Boat trailer Bang, every start and stop, solution found

[dan144k]

Shock absorber in trailer braking system.
This controls the banging starting/stopping noise.
Located between hitch ball and master cyclinder.

Well my trailer been doing this for a few years and I thought nothing of it.
2010 MFI trailer, and never worked on brakes. Brakes were squeaky (lightly). Inspect and found a cracked pad, so I started down the trailer brake repair fun.

Other posts for brakes on this sight list 1997-2000 Kia Sephia and are correct.
- brake pads is correct, I used ceramic. (after you remove the squeaky indicator bar)
- caliper rebuild (from kia sephia is correct,) (I used Oreileys Auto part #15202) cleaned rusty pistons with green skotch brite, look like new.
- calipers (very different brake line size and location)
- rotors used the ones, they still OK.
Then when we went to bleed the brakes, the master cylinder sounds squishy and gurgles so I replaced it.
At this point I found a shock absorber, which I never new existed

- Master cylinder I used, I order mine from trailerparts superstrore. Cheapest next day shipping I could find.
Many Other websites offer these components cheaper. (Amazon post just for simplicity and info)

- Reassembled, Bled the brakes and towed everything 400 miles and working great.
- was amazed to find the shock absorber and it resolved my banging noise, so thought I would share.
- I used info the FAQ and searched "MFI brakes" on this sight for most of my background information, and the information was great.

UPDATE
When bleeding your brakes. If you change your own oil and have the extractor for sucking oil out. Use it also to bleed your brakes. Works great.

 

[bolivas]

Thank you for the info. My trailer makes a clunking/banging noise as well. I just assumed it was normal for this type of trailer brake system. I've towed many a trailer in my day and this is the first time using this type of braking set up. I just chocked it up to my ignorance. I'll have to look and see what the warranty on the trailer is/was. I am right around 18 months from purchase. MAYBE..... I can get the dealership to cover this and have the shock replaced?.?.?.?.?. ?

 

[jetboater4life]

Shock absorber in trailer braking system.
This controls the banging starting/stopping noise.
Located between hitch ball and master cyclinder.
View attachment 135029

I bought my 2010 MFI trailer in 2012 and it has been banging for 8 years on me. I thought that was normal. You are saying that the shock absorber was essentially defective? I will have to take a look at mine. I lost a caliper two years ago to a curb and had my breaks completely redone.

 

[dan144k]

@jetboater4life
I would say check that shock. You have to take apart the front tongue sliding part of the trailer. The front round circlip pin, goes through the front of the shock.

 

[jetboater4life]

Thanks. I will give it a look.

 

[InmyElement]

I bought my 2010 MFI trailer in 2012 and it has been banging for 8 years on me. I thought that was normal. You are saying that the shock absorber was essentially defective? I will have to take a look at mine. I lost a caliper two years ago to a curb and had my breaks completely redone.

Me too, it drives me crazy at every light, its been that way for 4 years, I'll have to check it out!
Thanks for posting and the info..

 

[Ronnie]

I never like the sound when starting and stopping with a trailer in tow, so I bought a tI rattle devices similar to the one pitchered which resolved the problem for me. These are inexpensive and easy to install, I can’t think of many boating related things I can say that about.

 

[dan144k]

@Ronnie
That is a neat anti rattle device.

The bang from braking is a lot different than a rattling hitch.

 

[TimW451]

That shock absorber should be the surge brake actuator. As the tow vehicle slows down the shock compresses and gentlely applies the trailer brakes. If it isn’t working I’d image the trailer brakes would apply more suddenly and make slowing down quite jerky.

Good post of info to help others rebuild their system.

Shock absorber in trailer braking system.
This controls the banging starting/stopping noise.
Located between hitch ball and master cyclinder.
View attachment 135029
Well my trailer been doing this for a few years and I thought nothing of it.
2010 MFI trailer, and never worked on brakes. Brakes were squeaky (lightly). Inspect and found a cracked pad, so I started down the trailer brake repair fun.

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