The BSA A7-A10 Forum

Technical (Descriptive Topic Titles - Stay on Topic) => Frame => Topic started by: UncleD on 02.11. 2018 22:35

Title: A basic fork seal question
Post by: UncleD on 02.11. 2018 22:35
58 Super Rocket...new to me and older restoration so slowly working through its ailments.

I replaced the fork oil and have found that both forks are now leaking oil from the seal holder region (slow drip onto the floor of the workshop)

There was a quantity of oil in the forks originally but probably only a fifth of what should have been.

I have not dismantled forks before so am wondering about the construction material of the seals.  Are they a fibrous material?  I assume that they may have dried out while standing / unlubricated.  Are they made of a material that may swell and seal (given a little time) now that they have been oiled or are they probably stuffed?

I don't want to begin fiddling with forks unless I have to and then I will probably do the full job since I don't know the history of the bike and although not mistreated, he has been neglected.

Cheers
Title: Re: A basic fork seal question
Post by: chaterlea25 on 02.11. 2018 23:06
Hi,
The seals are rubber "garter" seals the same type as on most modernish bikes
The best ones have a dust lip on the outer face, rather than standard industrial seals
The BSA seal holders can trap water above the seals and corrode the legs  *sad2*

I had leaky fork seals on a modern bike that had sat idle for some time, they sealed up after some use

John
Title: Re: A basic fork seal question
Post by: mikeb on 03.11. 2018 05:14
you'll have to replace the seals to stop the leaks. its not too bad a job tho you need to get a tool to remove the seals like this:
http://shop.srmclassicbikes.com/product/fork-oil-seal-holder-removing-fitting-tool-61-3005 (http://shop.srmclassicbikes.com/product/fork-oil-seal-holder-removing-fitting-tool-61-3005) or make your own out of a bit of pipe of the right diameter. then you need to tool (or a magic broomstick) to put the fork back up into the triple clamp. ok its a PITA getting the tools, but the job is ok. part of the joys of BSA ownership! where buying or making strange tools is a new fun weekend activity. search the forum for lots of relevant posts.
AND... when they are out make sure the forks are not pitted - if they are then the oil will find its way past the new seals. (don't ask me how i know this)
Title: Re: A basic fork seal question
Post by: KiwiGF on 03.11. 2018 10:49
58 Super Rocket...new to me and older restoration so slowly working through its ailments.

I replaced the fork oil and have found that both forks are now leaking oil from the seal holder region (slow drip onto the floor of the workshop)

There was a quantity of oil in the forks originally but probably only a fifth of what should have been.

I have not dismantled forks before so am wondering about the construction material of the seals.  Are they a fibrous material?  I assume that they may have dried out while standing / unlubricated.  Are they made of a material that may swell and seal (given a little time) now that they have been oiled or are they probably stuffed?

I don't want to begin fiddling with forks unless I have to and then I will probably do the full job since I don't know the history of the bike and although not mistreated, he has been neglected.

Cheers

How much oil did you put in? The oil level is well below the seals so don’t usually leak badly even when completely shot?
Title: Re: A basic fork seal question
Post by: bsa-bill on 03.11. 2018 10:56
Quote
or make your own out of a bit of pipe of the right diameter.

My advise is buy the tool, I and friends have made our own and found it difficult to get correct dimension pipe and beefy enough to do the job, the bought tool is up to it and much easier to use
Title: Re: A basic fork seal question
Post by: UncleD on 03.11. 2018 11:01
Kiwi...that is a very good question.  I have been wondering why it has been leaking when standing still...

I did use the quantity from the Haynes manual but could have stuffed this up.  From memory it was a tad under 200ml per fork but I'll need to check.
Title: Re: A basic fork seal question
Post by: UncleD on 03.11. 2018 11:16
Manual said 213cc per fork....interestingly, it says this equates to 5.5 fl.oz....but I used a conversion App. and this say 5.5 oz (UK) equates to 156 ml.

Is this a typo or are my calculations inaccurate?

Title: Re: A basic fork seal question
Post by: paulmbsa on 03.11. 2018 11:39
a babys bottle is great for measuring these amounts and cheap to buy
Title: Re: A basic fork seal question
Post by: duTch on 03.11. 2018 15:03
 There's bumper stickers around that say "is it the truth....or did you read it in the *Local Paper* " (*Local Paper* being large of a conglomerate owned by a ex-pat- Australian ), I guess the same can be said for Haynes...

 A 10 Imp.oz beer is 285ml, so 5.5 fl.oz will be 5.0oz @ 142.5ml + 0.5oz @14.25  equals 156.75ml =5.5fl.oz.   

 (for those who like fractions *smile*;142,1/2ml+1/2oz @14,1/4ml)=156,3/4)

 For US users,  213ml =;  *eek*   *conf2* smaller *beer* 

 **Edit* Hour or so later....the Haynes is a bit confusing- even their 4oz/100cc is 25cc/Fl.oz contradicting a general ~28.5 ml/Fl.oz...maybe they allowed for density of ~90% , so 213 cc would be ~7.5 fl.oz - typo option sounds good *conf2*

 It's no comparison, but I think my Conical forks take 190cc per side, I'd expect yours to have slightly more volume......so 213 doesn't sound too wrong  *dunno*

Title: Re: A basic fork seal question
Post by: Swarfcut on 03.11. 2018 16:54
   To  keep it simple,  30ml is more or less 1 fl oz.

