New stanchions, bushings and seals but they leak... any suggestions?

gpzkat · Jul 14, 2022

A bit frustrated, I've rebuilt many forks but never Norton - they are the N15CS Roadholders with lowers from disc brake Commando. Just sitting there they leak past the seals overnight - no need to even compress them.

Before starting, I carefully examined all the dimensions of all parts since I had both N15CS and Commando sets. They mate up fine, so I can't see that being an issue - every internal dimension was the same. The seals are new quality metal ones, the bushings are new, the right oil capacity/weight is in there. Used complete fork kit 06-7092. Paper washer is there, no damage anywhere - assembly was straightforward, fully cleaned and no forcing needed.

I took them out to examine and nothing's damaged. The only difference between these forks and others I've rebuilt is they are stainless steel stanchions, not the usual hard chrome. I thought maybe polishing the stanchions but Mike at Walridge says he's not had any reports of this and he's always been straight up and helpful. Polishing is the only thing I can think of but it's a wild guess and possibly a waste of time.

Any help greatly appreciated ~Tom

Onder · Jul 14, 2022

Bit puzzled, as the internals must have some pressure in them or else how would they leak UP? Have you ridden the bike a bit to see what happens? Guess I'd get a different set of seals, they aren't expensive. Never heard of SS stanchions but I suppose chrome is such a pollution centre that SS may be the way forward. No matter cannot see how the would be the problem.
I say 'ride it and see'.

Shelby-Right · Jul 14, 2022

I'm sure a polish wouldn't hurt , you could use a proper buff etc, I recently did some goldwing gl1000 forks but they had a few stone specs in the chrome so I put them in the lathe and used 2000 and 3000 grit paper on them and then buffed , are the seals a good fit on the outer , or if having no luck what so ever are the seals a bit hard ? , I softened some intake boots last year with oil of wintergreen and isopropyl alcohol, just a thought.

gpzkat · Jul 14, 2022

Onder said:
Bit puzzled, as the internals must have some pressure in them or else how would they leak UP? Have you ridden the bike a bit to see what happens? Guess I'd get a different set of seals, they aren't expensive. Never heard of SS stanchions but I suppose chrome is such a pollution centre that SS may be the way forward. No matter cannot see how the would be the problem.
I say 'ride it and see'.

Yeah, chroming is getting more and more rare and expensive probably due to the regulations I suppose. The quantity of fork oil for the N15CS with the long stanchions is about an ounce more (6.5 from memory) per the manual. But the internals are the same so maybe I will drain it and fill it with less and see. Will be a while before it's all together to ride, still assembling major components.

gpzkat · Jul 14, 2022

Shelby-Right said:
I'm sure a polish wouldn't hurt , you could use a proper buff etc, I recently did some goldwing gl1000 forks but they had a few stone specs in the chrome so I put them in the lathe and used 2000 and 3000 grit paper on them and then buffed , are the seals a good fit on the outer , or if having no luck what so ever are the seals a bit hard ? , I softened some intake boots last year with oil of wintergreen and isopropyl alcohol, just a thought.

I've used wintergreen oil witches brew on rubber intake boots with good luck, jury still out on how long they stay pliable. I've cleaned up stanchions like you say and even filled some pits successfully, when on a strict budget, hey it worked.

lazyeye6 · Jul 14, 2022

I too was puzzled when my forks leaked after rebuilding with new seals. Turns out I had put the seals in backwards.

olympus · Jul 14, 2022

Seals fitted the wrong way up??

Mike40M · Jul 14, 2022

Had that problem on the Manx. Double paper washers with gasket goo helped a bit. The main reason was that oil crept via the threads. Some Teflon tape on the seal holder threads solved the problem.
Maybe thread sealant could have helped too.

gpzkat · Jul 14, 2022

olympus said:
Seals fitted the wrong way up??

Well they're spring side down as is the general rule and what I understand is right for these. I did make that mistake when I was a pup.

gpzkat · Jul 14, 2022

Mike40M said:
Had that problem on the Manx. Double paper washers with gasket goo helped a bit. The main reason was that oil crept via the threads. Some Teflon tape on the seal holder threads solved the problem.
Maybe thread sealant could have helped too.

