Author Topic: Is fork seal replacement really this easy?  (Read 10325 times)

0 Members and 1 Guest are viewing this topic.

Offline Old75_ratafe

  • CB750 Cave Spelunking
  • Expert
  • ****
  • Posts: 801
  • 1975 CB750K
Is fork seal replacement really this easy?
« on: December 16, 2010, 09:24:06 PM »
I was on carpys site the other day and noticed a tips section that lead me to a question.  To replace my fork seals do I really need to dissasymble the shock?  He made is sound like you could just remove them from the tripples remove the c-clip retainer pull the old one out and then use a piece of pvc pipe to push the new one on.  I did a search for fork seals on the forum but all I came up with didn't mention anything like this (mostly threads on trouble removing stuck seals).
1975 CB750K
Project Back in Black

Sent from my Texas Instruments TI99/4A Computer

Offline Flying J

  • Old Timer
  • ******
  • Posts: 3,386
Re: Is fork seal replacement really this easy?
« Reply #1 on: December 16, 2010, 09:29:10 PM »
Yes, the process is simple but there are a few tricks.
1) before you take the top cap off undo the allen head at the bottom.
2) Read all the threads you can about getting the seals out. Be carefull not to scratch the walls or crack the top like i did. Those suckers get stuck in there good after 30 years.  But with some practice i can change a set of seals in a few hours.
Good luck

Offline Duanob

  • Bold Timer
  • Old Timer
  • ******
  • Posts: 4,005
  • Gotcha!
Re: Is fork seal replacement really this easy?
« Reply #2 on: December 16, 2010, 10:14:51 PM »
This website is pretty good along with the repair manual.

http://oldmanhonda.com/MC/MC.html

And ffjmoore's number #1 tip is priceless!
"Just because you flush a boatload of money down the toilet, doesn't make the toilet worth more",  My Stepfather the Unknown Poet

1974 CB360T
1976 CB550K2 Resurrected
1976 CB550F2 Barn Find
1979 CX500 VG "HONDA-GUZZI"
2007 Moto Guzzi Breva 750ie
2015 BMW F700GS
Another 1976 CB550K Cafe?

  __o
_- \_<,
(*) /' (*)

Offline MidnightLamp

  • Wrenchy wrenchy wrench!
  • Enthusiast
  • **
  • Posts: 190
Re: Is fork seal replacement really this easy?
« Reply #3 on: December 16, 2010, 10:15:37 PM »
You know, a 750 engine comes out with only a few bolts. Eaaaaasy to remove the whole thing. Ten minutes tops  ;D

^^ exactly what has been said above. Also, buy a fork seal tool. I've seen some VERY bad advice online about fork seal removal using screwdrivers,picks,etc... The seal puller is $12 for a cheapie, and I've had seals that needed every bit of leverage that sucker can provide + heat + solvent. On a well taken care of bike, you might be okay, but once you start having water in there.....

Just my $0.02
'75 CB750 - Racer
'69 CB350 - Racer
'68 Enfield 350/440(flat top) - Steet
'54 Enfield 350 - Resto
'74 Commando 850 - Restomod
'67 Enfield 750 (TT7) - Resto

KingCustomCycles.com

  • Guest
Re: Is fork seal replacement really this easy?
« Reply #4 on: December 17, 2010, 04:51:54 AM »
I use mild heating with a propane torch and a screwdriver I bent the tip on to fit under the seal.  Protect the soft aluminum rim from dings and pop! I can do the whole job in about 2 hours with new fluid, some quick polishing of the chrome and wheel while they are off.  The new seals go in nicely with a 34mm socket or a smooth piece of PVC pipe.

Offline Toxic

  • Expert
  • ****
  • Posts: 1,200
Re: Is fork seal replacement really this easy?
« Reply #5 on: December 17, 2010, 07:47:57 AM »
I was on carpys site the other day and noticed a tips section that lead me to a question.  To replace my fork seals do I really need to dissasymble the shock?  He made is sound like you could just remove them from the tripples remove the c-clip retainer pull the old one out and then use a piece of pvc pipe to push the new one on.  I did a search for fork seals on the forum but all I came up with didn't mention anything like this (mostly threads on trouble removing stuck seals).

