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Old     (john211)      Join Date: Aug 2008       08-30-2010, 8:25 AM Reply   
My trailer this year has sure been a PITA. I had the Ďsurge brake actuatorí replaced this Spring, and now Iím replacing all four tires.

I did a rough estimate. With 280 hours on a 2006 boat bought new (and guessing 120 trailer miles for every 5 boat hours), I did not get 7,500 miles on these parts nor 75 launches.

I think I should have gotten better ... a lot better !!! Anyway, as I did not, attached below are some pics of the replaced surge brake actuator Ė just because in my time on this board Iíve never seen another pic of any, and it is a curious chunk of metal. I bet this could be re-furbished.
Attached Images
Old     (alans)      Join Date: Aug 2005       08-30-2010, 8:45 AM Reply   
Why does the solenoid look melted?
Old     (newty)      Join Date: May 2005       08-30-2010, 9:03 AM Reply   
Alan, I'll bet its just the paint bubbling off from the brake fluid leaking.

John what failed? You sure you don't just have a leak and emptying the resivoir?
Old     (alans)      Join Date: Aug 2005       08-30-2010, 9:08 AM Reply   
Good call on the paint. Yea, I want to know what failed? Everything looks good in the pics.
Old     (helinut)      Join Date: Apr 2007       08-30-2010, 9:39 AM Reply   
Funny to see this here this morning. I was just working on mine last night. I had to bleed the brakes like crazy. I'm now doubting my brakes ever worked from the day I picked the boat up 3 years ago. There was a bunch of air in the lines. They work now though! I need to take it out to see what it feels like to have trailer brakes.
Old     (Jeff)      Join Date: May 2010       08-30-2010, 9:42 AM Reply   
Parts can be replaced individually. That looks like a UFP A-60:

The main parts are a master cylinder, a shock, spring and a reversing solenoid. There are several small parts in there but they're relatively inexpensive. If it's well worn it's about the same price to replace the whole thing if you're looking at replacing the shock and the master cylinder plus a few small parts.

I was 90% sure mine was bad but didn't feel like spending the money. The reservoir was full of rust so I flushed it out with clean brake fluid. Sucked the old stuff out with a syringe the put new stuff in. Sucked the new stuff out and replaced it about 10-15 times until the fluid came out looking almost clear. Then I bled the brakes with a power bleeder several times. After that the brakes actually work and the actuator is 10 years old.
Old     (Jeff)      Join Date: May 2010       08-30-2010, 9:48 AM Reply   
Also, I would expect the actuator to last for years and tens of thousands of miles if used in fresh water and the fluid is changed regularly.
Old     (john211)      Join Date: Aug 2008       08-30-2010, 9:49 AM Reply   
My dealership and myself never made a definitive determination what was wrong. But the problem denied my the first 3 trips of the year. So I had it replaced.

Evidently, the trailer brakes were constantly applied. I would accelerate up to 35 mph or so, and the trailer brakes would heat up and brake so hard as to pull me down to a creep, then a stop.

While the brakes were hot, the dealership could jack up the trailer and show to itself and to me that all 4 trailer tires were locked (to being spun by hand, but it was possible to push or pull with the tow vehicle and they might (or might not) spin ... and if they did spin, the brakes were still applied then too).

When the brakes would cool down (say, next morning), the dealership by tractor could push and pull the trailer (real slow) without the problem repeating. And so I’d set off again for a next trip, and same problem. I never got a quarter mile away. The last time for me, the dealership came out to the side of the highway, and bled the brake fluid off. That let me return to the dealership with actuator disabled.

They guessed at the time that it was something between the cylinder and the solenoid. We reviewed options of servicing one, the other or both of the cylinder and solenoid ... versus complete replacement. Being impatient to get out on the water, I just had it replaced.

I gotta get to work. I cannot return for a day or two now. But I might check that paint on the solenoid and see if it looks heat melted or chemically attacked.
Old     (Jeff)      Join Date: May 2010       08-30-2010, 10:04 AM Reply   
It definitely looks like the brake fluid just ate the paint.