I've been trying to understand paper washers, seems a dodgy fix to a leak. I have never heard of them before near a fork seal. I thought maybe it was to separate different metals due to corrosion, given the metal housing of the seal and the bronze bushing but what do I know. The diagrams on the N15/P11 don't show them, the 68 and onward Commando do.

Mike40M · Jul 14, 2022

The idea is to prevent oil leaking on the outside of the seal. Most seals I've seen in Norton forks has metal on the outside of the seal. I've rarely seen seals with rubber on outer diameter in Norton forks. These rare birds might be better keeping oil where it should be and render paper washers obsolete.
Just my thoughts.

gpzkat · Jul 14, 2022

Mike40M said:
The idea is to prevent oil leaking on the outside of the seal. Most seals I've seen in Norton forks has metal on the outside of the seal. I've rarely seen seals with rubber on outer diameter in Norton forks. These rare birds might be better keeping oil where it should be and render paper washers obsolete.
Just my thoughts.

Maybe I should try some Leakproof seals but the question will be how long they sat on a shelf, are they still pliable.

CanukNortonNut · Jul 14, 2022

Let us know what you find to solve your leak?
I'm thinking the paper washers need to be under the seal.
Cheers,
Tom

gpzkat · Jul 14, 2022

CanukNortonNut said:
Let us know what you find to solve your leak?
I'm thinking the paper washers need to be under the seal.
Cheers,
Tom

Yes they are there now, first try I didn't use as the diagram didn't show them. But they came with the kit and Mike at Walridge said put em in. At first I though they were fixed but it just took longer for them to seep out. I'll sort it out, what I lack in talent I make up for in persistence.

HoveToo · Jul 15, 2022

You might check the stanchions for roundness. AN ones are ground to size and are round, other makes I've had were slightly out and one of them leaked.

gpzkat · Jul 15, 2022

HoveToo said:
You might check the stanchions for roundness. AN ones are ground to size and are round, other makes I've had were slightly out and one of them leaked.

I have no way to do this presently but will keep in mind. I thought they were AN products. Should have kept the packaging but can find out.

kommando · Jul 15, 2022

AN do not make stainless steel stanchions, they make them to the original spec steel tubing with hard chrome finish.

On the seals I use Loctite 515 on the OD as well as the paper washers. Also check that seal holder actually bottoms out on the top of the seal, if not the seal can move up and so the paper washer cannot seal.

cash · Jul 15, 2022

While the bike is standing over night the oil leaks out. Is it coming though the seals? I would have thought the oil level is below the seals. Might it be leaking from joint between the bottom of the dampers and sliders and leaking out around the front spindle? Just a thought.

gpzkat · Jul 15, 2022

cash said:
While the bike is standing over night the oil leaks out. Is it coming though the seals? I would have thought the oil level is below the seals. Might it be leaking from joint between the bottom of the dampers and sliders and leaking out around the front spindle? Just a thought.

Yes indeed, so would I. It is coming up through the seals, which is really odd as I put the right amount in there - but hold on... I'm just thinking, maybe the additional capacity of the N15CS is for the earlier Teledraulic and I've overfilled. The manuals don't specify which forks and there was a changeover.

Given that inside, the slider and damper mechanism is identical between the Commando and N15CS Roadholders, I am leaning this way and will investigate. If it's too much, fine, easy to adjust that but it seems to me if it leaks out the top just sitting there with 1 oz too much oil, I'm not going to have a good seal in use either.

gortnipper · Jul 15, 2022

gpzkat said:
Yes indeed, so would I. It is coming up through the seals, which is really odd as I put the right amount in there - but hold on... I'm just thinking, maybe the additional capacity of the N15CS is for the earlier Teledraulic and I've overfilled. The manuals don't specify which forks and there was a changeover.

Given that inside, the slider and damper mechanism is identical between the Commando and N15CS Roadholders, I am leaning this way and will investigate. If it's too much, fine, easy to adjust that but it seems to me if it leaks out the top just sitting there with 1 oz too much oil, I'm not going to have a good seal in use either.

5oz/150ml per leg for Commando

New stanchions, bushings and seals but they leak... any suggestions?

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