R1200RT Fork Oil Level?

I have ONE leaking front fork and plan to replace the dust & oil seal on only that ONE WITHOUT removing the front wheel (as per youtube). I have had the leak for some time and have lost a lot of oil. Since I am not REMOVING the entire slider assembly I was planning on measuring to the oil surface and then adding enough oil to bring it to the proper level. Does anyone know the PROPER dimension from the top of the slider tube (chrome stanchion fork tube removed) to the top of the oil in the slider?

Alternatively, I am guessing that I can siphon out nearly all of the remaining oil and then refill with (nearly) original required service manual amount - comments?

My service manual says that I should replace the nut (14mm) atop the stanchion with a NEW one - why? Maybe I just need to add some loctite blue on it?

Thanks!

I have ONE leaking front fork and plan to replace the dust & oil seal on only that ONE WITHOUT removing the front wheel (as per youtube). I have had the leak for some time and have lost a lot of oil. Since I am not REMOVING the entire slider assembly I was planning on measuring to the oil surface and then adding enough oil to bring it to the proper level. Does anyone know the PROPER dimension from the top of the slider tube (chrome stanchion fork tube removed) to the top of the oil in the slider?

 

Alternatively, I am guessing that I can siphon out nearly all of the remaining oil and then refill with (nearly) original required service manual amount - comments?

 

My service manual says that I should replace the nut (14mm) atop the stanchion with a NEW one - why? Maybe I just need to add some loctite blue on it?

 

Thanks!

Evening Dimond

I usually suck the old oil out with a vacuum jar. Long hose down to the bottom of fork & other hose to my vacuum pump (or vacuum fitting on running engine).

Jar is sealed at cap & hose entrance & large enough to hold all the fluid.

As for replacing the nut? (maybe)- If the nut is corroded or the hex is rounded off then I replace it. If it's still in good shape then I just reuse it with blue LockTite.

Don't forget to open the top bleeder screw & bleed the air out of the tube at reassembly.

Fortunately, I've never had to deal with a fork leak. When I do, I plan to try cleaning the seal first: https://www.youtube.com/results?search_query=leaking+fork+seal+fix

If it does not work, all I've lost is a little time. If it does work, I've saved a lot of time and effort.

You'll still need to figure out how much replacement oil to add.

According to Chris Harris, There is no need to replace the fork oil. (or to take half the bike apart like in the RepROM procedure.)

I replaced one of my seals with no issue following his procedure. (Although I don't think he mentions bleeding the air out of the fork after replacing the seal which I did)

YMMV

 

I usually suck the old oil out with a vacuum jar. ......

 

Very clever! I am going to give this a go. Thanks.

FYI. Here is how my seal replacement turned out. I went the route of NOT removing the fork - used the you tube video (BMW Service - R1150RT Fork Seal Replacement) method and just disconnected the tube at the top, as shown. The job went surprisingly easy - which was a big surprise to me as most of my repair projects take forever and somehow I manage to complicate things - but there were some tips/snags you need to know about - so read on. The mightyvac tip worked great as it easily removed all of the fork oil - which was very dark and am glad I put fresh back in. Used HD 10 weight fork oil that I got from Cycle Gear - it was clear - but what came out looked like ATF - had that reddish color - but totally dark - could not see through it - real yucky looking. I only did one fork (the leaky one of course!) as the video said that they rarely leak - and it seems way easier to only do one side completely at a time rather than have both disconnected. Couple of tools that helped (see photo) were a seal puller ($8) from Harbor Freight and a circlip puller (I paid $35 for mine but would make my own rather than buy it if I had known how simple it would be to fabricate). The seal came out easier than ANY seal I have ever removed - way better that trying to get a screwdriver in there to pry-pry-pry, plus the top of the tube is not fully accessible as it drops down below the upper bridge and working with screwdrivers would be more difficult as compared to removing the tube like I normally do with other bikes (note that BMW is not normal). The circlip is pretty big and not hard to get out - even without the circlip puller. I am not sure if you can see the tip in the photo but it has a small area at the top (say 3/16 inch) that is bent at a 15 degree angle with outer edge ground sharp in shape of circle - which enables one to get behind a small circlip to pry it out - very useful. Usually I use AllBalls (allballsracing.com) seals and bearings for my MC repairs - why? Well they are far less costly than BMW OEM (in this case nearly 4 times less - for a set - both sides - All Balls only sells in sets). Plus I think that their quality is excellent due to the fact they have been in business for some time and make products for many many bikes (guessing way more than BMW does). I got my AllBalls from an eBay vendor (they don't sell direct). The Part No ORIGINALLY purchased was provided as 56-161, which shows that it fit my bike. BUT IT DID NOT. When they arrived the inner diameter was too big. It seems as if the 55-161 is for a 41mm OD tube - but the BMW R1200RT HexHead tube is only 35mm OD. I called All Balls (Helen Turner) and she advised me that there was a NOTE in the file stating correct size was 56-115 BUT that they have not gotten around to changing their website OR advising any of their vendors. However, the 56-115s fit like a glove! So, when you use the Vendor website and plug in 56-115 it may show it will not fit your R1200RT - but it actually does! The eBay vendor was very cooperative in sending out what I requested while they awaited my return shipment - which saved a few days in getting the bike back in service.

Some things that were in the RepRom Service DVD that I DID NOT DUE follow:

1. I reused the o-ring on the air bleed nut. If it broke I could have purchased one from my local ace hardware.

2. I reused the nut holding the threaded rod to the upper fork bridge. It seems as if this was a locking nut. I did not use any locktite on it as the youtube video stated that this not did not need to be super tight. So, I tightened it using a ratchet wrench by hand without a torque wrench.

3. After I drove the seal in with the TUBE OUT I remembered that the RepRom differed from the YouTube video. The video shows driving the seal with the tube out but the RepRom wants us to drive the seal in with the TUBE IN! Here is what it says: From RepROM Service Manual- If the fixed fork tube is pulled out of the slider tube past the limit of its usual travel, the sharp-edged vent bore in the fixed fork tube can damage the shaft sealing ring in the slider tube.Do not pull the fixed fork tube out of the slider tube past the as-installed position. So far the seal is working fine with a 1000 miles on it - and I am not planning on doing anything until it leaks again. If it leaks prematurely I may consider driving the seal in AFTER the fork tube is installed. I replaced BOTH the DUST SEAL and the FORK SEAL as they come with the All Balls kit.

Thanks for reading!