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What the fork is wrong with my seals?
- Thread starter bosco659
- Start date
Vic, putting a 10 or 12" extension on the socket helps sometimes.
It helps you sight down it and better keep the seal squared up the lower.
It helps you sight down it and better keep the seal squared up the lower.
I'm gonna throw this out there, even though I'm certain Gary and Vic know this, but others might run across this thread in the future....
A common bench vise can ruin a fork lower in short order. They're cast aluminum, and not very thick a casting at that... 3-5mm would be my guess. Stick one in a vise somewhere around the middle and give the vise a good twist to lock it in, and there's a better than even chance you just egg shaped it... turned it into a boat anchor in other words. Cast aluminum has very poor elasticity.
Let the vise grab it down where the axle runs through, never on the "tube" part.
A common bench vise can ruin a fork lower in short order. They're cast aluminum, and not very thick a casting at that... 3-5mm would be my guess. Stick one in a vise somewhere around the middle and give the vise a good twist to lock it in, and there's a better than even chance you just egg shaped it... turned it into a boat anchor in other words. Cast aluminum has very poor elasticity.
Let the vise grab it down where the axle runs through, never on the "tube" part.
When needed I tend to clamp the vice on the brake caliper tabs. 
Yes, that's how I do it as well ......
..... and to hold assembled forks, I use an old triple tree assembly ......
We had to replace one of the lowers on my buddy's '80 because someone in the past had done this to it (IDK, maybe it was him, lol). The fork tube wouldn't slide in all the way. Funny thing is, he rode it that way for years, lol.
..... and to hold assembled forks, I use an old triple tree assembly ......
We had to replace one of the lowers on my buddy's '80 because someone in the past had done this to it (IDK, maybe it was him, lol). The fork tube wouldn't slide in all the way. Funny thing is, he rode it that way for years, lol.
Red or white lithium grease? Or is this also an application for red rubber grease?
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The thickest White lithium grease I could find. I haven't been able to find a thick lithium paste like was in a late model Yamaha fork seal when I went in for surgery.
The thickest White lithium grease I could find. I haven't been able to find a thick lithium paste like was in a late model Yamaha fork seal when I went in for surgery.
Look what I found when I went to buy grease today. This stuff if pretty thick. I’ll get a tub of it for you if you make it north if the border in June
Attachments
Yeah that looks like about what I have. Cheeze now they are trying to bribe me to visit... 
I packed the seals in the '83 full of red rubber grease when I serviced those forks ,,,,,,
The seals were good and not leaking so I didn't replace them. I just cleaned them out real good then packed them with grease. I also put some on the tops because I've found that snap ring and washer all rusty on some forks.
The seals were good and not leaking so I didn't replace them. I just cleaned them out real good then packed them with grease. I also put some on the tops because I've found that snap ring and washer all rusty on some forks.
I thought the red rubber grease might be good here. Well I have lots of options now! My new seals haven’t arrived yet.
Yes, on motor seals, I use regular grease, but on these fork seals, I thought the red rubber grease might be a good choice as well. Maybe help preserve them and keep them soft? Anyway, so far it's been working well.
As previously mentioned the po had put some gouges and scratches in the lower fork tubes where the seals seat. I cleaned out the marks and applied a smear of JB Weld. After 24 hours I carefully hand sanded the high spots of the epoxy. I was concerned if I used sandpaper, my fingertips would have a tendency to sand into the depressions that were now filled with epoxy. The upper tubes have an ID of 46 mm. I found some 2” sanding drums in stock that had a very stiff paper backing. I cut out a 1”x1” square and this worked perfectly to do a controlled sanding of the epoxy. It was the perfect radius with mild fingertip pressure.
I bought a couple of 1-1/2” 120 grip flap wheels to blend everything in. I chucked one in my small cordless drill to clean up the bore.
After the very mild sanding, I chucked up a 1-1/2” diameter red 3M scuffing pad and polished up the bores. I pretty sure the seals will now have a better chance of boring leak free on the OD.
On another matter, I used the @gggGary method to remove the fork seal using a tire iron, backed by a piece of aluminum. The next time I ever do this, I plan to add a thin piece of stiff rubber behind the aluminum piece. I think this will better protect the fork tube. I noticed on my tubes, there was a bit of deformation at the top of the tube, slightly squeezing in the groove where the retainer ring sits. I’ll post a pic later.
