Leaky Fork

[David13]

2008 R1200 RT.

 

I have a leaky fork.

 

I have reviewed dirtriders system for cleaning and stopping the leak, but after 10 years, well 11 I think it's better to replace the oil and the seals.

 

I also intend to replace the bushes of which there seem to be 2.  One on each side.  Seems to me there should be 4, but ...

 

My question of the bushes is, do they just fall out?  I suppose maybe they will if they are worn.  So they have to be pulled?  And pressed in?

 

They are cheap and, if easy to replace, I'd rather replace them.

 

As to the seals and 'protectors', why does the parts fiche list two different sets?   Which one do I need?  I do want oem.   So I won't go to ebay or etsy or etc. for some cheaper ones that should fit.

 

I also have two new tires which I have had for a year and haven't put on.  I may add those one while I'm dong this.

 

It would be nice if beemerboneyard had fork oil but they are sold out of #10 Liqui Moly so I'll have to find a substitute.

 

My plan is to remove the front tire, brakes, etc and cross member bolts and take them out and down.  I still want to remove the handle bars to find the bleed screw, replace the o rings, and then bleed the air on reassembly but not drop the upper tubes.

 

Do I need to replace any screws, bolts, etc?

 

Any suggestions would be appreciated.

Thanks

dc

 

 

 

[dirtrider]

52 minutes ago, David13 said:

2008 R1200 RT.

 

I have a leaky fork.

 

I have reviewed dirtriders system for cleaning and stopping the leak, but after 10 years, well 11 I think it's better to replace the oil and the seals.

 

I also intend to replace the bushes of which there seem to be 2.  One on each side.  Seems to me there should be 4, but ...

 

My question of the bushes is, do they just fall out?  I suppose maybe they will if they are worn.  So they have to be pulled?  And pressed in?

 

They are cheap and, if easy to replace, I'd rather replace them.

 

As to the seals and 'protectors', why does the parts fiche list two different sets?   Which one do I need?  I do want oem.   So I won't go to ebay or etsy or etc. for some cheaper ones that should fit.

 

I also have two new tires which I have had for a year and haven't put on.  I may add those one while I'm dong this.

 

It would be nice if beemerboneyard had fork oil but they are sold out of #10 Liqui Moly so I'll have to find a substitute.

 

My plan is to remove the front tire, brakes, etc and cross member bolts and take them out and down.  I still want to remove the handle bars to find the bleed screw, replace the o rings, and then bleed the air on reassembly but not drop the upper tubes.

 

Do I need to replace any screws, bolts, etc?

 

Any suggestions would be appreciated.

Thanks

dc

 

 

 

 

 

Afternoon David

 

I'm   a  l-o-n-g ways from my shop this weekend so don't have much available where I'm at.

 

Best I can do on the seals  is to suggest that you  either FULLY identity what forks that your bike has (there was a fork change sometime in the mid 1200 hexhead model run. (they definitely look different). What I usually suggest on the seals is to have your dealer look them up by vin number.

 

On the bushings -- those will usually come out but sometimes you have to make a hooked tool to coax them out with a little help.

 

Just watch the lower fork spacing (before tightening the lower cross brace bolts) as the spacing between the lowers at the axle area  is quite important at reassembly.

 

On the fork oil, you don't need anything special as  there is no valving inside the forks so just about any fork oil will work (even ATF) as it is just a lubricant. Just watch the quantity as that is different, plus there was a service bulletin on there being a mistake in some manuals (I can't remember the exact details & I am no where near my bulletins this holiday). Just verify the oil quantity in a couple of places & make sure that you are referring to the correct forks.

 

I hope the below picture is correct as it is all I have on my device, I do have it labeled 2008 1200RT. In any case verify that it matches what you have on your bike.  

 

[Tri750]

If I'm not mistaken, the fork difference is one is a rough cast and one is a machined finish on the upper fork lower if that makes any sense.

It's been several years.  

 I'll check in later to assist in which PN fits which. 

[Tri750]

The rough cast fork slider (lower) uses seal 3142 2311 988 and dust cover 3142 2311 980 

The machined fork slider seal is 3142 7666 225 dust cover 3142 7666 223

 

Our local CHP had '09's with the machined and the City PD had '08's with the cast. It's very possible late '08's would have the machined . 

BUT I always asked the tech's which fork leg the bike had no matter what as there are no guarantees what bike had what. 

 

[dirtrider]

Afternoon David

 

This is from that service bulletin that I was referring to above.

 

Details:

"The filling capacity for the telescopic fork listed in the 2nd Edition K2x RepRom and in the TSD disc, .62 liter,  is incorrect for the R 1200 RT(K26).

