Recently both front forks started leaking on my '04 R1150RT, with 38,605 miles. Oil is coming out from the dust covers and getting on the sliders, brake covers, fairing and even up on the windshield! I am not much of a mechanic, but checking with the Clymer manual, it looks like I might be able to accomplish the removal, repair and reinstallation of the forks. They probably both need new dust covers, retaining rings, oil seals and washers....plus new fork oil. Is there anything especially difficult about this process? I don't have the Haynes manual, so have no idea how many "wrenches" are depicted for this undertaking. Thanks much!
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2004 R1150RT front suspension...
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m_stock10506
Well-known member
This isn’t a difficult repair. Even though it seems like a lot of oil is leaking, very little fork oil makes a big mess. There are two easy approaches to the repair. One from below and the other from above. Chris Harris has a video removing the handlebars and pulling the fork tube out from above. This leaves the lower fork tube accessible with the dust cover and seal exposed enough to remove and replace with new. The other approach and video is from the Illinois BMW Riders club removing the front wheel and then taking the screws out from the fork bridge so that the lower legs can be dropped down. With the lower fork in your hand, you can replace the seals and dust cover and it is very easy to replace the fork oil if you want to. It isn’t necessary. You’ll need new fork seals and dust covers. Retaining clips and washers are reusable.
I will get the links for the two videos and post them a bit later. Although a screw driver or tire iron can be used to pull the seals, a real seal puller tool makes it easy. There is a tiny air bleed screw at the top of the fork tube. It needs a 3 mm hex key to open it. I took the 3 mm L tool from the kit and cut down the small end so it was about 1/4 inch and could fit into the opening.
I will get the links for the two videos and post them a bit later. Although a screw driver or tire iron can be used to pull the seals, a real seal puller tool makes it easy. There is a tiny air bleed screw at the top of the fork tube. It needs a 3 mm hex key to open it. I took the 3 mm L tool from the kit and cut down the small end so it was about 1/4 inch and could fit into the opening.
m_stock10506
Well-known member
Here are the two videos:
K1200LT Fork Oil & Seal Replacement - Illinois BMW (Note - K12LT fork seal is the same procedure as the R/RT)
https://www.youtube.com/watch?v=wFX2V6-svVE
R1150RT Fork Seal Replacement - Chris Harris
https://www.youtube.com/watch?v=uEL4MqHC90Q
Even though Chris Harris does his R&R with the fairing on the bike, you will have much more access to work if the fairing is removed. I replaced my fork seal at the same time I was doing a fuel filter replacement, so the gas tank was off too. This made for a lot more space to work and swing wrenches and the seal puller.
K1200LT Fork Oil & Seal Replacement - Illinois BMW (Note - K12LT fork seal is the same procedure as the R/RT)
https://www.youtube.com/watch?v=wFX2V6-svVE
R1150RT Fork Seal Replacement - Chris Harris
https://www.youtube.com/watch?v=uEL4MqHC90Q
Even though Chris Harris does his R&R with the fairing on the bike, you will have much more access to work if the fairing is removed. I replaced my fork seal at the same time I was doing a fuel filter replacement, so the gas tank was off too. This made for a lot more space to work and swing wrenches and the seal puller.
happy wanderer
Day Dreaming ...
I do it basically the same way Chris Harris does but with less cursing, complaining etc. I also put rags everywhere to keep the mess contained whereas Chris puts gloves on his hands but does not seem concerned with the mess and drips at all. His instructions are sometimes pretty sparse.
You absolutely need an impact tool to remove the 14mm bolt on top as the fork just spins when you use a wrench or socket the traditional way.
And despite what Chris says, I do put fresh oil in there. It is there for a reason. It does not play any role in suspension but does play a role in keeping the tubes from rusting and lets them slide in the sliders as they should. But not a hydraulic function like other bikes.
You absolutely need an impact tool to remove the 14mm bolt on top as the fork just spins when you use a wrench or socket the traditional way.
And despite what Chris says, I do put fresh oil in there. It is there for a reason. It does not play any role in suspension but does play a role in keeping the tubes from rusting and lets them slide in the sliders as they should. But not a hydraulic function like other bikes.
m_stock10506
Well-known member
"You absolutely need an impact tool to remove the 14 mm bolt on top as the fork just spins when you use a wrench or socket the traditional way."
