• Welcome to the new ER5-ER6 Forum. Please be sure to read the "Welcome to the new forum" thread in General Spouting. This contains some important information. I hope you enjoy the new site. Steve (The Gremlin) Just so you are aware the new URL for this site is: er5.bikersoracle.com

Fork seal replacement - How-to

romi

biker, times two
#1
Here it is a guide on how to replace the fork seals, from start to finish, including removal of the front wheel, change of fork oil, etc.

There are many aspects which can be discussed, like the best fork oil, its viscosity, how often to change it, other ways of seating the bushings and seals, etc.

The forum has a lot of advice which would benefit of having links here, for example:

Fork gators/gaiters/gaters, multigrade oil, tube taped to a ruler, fork driver, bushings, spacers, reduced air gap or thicker oil, etc.

Before you start, at least for the first time, make sure you have someone to help you, you have read this guide, advice from this forum, you have at least one manual handy, etc.

Do both forks at the same time, even if only one needs doing.

The terminology may be confusing - I have stick to one throughout the document. Other names are:

- stanchion: inner fork tube
- fork leg: outer fork tube
- outer or upper fork bushing: sliding bushing
- fork driver: fork seal driver
 

Attachments

romi

biker, times two
#2
To start the discussion...

it was difficult to push down one of the plugs as there was a lot of rust. We then put penetrating oil WD40 type and let if for a few minutes... it freed it up quite nicely. All the rust had to be cleaned before assembling, and the condition of the rubber O-ring checked.

When buying fork oil, only one litre bottle is required to do both forks.
 

fuel__2001

engineless with 2 wheels
#3
it was difficult to push down one of the plugs as there was a lot of rust. We then put penetrating oil WD40 type and let if for a few minutes... it freed it up quite nicely.
Normally smash mine with a hammer and drift :D to set it free ;)
 

lumpy

Wants to Shag BandyIrd
#5
unless..........

it was difficult to push down one of the plugs as there was a lot of rust. We then put penetrating oil WD40 type and let if for a few minutes... it freed it up quite nicely. All the rust had to be cleaned before assembling, and the condition of the rubber O-ring checked.

When buying fork oil, only one litre bottle is required to do both forks.
unless you're going to play with air gaps of course.

Excellent technical publication Romi, Haynes eat your heart out!!:congrats:
 
#6
My sons ER5 A1 has just passed MOT but with an advisory of misting on forks.After reading this great post I feel confident of doing this ourselves.Thankyou for taking the time to post :yo:
 
#8
Thanks Romi !!!!

I wouldnt of been able to do it without you! I passed my test a few week ago and have done about 700 miles on it and the forks havent "blown up" so we must have done it right! now im just looking for some decent panniers :)

thanks again!
 

romi

biker, times two
#9
and S Wilson must the brother of ian505050 :confused: I think you are ;) - We did sweat a bit that Saturday :rolleyes:, team effort :five:

Congrats on your test - go and ride and enjoy :burnout: but take it easy first, there is no rush.

consider fitting gaiters.

Panniers? soft or hard? top box is more practical tbh.
 
#10
lol ok seen as you love them so much i will seriously look at some gators,

I have got a givi rack for top box, im looking at the givi monokey types but there fairly pricey, 52 liter (?200 ish)

but i dont know if thats enough space for my gf's shoes, makeup, hair straitners etc. lol

Basically i want to make it like a bmw tourer set-up :p might need to weld some more fittings for panniers as i dont think er5's typicaly come with panniers still in the planning stages.
 

romi

biker, times two
#11
I would encourage you to start a new thread under accessories. I know some members have top boxes available (and near you!) and a member has a spare pannier rack - - - - - just a thought ;)
 
#14
Thank you

Thank you so much Romi. I replaced my bushes, oil seals and dust seals today with the aid of your excellent guide.:bow:

I did some things a little differently and I thought I would share my experiences with you:

Mod 1)
Having experienced difficulty trying to loosen off the lower damper rod bolts, my assistant suggested leaving them until the forks were off the bike (I know what you are thinking ;)). We did this, and with the complete fork assembly placed on its side and gripped between the two top sections of a Black and Decker Work Mate, we were able to give the tight damper bolts a helping hand with the aid of a lump hammer on the end of an allen key. This did the trick and they eventually came out without rounding off.

Mod 2)
We found removing the caps and clips at the top of the stanchions to be a very difficult, fiddly and time-consuming job. Even with one person levering downwards on the cap with a small wooden hammer shaft, it was 'nearly' impossible for the other person to release the clips; due mainly to lack of available working space. Everything just seemed to be in the way (bars, clocks, cables, master cylinder etc). In addition to this, the hammer shaft lever just kept slipping along the shiny chrome handlebars which bend just at the point where you need to lever against them. We did eventually get them out, but because of Mod 1) (above), we decided that we would have to put them back again temporarily until we had loosened the damper rod bolts with the forks in the Work Mate.

Having to refit them temporarily was initially infuriating, but by doing so, we later found out just how much easier it was to remove them with the forks off the bike. By comparison, it really was much, much easier, and less time consuming and I would not hesitate to do this next time.

