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Showa Inner Chamber Seals - Piston and Rod

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Friends-

I know that many of you keep these in stock for rainy days..

I need a favor -

Can anyone take a calipers and get me a OD and a HEIGHT of the 2 seals-

I am currently in South America.. and here seals are available, but by dimension -

I know the ID ( obviously the damper shaft and piston shaft ) but will need the OD and HEIGHTS to find the seals from the distributors -

NO TIME TO WAIT FOR A US SHIPMENT-

THANKS GUYS

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Oh.. and why don't I pull them myself and measure them -

I have to keep riding until I can find them here..

Cannot take them apart for a week while I have all the calls out-

Thanks again-

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sealx.jpg

I stole this photo from another post..

I can see that the seal to the left could be 10x20x6 ( I think this is the piston seal ) ..

but not the one to the right ( which is the cartridge rod seal )

Does anyone have the dimensions for the remaining seal ?

Thanks

TCE

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Didn't realize you needed the rod seal as well. It's 12x17 but don't know the height.

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I wasn't able to find the damper rod seal.. but it felt OK.. and I jsut changed the piston seal.. What a difference it made.. bleeding ( what made me head down this road ) was exactly how it should have been..

Got the data from Anthony at MXTECH - 12x17x3.5 ( I also later found a website that advertised a 12x17x3 )

I didn't get a business name.. but on Monday.. Suspension Direct recommended to me a guy named BRYCE - who spent a good amount of time with me on the phone troubleshooting and talking some IC theory- Which was why I started this whole journey... Huge Shoutout to BRYCE - Wherever you are-

So in case of emergency ( or raceday weekend ) and noone is shipping.. head to the industrial side of town and you might be able to find whichever of these you need- But otherwise.. support your local suspension shop-

Thanks everyone-

T

--

For the search bar

ICS Seal Dimensions / Specifications / measurements / sizes

Inner gas piston pressure seal 10x20x6

Damper rod lower cartridge seal 12x17x3 or 12x17x3.5

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If you buy the industrial non suspension free piston seal you will not be able to bleed the cartdridge correctly because the 10x20x6 seal that is suspension specific the inner lip is like 4mm heigth more or less and this allows the seal to reach the step in the road that holds the free piston has so when the inner lip reach this step it will be able to let the excess oil out with the industrial 10x20x6 seal you will also have 6mm inner lip so it will not be able to reache the step on the road and you will have a hydro loc

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Hey Pitioa.. interesting thought.. do you have any data to back this up? .. I only ask as After I installed the seals ( I was able to find SKF seals ) .. i was able to bleed the system as always-

The seal that came out original was a NTN .. a very common seal manufacturer .. I will pick it out of the can if the trash hasn't been taken out yet and see if I can find a fab number - and see how then spec out with the different manufacturers- and their tolerance and lip heights-

I am not challenging you.. just wanting to see how this turns out-

Not all of us live where buying parts and having them shop up the next day is a reality-

Sometimes you have to venture off the reservation to find out a really cool solution to a complex issue-

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I installed a set of skf oil seals as well for a friend and didn't have any issues. He didn't have the money to buy showa replacements and I found some skf on ebay for $1ea shipped. He has over 75 hours on those forks now and they were working fine when I did a recent oil change.

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I wouldn't consider myself an expert on seals.. but yes on hydraulics.. ( and I guess seals goes along with it ) ... Attached is some data from a major seal manufacturer..

All the seals available in the 10x20x6 variant-

HMS5 RG without secondary lip, nitrile rubber

HMS5 V without secondary lip, fluoro rubber

HMSA10 RG with secondary lip, nitrile rubber

HMSA10 V with secondary lip, fluoro rubber

ISO 6194-1 covers the uniformity of seals in the industry.. Nothing about lip depth- I would say that on average.. the sealing lip is about 2/3rds of the way into the seal.. ( 2/3rds of 6 is 4 )

T

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I have pictures but I don't know how to post it here but I measure the inner lip and on industrial seal the inner lip is the same heigth as the outer seal in this case 6 mm and the showa seal inner lip heigth is aprox 2 mm so to bleed the cartridge with the industrial seal you will have to compress the free piston 4mm more and on my case I couldn't do it the rod just got lockout with 15% of travel because the oil had no way to go out

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Pitioa is absolutely correct on this. I have tried using a different seal on these, and they will not bleed out.

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I have pictures but I don't know how to post it here. But I measured the inner lip and on industrial seal the inner lip is the same heigth as the outer seal, in this case 6 mm and the showa seal inner lip heigth is aprox 2 mm. So to bleed the cartridge with the industrial seal you will have to compress the free piston 4mm more (than normal) and on my case I couldn't do it. The rod just got lockout with 15% of travel because the oil had no way to go out.

Translated from a run on sentence to something readable...I hope he's typing on a phone... :smirk::bonk:

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Pitioa is absolutely correct on this. I have tried using a different seal on these, and they will not bleed out.

Well you have 2 people saying it wouldn't and you have 2 other people saying that they got it to work. This implies that there are variations in the available seals.

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Translated from a run on sentence to something readable...I hope he's typing on a phone... :smirk::bonk:

That and also english is not my native language:p

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Well you have 2 people saying it wouldn't and you have 2 other people saying that they got it to work. This implies that there are variations in the available seals.

I doubt that you bleed it correctly with the industrial seal most likely you leave air in the chamber if you do so the rod will go all the way in but it will go back out all the way too and it should stop like 85% to 90% of its travel if you leave no air in it.

Maybe if you really force the rod in you can get the oil to bleed out but I will not try it.

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Ok, I one picture worth a 1000 words

freepistonseal.th.jpg

Edited by Pitioa

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The seal that came out original was a NTN .. a very common seal manufacturer ..

The aftermarket seals I've received have always been NOK 91049. I've never really looked at the seals that I've pulled out.

I have pictures but I don't know how to post it here but I measure the inner lip and on industrial seal the inner lip is the same heigth as the outer seal in this case 6 mm and the showa seal inner lip heigth is aprox 2 mm so to bleed the cartridge with the industrial seal you will have to compress the free piston 4mm more and on my case I couldn't do it the rod just got lockout with 15% of travel because the oil had no way to go out

The NOK seal lip is 2.6mm tall and the skf seals I had were around 4.5mm tall.

I doubt that you bleed it correctly with the industrial seal most likely you leave air in the chamber if you do so the rod will go all the way in but it will go back out all the way too and it should stop like 85% to 90% of its travel if you leave no air in it.

Maybe if you really force the rod in you can get the oil to bleed out but I will

not try it.

I'm pretty familiar with how a TC kyb or showa should feel and act when it's been bleed correctly.

Ok, I one picture worth a 1000 word

I thought you were finding a pic of the other oil seal you tried to use. I could have posted a pic of the NOK as I have 3 pair here. I'm always helping people and friends service these fork and it never fails that they have bad ICS seals.

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Very interesting.. Good dialog-

The CHEVRON \ Radial oil type seal is what I was referincing in ISO.....

I definitely see that the seal in Pitioas photo has a very recessed sealing area.. That almost looks like valve guide type seal.. not designed to retain fluid.. but more as a scraper type seal.. seals that are designed to maintain a pressure area definitely have more lip and a deeper cavity - using that cavity to direct pressure through the seal wall and onto the shaft ( helping seal ) -

Pitoa.. that seal is the original, the replacement, or the "industrial"

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Pitoa.. that seal is the original, the replacement, or the "industrial"

It's the correct NOK replacement seal

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