Yep. Alternatively, there is a flat area near the top of the tube but below the 14 mm nut that fits a 22 mm open end wrench. So the wrench will hold the tube and keep it from spinning while you break the 14 mm nut free. That nut is on there very tight - or it was installed with loctite. So, I would apply some heat to the top nut before attempting to remove it.
Yep. Alternatively, there is a flat area near the top of the tube but below the 14 mm nut that fits a 22 mm open end wrench. So the wrench will hold the tube and keep it from spinning while you break the 14 mm nut free. That nut is on there very tight - or it was installed with loctite. So, I would apply some heat to the top nut before attempting to remove it.
AntonLargiader
Active member
The nut (14mm flats I think) is similar to a Nyloc. Heat isn't needed, but I do put a wrench on the hexagonal (or octagonal?) section at the top of the tube itself.
m_stock10506
Well-known member
If you get into it and have more questions either post them in this thread or PM me. I've done the fork seals using both of the methods posted.
2004 r1150rt
Thanks, Michael. The videos were very helpful. It looks a lot easier to remove the tubes from the bottom to access the seals, especially since I want to see how much fork oil I lost, and refill with new. I haven't started the process yet, but if I run into problems, I'll definitely be in touch. I really appreciate your quality input. Mike Todd.
Thanks, Michael. The videos were very helpful. It looks a lot easier to remove the tubes from the bottom to access the seals, especially since I want to see how much fork oil I lost, and refill with new. I haven't started the process yet, but if I run into problems, I'll definitely be in touch. I really appreciate your quality input. Mike Todd.
m_stock10506
Well-known member
The only "issue" that I ran into with removing the lower tubes was on the left side. In order to remove the lowers you have to detach the brake lines from both the left and right tubes - they are held onto each fork lower. The right was easy to remove, but the left is held by a small screw with a 3 mm hex button top. When I tried to remove the screw it stripped, so I changed that leg from the top instead.
2004 R1150RT fork seals
Yea...that left fork 3mm hex button was a pain to remove. I hit it with some WD-40 and let it sit for a while. It eventually came out, but with a lot of effort. Both forks are off. Taking them off from the bottom was a piece of cake compared to changing the seals from above! 420 ml in one and 410 in the other fork.
When I pulled the speedometer drive unit, it was full of crap, dirt, junk, etc. I cleaned it out, but realize I do have to put some lube/grease back into it. What would you recommend? How much does it need?
Ordering new dust covers and seals tonight. It's really been a pretty simple process, just time consuming. Thanks so much for the guidance!
Yea...that left fork 3mm hex button was a pain to remove. I hit it with some WD-40 and let it sit for a while. It eventually came out, but with a lot of effort. Both forks are off. Taking them off from the bottom was a piece of cake compared to changing the seals from above! 420 ml in one and 410 in the other fork.
When I pulled the speedometer drive unit, it was full of crap, dirt, junk, etc. I cleaned it out, but realize I do have to put some lube/grease back into it. What would you recommend? How much does it need?
Ordering new dust covers and seals tonight. It's really been a pretty simple process, just time consuming. Thanks so much for the guidance!
gsaddict
Pepperfool
I use white lithium grease on the speedo hub.
Fork seal replacement...
Michael - I got the RT front end back together today! I put in new fork seals, dust covers and fork oil. Your advice and that video from the Illinois BMW Club ref changing the seals from the bottom was a piece of cake! Everything worked just like he demonstrated. Thanks so much for your guidance. I learned much and gained a lot of "wrenching" experience.
Regards, Mike Todd.
Michael - I got the RT front end back together today! I put in new fork seals, dust covers and fork oil. Your advice and that video from the Illinois BMW Club ref changing the seals from the bottom was a piece of cake! Everything worked just like he demonstrated. Thanks so much for your guidance. I learned much and gained a lot of "wrenching" experience.
Regards, Mike Todd.
m_stock10506
Well-known member
Mike - glad to be helpful and share my past experiences. Thank you for posting the update with the end result.