To answer your specific question. In theory it might be possible to remove and replace the seal without disassembling the shock but I've never heard of anyone doing it.  I don't see how anyone would get the seal out with the forks still together.  You could remove the "C-clip" easy enough but I don't see how you would pry out the seal.  Give it a try and let us know how you make out.

But it is just as easy to take the whole thing apart.

follow FFJMORRE's tip.

If the seal won't come out easy immerse it in a boiling pot of water for a couple of minutes.  I've done this several times and they will pop right out.

Offline Old75_ratafe

  • CB750 Cave Spelunking
  • Expert
  • ****
  • Posts: 801
  • 1975 CB750K
Re: Is fork seal replacement really this easy?
« Reply #6 on: December 19, 2010, 12:42:25 AM »
Yes, the process is simple but there are a few tricks.
1) before you take the top cap off undo the allen head at the bottom.
2) Read all the threads you can about getting the seals out. Be carefull not to scratch the walls or crack the top like i did. Those suckers get stuck in there good after 30 years.  But with some practice i can change a set of seals in a few hours.
Good luck

This website is pretty good along with the repair manual.

http://oldmanhonda.com/MC/MC.html

And ffjmoore's number #1 tip is priceless!

Ok just looked at that and a question about the number one tip... id I undid the damper rod wouldn't that cause the bottom to shoot out?  Or did you just mean loosen not completely undo?  Also if the springs are under that much tension I am gonna assume that putting the cap on is gonna be a real PITA to compress the spring and screw it in at the same time.  Anyone know how much oil to put back in there btw I don't see it mentioned?
1975 CB750K
Project Back in Black

Sent from my Texas Instruments TI99/4A Computer

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: Is fork seal replacement really this easy?
« Reply #7 on: December 19, 2010, 12:51:31 AM »
 I think Carpy was talking about 72 and earlier, in the above quote.
 73 and up 750 can be done, with tubes left in trees..
« Last Edit: December 20, 2010, 08:49:12 AM by 754 »
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Duanob

  • Bold Timer
  • Old Timer
  • ******
  • Posts: 4,005
  • Gotcha!
Re: Is fork seal replacement really this easy?
« Reply #8 on: December 20, 2010, 08:22:54 AM »
Yes, the process is simple but there are a few tricks.
1) before you take the top cap off undo the allen head at the bottom.
2) Read all the threads you can about getting the seals out. Be carefull not to scratch the walls or crack the top like i did. Those suckers get stuck in there good after 30 years.  But with some practice i can change a set of seals in a few hours.
Good luck

This website is pretty good along with the repair manual.

http://oldmanhonda.com/MC/MC.html

And ffjmoore's number #1 tip is priceless!

Ok just looked at that and a question about the number one tip... id I undid the damper rod wouldn't that cause the bottom to shoot out?  Or did you just mean loosen not completely undo?  Also if the springs are under that much tension I am gonna assume that putting the cap on is gonna be a real PITA to compress the spring and screw it in at the same time.  Anyone know how much oil to put back in there btw I don't see it mentioned?

No the allen screw at the bottom needs to be removed to get the damper out of the top of the fork leg. But once you remove the top caps and relieve spring pressure, it's virtually impossible to remove that screw because the damper will just turn with it.

Capicity is 5.4oz and I hope that is for each leg because that's what I did and the forks seem fine.
"Just because you flush a boatload of money down the toilet, doesn't make the toilet worth more",  My Stepfather the Unknown Poet

1974 CB360T
1976 CB550K2 Resurrected
1976 CB550F2 Barn Find
1979 CX500 VG "HONDA-GUZZI"
2007 Moto Guzzi Breva 750ie
2015 BMW F700GS
Another 1976 CB550K Cafe?

  __o
_- \_<,
(*) /' (*)

Offline c(b)hris

  • Enthusiast
  • **
  • Posts: 243
Re: Is fork seal replacement really this easy?
« Reply #9 on: December 20, 2010, 09:10:49 AM »
75 CB550
74 CB750

Offline ksmith0034

  • When I grow up I want to be a
  • Hot Shot
  • ***
  • Posts: 616
    • Please subscribe to my motovlog
Re: Is fork seal replacement really this easy?
« Reply #10 on: December 20, 2010, 09:52:40 AM »
Man that dude is rough!  Bars banging the tank and everything!!!
With that being said, it looks like he has done this a few times as has some very good tips.  Using an impact on the lower hex is usually a necessity.  I especially like the rag on a string trick, as well as the fork in the vice when putting the top cap back on.  It's a bear to get started!
It took 10 years but she's finally done!
             ↓   ↓   ↓   ↓   ↓
Stocker 2 Rocker CAFE conversion

My YouTube channel HERE:
https://www.youtube.com/MotoCafeRacer

Offline Toxic

  • Expert
  • ****
  • Posts: 1,200
Re: Is fork seal replacement really this easy?
« Reply #11 on: December 20, 2010, 10:16:27 AM »
The best tip for installing the top fork cap is to buy a 3/8" round palm drive.