Brakes locking can be water in the system. The water sits in there and works similar to brake fluid when everything's cool. Then things get hot and the brakes start working and the water boils. Water turns into seam at a rate of something like 10,000:1 at atmospheric air pressure. So, the steam effectively applies the brakes by artificially increasing pressure in the braking system.
Old     (alans)      Join Date: Aug 2005       08-30-2010, 11:13 AM Reply   
Nice ^^^ Jeff knows his brakes. Not many other possibilities, hydraulic disks can not engage themselves.
Old    SamIngram            08-30-2010, 11:40 AM Reply   
Originally Posted by Jeff View Post
It definitely looks like the brake fluid just ate the paint.

Brakes locking can be water in the system. The water sits in there and works similar to brake fluid when everything's cool. Then things get hot and the brakes start working and the water boils. Water turns into seam at a rate of something like 10,000:1 at atmospheric air pressure. So, the steam effectively applies the brakes by artificially increasing pressure in the braking system.
Sorry, but all my mechanical engineering courses say this ain't so!

Conventional glycol-based brake fluid is hygroscopic, which means that it absorbs water. This is important, in order to keep condensation in the brake system from causing corrosion. However, eventually, the fluid will absorb all the moisture it can hold, reaching its point of saturation. Several things can happen at this point. Unabsorbed moisture can begin to collect in the system, causing corrosion in critical areas; the water can cause seals to swell and deteriorate, further contaminating the fluid; and the boiling point of of the fluid drops beyond recommended levels. This means that under high-heat braking conditions, such as during hard braking or repeated brake application while descending a mountain, the fluid will start boiling sooner, which will reduce braking performance. The pedal can begin to feel spongy, and as braking efficiency drops, it takes longer to stop the vehicle.

Steam can not operate a hydraulic system. What is probably happening is that the seals are going bad expand enough to displace either the fluid or mechanical components to KEEP the brakes engaged after being used and then locking up...
Old     (john211)      Join Date: Aug 2008       08-30-2010, 11:49 AM Reply   
I dunno about the water theory. The actuator was locked in its nearly fully compressed extreme (about 3/16 inch away from the pin limiting out at the front end of the about 2-1/2 inch long slot). I could pull the trailer forward to the point of skidding the tires and the actuator wouldn't pull extended at all from where it was locked. As soon as we bled the brake fluid, it slid freely.
Old     (Jeff)      Join Date: May 2010       08-30-2010, 11:49 AM Reply   
Originally Posted by SamIngram View Post
Sorry, but all my mechanical engineering courses say this ain't so!
Hmmm...... I was really just repeating something I had been told. I've never had first hand experience with them locking up due to moisture.
Old     (alans)      Join Date: Aug 2005       08-30-2010, 11:50 AM Reply   
Sam, good point. But what, then, would cause a linear increase in breaking pressure?
Old     (alans)      Join Date: Aug 2005       08-30-2010, 11:53 AM Reply   
John, that is strange, really strange.
Old    SamIngram            08-30-2010, 11:58 AM Reply   
They can lock due to moisture, the seals expand... Its a possibility that the fluid reached its point of saturation and the remaining water was then absorbed by the seals and locked the system...

The more probable reason is that the system was/is contaminated and the actuator locked as a result of expanding/bad seals. When he bled the system he reduced the overall pressure in the system letting the actuator break free. If this is case, when the actuator was changed I hope someone fully bled the system, otherwise another failure will probably happen again.
Old    SamIngram            08-30-2010, 11:59 AM Reply   
The solenoid could also be bad...
Old     (newty)      Join Date: May 2005       08-30-2010, 1:13 PM Reply   
Originally Posted by SamIngram View Post
The solenoid could also be bad...
Kinda what I was thinking. It's not letting the cylinder pull the fluid back when the break is released after a stop.

Or... is the solenoid installed backwards or wrong solenoid hot to dis-engauge instead of hot to engauge?

