Changing out the surge brake actuator.

[FSH 210 Sport]

Update:

First tow yesterday, about 20 mins to the second closest lake to me.. 50-55 mph.

I pulled out my heat gun and found that the non brake hubs were 76* drivers side and 80* passenger side. The brake hubs were 118* drivers side and 150* passenger side. I checked them again when I got home and the temps were the same. I checked them with my fingers and the hotter side was too hot to leave my fingers on for anything but a moment, the other side a skosh longer.

The brake pads on the drivers side had a tiny bit of play when the brakes were released, not that way on the passenger side. So, being concerned there might be a stuck caliper I went out to investigate today. To be fair I had never checked them before, at least that I can remember. So both rims had about the same amount of brake dust on them. I started probing around with a screw driver and couldn’t get anything to budge with it, no surprises there. So.. I grabbed my trusty pry bar, the one that got the jet pumps free the first time and started very gently applying force to the passenger side, back and forth, eventually I got to where it was sliding freely about, I dunno, maybe 3/8” of an inch or less. Did that several times just to make sure there were no snags in the travel. Went up to the tongue an pumped the brakes back up to re set the caliper, this is important so you do not push brake fluid out of the master cylinder reservoir. Then went to work on the drivers side, surprisingly this side was actually stiffer than the hot / passenger side. After I go it moving freely back and forth I pumped the brakes back up again. The next lake I go to will probably be 1.5 hours away on flatter ground so the temp check should be interesting.

I highly recommend that anyone who has brakes on their trailer use a pry bar like I did and exercise the brake calipers in their floating slots just to make sure that they are not trying to seize up on you.

That pry bar worked really well for removing the jet pumps the first time and for today’s caliper check. The curved ends allowed me to get between the caliper and the leaf springs and gently apply pressure on the caliper and then pull the caliper back using the more flat end. .



Here’s a few pics of the pry bar in action.. just be very gentle with the pry bar, move it around some to make sure you are not getting all the force off center. It took quite a few applications of pressure and then pulling it back-bottom pic- to get it to start moving back and forth.







Thanks for all the likes guys.. what a flippin journey this has been.

 

[AZMark]

@FSH 210 Sport do you know if your brakes lock up solid when you manually press the actuator and then let the lock hold it?

I’ve got mine on jack stands right now for new tires and I can still turn the wheels by hand with the brakes locked in that position. It’s braking some and is hard to turn but if that’s as far as the actuator goes then I have a problem.

Noticed some rust on the inside of one rotor so I’ve been checking everything out.

 

[FSH 210 Sport]

@FSH 210 Sport do you know if your brakes lock up solid when you manually press the actuator and then let the lock hold it?

I’ve got mine on jack stands right now for new tires and I can still turn the wheels by hand with the brakes locked in that position. It’s braking some and is hard to turn but if that’s as far as the actuator goes then I have a problem.

Noticed some rust on the inside of one rotor so I’ve been checking everything out.

My first reaction to your question would be an emphatic no, you should not be able to turn the braking wheels with the actuator fully depressed and locked. Without being there and being able to manually apply the brakes and feel the actuator, I’d say there is air in the system. If someone applies the brakes manually with a screwdriver and holds it can you still turn the wheel?

If there’s a good layer of rust on a rotor and the trailer has been used recently then the brake pad has not been pushing on that rotor surface. Another possible indicator of air in the system. The reservoir has brake fluid correct?

The manual states that the break away system is designed to apply the brakes but not lock the tires, and when you apply the brakes and the “lock” holds the actuator in that position, it is in fact the break away system except you applied the break away manually instead of the cable applying the break away system. Having said that, a person should not be able to turn the wheels by hand with the break away system applied fully.

If you have not done so already, get a big jug of brake fluid, maybe two, and fully bleed the brakes. Start off by sucking the old dirty brake fluid out of the master cylinder with an irrigation syringe or suitable device then add the new fluid. Bleed them until the fluid comes out clear / looking like new fluid starting with the wheel furthest from the master cylinder. After you get clean fluid go back and forth from the port caliper to the starboard caliper do this at least six times, I was amazed how I kept getting air out after I thought all the air had been removed. Along the way you will notice a change in how the actuator feels as air is expelled from the system.

And make sure the calipers will move with a pry bar too, but only one at a time, after you compress the piston manually apply the brakes with the actuator and push the piston back out. If you collapse both pistons you’ll push brake fluid out of the master cylinder reservoir.

 

[FSH 210 Sport]

Update:

With the brakes properly bled, there’s way less movement in the hitch after coming to a stop and then starting out again most of the time it’s barely perceptible.

 

[AZMark]

My first reaction to your question would be an emphatic no, you should not be able to turn the braking wheels with the actuator fully depressed and locked. Without being there and being able to manually apply the brakes and feel the actuator, I’d say there is air in the system. If someone applies the brakes manually with a screwdriver and holds it can you still turn the wheel?