Still waiting for seals…..
I bought a couple of 1-1/2” 120 grip flap wheels to blend everything in. I chucked one in my small cordless drill to clean up the bore.
After the very mild sanding, I chucked up a 1-1/2” diameter red 3M scuffing pad and polished up the bores. I pretty sure the seals will now have a better chance of boring leak free on the OD.
On another matter, I used the @gggGary method to remove the fork seal using a tire iron, backed by a piece of aluminum. The next time I ever do this, I plan to add a thin piece of stiff rubber behind the aluminum piece. I think this will better protect the fork tube. I noticed on my tubes, there was a bit of deformation at the top of the tube, slightly squeezing in the groove where the retainer ring sits. I’ll post a pic later.
Still waiting for seals…..
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I made up a couple "special tools" for fork seal removal. First, to protect the top of the lower, a small piece of aluminum angle with a "finger" cut into it and bent down. It sits very nicely on top of the lower ......
Then, for prying the seals out, I rounded the tip on a big old square shank screwdriver I had laying around. The square shank keeps the tip from rolling as I pry .....
I haven't met a fork seal yet I couldn't remove, lol, and this includes some old really stuck ones. But the worst was one on a powder coated leg, being "baked" in there and all.
Then, for prying the seals out, I rounded the tip on a big old square shank screwdriver I had laying around. The square shank keeps the tip from rolling as I pry .....
I haven't met a fork seal yet I couldn't remove, lol, and this includes some old really stuck ones. But the worst was one on a powder coated leg, being "baked" in there and all.
Your rounding of the tip of the screwdriver makes great sense. I’ll round the end of one of my tire irons. I noticed when removing my seals you have to be very careful to not nick the tube. I like your aluminum angle piece too. Maybe I’ll make one for the tool box. I used to have some larger dimensioned angle. I’ll have to look for that later today.
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Yes, but it's not iron, it's aluminum.
Still no seals and it’s been a week. Not happy
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I was thinking tonight about the suggestion to add extra oil to the fork legs. I never spent time to figure out why the extra oil makes a difference but I think the light just came on. Is it because the extra oil displaces a volume of air from the forks? With the lower volume of air, compression of that air becomes more difficult, hence making the forks feel stiffer? Or is it something else that I’m missing?
. I was thinking tonight about the suggestion to add extra oil to the fork legs. I never spent time to figure out why the extra oil makes a difference but I think the light just came on. Is it because the extra oil displaces a volume of air from the forks? With the lower volume of air, compression of that air becomes more difficult, hence making the forks feel stiffer? Or is it something else that I’m missing?
Yes, you are correct about the oil volume vs air volume. More oil=less air= air pressure increases quicker as fork is compressed= total "spring rate" increases.Still no seals and it’s been a week. Not happy
I was thinking tonight about the suggestion to add extra oil to the fork legs. I never spent time to figure out why the extra oil makes a difference but I think the light just came on. Is it because the extra oil displaces a volume of air from the forks? With the lower volume of air, compression of that air becomes more difficult, hence making the forks feel stiffer? Or is it something else that I’m missing?
Which I believe is the reason RaceTech and others now recommend straight rate springs, as the compression of the air adds to the force from the spring.
Well I got my seals today. They went into the lower tubes with old moderate bashing. They were most likely looser fitting than before since I cleaned up the bores where the seals sit. The first fork assembled well and I filled it with the appropriate amount of oil (15W this time), added the spring and mounted it on the bike. I assembled the second fork and the inner tube slid up and down smoothly, but when fully collapsed, with no spring, the inner tube gets “stuck” in the collapsed position. With a bit of tugging it would come free but when I went to fill it with oil and tried moving the tube, it was stuck in the collapsed position and no amount of tugging would free it up. I dissembled everything and couldn’t find anything out of the norm.
I know that in real riding conditions, the fork tube would never be this far collapsed with the spring in it, but I’d still like to figure out what’s causing this. Has anyone else experienced this and figured out why it’s happening?
New phone and camera coming soon. The wobble is driving me nuts.
I know that in real riding conditions, the fork tube would never be this far collapsed with the spring in it, but I’d still like to figure out what’s causing this. Has anyone else experienced this and figured out why it’s happening?
New phone and camera coming soon. The wobble is driving me nuts.