It's a circular socket drive that is about 21/2 in dia. and it helps by allowing you to apply direct downward pressure on the spring to get the cap started.

Well worth the 15 or 20 bucks.  I use mine frequently.

Offline paulages

  • Old Timer
  • ******
  • Posts: 3,876
  • 1976 cb735
    • DOOMTOWN RIDERS P.R.M.C.
Re: Is fork seal replacement really this easy?
« Reply #12 on: December 20, 2010, 11:46:39 AM »
I think Carpy was talking about 72 and earlier, in the above quote.
 73 and up 750 can be done, with tubes left in trees..

I was going to say the same thing... I loosen the fork caps, then lift the front end up with a cherry picker and remove the front wheel. Zip the allen bolt off with an impact driver, and the fork lower comes right off. Oh yeah, it's helpful to drain the oil first. On these models, it's under an hour for me.
paul
SOHC4 member #1050

1974 CB550 (735cc)
1976 CB550 (590cc) road racer
1973 CB750K3
1972 NORTON Commando Combat
1996 KLX650 R

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: Is fork seal replacement really this easy?
« Reply #13 on: December 20, 2010, 12:16:39 PM »
Thanks for that Paul, first time I mentioned it on here there was gnashing & moaning..like how much time are you saving, not hard to pull forks etc..

 Rusty stock forks can take time to re& re and clean why pull em if not needed.. Too bad it wont work on all models.. Cleaning.. run a rag thru the tube with a broomstick..

 If bike is new to you though, I recommend full dissasembly if only to check tubes to see if they are straight, and fix if they are not..

 BTW, I never have trouble with the nuts. First, weight off the forks.. second to install I use a 1/2 drive ratcheyt with 6 or 4 inch extension.. then lean onto/into the ratchet and nut to compress it, while turning it....easy..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline paulages

  • Old Timer
  • ******
  • Posts: 3,876
  • 1976 cb735
    • DOOMTOWN RIDERS P.R.M.C.
Re: Is fork seal replacement really this easy?
« Reply #14 on: December 20, 2010, 01:40:13 PM »
Thanks for that Paul, first time I mentioned it on here there was gnashing & moaning..like how much time are you saving, not hard to pull forks etc..

 Rusty stock forks can take time to re& re and clean why pull em if not needed.. Too bad it wont work on all models.. Cleaning.. run a rag thru the tube with a broomstick..

 If bike is new to you though, I recommend full dissasembly if only to check tubes to see if they are straight, and fix if they are not..

 BTW, I never have trouble with the nuts. First, weight off the forks.. second to install I use a 1/2 drive ratcheyt with 6 or 4 inch extension.. then lean onto/into the ratchet and nut to compress it, while turning it....easy..


Not worth the trouble? Really? Those people must've never done it both ways... You save dealing with the headlight ears, brake lines, cables, triple trees, and everything else that is the pain in the ass of having the entire upper front of the bike loose. No contest..
paul
SOHC4 member #1050

1974 CB550 (735cc)
1976 CB550 (590cc) road racer
1973 CB750K3
1972 NORTON Commando Combat
1996 KLX650 R

KingCustomCycles.com

  • Guest
Re: Is fork seal replacement really this easy?
« Reply #15 on: December 20, 2010, 02:21:13 PM »
Handy tool for removing the allen bolt in the bottom with the forks left in the triple tree:

Offline paulages

  • Old Timer
  • ******
  • Posts: 3,876
  • 1976 cb735
    • DOOMTOWN RIDERS P.R.M.C.
Re: Is fork seal replacement really this easy?
« Reply #16 on: December 20, 2010, 03:02:59 PM »
Handy tool for removing the allen bolt in the bottom with the forks left in the triple tree:

