Source
r/MechanicAdvice•
Dandedoo

Boat trailer hydraulic surge brake, as a permanent (months) parking brake. Good idea / bad idea? Does it force brake fluid through seals?

My question is, is it a bad idea to leave the hand lever on a hydraulic trailer surge brake on permanently (ie months) for parking the trailer long term (wheels are chocked with bricks also). Will it cause brake fluid to be forced out through cylinder seals etc., damaging or destroying the brake system.

We have a single axle boat trailer for a 6 meter boat. I also have a very old large box trailer, about 5.5 foot by 10 foot box, very heavy, tandem axles. Both have hydraulic surge brakes. Both are drum brakes, although boat trailer might be disk, can’t remember (it’s actually a family member’s).

I once left the handbrake on on the box trailer by mistake. (Not while driving, although we did that too, 7 years earlier, that’s why the brake system was fairly new...) After some months, much of the fluid was forced out past the slave cylinder seals, also causing corrosion and other damage. Most of the brake system had to be replaced, and it wasn’t very old (7 years) and barely used to begin with.

After that experience I have been vigilant with only using the handbrake to safely park/unhitch trailer, then disengaging and solely using wheel chocks. However using my relative’s boat trailer, she said she always left the handbrake on for long term parking, as well as wheel chocks (and a 1.5 ton boat sitting on it). Is this a problem? Is it more likely to force fluid out and have a shorter life span? Who is doing it right, me or her?

I always thought it was not great to leave them on, and was even advised as such by the mechanic who fixed the box trailer. However this would mean the trailers effectively don’t have a long term hand brake, and you have to rely on wheel chocks, which can be kind of a pain also.

-for those playing along at home, a surge brake on a trailer is a type of brake actuator that engages the brakes on the trailer when the towing vehicle brakes, and the trailer’s momentum pushes itself toward the tow vehicle, pushing a large rod, and applying the actuator. It can also be manually applied when you are stationary, with the hand lever.

What are your thoughts?

Posted Mar 11, 2019, 8:14 AM UTC

16
waynep712222•

Tandem axle trailers you can put a locking device Between the Wheels to lock them in place far safer than leaving the mechanical or hydraulic brake applied. Single axles you should have a wedge tire chock chained through the wheel with a padlock so nobody can pull the wedge out.

Put welded eyebolts on either end of your single tire chock with a chain on one to pass thru. Use a weather proof padlock or a pin type device to fasten the loose end of the chain to the eyebolt

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tomhalejr•

Climate is a big factor. Coastal saltwater (coastal air) is far harsher on components than inland freshwater. If you are blowing seals due to the effects of corrosion, then In that case you might be better on than off, to try and keep the cylinders from being exposed as much as possible. If you are concerned about the pressure, then set the chocks, disengage to relieve the pressure, and reengage for safety/storage. The weight should be on the chocks instead of the brakes, and that concern is completely mitigated.

We have a family boathouse/boat we store for winter over four generations now. :) As a rule, we do everything "three times". Once over top level boat, then boathouse. Double check / details boat, then boathouse. Final "lock down" of the boat, then boathouse. If you take the same time / process, you are always going to be twice as efficient as me, because you only have one hole in the water to pour money into. :)

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DandedooOP•

Actually now I think about it, when the seals blew, it was both the slave seals at the drum, and the master cylinder seals. So having the brake on would mean less of the master cylinder is exposed, but more of the slave cylinder is exposed right?

Our particular hole in the water functions as a crucial mode of transport for us (seriously), as well as a luxury item. Which kind of lets us justify all the money we pour into the water... : D

2
tomhalejr•

The master cylinder is enclosed / the seals are internal, outside of the end/rod seal. Whereas brake cylinders are "exposed", because they are the link between the sealed hydraulic system and the mechanical braking system. Usually a problem at the wheel(s) is what leads to a problem with the master cylinder, as the wheels are the most "exposed" point of the sealed system.

If you are using and relying on your trailers more than most, then your maintenance bills will be higher than most. As an example - My brother and I do side jobs for a few landscaping companies overhauling their trailers/hitches electrical after only a couple/few years, because of the usage and conditions. The owners plan on it, so they know they are going to be short a trailer/truck for a Saturday, and they can plan around their client schedule. If you can plan on mooring the boat for long enough to get your trailer inspected and serviced every year as part of your process, you are less likely to have to deal with an unexpected, emergency repair situation.

Do you do your own maintenance/repairs?

1
DandedooOP•

Hi, great responses, thank you. Tom, that’s a good point about keeping the cylinders unexposed. It is in fact a very harsh coastal climate where both trailers are stored (although the experience I had with the seals blowing was a few years ago, not near the coast). I’m thinking some kind of chock locked through the wheel would be the best solution, like you’re describing Wayne. It just seems more reliable and foolproof. I’ll have to try and find a product or fab something.

It does puzzle me actually, as to why manufactures don’t generally include some kind of basic wheel lock (not necessarily for security, just a parking lock) mechanism for parking. It can be a real safety issue, depending on the situation. That’s my experience (no wheel lock) with most box/cargo/boat trailers made where I live anyway - Melbourne, Australia.

I think I will put something through the wheel to lock it, then engage the brake lever very loosely to cover the piston/ram.

2
DandedooOP•

This is an example of the setup. Not my trailer or photo. http://i64.tinypic.com/29pc8ef.jpg

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