Last edited by newty; 08-30-2010 at 1:21 PM.
Old     (Jeff)      Join Date: May 2010       08-30-2010, 1:24 PM Reply   
Is this on a MasterCraft trailer? They had some bad calipers that were notorious for locking up. Most people with affected trailers have gone to Kodiak calipers.
Old    SamIngram            08-30-2010, 1:51 PM Reply   
The Kodiak Trailer Components are good stuff!!
Old     (chpthril)      Join Date: Oct 2007       08-30-2010, 3:26 PM Reply   
It's amazing what a couple shots of lube on the actuator keeps it freed up and prevents it from sticking an keeping the breaks applied.
Old     (john211)      Join Date: Aug 2008       08-31-2010, 9:01 AM Reply   
Never noticed before but, this thing disassembles ... like so. The solenoid looks fine. Itís halfway covered in a sock of like electric tape material. This could have so easily been re-built.

I know nothing about the calipers except the dealership and myself never suspected anything wrong with them (and do not today). This actuator was taken out of a 2004 Prestige trailer (for a 2006 Nautique 211. I have no idea why the trailer is two years older than the boat. It sure looked new when bought ... and Iím pretty sure it was at least un-used elsewhere. It was the license bureau told me about the age difference).
Attached Images
Old     (newty)      Join Date: May 2005       08-31-2010, 2:03 PM Reply   
From the looks of that solenoid I'll bet thats the problem. Effected either by heat or pressure.
Whats a new solenoid cost? That to me would be the only culprit, other than sticking brake cylinders.

Have you checked your wiring, and made sure your back-up lead isn't switched with something else or grounded?

Last edited by newty; 08-31-2010 at 2:11 PM.
Old     (john211)      Join Date: Aug 2008       08-31-2010, 2:23 PM Reply   
You know Newty, I couldn't reverse the trailer for the last 2 (of 4) years and always had to block the slide with bolts in the slot. I bet that solenoid had gone bad a long time ago. All seems solved now in Drive with the new actuator, but I will check the wiring condition for Reverse so as not to have another early failure of the solenoid.

And as I originally mentioned, getting less than 7,500 miles out of the tires burns me up just as much as the actuator.
Old    SamIngram            08-31-2010, 2:40 PM Reply   
The back-up solenoid valve is sold through Kodiak for about $50.

Take those four allen head screws off the cylinder and take a picture. Does it look like a regular brake cylinder? Just curious.
Old     (alans)      Join Date: Aug 2005       08-31-2010, 2:46 PM Reply   
Or $44
Old     (john211)      Join Date: Aug 2008       08-31-2010, 3:18 PM Reply   
Thanks Sam and Alan for identifying the solenoid.

Here's what the Buddy information says.

“The electrical lead from the solenoid valve (usually a blue wire) must be connected to the tow vehicles back-up lights. A ‘click’ should be heard when the tow vehicle is shifted into reverse and the back-up lights come on.”

I'll go out and listen for that click next time out. Here's what else the Buddy information says.

“This solenoid valve is fail-safe. That is, it will not open if it were to malfunction so the user will always have brakes when towing forward.”

OK .. so if it was malfunctioning and wouldn't open, could it trap pressurized brake fluid trapped behind it? I don't know. I'm giving up thinking about it. But I do see that all the parts are available. This could be easily re-built.

Hey Sam, in a day or two I'll post that picture you ask about. I'm curious too now.
Old     (superairdawg)      Join Date: May 2003       08-31-2010, 4:03 PM Reply   
You can definitely rebuild those actuators. Good article on it here --
Old     (Silverbullet555)      Join Date: May 2010       08-31-2010, 7:52 PM Reply   
I have a lot of the small parts for the UFP actuators if anyone needs some. I used to have UFP actuator, but I sold that boat and now have a different actuator.
Old     (john211)      Join Date: Aug 2008       09-06-2010, 5:28 PM Reply   
Last pics. After this, all gets re-cycled.

The bypass outlet for the solenoid valve is that pin-hole that is centered in the brass (or bronze) well (which the solenoid screws into). The bypass outletís valve-seat is that miniature conic boss which surrounds the centered pin-hole. The two larger holes are discharge end from the brake cylinder and intake to the brakes. Those holes are always open. The solenoid valve has a resilient (rubbery) dot which blocks flow of brake fluid into that pin-hole. Evidently, the pin-hole is always suctioning brake fluid into a bypass flow back into the reservoir. Therefore, the constant suction wants to hold the valve tight against the seat. However, when the solenoid is actuated (ie., when the voltage from the reverse lights energizes the solenoid), it lifts the valve off the seat Ė and hence a bypass flow back into the reservoir.

