MFI Trailer Work

[scokill]

So I've been putting off fixing my broken break away cable which is needed to pass trailer inspection and get registration. Once I got inside I found the master cylinder was rusted and frozen as well as the shock. I've long suspected the brakes didn't work but hasn't really been an issue as I only drive 2 mi across a bridge to launch and then back home. Let me tell you that they do not make it easy to get the unit out. You have to remove the flexible hose where it transitions to the brake lines and it's tight quarters for two wrenches. I used a wrench and needle nose vice grips to hold one side while using another wrench to remove the brake line. Once I did this the whole unit slid out with the rubber hose attached.

I ordered the replacement actuator assembly which contains everything. The hose was looking worn so I went ahead and ordered another hose. About $350 to get the brakes working again. I had already replaced one caliper assembly and the other one is still moving in and fine when I checked it. Mine were UFP A-75. It appears that the DX7.5L A-60 inner member and assembly are also compatible and I like the connector a little better, but I just didn't want to risk incompatibility even though it says it's compatible.

Once I got everything out and got the lay of the land on the parts and how they work it's really not that difficult. The most difficult part will be to hook the brake line back up inside a small opening in the trailer frame.

I'll be driving a few times without the brakes but it's no different than for a couple of years since they havent' worked anyway.

 

[scokill]

Waiting on the brake parts but got new wheels and Goodyears today.

 

[TimW451]

What brand/model are your wheels? They look real good.

 

[Beachbummer]

LOL, who needs brakes when you have shiny brand new wheels!!! I love what got the priority!

I know this was not intentional and you will hit the breaks soon with parts on order, but I was reading about a boring break repair job and next thing, BAM brand new wheels! Gave me a good chuckle.

Depending on how committed you are, you could run the lines on the outside of the frame and it won't brake any worse. Just a thought if the brake lines give you a lot of trouble.

 

[scokill]

What brand/model are your wheels? They look real good.

were not my first choice. I picked a couple of discontinued models first and wanted to stay under $500 for the wheels. Total with GY Marathons $1160. Discount Tire | Tires and Wheels for Sale | Online & In-Person

 

[scokill]

LOL, who needs brakes when you have shiny brand new wheels!!! I love what got the priority!

I know this was not intentional and you will hit the breaks soon with parts on order, but I was reading about a boring break repair job and next thing, BAM brand new wheels! Gave me a good chuckle.

Depending on how committed you are, you could run the lines on the outside of the frame and it won't brake any worse. Just a thought if the brake lines give you a lot of trouble.

It will be OK. Everything except the new brake hose is coming tomorrow. I experienced taking it off so now I know what to expect.

 

[scokill]

So I got the actuator assembly and the brake hose in and replaced both this weekend. It wasn't near as bad as I thought connecting the brake hose to the brake line in tight quarters. Both the line and hose had enough slack to come all the way out of the trailer. The actuator slides in to tight quarters and for some reason I had to remove the top plastic wear piece to get it in properly. Once I got it installed I had to bleed both sides. I used wheel chocks front and back and just backed up and pulled forward, put on emergency brake to keep from rolling forward, and then opened the bleeders. The brake lines essentially had air and rusty water in them. I just kept on repeating the process until I got a stream of clean fluid a few times on both sides. I was going to use my extractor for bleeding but it was just too much of a hassle. I just used 1/4" tubing in a clear bottle with a hole drilled in the cap. I put some brake fluid in and could monitor the air bubbles and rusty liquid coming out. I drove around for a bit and then unplugged from trailer when I was backing in the driveway. Sure enough the brakes locked up when going in reverse. I then plugged the trailer back in to test the reverse lockout solenoid and it was working properly. It was a PITA in the 97 degree weekend here in DFW, but glad I now have brakes.

 

[PEARCE]

@scokill are you required in Dallas County to get it inspected to get it registered? It's below a certain weight capacity where I don't need to have it inspected in Kaufman County. I do have to get my camper inspected though.

 

[scokill]

@scokill are you required in Dallas County to get it inspected to get it registered? It's below a certain weight capacity where I don't need to have it inspected in Kaufman County. I do have to get my camper inspected though.

You don’t need an inspection any longer for our boat trailers. I was living in the past. I know there are trailers that need it still.

 

[biffdotorg]

This is a great write up, thank you Scokill.

My MFI galvanized is starting to lock up in reverse, so I fear the solenoid may be bad. But it may be worth starting with a fluid change, as this trailer has never been serviced, other than new tires.

Like what has been mentioned, I use my trailer so infrequently anymore, that it gets ignored sitting in my pole building summer and winter.

 

[scokill]

This is a great write up, thank you Scokill.

My MFI galvanized is starting to lock up in reverse, so I fear the solenoid may be bad. But it may be worth starting with a fluid change, as this trailer has never been serviced, other than new tires.

Like what has been mentioned, I use my trailer so infrequently anymore, that it gets ignored sitting in my pole building summer and winter.

What I found is the plunger freezes up/corrodes and/or the strut the keeps pressure forward wears out. The solenoid could be bad but what I found is you can just replace the entire slide/couple assembly that has all new components.....master cylinder, solenoid, strut, etc. etc. I think it's about $239