Hyde fork brace question. More oil needed for extensions?

The seal extenders obviously extend the overall length of the lowers. Should I be adding more fork oil to compensate? Nothing is really specified in the instructions except a mention of a top up.

I still think my leakproof seals will move out of the seal extenders as there is nothing really holding them in there.

Coco said:

The seal extenders obviously extend the overall length of the lowers. Should I be adding more fork oil to compensate? Nothing is really specified in the instructions except a mention of a top up.

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I don't think the extensions would affect the oil level by much? But you can use up to 200cc in each fork leg I believe, and I always use 170cc (recommended by Mick Hemmings) in the standard forks.

Coco said:

I still think my leakproof seals will move out of the seal extenders as there is nothing really holding them in there.

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If you don't fit Leakproof (press fit) retaining washers, then Leakproof seals will probably not stay in position, as they are designed to "self align" (move about) under the retainers. The retainers should not be pressed down tight against the seals, as a space must be left between the seal and the retainer in order for Leakproof seals to work properly. As this would be a non-standard application, the retaining washers for Norton Leakproof seals may not actually be available, as for example, they are for the OIF Triumph twins, for instance? http://www.britishcycle.com/Manuals/Lea ... alInst.pdf
So it could be better to use conventional seals in the Hyde extensions?

The amount of oil needed relates to the need to cover the dampener tube during all conditions 150cc is minimum with 200cc often quoted as being OK. You need to check this out by doing some reading that reveals the concept of how it works and why.(haynes manual) Most of the changes you are doing do not effect the oil volume requirements as the springs and seals sit on top of the the dampener caps in the stack up.
If your new seals are not retained what is going to hold your High hat bushings? On a stock front end the seals are jam nutted by the seal retainers so the seals end up holding the High hat bushings. When you convert this system to leak proof seals the seal height is narrower than stock to allow for some floating movement by design the high hat can move a little too this does no harm but it is a good idea to file some groves into the top edge of the high hat to get some oil flowing under the new Leak proof seals. Now you are breaking some new ground with the adding of the Hyde brace,high hat bushing extensions. I would work hard at discovering the working concept and come up with my own amount and test it out. After four or five times the front end comes right out in a Jiffy.

Thanks guys. I knew the Leak Proof seals needed something to keep them in there and L.A.B. confirmed my suspicions.

Can't the same be said for the stock OEM type seal with the Hyde extensions? Without a screw in retainer, what keeps them in place? This has me stumped and wondering if all the fuss is worth it for this damn fork brace.

I put in 150cc as per the manual so maybe I'll up the levels 20cc in each leg.

norbsa48503 said:

If your new seals are not retained what is going to hold your High hat bushings?

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the Hyde seal extensions thread in where the normal seal retainer would go, holding the bushing in place. The seal goes into the top of the Hyde extensions with just the dust cover/wiper on top. There is nothing to hold the seal in there whether it be Leak Proof or OEM. Gravity and friction cant be the only thing holding the OEM seal in there can it? I can't see this working properly but Hyde has sold a ton of them so the seals must stay in place somehow.

Coco said:

There is nothing to hold the seal in there whether it be Leak Proof or OEM. Gravity and friction cant be the only thing holding the OEM seal in there can it?

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Why not? As I did say before, Triumph OIF conventional type seals (fitted before 1978) had no retainer, they were a just a press fit in the slider.

Triumph OIF fork seal [29]:



Both sets of fork seals on my R and K series BMWs have no retaining circlips, the seal [3] just presses in, and I've never had one blow out yet.

R Series BMW fork seal:


The K Series fork did have circlip/snap ring retainers from 09/87-on, but my '85 K model certainly does not have them.

Thanks L.A.B.

The OEM type seals are really tight and can not be pressed in by hand into the extensions so I'll have to make a drift of some sort to press the seal in to the Hyde extension so I don't damage the seal. I'm too cheap to buy the factory tool so maybe I can find a suitably sized piece of pipe or something.

I was hoping to be finished with fork work but now I'll have to swap the seals to OEM. At least aligning the brace wasn't too much of a chore as I'd heard from others so getting it aligned again won't be so bad.

Wait, why can't you use the Leak Proof retaining washers? I missed that part. Shouldn't the washers be an tight fit above the seals?

Were there no washers in the kit with the seals?

I'm not sure on a Norton but on Hondas folks use a length of PVC tubing to drive seals. I used to use a truck socket.

swooshdave said:

Wait, why can't you use the Leak Proof retaining washers? I missed that part. Shouldn't the washers be an tight fit above the seals?

Were there no washers in the kit with the seals?

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Nope, no washers. They assume your using the stock seal retainers. I'd have to buy the retaining rings seperately but I have two sets of OEM seals on hand so I'll use a set of those and get these forks back together.

So far this has been the only really annoying and time wasting thing to come up during my MKIII build besides the usual wait for small parts I forgot to order. I was hoping to be driving my Commando by now but I guess sometime in July is a more reasonable finish time.

Cookie said:

I'm not sure on a Norton but on Hondas folks use a length of PVC tubing to drive seals. I used to use a truck socket.

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Good plan Cookie. I'll grab a seal at lunch time and bring it to work here. I've got lots of large sockets on hand and PVC pipe here.