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Recommendation for Rebuilding a Trailer Braking System on a Boat Trailer  


Hello, the master cylinder on my trailer brakes is filled with crud and such. I attempted to bleed and was not able to get fluid to go through. I have been told that I would do well to replace the complete actuator, wheel cylinders and break lines. Possibly best to convert to disc brakes. Please tell me what conciderations I should be looking at to make that choice and how to the correct parts.


Expert Reply:

First, lets start with master cylinder replacement. The recommendation you got for replacing the complete actuator, is most likely a good idea because there is a reason for the crud and such that you are finding in the master cylinder and replacing the master cylinder itself is a pretty involved undertaking. We have a video showing a master cylinder replacement that should be helpful, if you decide to go this route. Other reasons for replacing the whole actuator would be that you will have all new parts and would not have to worry about other parts failing in the near future.

Replacing the brake lines, see link, and wheel cylinders, see link, on the drum brakes would probably be a good idea also, since there could be corrosion or crud in the lines and wheel cylinders that would cause problems. If you are replacing the wheel cylinders, it is most likely just as cost effective to replace the whole brake assembly, see link, that way you would have all new parts, just like with the actuator.

To determine the correct wheel cylinders for your brakes you will need to know the brake assembly manufacturer and diameter of the brake assembly on your trailer. To replace the whole assembly the diameter of the brake assembly and the width of the brake shoes would be needed.

If you want to switch over to disc brakes on the trailer, and your trailer has 3,500 lb axles with L68149 inner and L44649 outer bearings, you would be able to select a disc brake and actuator kit with brake lines included. This would be the simplest way to replace the braking system on your trailer if the parts are compatible. You would also need to make sure the tongue of your trailer is a 3 inch wide channel tongue to accept the actuators in these kits, and that your wheel bolt pattern is 5 on 4-1/2 inches. If your tongue is a different size, you could go with one of the electric over hydraulic units we have, see link.

I added links to FAQ articles we have on adding electric over hydraulic disc brakes and electric over hydraulic drum brakes to a trailer that you might find helpful also.

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