Hydralic Trailer Brakes

Discussion in 'Trailering' started by Loyd Dinneen, Aug 2, 2017.

  1. Loyd Dinneen

    Loyd Dinneen Member

    154
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I have a 1977 Magnum trailer and the master cylinder is shot. I have looked and only found something similar but wouldn't mind changing out the whole coupler assembly. The problem I see is how to change it out with what is available, has anyone out there dealt with a trailer of that year and make and changed out the coupler?
     
  2. RollerCoastr

    RollerCoastr Well-Known Member

    Nov 15, 2007
    Cedar Point, OH / Miami, FL / MacRay Harbor, MI
    1997 400DA
    340HP 7.4 Mercruiser Bluewaters
    Garmin 8212, 741 24HD, Intellian I2
    1999 280BR
    Twin 250HP Merc 350 Alpha Ones
    I'm not familiar with your trailer, but I'd be surprised if Titan doesn't make an actuator that will work for you.
     
  3. Loyd Dinneen

    Loyd Dinneen Member

    154
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I think they might I was hoping to change the complete coupler assembly, the hookup on this trailer is very strange and I think that the only way to change it is to cut the welds. I'll have a closer look at it.
     
  4. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    Can you post a picture?
     
  5. Loyd Dinneen

    Loyd Dinneen Member

    154
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    Here are pictures of the coupler assembly the cover says attwood, didn't see that before.
     

    Attached Files:

  6. NorCal Boater

    NorCal Boater Well-Known Member SILVER Sponsor

    Jan 24, 2008
    Covington, LA
    Cobalt CM23
    GM SB 383" Stroker" Alpha Gen I
    Yikes! That's a new one for me. I think your best bet would be to take it to a place that does trailer repair. I used to live in Las Vegas and if I remember there were a couple of good ones....I just cant remember where they are. Converting it to a newer type of coupler/actuator is probably the best way to go but to me this looks like a job for a professional to insure proper alignment, function and safety, etc.

    Shawn
     
  7. Loyd Dinneen

    Loyd Dinneen Member

    154
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I did find a phone number for magnum trailer and got a hold of the parts guy and I am sending him pictures of all of it. I took a good look at the front of it and can't see how another piece of 3" square can be added to mount another coupler. A replacement master would be faster just not sure how safe the existing coupler is.
     
  8. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    Oh boy, that is an oldie but goodie, isn't it?!? :)

    You might be able to find parts to rebuild it, I seem to recall we worked on one of these a few years ago. But haven't seen one in a while. I don't really recall much about the service. Give Atwood (one "T") a call see what/who they can recommend for parts.

    I do think you could cut out the entire coupler assembly, along with the square tongue. Then replace the tongue with a 3"x4" tongue, all the way back to that first crossmember (not in the picture). At that point, you can go with just about any newer style coupler.

    BUT... before you do any of this... are you 100% positive that the rest of the trailer is OK? Have you checked out the crossmembers, especially the bottom of them? What condition are the brakes and tires in? Point is, you may start spending a lot of money on a frame that isn't worth it. And you may have been better off just getting a new trailer.
     
  9. Loyd Dinneen

    Loyd Dinneen Member

    154
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I haven't taken the wheels off yet but what I do know about trailer brakes is that they are really easy to replace and not to expensive the trailer itself looks really good with no rust and looks sound. It's still to hot to work on stuff outside here in Vegas but as soon as I can I'm going to tear into it and see whats up.The brake lines look clean inside so I I would presume that the wheel cylinders are most likely froze up from lack of brake fluid thus just replacing with a backing plate kit. I can always wire brush any rust from the drums the only issue is that darn coupler master cylinder. I have a pacemaker so any welding is a no no. I just looked at it again and what I see is the top of old assembly is 3 1/2" wide and inside is 3" if I take the assembly off and slide a 3" tube into the recess and weld into place I can then put a up dated coupler on the trailer, what do you think?
     
  10. Lazy Daze

    Lazy Daze Well-Known Member TECHNICAL Contributor GOLD Sponsor

    Apr 21, 2009
    PA
    Various
    Various
    I didn't realize you're in the desert. When I see rust like what's behind the jack on the vertical surface of the square tube, that usually means it's worse other places. Just be double sure that it's worth saving before you sink money into it. Bottom/center of crossmembers - especially if they're boxed.

    I think what you're proposing could work. But I'd feel much more comfortable replacing the entire tongue section, all the way back to that first cross member. It would would be stronger and it really isn't much more work. If you do it the first way, do some plug welds, in addition the edges.
     
  11. Loyd Dinneen

    Loyd Dinneen Member

    154
    Jul 29, 2017
    Las Vegas
    1977 Sea ray 240 SDA cruiser w/ twin 470 mercs.
    Twin 470 Mercruisers
    I found out from the Magnum Trailer parts department that a master cylinder from a 64 -66 ford will replace the master cylinder and is less expensive than the titan one that the trailer parts places sell. I'll double check for rust but so far I can't see any major rust. I did see that to put on a coupler would require alot of butchering of the front end and I really don't want to change how the boat bumper is setup.
     

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