If there’s a good layer of rust on a rotor and the trailer has been used recently then the brake pad has not been pushing on that rotor surface. Another possible indicator of air in the system. The reservoir has brake fluid correct?

The manual states that the break away system is designed to apply the brakes but not lock the tires, and when you apply the brakes and the “lock” holds the actuator in that position, it is in fact the break away system except you applied the break away manually instead of the cable applying the break away system. Having said that, a person should not be able to turn the wheels by hand with the break away system applied fully.

If you have not done so already, get a big jug of brake fluid, maybe two, and fully bleed the brakes. Start off by sucking the old dirty brake fluid out of the master cylinder with an irrigation syringe or suitable device then add the new fluid. Bleed them until the fluid comes out clear / looking like new fluid starting with the wheel furthest from the master cylinder. After you get clean fluid go back and forth from the port caliper to the starboard caliper do this at least six times, I was amazed how I kept getting air out after I thought all the air had been removed. Along the way you will notice a change in how the actuator feels as air is expelled from the system.

And make sure the calipers will move with a pry bar too, but only one at a time, after you compress the piston manually apply the brakes with the actuator and push the piston back out. If you collapse both pistons you’ll push brake fluid out of the master cylinder reservoir.

Thank you.

It seems like this just started as it was just a light coat of rust on part of one rotor. I can push that master cylinder rod in as far as I can get a screwdriver into that access hole which is probably also a bad sign.

I haven’t had anyone around to help me yet which is why I’m kind of guessing on whether it’s working right or not. Looks like wifey is going to learn to bleed brakes.

 

[FSH 210 Sport]

Thank you.

It seems like this just started as it was just a light coat of rust on part of one rotor. I can push that master cylinder rod in as far as I can get a screwdriver into that access hole which is probably also a bad sign.

I haven’t had anyone around to help me yet which is why I’m kind of guessing on whether it’s working right or not. Looks like wifey is going to learn to bleed brakes.

Is there brake fluid in the reservoir?

 

[AZMark]

Is there brake fluid in the reservoir?

There was but it was only about 1/3 full. I topped it off before pumping it up with the screwdriver. I just need to flush and bleed them.

I was trying to short cut it until I had more time but this is usually how things go when I do that.

 

[FSH 210 Sport]

There was but it was only about 1/3 full. I topped it off before pumping it up with the screwdriver. I just need to flush and bleed them.

I was trying to short cut it until I had more time but this is usually how things go when I do that.

I’m guessing it sucked air at that level. Had you ever checked it before? Wondering if there is a leak somewhere or

 

[FSH 210 Sport]

Did a longer run today on the interstate at 65 mph, after about 50 miles there was a rest area and I slowed down very gradually so I wouldn’t build up heat in the braking hubs. Checked all four hubs with a heat gun, here’s what I observed. Hub temps after 65 mph on the highway for 50 miles was 108 front axle / brake axle 118° passengers side and in the sun, 88 front axle / brake axle 90° drivers side, outside air temp was 90°.

This was a good opportunity to check the hub temperature with functioning brakes without being in the hills.

 

[1WetBoat]

Did a longer run today on the interstate at 65 mph, after about 50 miles there was a rest area and I slowed down very gradually so I wouldn’t build up heat in the braking hubs. Checked all four hubs with a heat gun, here’s what I observed. Hub temps after 65 mph on the highway for 50 miles was 108 front axle / brake axle 118° passengers side and in the sun, 88 front axle / brake axle 90° drivers side, outside air temp was 90°.

This was a good opportunity to check the hub temperature with functioning brakes without being in the hills.

Those are similar numbers to what I saw on my trip a couple weeks ago. Measured it when I got off the highway and stopped for gas.

 

[anmut]

Glad I'm not the only one with an IR gun who's obsessed with checking temps on his trailer at every stop. Sometimes I wonder what others are thinking... LOL.

 

[Babin Farms]

Glad I'm not the only one with an IR gun who's obsessed with checking temps on his trailer at every stop. Sometimes I wonder what others are thinking... LOL.

Whenever we stop I’ll just walk around and touch the hubs with my fingers to find out if they’re too hot. Hasn’t let me down on any of my trailers in 25+ years.

 

[FSH 210 Sport]

Those are similar numbers to what I saw on my trip a couple weeks ago. Measured it when I got off the highway and stopped for gas.

Thanks for that info !

 

[FSH 210 Sport]

On the way home the drivers side, sunny side, was 109° / 111°, the passenger side was 113°/123°. So the higher temp side didn’t change much . All good, the hotter one probably just has a skosh less play than the other side, not hot enough to worry and it was consistent.

 

[FSH 210 Sport]

I’ve mentioned this before, with the surge brake properly bled not only do the brakes work very well, but when accelerating after a full stop there is minimal movement as the tongue pulls forward, if you just let off the brake and let the truck roll forward a few feet before applying the throttle I don‘t feel any movement at all from the surge brake.