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smedman

Trailer Brake Fluid - How often do you check it?

Trailer Brake Fluid Checks   131 members have voted

  1. 1. How often do you check it?

    • Never / haven't checked it yet
      45
    • Once a year
      34
    • A couple of times a season
      25
    • Monthly (during season)
      20
    • Weekly (during season)
      0
    • Every time I tow the boat
      9

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38 posts in this topic

My trailer hitch is etched with instructions saying to check the brake fluid before towing. I'm curious if people do this and how often?

Edited by smedman

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Even though I go out every weekend I know it only takes two seconds to pop off the master cylinder cover and look to see where the fluid is. This is part of my checklist that I will always perform therefor it's one less thing I have to worry about.

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We (I) check it once a month but it really depends how much your boat is trailered a few miles or few hundred miles. I’ve only had to add fluid once in 7 years.

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I check it once a year in the spring. I don't trailer much. I do change out the fluid every few years as it aborbs water and you can tell when it starts looking a little brown.

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I check it every time now. I checked it after winter layup one spring and it was dry. Shocking.gif Worth the peace of mind.

Edited by dlb

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I check the brake fluid at the beginning of each season, and flush it with new fluid (before storing the bu) at the end of the season... Brake fluid is hygroscopic (it adsorbs moisture) and causes corrosion in the master cylinder, tubing and wheel cylinders or calipers if it's flushed regularly. Just the nature of boating encourages moisture adsorption by the fluid...

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Think you missed a 'not' in there....

causes corrosion in the master cylinder, tubing and wheel cylinders or calipers if it's NOT flushed regularly.

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All you guys should really be using DOT 5 fluid. It's synthetic and does not absorb water like DOT 1-4 will and it has a much higher boiling point. You can get it at Winchester Auto parts. It is pricey but, my superb D.H.M. trailer came with it standard. I know Extreme only uses cheap-o Dot 3.

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I check the brake fluid at the beginning of each season, and flush it with new fluid (before storing the bu) at the end of the season... Brake fluid is hygroscopic (it adsorbs moisture) and causes corrosion in the master cylinder, tubing and wheel cylinders or calipers if it's flushed regularly. Just the nature of boating encourages moisture adsorption by the fluid...

So for us dummies.... How do we flush? :blush:

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Depends on the actuator & what type of brakes you have....

For most of the 'bu trailers, they use a UFP actuator & here's the bleeding instructions from their site.

UFP Brake Bleed

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Sorry about the typo on the previous message ... Flushing the fluid can be done several ways, either pushing fresh fluid or pulling fresh fluid. I have a pressure bleeder so after sucking out the old fluid with a bulb suction device, I put an adapter on the master cylinder and open the wheel cylinders (starting at the farthest first) and flush until clear fluid appears. If you don't have a pressure bleeder, you can pull the old fluid out with a small hand held vacuum pump with a plastic canister (available at auto parts stores for $25.00). Do each wheel cylinder at a time (starting at the farthest first) and the fresh fluid will be sucked into the pump. Just remember to keep the master cylinder full during the process or air will enter the system. The type 5 fluid is great for brake systems with stainless steel components, but I believe the type 3 or 4 fluid actually helps to keep the moisture away from the vulnerable steel parts of non-stainless systems.

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All you guys should really be using DOT 5 fluid. It's synthetic and does not absorb water like DOT 1-4 will and it has a much higher boiling point. You can get it at Winchester Auto parts. It is pricey but, my superb D.H.M. trailer came with it standard. I know Extreme only uses cheap-o Dot 3.

Pete... Will you buy me some DOT 5 fluid for my extreme trailer? Tease2.gif

Oh... I look the entire trailer over monthly, including the fluid.

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Sorry about the typo on the previous message ... Flushing the fluid can be done several ways, either pushing fresh fluid or pulling fresh fluid. I have a pressure bleeder so after sucking out the old fluid with a bulb suction device, I put an adapter on the master cylinder and open the wheel cylinders (starting at the farthest first) and flush until clear fluid appears. If you don't have a pressure bleeder, you can pull the old fluid out with a small hand held vacuum pump with a plastic canister (available at auto parts stores for $25.00). Do each wheel cylinder at a time (starting at the farthest first) and the fresh fluid will be sucked into the pump. Just remember to keep the master cylinder full during the process or air will enter the system. The type 5 fluid is great for brake systems with stainless steel components, but I believe the type 3 or 4 fluid actually helps to keep the moisture away from the vulnerable steel parts of non-stainless systems.

