Trouble with surge brakes going downhill

[sunbyrned]

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/

Yep! That's where I'm going to start, looking at my hitch height options. I'll try turning mine over first and see where that gets me. If that doesn't work, I'll get something with height options. Yours looks perfect. @swatski also posted a pic of one on page one of this thread. You might want to take a look at that one too. It's pretty sweet. It's on his second post and is embedded in the "quote". Thanks for your help!

 

[2kwik4u]

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.

I 100% agree. There is no replacement for experience. Period. You have significantly more experience with this mechanism than I do. I've rebuilt a couple, and used them a handful of times, (Interestingly enough one of those tows was on this exact hill with a early '90's 24ft cuddy cabin) but despise surge brakes so badly that if I have the opportunity to tow something with surge brakes I tend to pass all together.

There very well could be other complicating factors that aren't considered in just the math of the height change. Mechanism design, manufacturing tolerances, and a whole slew of other items come into play. If you do this on a daily basis and say that a level hitch works better, no amount of math can contradict that.

A level trailer is good for tire wear, towing dynamics, brake application, and many other reasons. It's a good place to start for all those reasons. I think he'll find something is awry elsewhere, but that doesn't mean he shouldn't level the trailer as well. I get carried away with root cause analysis and tend to overlook the small incremental changes helping along the way.

To summarize for those reading in the future, here's what the group has come up with:
- Check Spring in Actuator
- Check Plastic slide in Actuator
- Level Trailer and verify tongue weight
- Check fluid in reservoir, and bleed brakes
- Check for grease from bearing on braking surface

 

[2kwik4u]

@swatski

When you're towing, do you run that WeighSafe hitch the entire time you tow, or do you just use it as a tool to setup the hitch initially (both height and tongue weight), then swap to a more traditional steel drawbar/ball setup?

If you're using it all the time, have you had any issues with seals or mechanism wear within the ball mount/scale?

Looks like they're about $290 from Amazon. Might add this to the christmas list this year.

 

[sunbyrned]

I 100% agree. There is no replacement for experience. Period. You have significantly more experience with this mechanism than I do. I've rebuilt a couple, and used them a handful of times, (Interestingly enough one of those tows was on this exact hill with a early '90's 24ft cuddy cabin) but despise surge brakes so badly that if I have the opportunity to tow something with surge brakes I tend to pass all together.

There very well could be other complicating factors that aren't considered in just the math of the height change. Mechanism design, manufacturing tolerances, and a whole slew of other items come into play. If you do this on a daily basis and say that a level hitch works better, no amount of math can contradict that.

A level trailer is good for tire wear, towing dynamics, brake application, and many other reasons. It's a good place to start for all those reasons. I think he'll find something is awry elsewhere, but that doesn't mean he shouldn't level the trailer as well. I get carried away with root cause analysis and tend to overlook the small incremental changes helping along the way.

To summarize for those reading in the future, here's what the group has come up with:
- Check Spring in Actuator
- Check Plastic slide in Actuator
- Level Trailer and verify tongue weight
- Check fluid in reservoir, and bleed brakes
- Check for grease from bearing on braking surface

That's the beauty of this forum. Many experiences, opinions and knowledgable people to draw from. It all gives me a starting place to trouble shooting. Who knows what I'll find but at least I have an idea what to expect. I will return with what I discover. Thanks in advance everyone!

 

[swatski]

@swatski

When you're towing, do you run that WeighSafe hitch the entire time you tow, or do you just use it as a tool to setup the hitch initially (both height and tongue weight), then swap to a more traditional steel drawbar/ball setup?

If you're using it all the time, have you had any issues with seals or mechanism wear within the ball mount/scale?

Looks like they're about $290 from Amazon. Might add this to the christmas list this year.

I use it primarily as a tow hitch, hardly look at the scale to be honest.
It is the most solid hitch I ever had, by far, the way it fits in the receiver and adjusts, no rattling etc. Solid piece, very high quality.

--

 

[sunbyrned]

Okay, an update. I measured the hitch height before and after putting on the trailer. The bottom of the hitch before putting the boat on was at roughly 17.5”. After putting the boat on, the height was at 16”. The car dropped roughly 1.5”. However, I also show where the trailer needs to be to be level. When I put it on the hitch and lower it though, the car does not drop enough to get the boat at level. So, I think that rules out raising the hitch any. Perhaps I need to lower it a bit actually. Next on my list is to figure out how to tell if the actuator spring is broken. Pics are included but it may be hard to tell what I’m trying to demonstrate.

 

[Recoveringfiberglassaddic]

Im assuming this pic was taken with the tongue jack/wheel up and vehicle suspension is holding the tongue weight. Looks like that bubble is buried on the wrong side of the line.

 

[sunbyrned]

Im assuming this pic was taken with the tongue jack/wheel up and vehicle suspension is holding the tongue weight. Looks like that bubble is buried on the wrong side of the line.

Correct. Wheel up. The tongue would need to go further down to be level. In the other pic, I show it level but not on the hitch. The car won’t allow it it to get level.

 

[Recoveringfiberglassaddic]

Gotcha. So you need a little more drop in your hitch. Blows my riding low theory away. Brake bleed shouldnt be too expensive at a local trailer/tire shop. Or you can DIY it.

Good luck. Going to keep following this one closely.

