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Beta Evo 38mm right fork bottom bolt problem


harryharls
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Hi all,

I'm really really stuck! I was changing the fork seals on my son's Evo 80 (2018) and I stupidly loosened the bottom bolt at the bottom of the fork body on the right fork (the damping side). I had just presumed (wrongly as it seems) that this bolt would have to be removed to remove the oil seal. The issue is, now that I've loosened it, it will neither fully undo nor tighten. I presume it's got thread sealant of some kind on too which is exacerbating the issue no doubt. I'm pretty sure the forks are more or less identical to adult Evo forks such as my own 2014 250. However, I just can't find a solution to this online. I've seen quite a few suggestions about broom handles, compressing, pulling etc. but this is the non-spring side so nothing is really relevant to this.

Looking down the stanchion, there is a sort of disc at the lower end of the damping tube/rod with two slots. I can hold this by the slot with a suitable device but the bolt continues to spin on whatever is at the very bottom, obviously whatever's there is connected but able to turn independently of the top damping tube/rod.

There is no space to get past the damping rod/disc to get to whatever the bolt screws into. The stanchion won't come out without the lower bolt being removed.

I've tried pulling on the damping rod and pressing on the lower end of the damping rod whilst turning the bolt, but no luck.

Please help if you can, I'm completely stumped by this.

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image.png.205dbe3bcdb506b228f3adffae9ec3bc.png

Part number 5 (damper rod) is the part with the slotted disc at the base that I can see. Part number 6 is what I presume the bolt screws into from underneath. I don't know how 5 and 6 are connected but there is obviously independence between them (they are able to spin on each other).

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No, the base of the damping rod with the two slots is below the top of the fork body with the rod fully extended. Beside, locking that just allows the component below if to spin independently. It's a very strange situation, it seems to defy logic! If I either push or pull on the damping rod it does cause the bolt to tighten slightly, but only slightly. I feel the issues are: 1. the oil is creating lubrication and exacerbating the issue, and 2. there will be thread lock/sealant on the bolt...I know this because I'd taken the spring side fork bolt out and that had thread lock on it.

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41 minutes ago, harryharls said:

No, the base of the damping rod with the two slots is below the top of the fork body with the rod fully extended. Beside, locking that just allows the component below if to spin independently. It's a very strange situation, it seems to defy logic! If I either push or pull on the damping rod it does cause the bolt to tighten slightly, but only slightly. I feel the issues are: 1. the oil is creating lubrication and exacerbating the issue, and 2. there will be thread lock/sealant on the bolt...I know this because I'd taken the spring side fork bolt out and that had thread lock on it.

How about the other end ? 

Rinse the leg with brake cleaner or similar to improve friction.

Have you googled to see if there is anything available to break down thread lock ?

Edited by b40rt
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PHEW! Turns out it was indeed a good call b40rt. Problem sorted. I was beginning to think about giving up TBH and trying to find a used one to buy.

I rinsed it out thoroughly 3 or 4 times with neat petrol, draining fully after each one (much easier with thin petrol than oil)

Once thoroughly degreased I held the slotted 'ring' at the bottom of damper tube with an alloy rod type thing, whilst simultaneously pressing on the top of the damper tube (hard!).

I could tell straight away that there was more resistance on the bolt and it tightened up nicely.

Thanks for all your suggestions.

Note to self: never loosen the bottom bolt again!

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  • 4 weeks later...
 

I feel your pain Jonevo! There will probably be some threadlock on the bolt so that doesn't help. Is it loose and spinning or have you already removed it? The thorough rinsing with petrol is what solved it for me. Try to increase the pressure on the damping rod a little more, if it's thoroughly degreased you should be able to get enough friction. There's no other way I don't think, so it just 'has to work' I'm afraid. Also try turning the bolt extremely slowly and carefully as you apply pressure on the rod.

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Thanks, the lower drain bolt is still in the fork leg spinning both directions, even with the lower internal damper washer (the one with the slot across) locked to prevent turning with a tool I made. I can't even get the stanchion out of the leg.

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  • 7 months later...

I’ve just had the same problem and ended up drilling the head off the bolt. When apart the bolt threaded into a piston on the bottom of the damping cartridge which had an o ring round it and was held in place by a clip, without lock tight the job would have been easy!! See picture. 

167161F2-539D-4B63-9811-BEB94C04A05B.jpeg

Edited by Richard4rt
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  • 5 months later...
 

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