Graco 3900 alignment….er RE-alignment

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    Got a couple, couple year old, 3900s and both of the casters have, throughout the season, managed to work themselves out of line when locked into a hole. I’ve resorted to releasing the caster lock, running down a chalkline then locking it into place with the threaded radius locking bolt. everything seems to be square with regards to the fork so, my early deduction is that I might need to add a bushing/washer to the nut/bolt assembly to the frame. I haven’t really looked too deep, so it might be a pretty easy fix. Anyone else run into this? Thanks


    I have not but from what I remember in the manual it’s the washer that needs replaced.


    Hello DB
    I had to work on mine. But it was my fault. It was a simple cable break and I didn’t care at the time. I just need to get done. That said…are you meaning the small pin that interlocks with the sprocket like feature just comes out…?…and then …much to your surprise…your front tire is now on “swivel”…?
    If so…is the pin that interlocks too short…?…or is the spring that holds it in tightly, too weak?
    My only thought is that my 5 or 6 year old 3900 has “certain parts” on it…but…your “couple year old” 3900 may have different parts on it…to save the MFG cash in production.
    The only way to check would be to see a pin on a parts list…or see if the current pin is all the way engaged into the “cutout” on the sprocket like feature. If it’s not bottoming out…it may be the pin length, mating sprocket cutout or the wrong spring to push it hard into the cutout and also hold it there.
    Let me know. I hope those suggestions are simple to check and / or cheaper and easier to fix.
    Again…let me know…good luck.
    Last…when I finally replaced my cable, It seemed I had to adjust it. I wonder if the cable is tight and won’t let the pin “bottom out” into the sprocket.
    ( Although…that phenomenon happening on two machines seems unlikely. )
    I’d check the spring to see if it’s too short or weak. I would imagine it should not be loose or ineffective when the pin is engaged. It should still have length and holding power.
    ( I hope that makes sense. )
    Maybe…they changed the pin length and did not see this coming.
    ( But, that means a nationwide complaint too. )
    Maybe the female sprocket cutout is partially blocked…?…that seems unlikely on two machines too.
    I’d still check those things first.
    I hope I helped.


    Well, it was infinitely easier than I had ever anticipated. I finally got around to getting the machines season ready a couple weeks ago. Should’ve known it was as simple as a single bolt with an adjustment slotted hole. The most time consuming part was ensuring that I had it completely squared up. I had it in the vice and tinkered with that, but it came down to just installing it (snuggly, not overly tight) and running it about a 40′ length of chalk line. Took a couple tap taps to one side then a tap the other way straightening it out, but once I could run that length of line w/o variation I cranked in down. Should be good to go. Bring on spring!


    Hello DB
    You are the man.
    DB…I hope you have a great year.
    Keep in touch.

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