch being low can increase. I was looking at the wrong side of the FBD. Figures that I type something out only to review it and see the other side as soon as I post. Anywho, the reaction force change will be the sine of the angle change x the tongue weight. So a 500lb tongue weight at a 10deg decline would add 56lb load (~17%) on the actuator. The angle is much likely FAR less than that. Assume a 24ft wheel to hitch distance and a 3in drop on the hitch is only ~ 0.5deg drop. Which equates to a 5.2lb force on the actuator.......I stand by the statement of it not being the culprit in this case, but revise my stance on no additional force.......There is some additional force, but wow is it small.

For the issue at hand, and how to remedy it.......I'm not sure. Without locking out the brakes before going downhill then the surge system will remain active and braking. It's doing what it's supposed to, it just doesn't have the thermal capacity for the long steep downgrade.

Best option is to move to electrics, or an electric over hydraulic system, but that's spendy and not something that gets done overnight.

 

[sunbyrned]

A @sunbyrned Which lake? I'm local and know a few, just curious which is causing you the problems. I remember the decent into a few of Cumberlands marina's being sketchy at best.

To address some of the other comments above (as if someone asked me), the angle created by the tongue being downhill due to a low ball height will create no change in the horizontal force dictated by the stopping motion of the trailer. Just because something is angled down, does not mean the direction of the force changes. Put a trailer on flat pavement. Lower the tongue jack until it's as low as it can go. Does the trailer suddenly start moving forward? The reaction force INTO the trailer from the ground will change angle in relation to the trailer frame, but not in relation to the ground. The hitch is the ground in this case. A level trailer is best for a myriad of reasons, but this is not the culprit here. I'll be happy to draw the free body diagrams for anyone interested. I just scribbled them myself before posting to make sure what I had in my head was correct.

For the issue at hand, and how to remedy it.......I'm not sure. Without locking out the brakes before going downhill then the surge system will remain active and braking. It's doing what it's supposed to, it just doesn't have the thermal capacity for the long steep downgrade.

Best option is to move to electrics, or an electric over hydraulic system, but that's spendy and not something that gets done overnight.

I’m learning a lot through all this. Can’t wait to find the solution. The lake is Taylorsville Lake, the marina ramp. That is the only place I experience this issue, but it happens every time. The guy behind me didn’t think my tires were spinning at all. It doesn’t feel like I’m dragging them down the road though. They’re just smoking like hell at the end. Ha!

 

[2kwik4u]

I’m learning a lot through all this. Can’t wait to find the solution. The lake is Taylorsville Lake, the marina ramp. That is the only place I experience this issue, but it happens every time. The guy behind me didn’t think my tires were spinning at all. It doesn’t feel like I’m dragging them down the road though. They’re just smoking like hell at the end. Ha!

I was just out there on Saturday. That ramp at Settlers Trace is significantly steep, and goes for a good distance. I've had other, large boats out there at that ramp without this problem. Your boat isn't white with blue graphics is it? saw a nice 24ft anchored for a long time at a bend up towards the far end of the lake where it hangs a right. We anchored over near shore for a bit. Was that you?

Something to check would be the return spring on the sliding hitch assembly. A weak or broken spring there would allow too much movement in the actuator which would lead to increased brake application.

 

[sunbyrned]

I was just out there on Saturday. That ramp at Settlers Trace is significantly steep, and goes for a good distance. I've had other, large boats out there at that ramp without this problem. Your boat isn't white with blue graphics is it? saw a nice 24ft anchored for a long time at a bend up towards the far end of the lake where it hangs a right. We anchored over near shore for a bit. Was that you?

Something to check would be the return spring on the sliding hitch assembly. A weak or broken spring there would allow too much movement in the actuator which would lead to increased brake application.

The ramp’s not the issue, it’s the road that gets me there when this happens. I’ll check the spring. Good advice! Thank you! This entire thing will give me a chance to get to know my trailer better, which I need to learn about anyway.

My boat has a black hull and white top so that was not me out there. I’ll send you a note next time I go and see if you’re heading there too. Side note, someone drowned out there on Saturday I believe. Different ramp area though.

 

[djetok]

A @sunbyrned Which lake? I'm local and know a few, just curious which is causing you the problems. I remember the decent into a few of Cumberlands marina's being sketchy at best.

To address some of the other comments above (as if someone asked me), the angle created by the tongue being downhill due to a low ball height will create no change in the horizontal force dictated by the stopping motion of the trailer. Just because something is angled down, does not mean the direction of the force changes. Put a trailer on flat pavement. Lower the tongue jack until it's as low as it can go. Does the trailer suddenly start moving forward? The reaction force INTO the trailer from the ground will change angle in relation to the trailer frame, but not in relation to the ground. The hitch is the ground in this case. A level trailer is best for a myriad of reasons, but this is not the culprit here. I'll be happy to draw the free body diagrams for anyone interested. I just scribbled them myself before posting to make sure what I had in my head was correct.

