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View Full Version : 98 prostar single axle trailer brake line bleed


Jaysonsmith
06-22-2005, 01:09 AM
I realized the surge brake res. was empty the other day so I vacuum bled the lines and what came out wasn't pretty. Dirty dishwater looking fluid. I vacuumed it until clear came thru. Looks like water got in there. The bakes seem to be working again. Am I looking at a brake job?

jake
06-22-2005, 09:29 AM
I would wonder how the water got in there. I'd give your lines a good inspection to be sure you don't have a leak somewhere. On my 93' I know the line was encased in a rubber tube, so the brake line had rusted through but the system would hold some pressure because the rubber lining hadn't worn through. Only under hard braking would the fluid escape the lining and empty out the system almost completely. I ended up having to replace the lines.

I think I've heard the rubber cover on the brake lines was unique to one or two years, so you may not have that problem, but the point is an intermittent leak under pressure could be an issue.

Good luck.

Tom023
06-22-2005, 09:39 AM
I bled mine for the first time two years ago and had the same nasty brown fluid come out for just a little bit. I couldn't figure out how it got contaminated, but it was limited to close to the wheel cylinders. My master cylinder never went dry. Now I just do a quick bleed every year and replace the master cylinder fluid.

FrankSchwab
06-22-2005, 10:21 AM
You're always gonna get water in the brake system on the trailer. It's just a fact of life.

Everytime you launch/retrieve the boat, you're completely submerging the wheel cylinder; probably filling the dust boots up with water, and getting water around the piston. The seals on the piston are designed to retain brake fluid pressure, not to prevent water intrusion, so when you start towing and the brake piston moves in and out, small amounts of water get by the seal.

Contrast that with your car, where if you get water up to the level of the wheel cylinder, you've probably filled the footwells of the passenger compartment also.

Do a flush on the brake system every year, and you'll be a long way ahead of most boat owners, some of whom never even notice their trailer brakes aren't working (until they need'em in a panic stop).

/frank

p.s. Here's (http://www.ufpnet.com/PDF/A60-70Maint.PDF) the user's manual for the braking system on your trailer, if it's the same as mine. Shows how to bleed and adjust the brakes.

MarkP
06-22-2005, 11:50 AM
You're always gonna get water in the brake system on the trailer. It's just a fact of life.

Everytime you launch/retrieve the boat, you're completely submerging the wheel cylinder; probably filling the dust boots up with water, and getting water around the piston. The seals on the piston are designed to retain brake fluid pressure, not to prevent water intrusion, so when you start towing and the brake piston moves in and out, small amounts of water get by the seal.

Contrast that with your car, where if you get water up to the level of the wheel cylinder, you've probably filled the footwells of the passenger compartment also.

Do a flush on the brake system every year, and you'll be a long way ahead of most boat owners, some of whom never even notice their trailer brakes aren't working (until they need'em in a panic stop).

/frank

p.s. Here's (http://www.ufpnet.com/PDF/A60-70Maint.PDF) the user's manual for the braking system on your trailer, if it's the same as mine. Shows how to bleed and adjust the brakes.Great info! Thanks Frank..