After examination, we found the following. The solenoid works. The brake fluid at that time was definitely water logged and was also contaminated with a lot of sludge. And then curiously, the piston in the brake cylinder was produced from a lightweight material which a magnet would not pick up. I guess aluminum but it was a strange material.

And so on. That guy with the Bryant boat definitely did not need to remove the whole actuator simply to replace the cable. That can be done without disassembling anything. But now I know, he did himself a big favor by changing his charge of brake fluid.
Attached Images
Old     (blake_hughes)      Join Date: May 2004       09-06-2010, 9:56 PM Reply   
Thanks for posting all the pics, that will be very helpful to a lot of people. I'm about to disassemble my trailer brake system this winter... I'm not looking forward to it.
Old     (cadunkle)      Join Date: Jul 2009       09-07-2010, 6:57 AM Reply   
Basically it's the same idea as rebuilding a master cylinder in a car. Kit is probably about $10 or $15 at most to go through that and replace all the rubber seals and such. Pretty straightforward if you're machanically inclined.
Old     (Jeff)      Join Date: May 2010       09-07-2010, 7:42 AM Reply   
Originally Posted by cadunkle View Post
Kit is probably about $10 or $15 at most
Any ideas on where to actually get this? I've contacted UFP in the past about rebuild kits and they said they didn't offer them and the only solution was to replace the whole master cylinder.
Old     (rexlex01)      Join Date: Mar 2010       08-12-2015, 3:09 PM Reply   
Originally Posted by alans View Post
UPDATE:Trailer dealers have had problems with their newer trailers because this valve randomly is not grounding like it should through the actuator so while waiting for the updated part fix you simply make your own ground wire from the bottom of the valve to the actuator somewhere.

Part #32220 is the electrical part only

Part #34500 is the whole assembly kit.
Old     (jmanolinsky)      Join Date: Dec 2005       08-13-2015, 11:17 AM Reply   
Pacific trailers is where I bought everything to completely overhaul my entire brake system. I got zinc plated rotors, bearings, upgraded aluminum calipers, actuator and flexible lines for less than $500. Shipping to east TN was free. At other retailers shipping was over $50 for UPS ground due to the weight. One of my rotors broke during shipping and they were great to get one shipped out ASAP. I started to fix my actuator instead of replacing it, but decided to just get a new one so I knew that everything was fresh. It sure is nice to have trailer brakes again.
Old     (john211)      Join Date: Aug 2008       08-13-2015, 11:29 AM Reply   
UPDATE on mine. So I got a whole new actuator installed on mine in the Spring of 2010. While the braking system works fine in forward, even the new one locks in reverse. I never bothered to chase the cause of the problem down and have minimized the annoyance by doing two things. 1 - I got a slip and lift at a marina, and 2 - I just use those spacers the two times a year I do trailer the boat.

There was a thread sometime back where people were sharing experiences that, between the boat and the trailer, the trailer seems to serve up the most misery. Indeed, that has been true for me. With the boat, I've only replaced the original batteries.
Old     (svnfightsvn)      Join Date: Mar 2011       08-14-2015, 6:18 AM Reply   
I think the actuators are supposed to sense when the vehicle is put in reverse that will effectively prevent it from applying the brakes. This is done via current being applied via a circuit in the wiring harness... I think it's a blue wire. If your connector is only a 4 pin, you don't have that function
Old     (john211)      Join Date: Aug 2008       08-14-2015, 11:38 AM Reply   
That's the plan ... at least on paper (although I'm not sure which color wire now, but I think it ties in to the wires that energize the reverse lights).

My memory is sketchy here, but I also thought there was supposed to a manual option to unlock the brakes. Anyway, that tab near the top of the second picture has some function like that (ie., as framed by a background comprising the socket for the ball).

No luck there either. I've given up ... and just resort to those spacers.


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