Leaf Spring Question

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Dan Salvin

Seaman Apprentice
Joined
Jul 21, 2010
Messages
39
I have a small Mastercraft trailer from 1971. I use of for a 14' aluminum Starcraft. Often, the passenger side of the trailer gets stuck down (so the boat is tilted toward the passenger side), like the leaf spring does not spring back. If I pull up on the trailer, it pops back up to be level with the other side. The leaf springs are fairly rusted. I assume the spring is shot and first thought I could replace the leaf springs but now see that they appear to by welded to the axle in addition to being attached with two U bolts and a metal plate. Is there any way to replace the leaf springs and shackles without also replacing the axle? Thanks.
 
Bob_VT

Bob_VT

Moderator & Unofficial iBoats Historian
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May 19, 2001
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26,022
Re: Leaf Spring Question

I really doubt it is welded to the axle...... maybe it is?

Have you tried spraying it down with PB Buster ot a light weight oil...... maybe one you oil it it will clear some of the rust and not get stuck

Tractor supply sells axles with springs as an assembly if you need to replace it
 
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Dan Salvin

Seaman Apprentice
Joined
Jul 21, 2010
Messages
39
Re: Leaf Spring Question

Thanks. That is a good idea to try to oil it if I can avoid replacing the springs. Does it make sense that the spring would get stuck down and then pop up when I pull up on it? I'll try to post a picture of the spring.
 
J

jeffnick

Senior Chief Petty Officer
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May 24, 2004
Messages
695
Re: Leaf Spring Question

It's possible that a shackle or equalizer gets reversed.
shackle.jpg

The circled one is wrong.
 
D

Dan Salvin

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Jul 21, 2010
Messages
39
Re: Leaf Spring Question

Thanks. It is a single axle trailer so I don't think it has an equalizer but you may be right that the shackle it getting stuck up instead of the spring. I will check that next time it happens. If that is the case, do you think some oil would help?
 
109jb

109jb

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Re: Leaf Spring Question

Is it possible that the springs are too short and are causing the shackles to bind?
 
D

Dan Salvin

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Jul 21, 2010
Messages
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Re: Leaf Spring Question

I don't know, I will try to post a picture when I get home. I believe the springs are original to the trailer. Thanks!
 
Silvertip

Silvertip

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Sep 22, 2003
Messages
28,762
Re: Leaf Spring Question

On a single axle trailer the rear spring shackle should angle backwards slightly. If it is straight down or angled forward it can bind or fold forward and lock in that position until the trailer is raised. Angle backward and angle forward is defined as observing the lower end of the shackle. Two things can cause this issue. 1) The shackle is mounted to the frame in the incorrect position or 2) the spring is the incorrect length. Leaf springs cannot and should not be welded as they will no longer be springs. Welding heat would destroy it.
 
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Dan Salvin

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Jul 21, 2010
Messages
39
Re: Leaf Spring Question

Thanks for all the advice. I looked more closely when I got home and realized that it is the square piece on the axle that holds the spring that is welded and not the spring itself. I'm new to this so didn't distinguish between the spring and the seat on the axle. Once I get the boat off, I will measure the springs and replace both the springs and the shackles. Thanks for all the help!
 
D

Dan Salvin

Seaman Apprentice
Joined
Jul 21, 2010
Messages
39
Re: Leaf Spring Question

Here is a before and after picture of the spring and shackle getting hung up. The shackles are angles backward but are still binding with the shackle. Should I replace both? Any good advice for a resources about how to properly measure the spring? Thanks
 

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