Rear drive oil seal?

[John L]

Just found this today and haven't got time to look at it until tomorrow, anyone else had a leaking rear drive seal. It's not over filled as it's done a couple of thousand km's since it was last changed and it's only just happened. 86,000km all up.

 

[scottmastrocinque]

Not uncommon nor unexpected at that mileage.

However, the source has not been determined.

It can be leaking out the bottom of the drain plug from a crush washers used far too many times or it could be a leaking pinion/crown ring seal. It could also be oil that blew out of the vent at the top of the final drive.

You don’t have enough information yet.

 

[John L]

Not uncommon nor unexpected at that mileage.

However, the source has not been determined.

It can be leaking out the bottom of the drain plug from a crush washers used far too many times or it could be a leaking pinion/crown ring seal. It could also be oil that blew out of the vent at the top of the final drive.

You don’t have enough information yet.

Definitely not the drain plug and I don't think it's blown out of the vent because it's been fine for the last 2,000km since it was changed. Hopefully I will have time tomorrow to get the wheel off.

 

[Moto-Uno]

Did you change to a new type of gear oil (synthetic vs mineral) with the last change ? Peter

 

[John L]

Did you change to a new type of gear oil (synthetic vs mineral) with the last change ? Peter

Yes Peter I did, I could only find GL-4 in synthetic at the last oil change, could that be the problem? It is definitely leaking at the seal. If the seal needs to be replaced the next question is how do I get at it. I've had a look trough a PDF manual but couldn't find anything about it.

 

[John L]

Definitely not the drain plug and I don't think it's blown out of the vent because it's been fine for the last 2,000km since it was changed. Hopefully I will have time tomorrow to get the wheel off.

Not uncommon nor unexpected at that mileage.

However, the source has not been determined.

It can be leaking out the bottom of the drain plug from a crush washers used far too many times or it could be a leaking pinion/crown ring seal. It could also be oil that blew out of the vent at the top of the final drive.

You don’t have enough information yet.

It's definitely the seal, do I get to it by removing the ring of bolts around the outside? I've had a look at a PDF manual but couldn't find anything. Also as Peter (Moto-Uno) asked I did change to synthetic oil last time because that is all I could find in GL-4

 

[Moto-Uno]

You might find removing that plastic cover ( held on by those 3 hex head bolts) might make the seal
more visible. Some time ago , when people were trying synthetic oils to take advantage of their benefits,
oil leaks started becoming a not uncommon occurrence . At that time the synthetics were better at cleaning
the surfaces the seals were riding on . This build up of deposits from the mineral oils were ever so slightly
adding to the seals ability to reduce leakage . Whether that's as noticeable today as then I can't honestly
say .(I've pretty much stuck with synthetics for literally decades now ) . Look forward to your cure . Peter

 

[John L]

You might find removing that plastic cover ( held on by those 3 hex head bolts) might make the seal
more visible. Some time ago , when people were trying synthetic oils to take advantage of their benefits,
oil leaks started becoming a not uncommon occurrence . At that time the synthetics were better at cleaning
the surfaces the seals were riding on . This build up of deposits from the mineral oils were ever so slightly
adding to the seals ability to reduce leakage . Whether that's as noticeable today as then I can't honestly
say .(I've pretty much stuck with synthetics for literally decades now ) . Look forward to your cure . Peter

Taking the plastic cover off doesn't make much difference, possibly you get to it by removing all the bolts around the rim but I'm not sure. Will let you know what I find

 

[Kevin.NZ]

When I replaced the seal on my Breva, I removed the final drive (CARC) put it on the bench and screwed in a self tapping screw into the wall of the seal. I then used a pair of pliers to pull it out. Of course you may have a seal puller. Refitted a new seal and its been fine for 40,000Kms. Looks like you need to see a bit more of the seal before you try that .

 

[scottmastrocinque]

Although it can be done in place on the motorcycle, it is extremely difficult to do so unless you have a lift to raise the motorcycle to eye level. Even then, I would not attempt a replacement with the swingarm in place.

Bottom line is that this is not a job you can really do crawling around on the floor.

The preferred method involves removing the swingarm, putting it into a bench, removing anything in the hub covering the seal, and pulling out the existing seal and pressing in a new one like Kevin said.

Specialized tools make the job much easier as this is a tricky repair.

This is a photo of the same thing on a BMW, and you can see the basic layout of how a crown ring seal works.

The oil is removed from the unit. The old seal is pulled out towards you and the new seal, (usually an upgraded design), is pressed back into place to hold the oil inside the housing.

 

[John L]

Thanks for the replies, I have got the bike up on a lift but now I'm having trouble removing the plate on the back of the diff, taken all the bolts out but can't get it to budge, the seal should come out with the plate. Has anyone taken one of these off? are they the same as other big block models?

 

[scottmastrocinque]

No. I have not done this on a 1400 but many others, and I do not believe the seal comes out with the plate.

Kevin told you precisely how he did his Breva which is exactly how I have done many BMW’s.

Have you even looked at a parts diagram to ascertain anything?

The seal is right there. It gets pulled out and the new one gets pressed back in.

 

[John L]

No. The seal does not come out with the plate.

Have you even looked at a parts diagram to ascertain anything or you just grabbed tools and started pulling stuff off?

