Just found out that one of the main pivot bolts on the downtube-located linkages has completely sheared off! Had the bike for yrs so i suppose everything has a failure point but i've never heard of this going before.
Anyone else had a similar problem, & had it damaged the frame in the process?

Never heard of that one – which model?

Did you ever check the nut/bolt torques throughout it's life?

'04 Mount Vision QUAD – the double-banana frame with the twin linkages.
Unusual i reckon but when you realise that the two parts of the frame are held together with 4mm bolts then the stresses those bolts are under must be quite high.
The hex-key head has sheared off and the bolt started to work it's way through the lnkage. Only noticed it when i was doing a safety check as part of a mtb class i volunteer at! We were teaching the kids the importance of such a check when i unwittingly became an oblect lesson! 😳

Seen it a couple of times on the old 'type' Quad frame (Mount Vision and Attack Ttrail), just stick another bolt in of the same size and length until your dealer gets you a proper one.
No damage, as the heads had just fell off, so the majority of the bolt was still inplace.

No, never touched the bolts – only been touched when the shop had replaced the bearings (twice in yrs i think).

Bit of a lesson in checking the bolts then!

Hi MD…yep..happened to my Rift Zone and I think our bikes are about the same age (possibly 2004 or 2005…?).
I went into the garage one morning and just found the head of the bolt laying on the floor – took me a while to realise where it had come from.

I took it to Cooksons and they sorted it free (but it was a few years ago now)…think there was a story of a 'bad batch'.

I'm off to Cooksons in a little while actually 🙂 Rang them yesterday and they told me they have some bolts in but to bring the bike in to get the right one. It's only a tenner or so so not a huge hole in the pocket.

Not really complaining as every metal part will eventually fail & it's been ridden for 6yrs. I was just wondering if the frame/swingarm is damaged will the lifetime warranty cover the bike?

This was a known problem with QUAD Marins. I broke virtually all the bolts on my Marin, the shop where I got mine from said there was a problem with the first batch of bikes and as I broke the bolts just gave me a new one. Not sure why they didn't give me a complete new set!

Went to Cooksons, didn't have the right bolt so they rang the Marin people who are sending me a replacement bolt set free of charge – result!

Now, how easy is it to fit them? 😆

easy..

I was just wondering if the frame/swingarm is damaged will the lifetime warranty cover the bike?

Well they replaced my 06 one, though it is silver where-as the rest of the frame is black 😕

Looks like i'll be spending friday with the spanners then…