That is a handy tool, though the impact wrench is even handier.  ;)
paul
SOHC4 member #1050

1974 CB550 (735cc)
1976 CB550 (590cc) road racer
1973 CB750K3
1972 NORTON Commando Combat
1996 KLX650 R

Offline Gordon

  • Global Moderator
  • Really Old Timer ...
  • *****
  • Posts: 12,114
  • 750K1, 550K2
Re: Is fork seal replacement really this easy?
« Reply #17 on: December 20, 2010, 03:53:56 PM »
Thanks for that Paul, first time I mentioned it on here there was gnashing & moaning..like how much time are you saving, not hard to pull forks etc..

 Rusty stock forks can take time to re& re and clean why pull em if not needed.. Too bad it wont work on all models.. Cleaning.. run a rag thru the tube with a broomstick..

 If bike is new to you though, I recommend full dissasembly if only to check tubes to see if they are straight, and fix if they are not..

 BTW, I never have trouble with the nuts. First, weight off the forks.. second to install I use a 1/2 drive ratcheyt with 6 or 4 inch extension.. then lean onto/into the ratchet and nut to compress it, while turning it....easy..


Not worth the trouble? Really? Those people must've never done it both ways... You save dealing with the headlight ears, brake lines, cables, triple trees, and everything else that is the pain in the ass of having the entire upper front of the bike loose. No contest..

You remove the brake lines and control cables when removing your forks from the triple trees? 

Offline paulages

  • Old Timer
  • ******
  • Posts: 3,876
  • 1976 cb735
    • DOOMTOWN RIDERS P.R.M.C.
Re: Is fork seal replacement really this easy?
« Reply #18 on: December 21, 2010, 12:57:36 AM »
Thanks for that Paul, first time I mentioned it on here there was gnashing & moaning..like how much time are you saving, not hard to pull forks etc..

 Rusty stock forks can take time to re& re and clean why pull em if not needed.. Too bad it wont work on all models.. Cleaning.. run a rag thru the tube with a broomstick..

 If bike is new to you though, I recommend full dissasembly if only to check tubes to see if they are straight, and fix if they are not..

 BTW, I never have trouble with the nuts. First, weight off the forks.. second to install I use a 1/2 drive ratcheyt with 6 or 4 inch extension.. then lean onto/into the ratchet and nut to compress it, while turning it....easy..


Not worth the trouble? Really? Those people must've never done it both ways... You save dealing with the headlight ears, brake lines, cables, triple trees, and everything else that is the pain in the ass of having the entire upper front of the bike loose. No contest..

You remove the brake lines and control cables when removing your forks from the triple trees? 

no, but it all ends up lying in a tangled limp mess, and you have to make sure everything routes right when fitting the forks back in. big deal? not really, but it's a lot easier not to.
paul
SOHC4 member #1050

1974 CB550 (735cc)
1976 CB550 (590cc) road racer
1973 CB750K3
1972 NORTON Commando Combat
1996 KLX650 R

Offline dave500

  • Really Old Timer ...
  • *******
  • Posts: 16,997
  • WHAT?no gravy?
Re: Is fork seal replacement really this easy?
« Reply #19 on: December 21, 2010, 01:15:22 AM »
one wipe through with a rag is not fully clean,wash trough and compressed air please,dont overload your rachets use a breaker bar.

KingCustomCycles.com

  • Guest
Re: Is fork seal replacement really this easy?
« Reply #20 on: December 21, 2010, 02:39:40 AM »
Handy tool for removing the allen bolt in the bottom with the forks left in the triple tree:

That is a handy tool, though the impact wrench is even handier.  ;)

What do you use to keep the lower from spinning?  Being an aircraft mechanic, I shy away from pneumatics and use only as a last resort.  I know how seized they can be.  After stripping the head, I have driven a six point torq bit into the head with a hammer and extracted the bolt with heat applied.  That is bench work though, and a wood jaw vise is the tool of choice.

Offline fastbroshi

  • Puppet
  • Old Timer
  • ******
  • Posts: 2,645
Re: Is fork seal replacement really this easy?
« Reply #21 on: December 21, 2010, 03:26:08 AM »
   That video is a perfect example of why not to use a screwdriver.  That person is using all their body weight on the screwdriver on the first couple tries and it doesn't come out.  I wonder why?  They were basically levering the screwdriver on the "ledge" on the inside of the leg, not the seal.   Either the seal should pop out or the driver will slip off/out of the seal.  Even with the oldest, hardest of seals, I don't see a crusty one holding up to a person's weight.

