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Leaking Final Drive

6.1K views 53 replies 12 participants last post by  Ddraayer  
#1 ·
The final drive is leaking on my 86 Goldwing. It drips below the rubber boot, kind of below where a riders right foot would be. I know oil can leak in one location, and drip out in another location. I've been told that there is a seal that needs to be replaced. I have the seal and will be attempting the operation asap. The question I have is this. When exactly is that seal that I'm replacing? Is it where the four bolts are that attach the drive to the drive shaft near where the rear shock attaches? Thanks,
 
#5 ·
Reply

Sorry, I don't know what the different parts are called.
It leaks from the rubber section about where a riders right foot would be. I've been told that the seal is leaking and gear oil runs down the shaft and comes out at that rubber section. It only leaks after I've ridden it. After is sits for a while, no more leaking.
 
#10 ·
My understanding is that the gear oil is suppose to stay in the final drive or in the area of the rear tire. I'm assuming there is some type of seal that keeps the oil from getting into the shaft area (or is oil suppose to be in the shaft area?) or towards the engine. When I researched this before, I was told the seal that is leaking is allowing oil to go down the shaft (towards the front of the bike) and leak in the area of a riders right foot, this is why I've assumed that the seal I need to replace is in the area of the rear shock, but now I'm not so sure. The leak isn't too bad, about the size of a silver dollar after a ride. But I hate making a mess where ever I park.
By the way, I'm 100% positive that it's gear oil, not motor oil.
 
#13 ·
He says he is 100% sure it is gear oil in post #10. It really sound like the pinion seal is leaking but just be sure the final drive is not over full. ( I doubt that is your issue.) Also be sur the bearing just behind the seal is good and tight. Even a good seal can't seal something that is jumping around because the bearing is loose.
 

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#14 ·
The seal you want is #29 as posted by Dennis (probably bike). Once you remove the drive line, look carefully inside the flange on the input for the final drive. You'll find two small holes that allow gear lube into the area. When the seal goes, gear lube travels up the drive shaft and leaks out of the boot. Always fill the cavity with moly paste to help close those holes. Install the new seal and you're good to go.
 
#19 ·
I am not sure I agree with you GL. These are only my conclusions some may disagree. The purpose of the seal is to keep the moly in the coupler. No gear oil should travel in to the coupler if all is well. I think the purpose of the holes in the flange is to act as a vent. A the drive shaft swings at a radius it will also travel in and out of the flange. If not for the "vent" holes the seal #29 could get "pumped" out bu the driveshaft pumping action. I am almost positive no final drive oil will travel in the coupler unless way over full.
I would hate to see him take the thing apart and not fix the right thing. I strongly believe seal #29 has nothing to do with sealing gear oil. It just keep the Moly paste where it belongs.
 
#15 ·
Thanks so much for the replies.
As for the operation/fix/disassembly, procedure, do I start by removing the rear wheel and move my way forward or what is the correct process? I'm assuming that once I get into it I'll figure out what needs to be done, but if I have a overall process idea, I'm sure things will go smoother.
 
#20 ·
redwing52. I don't know what your problem is, or why you are so contrary to my posts. But you are wrong. From the factory, there is no lube at the rear of the driveline. Moly paste is something we add upon reassembly. There is no need to vent there, as the the final drive already has a vent. I don't post with "maybes" and "I don't think so's". I make statements based on experience. If you'd had one apart, you'd know that seal #29 fits directly into the pinion flange, preventing gear lube from traveling up the driveshaft. You may disagree all you want, but facts is facts.
 
#22 ·
Certainly didn't mean anything personally. Just didn't want to see the OP do the job twice. Yes, I have had more than one apart and the last one was about a year ago. If you click on the link below you will notice I started a post at that time regarding the holes. There are some pretty knowledgeable people who posted that do not agree with you. Many Wing owners have had spline failures with low mileage. My 2000 only had 45K and the pinion seal failed. My experience is that the odds are if the final is leaking it is much more likely the pinion seal has failed. The reason I say this is because the seal on the shaft is stationary. It never moves in relation to the shaft. It basically sits still in relation to the shaft. Why would it fail as compared to the pinion seal which is constantly contacting a spinning coupler.

I certainly didn't realize I was being contrary to your posts. There have been time I did not agree with all kinds of people. Unfortunately most of the time I was wrong. :) I know that is how I learn and I hope others who read the posts learn as well. I think the purpose of the forum is to help each other do repairs right the first time and learn more about the bikes. I don't like to speak in absolutes. I believe some find this offensive and I have learned that even though I feel like I know a lot about the bikes I certainly will learn more from the guys here. No offense meant toward you. I didn't think I was being contrary. Maybe just not agreeing. Hopefully you understand better now that you know my thoughts and reasons. I will still bet you a beer the pinion seal is the culprit if it is a seal. Also the bearing on my 2000 was loose which certainly could have been the root cause. :)

http://www.goldwingfacts.com/forums...ldwing-technical-forum/644153-gear-oil-lubes-driveshaft-spline-final-drive.html
 
#21 ·
I agree that the function of the shaft seal is to keep the drive oil from leaving the drive, and those holes are to lube the splines on the shaft. I don't understand why the Honda engineers designed the system that way but they must have had a reason.

I went through a couple of pinion seals and don't recall the oil ever working its way up the shaft. It pooled at the back of the tube and dripped, spread or whatever. When I first noticed, I thought the shock was leaking.

If you look at the pic, the oil is coming from outside the shaft cavity. I think it just gets thrown off of the surface and may occasionally drip on the shaft, but surely not enough to travel forward to the u-joint area.
 

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#23 ·
1200 and 1500 FD assemblies are virtually the same at the pinion bearing end.

