What to use to hold the seat mount in the seat post?

russboy
russboy Posts: 436
edited May 2015 in Workshop
So basically the seat mount on my 2013 Fuji Gran Fondo push fits into the seat post but after a few thousand miles its worked lose.

Whats best to use to hold it back in place again?

Cheers,

Russ

Comments

  • keef66
    keef66 Posts: 13,123
    Sounds like you need a new seat post.

    Not sure I'd feel safe riding around on something just pushed into the top of a seat post...
  • desweller
    desweller Posts: 5,175
    How loose is it? Are there any cracks in the post that might have led to the failure?

    If there's no sign of cracks and it's not rattling around in the post I would just araldite it back in. Probably stick it in the oven at 60degC to help the epoxy to flow and cure.
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  • russboy
    russboy Posts: 436
    I can pull the seat out as it is but with a struggle, but I think it is down to wear & tear as I've had the bike for 2 years & clocked up in excess of 3000 miles in all weathers as I commute to work.

    Before replacing it's worth trying as in the end I may only end up replacing anyway. Need to clean the old bit up with a wire brush as there are grooves for the adhesive (whatever it may be) to go into to get a good bond.

    Good idea about the oven, hadn't though of that. Have to admit I used ceramic tile adhesive on it last night (it was too hand & when it dries it's like cement) but it was no good this morning but that's because it didn't cure, must try harder!
  • sungod
    sungod Posts: 17,348
    are any of the mating parts aluminium? riding all weathers maybe there's been some corrosion

    i 'd check carefully and recheck regularly as if there's any surface damage it increases the chance of cracks forming and (possibly sudden) fatigue failure
    my bike - faster than god's and twice as shiny
  • russboy
    russboy Posts: 436
    The seat post itself is carbon, the seat mount (the part that inserts) is ali, although that looks is good condition.

    Just had a quick look at the seat post, no cracks etc.
  • sungod
    sungod Posts: 17,348
    cf+aluminium can result in corrosion damage to the al if moisture gets in, especially any from salted roads (galvanic reaction)

    personally i'd get a new post, but if you are absolutely certain all is ok: no cracks/roughness/abrasion, no hint of any white powdery substance (which is how corroded al often appears), clean and degrease both, use epoxy to bond it, go for a standard cure one, they heat less than rapid cure
    my bike - faster than god's and twice as shiny
  • russboy
    russboy Posts: 436
    Cleaned it, mixed up some Araldite, then 80 degrees for 30 mins.

    Now cooling, will find out in the morning if its worked, nothing to lose really.
  • keef66
    keef66 Posts: 13,123
    Russboy wrote:
    Cleaned it, mixed up some Araldite, then 80 degrees for 30 mins.

    Now cooling, will find out in the morning if its worked, nothing to lose really.

    You've clearly never sat on a seatpost thinking it had a saddle on it.
  • russboy
    russboy Posts: 436
    I meant nothing to lose as its cost me nothing so far & if I did need to buy a new seat post in future all it's cost me is time, especially as the Araldite has been sat in the cupboard waiting to be used for a few years.

    As it happens I used it on the commute this morning & appears to be solid as a rock, will give it a few more miles & days before final judgement on it but so far so good.
  • keef66
    keef66 Posts: 13,123
    Splendid work that man! Few things in life more satisfying than fixing something for next to nothing :D
  • Alpinemonkey
    Alpinemonkey Posts: 1
    I seem to have the same problem where the seat mount has come loose but this time the post is alloy as well. What adhesive would you use in this case?
    Thanks
  • sungod
    sungod Posts: 17,348
    as above

    clean off whatever adhesive has failed, check very carefully and make very sure there's no cracking or corrosion

    degrease, then use epoxy to bond, allow correct cure time before riding
    my bike - faster than god's and twice as shiny

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