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machinman

Fork seal advice again!

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machinman

Hi all, recently had the fork seals replaced at 34,000 miles and within a week they both started weeping again.

Stanchions look fine, genuine seals.

I watched the techy do the job, no issues. He protected the seal on installation and used a seal driver.

Running low on ideas, maybe thinking bushings, though they looked ok, though im aware they are sensitive . The milage might say otherwise.

Any thoughts?

Cheers.

 

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embee
Posted (edited)

Are the seals the right way up? There's a top and bottom to them.

Are they genuine or pattern, I've had good results with both but obviously pattern parts can be a mixed bag (EDIT - sorry just re-read your post, genuine).

Is the oil level correct? Too much can force its way past the seals on full bump.

I always crosshatch the stanchions using scotchbrite pad if they are polished where the seal/bushing runs. If you look at a new stanchion (or an unworn area) it is a fine ground finish which allows oil (molecules not wet layer) to be held in the surface to lubricate the seal.

Edited by embee
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machinman

Seals definitely right way up (double lipped). The stanchions look polished almost dull, but blemish free.

I did see a measured amount of oil go in, but i cant recall  him checking air gap or working stanchion up and down to bleed.

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michael

Both?  That's unusual. Usually - okay in my limited experience - one fork seal goes and so both legs are changed at the time same.  It's unusual to have both fail, particularly new, factory parts.  I'm thinking one of a few scenarios: too much oil as already stated. Seals damaged during installation.  Bushings? Perhaps yet less likely as bushings worn that much would likely be felt in testing (pulling the forks to and fro or when braking - that audible 'click.')

 

I'd put my money on: seals damaged during installation.

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Tex

Michael is right. Both seals failing points to it being an ‘assembly’ (global term) rather than a mechanical fault. And double check the seals were for the correct model (by VIN number). Could be that, for example, that 700 and 750 seals have a tiny difference?

 

In the period between the new seals being fitted and them failing how did the forks feel? Any stiffer than normal might indicate too small an air gap (too much fluid).

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machinman
Posted (edited)

Thankyou all so far, i did watch the techy do it, and he did use a proper seal driver, though he was probably a little heavy handed with it IMO. Once its home it cant go any further, but he did give it a fair few whacks, so possibly it could be seal damage.

After watching him do it an and a few vids im confident to do it myself.

Ive bit the bullet and purchased (all genuine) a new stanchion, bushings and seal.

Probably overkill on my part, but i dont want to keep taking it apart

Its approaching 35,000 miles and its looked after me well.

Cant stop looking at the new tracer GT though😍

 

Edited by machinman
Typo again

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Trumpet
Posted (edited)
On 01/06/2018 at 10:24, machinman said:

Seals definitely right way up (double lipped). The stanchions look polished almost dull, but blemish free.

I did see a measured amount of oil go in, but i cant recall  him checking air gap or working stanchion up and down to bleed.

Yes Genuine Honda seals are double lipped, with spring tensioners on both sides, but they must be fitted the right way up, they are designed to work only one way round, although they look like they could be fitted either way. I fell foul of that, on a CBF500, and within a week they leaked.

Edited by Trumpet
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embee

Indeed. The lips are designed with different angles on the "wet and dry" sides, and as the stanchion slides back and forth the oil is moved in one direction (towards the wet side). Also the precise detail of the garter spring position will apply a tilt to the sealing lip, adding to the effect.

If they are upside down they effectively "pump" oil up past the seals.

 

This will be a rotary shaft seal, but you can see the principle, which will be similar in a fork seal.

 

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chrisl01

I may be a bit late on this,

fit some pro-moly seals P/No 5247 (41x54x11) they will never leak again.

used them on loads of bikes they are 100% guaranteed not to leak. they are a quite different design to standard seals

about £25 set.

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machinman

Thanks Chris, but ive already brought new stanchion, bushings etc.

Im starting to believe the tecchy screwed up when he fitted them......twice!!

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trisaki
1 hour ago, machinman said:

Thanks Chris, but ive already brought new stanchion, bushings etc.

Im starting to believe the tecchy screwed up when he fitted them......twice!!

 

3 hours ago, chrisl01 said:

I may be a bit late on this,

fit some pro-moly seals P/No 5247 (41x54x11) they will never leak again.

used them on loads of bikes they are 100% guaranteed not to leak. they are a quite different design to standard seals

about £25 set.

Where from  

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Reckless
On 03/06/2018 at 22:19, Trumpet said:

Yes Genuine Honda seals are double lipped, with spring tensioners on both sides, but they must be fitted the right way up, they are designed to work only one way round, although they look like they could be fitted either way. I fell foul of that, on a CBF500, and within a week they leaked.

I had a lot of bother when I was at work with people ordering the wrong type of seals, they were ordering double lipped seals when what was really wanted were dual opposed lip seals, many arguments in the stores until I got them to order what was needed

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DaveM59

Oil seals differ between those for radial use like wheel bearings and those for longitudinal travel as in forks.

They often carry similar descriptions like dual or double lips but are quite different.

If you put the dimensions given on an earlier post into www.simplybearings.co.uk it list only 2 seals both specifically for forks. One is a double type, one a conventional closed type. I reckon if you bashed a double sided one too hard when drifting it in, you will knacker it.

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machinman
2 hours ago, DaveM59 said:

I reckon if you bashed a double sided one too hard when drifting it in, you will knacker it.

Thats my suspicion. Got all my parts and a seal driver, so will have a go myself.

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Graham NZ

Seal damage during installation can occur as the seals are offered onto the top of the stanchions.  There is a trick using thin plastic sheet curled into a sort of funnel placed over the top of the stanchions and the seals slid down on the plastic. Stanchions are commonly pitted above the working zones but the new seals still need to pass over those areas. Only driving the seals into the slider housings should be done with the impact driver.  Of course the seals should be lubed before fitting.  Some say to wipe the lips with fork oil but others like me like to fill the space between the seal lips with silicone grease.

 

All the other advice here I agree with.

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Trumpet
On 13/06/2018 at 15:07, Reckless said:

I had a lot of bother when I was at work with people ordering the wrong type of seals, they were ordering double lipped seals when what was really wanted were dual opposed lip seals, many arguments in the stores until I got them to order what was needed

Just buy Genuine seals. Life's too short :console:

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Reckless

You get what you ask for, whether or not it’s what you really want, take care to match what you ask for to what you want

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