Plus1.gif Just flushed my system last week with and used about 3 quarts. I know it was a over kill but had the time and fluid.

Pete put me down on the list with woody. Thumbup.gif

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I check/fill it everytime I buy another boat pretty much...

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I check/fill it everytime I buy another boat pretty much...

So that's what???...2-3 times a year. :lol:

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All you guys should really be using DOT 5 fluid. It's synthetic and does not absorb water like DOT 1-4 will and it has a much higher boiling point. You can get it at Winchester Auto parts. It is pricey but, my superb D.H.M. trailer came with it standard. I know Extreme only uses cheap-o Dot 3.

Pete... Will you buy me some DOT 5 fluid for my extreme trailer? Tease2.gif

Oh... I look the entire trailer over monthly, including the fluid.

Hey guys,

It's no joke Mad.gif

Both of you guys should know how caustic brake fluid is. I've had two separate leaks around my surge brake unit that would have caused major paint and hull damage to the tow vehicle and boat if it were not for the synthetic fluid. (leaks thanks to UPF, not D.H.M. trailers you know)

I have about 3 cans on hand at all times at the house (back ups for the back ups). They're about $15 a can for about a half a pint. I don't even run this stuff in my motorcycles, only the trailer.

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Plus1.gif Just flushed my system last week with and used about 3 quarts. I know it was a over kill but had the time and fluid.

Pete put me down on the list with woody. Thumbup.gif

If you did it right, it would have only taken one qt. Whistling.gif

And, don't get me started about how much free time you have... ROFL.gif

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All you guys should really be using DOT 5 fluid. It's synthetic and does not absorb water like DOT 1-4 will and it has a much higher boiling point. You can get it at Winchester Auto parts. It is pricey but, my superb D.H.M. trailer came with it standard. I know Extreme only uses cheap-o Dot 3.

Pete... Will you buy me some DOT 5 fluid for my extreme trailer? Tease2.gif

Oh... I look the entire trailer over monthly, including the fluid.

Hey guys,

It's no joke Mad.gif

Both of you guys should know how caustic brake fluid is. I've had two separate leaks around my surge brake unit that would have caused major paint and hull damage to the tow vehicle and boat if it were not for the synthetic fluid. (leaks thanks to UPF, not D.H.M. trailers you know)

I have about 3 cans on hand at all times at the house (back ups for the back ups). They're about $15 a can for about a half a pint. I don't even run this stuff in my motorcycles, only the trailer.

Your exactly right... Brake fluid is so caustic. It will eat the paint off anything.

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All you guys should really be using DOT 5 fluid. It's synthetic and does not absorb water like DOT 1-4 will and it has a much higher boiling point. You can get it at Winchester Auto parts. It is pricey but, my superb D.H.M. trailer came with it standard. I know Extreme only uses cheap-o Dot 3.

Is there any compatability problems with seals, hoses, or metals if someone was to convert to DOT-5.

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No,

But, you can only go up in the DOT range, not down. Meaning if you go to DOT 5, you gotta stay with it not, convert back down.

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Quick responce,...Thanks.

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Plus1.gif Just flushed my system last week with and used about 3 quarts. I know it was a over kill but had the time and fluid.

Pete put me down on the list with woody. Thumbup.gif

If you did it right, it would have only taken one qt. Whistling.gif

And, don't get me started about how much free time you have... ROFL.gif

Ok Pete...spill it....how is it done right so that only one quart is used? Just curious to how a master mechanic does it.

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iirc, and that's always a stretch, there are compatibility problems w synthetic v non-synthetic.

i don't recall what the problems are (maybe seals?), and i could be wrong.

just wanted to post the observation as a warning because a mistake could be costly.

you may want to consider doing the homework before doing the deed.

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Agreed.

John, maybe you shouldn't do the upgrade.

My trailer always had synthetic but, I've been told by an even more master mechanic, that you can upgrade in DOT range but, don't hold me to it.

Edited by Pistol Pete

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And, to answer Ken's question. The master cylinder reservoir only holds about a half a cup of fluid. If you used one quart to flush the system, that seems like it'd be plenty. 3 qts. would be about the equivalent of flushing the system completely about 20 times.

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