View attachment 26058

View attachment 26059

Yes I have looked at the diagram, I have removed all the bolts from the plate (which is all that holds it on as far as I can see in the diagram) and I am having trouble removing it, maybe it is stuck on with sealant and I don't want to force it unnecessarily, so my query was to see if anyone else has removed it. I haven't just grabbed tools and started pulling things off, I have just got to point where I am unsure how the plate is held on apart from the bolts so I thought I was just asking a simple question. If nobody knows the answer then I will look elsewhere. Whether the seal comes off with the plate or not is a mute point, I still need to get the plate off. After 50+ years of having and working on bikes I have a pretty good idea of what I am capable of and I have learnt over the years that if I'm not sure of something I should ask questions before I pick up the big hammer. All I need to know is what is holding that plate on.

 

[scottmastrocinque]

You don’t listen. I’ve replaced at least 50 crown ring seals.

The plate does not hold it in.

It’s held there by compression of the seal only.

Using a pick or a screw like Kevin said, you pull the seal out from right there.

Do you have the replacement seal? You would see.

Have you removed all of the oil because if not, you are in for a huge mess.

Also, pressing in the new seal in situ like that, is going to be almost impossible like I told you before. It needs to be laying horizontally on a bench.

 

[John L]

You don’t listen. I’ve replaced at least 50 crown ring seals.

The plate does not hold it in.

It’s held there by compression of the seal only.

Using a pick or a screw like Kevin said, you pull the seal out from right there.

Do you have the replacement seal? You would see.

Have you removed all of the oil because if not, you are in for a huge mess.

Also, pressing in the new seal in situ like that, is going to be almost impossible like I told you before. It needs to be laying horizontally on a bench.

I have been told there are 3 seals in total and that I should replace them all while I am at it. If it needs to go on the bench I will just remove the diff via the 4 nuts holding it to the end of the drive shaft. If I get to a point where I do not feel comfortable doing it I will find somewhere to take it to.

 

[scottmastrocinque]

Ok, Good luck.

I’ve tried to tell you that you are undertaking a complex job that you seem to want to insist that this is just a breeze and you should be able to just remove a few screws and voila!

Yes there are inner and outer seals but replacement requires disassembly of the pinion and crown ring gear and re-shimming of the entire hub. If they are not leaking then it is foolish to tear it apart.

I’m sure you do not have the tools or know how to accomplish this.

I cannot help you any further. You are way too headstrong in your path for me and I will not try and save you from yourself any more.

Good luck.

 

[John L]

I have been told there are 3 seals in total and that I should replace them all while I am at it. If it needs to go on the bench I will just remove the diff via the 4 nuts holding it to the end of the drive shaft.

Ok, Good luck.

I’ve tried to tell you that you are undertaking a complex job that you seem to want to insist that this is just a breeze and you should be able to just remove a few screws and voila!

Yes there are inner and outer seals but replacement requires disassembly of the pinion and crown ring gear and re-shimming of the entire hub. If they are not leaking then it is foolish to tear it apart.

I’m sure you do not have the tools or know how to accomplish this.

I cannot help you any further. You are way too headstrong in your path for me and I will not try and save you from yourself any more.

Good luck.

You are telling me everything except the one thing I asked, what is holding the plate on now that the bolts are removed, if I can get that off then I will be able to see what lies ahead. If then I think I am incapable of doing it I will pass it on to someone who can.

 

[scottmastrocinque]

I have told you repeatedly that I have not done this on a 1400 but that I do not believe that plate needs to be removed to pull and press in the new seal. I cannot tell completely by your one blurry photo.

If you look at the photos of the BMW hub you see the seal in black and then the replaced seal in brown. You just pry, remove, press in new.

I believe yours is the same.

Why don’t you drain the oil, use a seal pick or the screw method Kevin said he used, and try pulling out the black seal. I bet it comes right out. If not, you are no worse for the wear for having tried and you can get clarification from a Moto Guzzi mechanic right there in Australia.

You’re in Australia. Call Pete Roper in Bungedore at Moda Moto. I’m sure he’s done several of these on 1400’s

A 2 minute phone call will get you what you need.

Good luck.

 

[John L]

I have told you repeatedly that I have not done this on a 1400 but that I do not believe that plate needs to be removed to pull and press in the new seal. I cannot tell completely by your one blurry photo.

If you look at the photos of the BMW hub you see the seal in black and then the replaced seal in brown. You just pry, remove, press in new.

I believe yours is the same.

Why don’t you drain the oil, use a seal pick or the screw method Kevin said he used, and try pulling out the black seal. I bet it comes right out. If not, you are no worse for the wear for having tried and you can get clarification from a Moto Guzzi mechanic right there in Australia.

You’re in Australia. Call Pete Roper in Bungedore at Moda Moto. I’m sure he’s done several of these on 1400’s

A 2 minute phone call will get you what you need.

Good luck.

View attachment 26060

 

[John L]

Thank you, if you had put it like that to start with I would have been happy to give it a go, Kevin said he wasn't sure if I could see enough of the seal for the pick or screw method to work, there certainly isn't much room to get a screw into it, that's why I thought if I could get that cover off I would have better look at what was needed. If I am only capable of replacing the outer seal that is all I will do, I am certainly not going to start messing around pulling bevel gears apart. I sent an email to Peter earlier and hopefully I will get a reply in the morning, if I had someone like Peter closer to me I would happily dump the whole thing in his lap but unfortunately there is no one close enough that knows much about Guzzis so I'm pretty much on my own.