   I know, let's talk about changing tires with screwdrivers!!
Just call me Timmaaaaay!!!

Offline 754

  • Really Old Timer ...
  • *******
  • Posts: 29,058
Re: Is fork seal replacement really this easy?
« Reply #22 on: December 21, 2010, 07:43:31 AM »
 I dont think getting the allen bolt out is usually seizing (although a few fools probably have used RED LOCTITE ::), it usually more of a problem of the small surface area at bottom of damper allowing it to spin..just crack em loose while the spring is in..

 Pulling fork seals, I only use the sheet metal screw method, better than damaging the bore or lip... its savage what some people think is an acceptable means of pulling them out..
Maker of the WELDLESS 750 Frame Kit
dodogas99@gmail.com
Kelowna B.C.       Canada

My next bike will be a ..ANFOB.....

It's All part of the ADVENTURE...

73 836cc.. Green, had it for 3 decades!!
Lost quite a few CB 750's along the way

Offline Duanob

  • Bold Timer
  • Old Timer
  • ******
  • Posts: 4,005
  • Gotcha!
Re: Is fork seal replacement really this easy?
« Reply #23 on: December 21, 2010, 10:37:20 AM »
When all else fails in getting the allen bolt out, drill it! Buy new SS bolts and copper washers. they are cheap. Once you take the damper rod out the rest of the bolt usually comes right out. it's the allen head, the ciopper washer, and the aluminum leg difference of metal surfaces that cause the corrosion and stickiness.

The seals can be a test of patience but they are cheap so wasting the old ones getting them out is no big deal. Wasting the fork leg seal surface is a big deal. If you do score the seal surface, use a product called OMC perfect seal from the boating world. it fills in the gouges and seals up great. (Ask me how I know) it lets go pretty easy too for replacement.
"Just because you flush a boatload of money down the toilet, doesn't make the toilet worth more",  My Stepfather the Unknown Poet

1974 CB360T
1976 CB550K2 Resurrected
1976 CB550F2 Barn Find
1979 CX500 VG "HONDA-GUZZI"
2007 Moto Guzzi Breva 750ie
2015 BMW F700GS
Another 1976 CB550K Cafe?

  __o
_- \_<,
(*) /' (*)

Offline paulages

  • Old Timer
  • ******
  • Posts: 3,876
  • 1976 cb735
    • DOOMTOWN RIDERS P.R.M.C.
Re: Is fork seal replacement really this easy?
« Reply #24 on: December 21, 2010, 11:55:09 AM »
Handy tool for removing the allen bolt in the bottom with the forks left in the triple tree:

That is a handy tool, though the impact wrench is even handier.  ;)

What do you use to keep the lower from spinning?  Being an aircraft mechanic, I shy away from pneumatics and use only as a last resort.  I know how seized they can be.  After stripping the head, I have driven a six point torq bit into the head with a hammer and extracted the bolt with heat applied.  That is bench work though, and a wood jaw vise is the tool of choice.

I've NEVER stripped one with the appropriate sized allen socket. The process is simple... loosen fork caps (but leave them on so that the springs maintain tension on the little piece that holds the upper and lower together), drain fork oil, remove the retaining screw with impact driver, drop lower leaving fork tube in trees. The lower doesn't even begin to spin when using the impact wrench. In fact, you don't even need to hold it with your hand.

+1 on 754's recommendation to use woodscrews to remove the seals, though they're sometimes in there a little too tight. My slide hammer will clamp directly onto the screw, then it's just alternate between one and the other, and it's out. That said, I've used the claw end of my shop hammer many times and it doesn't mar the surface... you just have to be careful not to gouge the inner surface of the fork with the claw. The claw grabs two places instead of the single point a seal remover tool does. I set it on the end of the work bench so that the top of the hammer is contacting the workbench rather than the top of the fork lower... pry, rotate, pry, rotate, etc. and it'll always work when the screws don't.
paul
SOHC4 member #1050

1974 CB550 (735cc)
1976 CB550 (590cc) road racer
1973 CB750K3
1972 NORTON Commando Combat
1996 KLX650 R