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Leaking fork seals


stu109
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I am having problems sealing my front forks on a 2013 Beta Evo 4T.

I have changed the seals (not for the first time) but they still leak.

Tried new bushes and another set of good quality fork seals, still no joy.

Legs are smooth with no blemishes although the black friction coat has worn away.

Any thoughts?  Should I be looking to get the legs re-chromed or could there be something else amiss?

Having looked at the parts catalogue internals look more like the 2014 model - https://cdn.shopify.com/s/files/1/0312/4301/0185/files/2014_Evo_4_stroke_parts.pdf?v=1592579609

Edited by stu109
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If your upper fork legs are smooth with no wear or blemishes you are lucky.  Do NOT use the fork bushings when any of the black friction coating is worn down to the metal. it will destroy your upper forks in short order. As for fork seals & wipers, If you use old stock -they can harden with age and be prone to leakage.     If the fork bushings that contact -rub on inner part of lower fork legs are worn down to metal-- usually copper-- it will be grinding away on much softer aluminum. not good.

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Fork alignment. In my opinion, the only way to correctly to do this -- is to buy this and use it.  Motion pro Fork Tru Fork Alignment Tool.     www.MotionPro.com.    This is for Aligning front forks to ensure that they are parallel from top to bottom. Bouncing on loose fork legs- grabbing front break then tightening fork axle is useless. any of these methods are.  -    The fork tool will greatly add to the life of fork bearings, forks will have less drag.

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23 minutes ago, magnapoxy said:

Fork alignment. In my opinion, the only way to correctly to do this -- is to buy this and use it.  Motion pro Fork Tru Fork Alignment Tool.     www.MotionPro.com.    This is for Aligning front forks to ensure that they are parallel from top to bottom. Bouncing on loose fork legs- grabbing front break then tightening fork axle is useless. any of these methods are.  -    The fork tool will greatly add to the life of fork bearings, forks will have less drag.

You on commission ?

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The black coating is a sort of  DLS-coating. Very hard and has low friction. Under DLS you often find hard crome on stanchions.

I do not remember which year Beta started putting  SKF-seals in their forks but SKF-seals should fit any Evo and possibly(?) also Rev. I have SKF seals in my 2009 4T. Very happy with them. Innteck have dimension lists

In order to make the seals sealing properly the stanchions must be in good condition

And, it is easy to scratch the seals.

To avoid this you can:

1 Put the seal(s) on the stainchion first with  protection from tape(at the end of stanchion) and some oil

2 Put everything into the lower leg.

3 You may have to make (or buy) an assembling tube to press the seal into the lower leg. In fact I think it is needed.

Sometimes if leaking, cleaning the seal between the sealing surface and stainchion will help. You can do this with a thin deburred feeler gauge. Use  oil to lower the friction when doing this.

Afterwards, the forks must be aligned properly. Also make sure your lower legs not are severe dented but this of course has nothing to do with leaking seals.

 

DimensioniSeals.pdf

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  • 3 weeks later...

Have managed to solve the issue.

Got some new All Balls seals and fitted with the plastic bag tip.

One stanchion had a pinhead sized blemish (a manufacturing fault I think) the other a small area of superficial scratching.  I smoothed off both with fine emery paper.  I did try filling with epoxy, and superglue/baking soda, and just superglue, but any remaining indentations were so shallow nothing would take.

Carefully cleaned everything on reassembly and used level to set oil rather than quantity. 

Hopefully will last a bit!

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