*edit*.......this is a quick edit, I can see how the force into the actuator from the hitch being low can increase. I was looking at the wrong side of the FBD. Figures that I type something out only to review it and see the other side as soon as I post. Anywho, the reaction force change will be the sine of the angle change x the tongue weight. So a 500lb tongue weight at a 10deg decline would add 56lb load (~17%) on the actuator. The angle is much likely FAR less than that. Assume a 24ft wheel to hitch distance and a 3in drop on the hitch is only ~ 0.5deg drop. Which equates to a 5.2lb force on the actuator.......I stand by the statement of it not being the culprit in this case, but revise my stance on no additional force.......There is some additional force, but wow is it small.

For the issue at hand, and how to remedy it.......I'm not sure. Without locking out the brakes before going downhill then the surge system will remain active and braking. It's doing what it's supposed to, it just doesn't have the thermal capacity for the long steep downgrade.

Best option is to move to electrics, or an electric over hydraulic system, but that's spendy and not something that gets done overnight.

The leveling of the trailer will allow for equal weight distribution and will also give you equal brake application, since the weight is distributed better. Regardless of brakes the trailer should be as level as possible.

When your traveling down hill with 5k plus behind you, you have to control it.

 

[Sbrown]

I'll throw another couple of thoughts at you. The first thing that comes to mind and would be the first thing I would check is simply this: look at your grease seals on the back side of your hubs and see if there is signs of grease coming out, usually it'll leak a bit and is positioned such that the grease being flung about usually goes into the rotor cooling fins, which are between the front and rear friction surfaces. Then when the rotor gets a bit more heat into it than usual, the heated grease smokes like green pine needles on a campfire. Makes you think there's a bigger problem than there actually is.

Second thought is if its a big enough concern and the brakes are actually overheating, add a set of brakes to the rear axle, or if the trailer already has brakes on both axles, upgrade the the next larger brake size. Usually on our trailers that means upgrading the 10 inch brakes to 12 inch brakes.
Being up in Pa near the Poconos, I tow a lot of uphill/downhill and have had to deal with exactly this same issue before, myself. It is far better to overheat the trailer brakes than it is to overheat the tow vehicle brakes.

 

[sunbyrned]

I'll throw another couple of thoughts at you. The first thing that comes to mind and would be the first thing I would check is simply this: look at your grease seals on the back side of your hubs and see if there is signs of grease coming out, usually it'll leak a bit and is positioned such that the grease being flung about usually goes into the rotor cooling fins, which are between the front and rear friction surfaces. Then when the rotor gets a bit more heat into it than usual, the heated grease smokes like green pine needles on a campfire. Makes you think there's a bigger problem than there actually is.

Second thought is if its a big enough concern and the brakes are actually overheating, add a set of brakes to the rear axle, or if the trailer already has brakes on both axles, upgrade the the next larger brake size. Usually on our trailers that means upgrading the 10 inch brakes to 12 inch brakes.
Being up in Pa near the Poconos, I tow a lot of uphill/downhill and have had to deal with exactly this same issue before, myself. It is far better to overheat the trailer brakes than it is to overheat the tow vehicle brakes.

Okay, cool! I'll check on both those suggestions. I have no idea what size brakes I have or what tires have brakes being applied to them. Certainly something I would have never thought about. Thanks for chiming in!

 

[grywlfbg]

Anywho, the reaction force change will be the sine of the angle change x the tongue weight. So a 500lb tongue weight at a 10deg decline would add 56lb load (~17%) on the actuator. The angle is much likely FAR less than that. Assume a 24ft wheel to hitch distance and a 3in drop on the hitch is only ~ 0.5deg drop. Which equates to a 5.2lb force on the actuator.......I stand by the statement of it not being the culprit in this case, but revise my stance on no additional force.......There is some additional force, but wow is it small.

I don't have anything to add to the thread, but I just wanted to say that I'm glad we have some proper nerds here

 

[Betik]

Surprisingly I do agree with @Sbrown
Making sure both axles have brakes is a good idea especially if you are going downhill. Since I upgraded my trailer brakes ( post to come in next month or so), my trailer can actually stop itself and the truck. Before my upgrade I felt that the trailer was not pushing my truck. Now I feel the trailer actually stopping the truck. Still piling with electric controller gains level but if I hit the brakes I can feel it.
If I read your post correctly you are doing 35mph for 1 mile, right ??? Your friend also said that you were smoking the hole way down the hill..... I can’t see how those brakes will heat so quickly in 2 minutes of light and then heavy breaking. Maybe at the very end but the whole way!!! Unless you are cooking them prior to getting on that hill you should see them heat up like in such a short distance.