 

[sunbyrned]

Gotcha. So you need a little more drop in your hitch. Blows my riding low theory away. Brake bleed shouldnt be too expensive at a local trailer/tire shop. Or you can DIY it.

Good luck. Going to keep following this one closely.

You saw where the bubble ended up. Was that enough to make it have the same effect? Do you think if I lowered the hitch to make the trailer level, that could still solve the problem? In other words, can your V illustration work the opposite as well?

 

[Julian]

You saw where the bubble ended up. Was that enough to make it have the same effect? Do you think if I lowered the hitch to make the trailer level, that could still solve the problem? In other words, can your V illustration work the opposite as well?

No, if anything, being hitch high should slightly reduce the pressure on your brakes....hitch height is not your issue.

 

[Recoveringfiberglassaddic]

You saw where the bubble ended up. Was that enough to make it have the same effect? Do you think if I lowered the hitch to make the trailer level, that could still solve the problem? In other words, can your V illustration work the opposite as well?

Not in my experience. Hitch high wont exacerbate braking like hitch low will. Gonna have to do some stretching so I can get my foot all the way into my mouth today ??

 

[swatski]

There are some caveats here, an obvious one is how flat/plane/even is that gravel parking lot. Also, the Shorlandr folding tongue hinge and the pin have some play so the tongue level may not represent trailer frame level super accurately. (albeit it does look like teh tongue is high, I don;t disagree!)
But most importantly, this is all static load. If the rear suspension is soft it may have enough bounce to momentarily squat enough to push the coupler under a low angle, just like @Recoveringfiberglassaddic describes. It would not need to be apparent in a flat driveway.

I'm probably the next one here to start stretching my leg (and put my foot in my mouth), lol. But speaking from my own experience with rear air-coils (in my case in a Toyota Landcruiser, so quite similar) - my ride is way firmer and more controlled with the bags inflated.

--

 

[sunbyrned]

There are some caveats here, an obvious one is how flat/plane/even is that gravel parking lot. Also, the Shorlandr folding tongue hinge and the pin have some play so the tongue level may not represent trailer frame level super accurately. (albeit it does look like teh tongue is high, I don;t disagree!)
But most importantly, this is all static load. If the rear suspension is soft it may have enough bounce to momentarily squat enough to push the coupler under a low angle, just like @Recoveringfiberglassaddic describes. It would not need to be apparent in a flat driveway.

I'm probably the next one here to start stretching my leg (and put my foot in my mouth), lol. But speaking from my own experience with rear air-coils (in my case in a Toyota Landcruiser, so quite similar) - my ride is way firmer and more controlled with the bags inflated.

--

Well, I’m kind of with you in that I wonder if going downhill still plays a factor in this. I think I’m going to go ahead and buy a hitch with height options, go to the steep road and try some different things out. I already have two new tires on the way so what the heck? I made sure the trailer was level the best I could on the gravel and tried different spots for the level to get a sense of an accurate reading. Good point though nonetheless. Thanks!

 

[2kwik4u]

I was talking to my friend with the 22ft cuddy cabin last night. He mentioned that he has "smoked the brakes" on his trailer a few times. Every single time it has been due to a failure to lubricate the actuator, having a heavy braking event (like an off ramp from the expressway), and the actuator "locking" itself into place. This forces the brakes to be somewhat engaged for the entirety of the trip, then when he needs them again at the ramp, they will overheat on the way down the hill.

So, perhaps your geometry is just fine, and all you need is to lubricate the slide in the actuator to prevent the heavy "pre-heat" on the brakes. Just another theory to throw out there.

I know the road in question does have a nice little "rolling dip" about 1/2 way down, wonder if that is "setting" the brakes, and they are releasing after that due to some binding in the actuator?

 

[sunbyrned]

I was talking to my friend with the 22ft cuddy cabin last night. He mentioned that he has "smoked the brakes" on his trailer a few times. Every single time it has been due to a failure to lubricate the actuator, having a heavy braking event (like an off ramp from the expressway), and the actuator "locking" itself into place. This forces the brakes to be somewhat engaged for the entirety of the trip, then when he needs them again at the ramp, they will overheat on the way down the hill.

So, perhaps your geometry is just fine, and all you need is to lubricate the slide in the actuator to prevent the heavy "pre-heat" on the brakes. Just another theory to throw out there.

I know the road in question does have a nice little "rolling dip" about 1/2 way down, wonder if that is "setting" the brakes, and they are releasing after that due to some binding in the actuator?

Perfect timing with this suggestion. Was planning on bleeding the brakes this evening, something I really wouldn’t mind postponing. I’ll take a look at this and various heights first. Thanks again!

 

[sunbyrned]

Update: I checked the boat level again on level pavement. It's spot on so I don't need a new hitch. The spring is not broken. I couldn't figure out how to lubricate the actuator but I sprayed WD40 onto the spring and in the coupler. So, I ended up bleeding the brakes. (I never did this before but there's a great how-to video by "Asian Bass Guy") While I was doing that, I recognized the smell of the fluid. It's the same smell as at the ramp so I was optimistic this could be the culprit. Took it out to the road in question and no locked up tires, no smoke or burning smell. I learned a lot, including how to replace a broken lug.(another story) Can't thank everyone enough. Next time I see you, beer is on me! Thanks for all the time and advice. I now know my trailer much better, which is a good thing.