   Swarfy
Title: Re: A basic fork seal question
Post by: duTch on 03.11. 2018 17:41

 
Quote
To  keep it simple,  30ml is more or less 1 fl oz.

 Yeah sure- good enough for a vague estimate, but if people are fed the wrong information, that becomes 'not simple' too....I used the 10oz beer example because it was a simple conversion to 5.5 ...and arrived at much the same 156ml figure as U-D instead of 165...

                   *beer*........................... *beer*
Title: Re: A basic fork seal question
Post by: chaterlea25 on 03.11. 2018 18:58
Hi All,
I got totally confused with US measurements during my recent trip there  *pull hair out* *pull hair out*

When you asked for a beer or coffee they wanted to know how heavy you wanted it to be  *conf2* *conf2*

 *lol* *lol*
John
Title: Re: A basic fork seal question
Post by: muskrat on 03.11. 2018 19:48
G'day fellas.
1 US oz = 29.57ml, 1 UK oz = 28.41ml.
To confuse it even further
1 US gallon = 3785.41ml, 1 UK gallon = 4546.09ml
Cheers
Title: Re: A basic fork seal question
Post by: duTch on 03.11. 2018 22:54

 In adddition (reckon I have addd ?  *smile*) to above, for those of us who've forgotten;

 1 US pint = 16 oz = 1Lb (pound)    1 US pound = 8Lbs / 128 oz



 1 Imperial Pint =20 oz              1 Imperial gallon = 10 Lbs 160 oz

 8 Pints = 1 gallon  both  Imp. pints & US pints

 The US Pint/Gallon is based on what the British system was until the 1820's when it was revised for the Gallon to weigh 10 Lb, probably to simplify shipping and storage calculations among other reasons. 

 The US didn't adopt it, probably due to having not much earlier escaped the clutches of the Empire   *fight*

 There's a lot more to it, but that's the essence of what I learned when I looked it up  a couple of years ago, and probably nothing new to many...... *conf2*



Title: Re: A basic fork seal question
Post by: muskrat on 04.11. 2018 03:25
G'day fellas.
Getting a bit off topic but I think I made the rod for my dampers 1 cubit long (including threads).
Cheers
Title: Re: A basic fork seal question
Post by: bsa-bill on 04.11. 2018 09:48
Quote
I made the rod for my dampers 1 cubit long

was that a metric, cycle or Rubic cubit
Title: Re: A basic fork seal question
Post by: duTch on 04.11. 2018 10:54

 I didn't mean to stray in my last post, I was trying to find a correlation between 5.5oz and 213cc, but..... I *may* have it now...
...in the 'BSA book by OCEE RITCH' from 1970, Page 117 says to effect 'the A50/65's take 190cc (so I may have been right there *smile*) , up to '52 takes 142cc in the forks, and after that up to '66 they all take 213cc '.....if I recall, Richard L also has a copy of this book
 
 I'll attempt to take a pic of it and add it when my phone stops bouncing down the driveway.... *eek*



 
Quote
..I got totally confused with US measurements during my recent trip there  *pull hair out* *pull hair out*

When you asked for a beer or coffee they wanted to know how heavy you wanted it to be  *conf2* *conf2*......

 That's the good oil...did you order straight 40 or multigrade...I have to say the Guinness they sell here is not as viscous as I recall it should be  *conf2* only 4.2....did you know that K.L Guinness was the creator of KLG spark plugs ? oohh , whoops *shh*

Title: Re: A basic fork seal question
Post by: RogerSB on 04.11. 2018 16:23
Manual said 213cc per fork....interestingly, it says this equates to 5.5 fl.oz....but I used a conversion App. and this say 5.5 oz (UK) equates to 156 ml.
Is this a typo or are my calculations inaccurate?

213 cc = 7.5 (UK) fl oz
or
7.2 (US) fl oz.
Title: Re: A basic fork seal question
Post by: duTch on 05.11. 2018 00:04

 
Quote
...

213 cc = 7.5 (UK) fl oz...
I think I suggested that...but was *guessing*

 Here's a pic of the paragraph from Ocee Ritch; phone didn't bounce- this time ... *eek*

 
Title: Re: A basic fork seal question
Post by: mikeb on 05.11. 2018 02:20
maybe the wikipedia page on weights and measure could be replaced with one about BSA fork seals? then order will be returned.
Title: Re: A basic fork seal question
Post by: RichardL on 07.01. 2019 03:12
I have a new question, I think, in this topic. Are fork seal holders available in flared and straight versions to accommodate gaitors vs. shrouds, respectively? Otherwise, are they all flared so that the flare centers the seal holder in the shroud? I seem to see both types online, but it seems they are all called 29-5310.

Thanks,

Richard L.
Title: Re: A basic fork seal question
Post by: RichardL on 07.01. 2019 09:11
Well, just called Draganfly and, according to them, they're all flared.
Title: Re: A basic fork seal question
Post by: Jules on 13.01. 2019 10:46
a question Uncle D, is the oil leaking past the seal and up the stanchion, or is it leaking past the threaded seal holder? there is known issues with leaks past the threaded seal holder which you can read up on old threads, and naturally this isn't such an issue compared to the seals themselves, albeit dripping on the floor!