 

[2kwik4u]

Surprisingly I do agree with @Sbrown
Making sure both axles have brakes is a good idea especially if you are going downhill. Since I upgraded my trailer brakes ( post to come in next month or so), my trailer can actually stop itself and the truck. Before my upgrade I felt that the trailer was not pushing my truck. Now I feel the trailer actually stopping the truck. Still piling with electric controller gains level but if I hit the brakes I can feel it.
If I read your post correctly you are doing 35mph for 1 mile, right ??? Your friend also said that you were smoking the hole way down the hill..... I can’t see how those brakes will heat so quickly in 2 minutes of light and then heavy breaking. Maybe at the very end but the whole way!!! Unless you are cooking them prior to getting on that hill you should see them heat up like in such a short distance.

I've driven the hill in question many times. it's long enough and steep enough that you really do question your brakes from time to time. My truck can not maintain speed with just gearing alone, and that is with a little 19ft boat behind it. I'm certain a 24ft would be a handful. It's not very wide either, and that doesn't help the "pucker factor" of the drive.

Here is the elevation profile of the road in question. This is from the flattest part I know of at the top all the way down to the ramp. It's about 1/2 mile or so. Two spots over 10% grade for a decent distance. Total drop is 165ft of elevation in 0.53 miles



It's steep and sketchy decent. Still shouldn't be heating the brakes like that though, something is awry with that trailer.

 

[sunbyrned]

I've driven the hill in question many times. it's long enough and steep enough that you really do question your brakes from time to time. My truck can not maintain speed with just gearing alone, and that is with a little 19ft boat behind it. I'm certain a 24ft would be a handful. It's not very wide either, and that doesn't help the "pucker factor" of the drive.

Here is the elevation profile of the road in question. This is from the flattest part I know of at the top all the way down to the ramp. It's about 1/2 mile or so. Two spots over 10% grade for a decent distance. Total drop is 165ft of elevation in 0.53 miles

View attachment 102110

It's steep and sketchy decent. Still shouldn't be heating the brakes like that though, something is awry with that trailer.

WOW! That's impressive! What do you do for a living? Yep, it's that last third that's killing me. @Betik, the smoke was only happening on the steepest part of the down slope at the very end, as you're suggesting is a possibility. Not the entire half mile or so. Thanks for trying to help me figure this out. I'll work on leveling and check the coupler spring first and go from there.

 

[2kwik4u]

WOW! That's impressive! What do you do for a living?

R&D Engineer for a local manufacturing company.

I'll work on leveling and check the coupler spring first and go from there.

Level trailer will help all around towing for sure. The spring is my bet, obviously. @Sbrown suggestion of grease on the rotors is equally as likely though, and would create similar symptoms.

Harbor Freight has cheap IR thermometer guns. Worth the $10 to monitor hub and brakes temps.

Ohhhh, just had another thought. If you have a failing bearing on the brakes axle, then it could be exceptionally hot to begin the descent, and the brakes are just adding enough to smoke. Might be worth a stop at the gas station at the entrance to check the hubs before descent next time.

 

[sunbyrned]

R&D Engineer for a local manufacturing company.



Level trailer will help all around towing for sure. The spring is my bet, obviously. @Sbrown suggestion of grease on the rotors is equally as likely though, and would create similar symptoms.

Harbor Freight has cheap IR thermometer guns. Worth the $10 to monitor hub and brakes temps.

Ohhhh, just had another thought. If you have a failing bearing on the brakes axle, then it could be exceptionally hot to begin the descent, and the brakes are just adding enough to smoke. Might be worth a stop at the gas station at the entrance to check the hubs before descent next time.

Thanks! I checked the bearings (because honestly that's all I knew to try) and they were fine. Now I know what else to look for though. Hopefully, if I trouble shoot well enough, this won't happen again.

 

[Recoveringfiberglassaddic]

2kwick, you obviously have a lot more education and math skills than me. Theres only one variable that I would offer into your math.

The little plastic skid plate in the actuator assembly. When the ride height is low in my experience the plate offers very little friction in the equation. With the tongue level the skid plate starts offering up a friction co-efficient that has to be overcome before the brake cylinder comes into play. Because the actuator pivots a bit in the trailer tongue.

I push surge brake equipped trailers around the lot on a forklift all day. It's a personal game for me to not put the lockout in. If you carry the trailer low it will lock up super easy. If you keep tongue height high you can often push trailers in forward and reverse with no lockout in place.

Its the trailers that need a brake bleed that hose you. Just my experience. I'm sure Im wrong.

My take is correcting ride height and throwing a brake bleed at the trailer cant hurt anything.

 

[WestMIJet]

This forum is great. Everyone is always helping out. You can find a bunch of threads on here about leveling your trailer and hitch connection. I went through the same process, after that I realized I needed to increase the height of my hitch. I posted this when I was done. I have a nice inexpensive steel hitch option and if you read down the thread there is also a slightly more but what I would call and inexpensive aluminum option as well. You might want a hitch like this, it will help you dial it in.

https://jetboaters.net/threads/height-adjustable-hitch.23187/