The 1200 FD pinion joint has two holes in it from the factory - see attachment. This pinion joint is attached to the FD pinion shaft. There is an oil seal P/N 34 that keeps the FD oil in the FD because the pinion bearing is lubricated by FD oil, and the pinion joint fits onto the pinion shaft and past the prop shaft oil seal - see attachment - P/N 34. Had the FD apart to replace the pinion bearing.

My bike had never had the prop shaft out in 115K Kms, or the person that did the maintenance did not remove the retaining spring as detailed in the OEM service manual - see attachment - oil seal P/N 29. Not knowing which occurred, the splines are in very good shape after 115K KMs. If the prop shaft was never taken out, there had to be lubrication from somewhere, in this case it was wet with FD oil. When I removed the prop shaft from the FD and checked the pinion shaft for "play", I could move the pinion shaft about 1/32" - new pinion bearing required, and the reason for taking the FD apart. Replaced the oil seal P/N 34 as well. Even with excessive play in the pinion bearing the oil seal (P/N 34) did not fail and allow FD oil to flow past the pinion joint sealing face.

I have attached a picture of the new pinion bearing installed in the FD. The attachment showing the pinion retainer and FD oil seal show the final installation before the pinon joint is attached. I do not have a picture of how the pinion joint mates with the pinion shaft and against the pinion bearing, but since there are holes in the pinion joint, and the pinion joint does not have a sealing fit against the pinion bearing, no reason why FD oil cannot get into the pinion joint cavity providing lubrication to the splines.

When I reinstalled the FD after this maintenance, I used Moly paste on the prop shaft splines that fit into the FD. Next time I removed the FD, always drain the FD to keep from making a mess, the FD oil was gray and had mixed with the moly paste. I have since changed the FD oil several times, do not put any Moly paste or grease on the prop shaft splines that fit into the FD, and every time I remove the FD for maintenance and remove the prop shaft from the FD, it is coated with FD oil. The holes in the pinion joint allow FD oil into the prop shaft cavity. If the vent on the FD is working correctly, there will be no pressure in the pinion joint cavity, ergo the prop shaft oil seal, and it is called an oil seal by Honda, will not move.

If the FD vent is plugged and/or not working properly, it is possible that FD oil could be forced out past the prop shaft oil seal - how far it would travel is an unknown. Moly paste could be as well if used but because of the consistency of moly paste, highly unlikely it would travel too far up the swing arm tube, and leak out like an oil per say. The FD oil could also be forced out past the pinion bearing oil seal, but the design of the oil seal is such that when installed correctly, the shape of the sealing face is supposed to resist any leakage.

I would think there would be a fair bit of pressure build up to force oil past an oil seal.

Hopefully, oil seal P/N 34 is not the issue. Pain getting the pinion bearing retainer out. Not easy to identify it as leaking either.

As has been mentioned, can't say what the Honda engineers' intent for the holes in the pinion joint are, but can attest to what I have observed on my bike.

Just my thoughts and observations.

Cheers
 

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#24 ·
I have no idea what to think. It seems different people have different experience related to the holes. If you look at the attached picture notice the shinny part where the drive coupler is tightened against the bearing inner race. By doing so it blocks off most of the hole. Add to that the only oil that is available to the hole is what can travel up the spline which is blocked from the oil completely. As you can see in post #22 many members have theories. Right now I'm just baffled.

As I look closer at the coupler picture there seems there might be a very small area that could be open too oil. It might just be coincidence or maybe by design?
 

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#25 ·
redwing52 - lots of theories and personal experiences out there regardless of the topic/issue. Short of having the information from Honda, the best anyone can do is what works for them. On page 11-17 of the OEM service manual it mentions to lubricate the drive shaft splines (plural) and oil seal with Honda Moly 45. This to me is to use Moly paste on the splines, both ends. My personal experience has indicated that there is FD oil getting to the prop shaft, yours may differ. Can't go wrong following the OEM service manual. I take my FD and prop shaft out at least once a year, more if other maintenance is required. If the situation changes I will change with it.

Cheers
 
#26 ·
Ernest,
I agree with you completely. I can't for the life of me figure this out. Even the service manuals don't agree with each other. Some say use grease while others say use Moly paste. I think whatever Honda hoped for did not work. Then they went to plan "B." That is lube it during maintenance. The last one I did I lubed with grease. Sold the bike so I will probably never know any results though I bet it will be fine. I agree the Moly is a better choice and I will use that from now on. It is wonderful stuff but it has a price that goes with it. :)
 
#27 ·
Thanks so much for all the replies.
Is there anyway to rule out the vent? As mentioned I tried prying on it but it didn't seem to move much. Most vents I've seen can be unscrewed but this one looks pressed in or something. Is there anyway to remove it without disassembling of the final drive? A little more history on this bike. I got it a year ago this month and it has about 33K miles on it. I swapped out the timing belt, changed the oil and general maintenance. It ran great for several months then one day I noticed some gear oil. The previous owner was storing it for a friend that died and he would start it every so often to keep things fresh, but I don't think it got ridden much. Does that give any more clues? Any ideas on the vent to rule that out? Thanks again.
 
#28 ·
As foor your descrription of the bikes history I see nothing that would indicate an issue related to your problem/ Many Wings sit for years with no final drive issues once put back in service.
Though a little crude I would check the vent by putting a hose in the oil filler hole. Pack a rag or plastic to seal the hose to the outside diameter of the hole. Now blow in the hose and see if air (your breath) comes out of the breather. It should of course. If you don't want to blow on the hose you could use miniscule air pressure from a compressor. Don't use over one or two PSI if you use a compressor.
 
#30 ·
Honda had a service bulletin on installing the pinion shaft seal the correct way that I posted on some years back. The rear end oil also leaks out the front L/R side front swing arm gusset areas that were not welded in spots as I found on my 86 A.