Oil dripping from front fork?

[Wallowgreen]

I've just noticed a small amount of oil on the garage floor under one of the front forks on my '82 1100GL. Looks like it's actually coming out of the bottom of the fork - could that be right? I've seen oil seeping past the seal at the top but this is the first time leaking out the bottom.

I suppose it means it's time to strip the forks down and replace all the seals.

[tkent02]

Maybe the fork oil drain screw is loose or crossthreaded, or maybe it's dripping brake fluid?

[Wallowgreen]

Don't think it's brake fluid, the caliper is dry, it's black anyway not brown (I've just flushed and changed the brake fluid). I can only find a drop of oil right on the bottom of the fork. Strange!

[Wallowgreen]

So is that an allen key drain plug in the bottom end of the fork? If so, anyone able to tell me what size it is? I don't have anything close to fitting it.

Thanks.

[reddirtrider]

So is that an allen key drain plug in the bottom end of the fork? If so, anyone able to tell me what size it is? I don't have anything close to fitting it.

Thanks.

It's metric and it isn't a drain plug. Well, it can act as one, but that's not it's intended function. The drain plug should be on the side of the forks near the bottom. The bolt you are refering to does have a copper washer that acts as a seal for the fork oil. It could be leaking from that. If you remove that bolt you'll need to refill the forks since quite a bit of oil will drain out. This plus the fact that that bolt (I blieve) requires thread sealer.

When was the last time you serviced your forks? If it's been a while order some new seals and get 'er done. The forks I just went through had oil that was so dirty it was black and thick. Nasty stuff and may have never been changed.

[Wallowgreen]

Thanks for the clarification. I'm afraid I don't know when the forks were last serviced, I've only owned the machine since January so that was one job on the list still to do. I guess it just bubbled up in priority.

BTW, I measured the plug at the bottom of the fork leg this morning, it's 8mm hex so I got one on the way to work. At least I'll be able to tell if that's the culprit tonight.

Time to do a search and see if there's anything else I should do at the same time. Read something about progressive springs as an upgrade but can't remember the details. Maybe that was just on the rear?

[twr1776]

Wallowgreen, actually the front springs IMHO are more important than the rears to change but you should do both if you are keeping the bike. The front springs are about $ 80.00 for a set. I used the blue loctite on that allen bolt when I reassembled my forks. If your hex is loose I would not ride the bike until you fix it. I am not sure what would happen if you did but the hex bolt is what holds the damper rod to the bottom of the fork. There is a tutorial on Basscliffs website by Matchless that shows the forks disassembled and a "special tool" used to tighten the allan bolt.

[Wallowgreen]

Basscliffe's site is a regular stop for me whenever I'm about to embark on maintenance for anything so I've already printed off a couple of copies of the front fork rebuild paper.

So a more general question: if I'm about to rebuild the forks, the list of parts needed only mentions the main oil seal but looking at the fiche there are a number of o-rings, gaskets and such. Anyone advocate having all those to hand and replace the whole lot?

Also, at the expense of opening up a can of worms and getting flamed, can anyone give me a management type overview (i.e. short and sweet) on the benefits of installing progressive over stock springs? I've done some searches on the subject and I suppose it comes down to personal choice in the end but what I couldn't find was a concise comparison describing what the advantages are in terms of handling / comfort / maintainability and the like.

Thanks.

[Wallowgreen]

BTW, forgot to mention, I went home at lunch time and tried the hex bolt at the bottom of the fork. All is tight.

I've still not convinced myself where this oil is coming from. Everything seems dry except the small drop right on the bottom of the fork leg.

[Big T]

BTW, forgot to mention, I went home at lunch time and tried the hex bolt at the bottom of the fork. All is tight.

I've still not convinced myself where this oil is coming from. Everything seems dry except the small drop right on the bottom of the fork leg.

Post up a picture of your leak area. It can only be coming from the drain plug, the allen bolt or a crack in the fork tube.

There's really nothing to replace but seals and oil for a fork rebuild. You can check the bushing clearance and replace those as necessary. The other O rings rarely wear out.

As for the springs, you'll get a firmer, more controlled ride and better brake feel with upgraded springs.

[bwringer]

FWIW, I last had my forks apart at about 86,000 miles, and the bushings were still in good shape, with no looseness.

Good thing, because you can't get the upper ones for my bike for some reason.

So if your bike has somewhat fewer miles, don't worry about the bushings. There's also a plastic "piston ring" around the damper rod, but it's also not really worth replacing. Even at very high mileage, the one in my bike wasn't worn.

[Wallowgreen]

I tried to get a picture late last night after I noticed the spot on the floor but it's pretty difficult to get the camera in there under the bottom of the fork and get a close up. I'll try again when I get home today.

[reddirtrider]

When rebuilding forks on these girls I typically check the dust boots for cracks and holes. Inspect closely and replace them if you find any defects. You might want to order some o-rings for the top nut and check on the air seals (if your forks are pressurized). Other than that it's always new oil seal, oil (of course), and if you want to go all out replace the copper washers on the bolt at the bottom of your forks. That takes care of most rebuilds.

[bwringer]

I would also order up new damper rod bolts (these are the bolts you're removing with the 8mm hex).

They are an oddball thread, and there's a chance you might booger up the head on one of them getting it out.

[Wallowgreen]

Thanks Brian, good advice I'll heed.

So I've been reading the manual this evening trying to determine how much fork oil I'm going to need for one thing. As is pretty usual with me, the only model not listed in the spec tables is the 1100GL like I have. I assume I follow the directives as per the 1000GL which is listed as requiring 245cc (8.3oz) per leg - right?

I also went out to take a picture of the offending drip but of course it's not dripping any more. I hope that's not all the oil that was in the fork because there was precious little of it if so.

One last thing, I've been doing some digging into progressive springs for the front. I assume it's ok to only change the front springs for the time being without spending the extra $250 for matching rear shocks right now. I'd like to put that expense off for later so long as it's not a requirement to change front and back simultaneously.

Thanks again to all for their input.