Mod 3)
Rather than using a plastic ruler to drive the upper bushing home and bits of wood for the oil seal, I adapted what I had seen others do on the net and made my own fork seal driver to perform both functions:

The driver was very easy to cunstruct using just a length of 'Wickes' 43mm X 1.9mm solvent fix waste pipe (must be solvent fix, rather than compression fix or push fix) and a straight 40mm solvent weld coupling (see pics). This particular waste pipe has an internal diameter of approx 38mm - only very slightly wider than the diameter of the stanchion, so it will slide over fairly snugly but without scratching. The addition of the straight pipe connector at one end of the pipe, increases the external diameter just sufficiently so that it will sit on the old fork seal bang in the middle of the flat section (where you most want the presure to be).

aaP040510_18 (1).jpg abp.jpg aP040510_18 (2).jpg aP040510_18 (3).jpg aP040510_18 (4).jpg aP040510_18 (5).jpg
 

romi

biker, times two
#15
:congrats:

We learn from experience ;) . Having also learnt from experience, I now have a selection of tubes diameters :)

Mod 1) Sometimes I fit the correct tool on a screw/bolt and hammer it a bit, then try to torque a bit more, and then unscrew and it comes out easily. An alternative would be to use the closed end of a spanner on the other end of the Allen key to give more leverage. Whatever works best with the tools available at the time.

Mod 2) I am not sure I understand. Did you remove the circlip and cap with the forks on the bike or on the WorkMate? Where did you clamp the fork on the WorkMate (doing it on the lower fork would not help)? :dunno:


How long did it take you? what oil weight did you use? Did you add extra oil (reduced the air gap)? How did you measure the air gap (tube and syringe)?

Just add fork gaters for added protection :D
 
#16
:congrats:
Mod 2) I am not sure I understand. Did you remove the circlip and cap with the forks on the bike or on the WorkMate? Where did you clamp the fork on the WorkMate (doing it on the lower fork would not help)? :dunno:


How long did it take you? what oil weight did you use? Did you add extra oil (reduced the air gap)? How did you measure the air gap (tube and syringe)?
To answer your questions:

Mod 2) - both, but it was much easier taking the circlips and caps out with the forks off the bike. Yes, we used the Work Mate with the fork positioned pretty much as it is in the photos, but the jaws of the workmate were tightened on the top of the stanchion.

Time, well, urrrmmmm:eek::eek:, It was probably about 12 hours in total, but that included a short lunch break, several cups of tea, a quick trip to the local car garage and of course tidying up afterwards.

I used standard weight oil in the standard quantity (127mm from top of stanchion). This was measured using a narrow, plastic ruler and any excess was taken out using a syringe and a piece of plastic tube.

There did not appear to be that much of the old oil in the forks, so I thought I was keep it standard and maybe have a play with the quantity/weight at a later date. I also noted that the stanchion tops were approx 4-5 mm lower than the top face of the upper triple clamp (making the front of the bike higher), so this was reset to standard spec also.
 

romi

biker, times two
#17
we used the Work Mate with the fork positioned pretty much as it is in the photos, but the jaws of the workmate were tightened on the top of the stanchion.
That is what I don't understand. The lower leg (where the mudgard and brake caliper bolts on) would have to be free, and not clamped. The stachion (upper leg) would have to be clamped, but the work mate is too short (close to the ground) to do that :dunno:

Did you have to ask someone to sit at the other side of the WorkMate while pushing the cap in to release the circlip?

Did you also use the WorkMate to fit the circlip and cap once the fork had the new oil?
 
#18
That is what I don't understand. The lower leg (where the mudgard and brake caliper bolts on) would have to be free, and not clamped. The stachion (upper leg) would have to be clamped, but the work mate is too short (close to the ground) to do that :dunno:

Did you have to ask someone to sit at the other side of the WorkMate while pushing the cap in to release the circlip?

Did you also use the WorkMate to fit the circlip and cap once the fork had the new oil?
It really was set up just as in the photo, but obviously without the seal driver tool in situ (the work mate is tall enought to clamp the stanchion). The only difference was that in the photo, I think you can just see a 4 inch block of wood placed beneath the bottom fork leg to protect it when the seal tool was being hit from above with a lump hammer. Using just an old towel for protection, instead of the wood would obviously lower the whole assemply a few inches closer to the ground. I cannot remember whether or not I had drained the oil out before temporarily refitting the caps (this would have allowed the forks to be compresses more), but regardless of this, the height of the workmate was sufficient to be able to grip the stanchion tightly enough to help keep it steady, but without risking damaging the stanchion.

There was no need for anyone to sit on the workmate. With the stanchion gripped carefully between the wooden jaws, I held the fork assembly with my left hand and used my right hand to remove the circlip with a precision screwdriver whilst my assistant pushed down to compress the cap with a 1/2 inch T-bar from above.

The work mate was also used in a similar manner to fit the caps and circlips after the new oil had been added.

I do seem to recall that the jaws of the workmate gripped the stanchion a little lower than they had on removal (possibly more oil in now), but I think it was just above where the normal range of travel would stop, and the workmate grip was not that tight as to risk damaging the stanchion anyway.


Has this answered you question Romi? I really wish I had taken more photos now:eek:.
 
Last edited:

romi

biker, times two
#19
thanks for the explanation. A picture is worth more than 1000 words and 3 posts :lol:

I just thought that the WorkMate was too short to grip the stachion without the lower leg touching the ground, and I also thought that the wooden grip would not be strong enough to remove/fit the caps and circlip and at the same time delicate enough not to damage the stachion.

It may be true that removing the Allen bolt at the bottom, and the drain of oil that way, would make removing the cap and circlip a bit easier, as it would not be air and oil pressure built up inside, but just the spring.

For those reading this......... if you only aim to replace the oil, there is no need to do all of the above!!
 
Top