The correct fork oil capacity for the R 1200 RT(K26) = 450 ml per fork"

[David13]

I think my computer disc recommends 470 ml.  It is the K2x, 4th edition.

 

Thanks to dirtrider and also Tri750 for the information and all.

 

Tri750 I see my forks as looking like that diagram, rather than the smoother machined type shown in the second diagram. 

 

I notice that the machined type has a notation or title on it of 41 mm.  I have yet to measure that, but I'm assuming I'll find mine are not 41 mm. 

 

I think I also now realize that the fiche is saying 2 bushes per fork, total 4 for the bike.  Whcih makes sense.  I just hope I'm able to get the lower bush out to replace it. 

 

Actually, shouldn't the lower bush be attached or press fitted onto the end of the upper slide tube?  I can't imagine the tube to be popping in and out of the bush on it's travel, but I have yet to figure out how these things work.

 

Thanks

dc

[dirtrider]

6 minutes ago, David13 said:

I think my computer disc recommends 470 ml.  It is the K2x, 4th edition.

 

Thanks to dirtrider and also Tri750 for the information and all.

 

Tri750 I see my forks as looking like that diagram, rather than the smoother machined type shown in the second diagram. 

 

I notice that the machined type has a notation or title on it of 41 mm.  I have yet to measure that, but I'm assuming I'll find mine are not 41 mm. 

 

I think I also now realize that the fiche is saying 2 bushes per fork, total 4 for the bike.  Whcih makes sense.  I just hope I'm able to get the lower bush out to replace it. 

 

Actually, shouldn't the lower bush be attached or press fitted onto the end of the upper slide tube?  I can't imagine the tube to be popping in and out of the bush on it's travel, but I have yet to figure out how these things work.

 

Thanks

dc

 

 

Evening Dave

 

No bushing ON the upper tube or then it wouldn't come out through the seal.

[Dann]

Dave,

Here's a link to video of a fork seal change on an R1150Rt.

R1150Rt fork seal replacement

Same as my 07. This is basically what I did when I changed my right fork seal a few years ago.

Much simpler procedure than the one on the BMW RepROM (Called RSD manual now)

 

Hope this helps

[dirtrider]

10 minutes ago, Dann said:

Dave,

Here's a link to video of a fork seal change on an R1150Rt.

R1150Rt fork seal replacement

Same as my 07. This is basically what I did when I changed my right fork seal a few years ago.

Much simpler procedure than the one on the BMW RepROM (Called RSD manual now)

 

Hope this helps

 

Evening Dann

 

I didn't see you bleed the air out of the fork tube before reassembling (looked pretty springy as you reinstalled the upper tube).

 

Did I miss the bleeding part or did you not bleed the trapped air out?

 

 

[dirtrider]

Evening David

 

I forgot to mention above__

 

When ordering parts you might want to order new  rubber protector caps for the top of the upper tubes (I believe P/N  31422330541) as for some reason I usually find those degraded on older 1200 bikes.  Or at least take a close look at yours before making your order.

 

 

[David13]

Dann

Thanks for that video link.  I had just watched that one.  But a review of it will help me with my final procedure.

dc

 

 

[David13]

dirtrider

I don't think it's Dann in the video.  I think in the video his name is Chris.

 

He has some writing over the video where he says he didn't film the bleeding.  But they did the bleeding.  I will definitely be doing the bleeding.

 

But I do think I will also drop the two upper tubes as the leaky one does have a 'shot' cap.  And I believe the only way to change that is to take off the upper tubes. 

 

But my main work will be in removing the bottom, and getting the new tires mounted.  I think.

 

Thanks

dc

[dirtrider]

9 hours ago, David13 said:

But I do think I will also drop the two upper tubes as the leaky one does have a 'shot' cap.  And I believe the only way to change that is to take off the upper tubes. 

 

 

 

 

Morning David

 

If you hadn't planned on removing the upper tubes then you might be able to slide those rubber caps up the tube from the bottom. They have only a small lip where they lock over the top of the tube so  with new pliant rubber caps they might stretch enough to go on that way.

 

You might try removing the old ones that way just to see if it will work. 

[David13]

dirtrider

 

I will try that to see if it works. 

 

I'm wondering how many bushes to get.  I am thinking the upper ones may come out easy.  But the lower ones, I'm not so sure.  I'm guessing that once the seal is out, those plastic spacers will just slide out with gravity.  But what about that lower bushing?  I don't know that I want to try to pry that all the way to the top of the fork tube.  Any ideas?

 

Thanks

dc

[dirtrider]

Evening David

 

Those bushings are not cheap & I doubt that you will find much wear due to the suspension design.

 

The upper bushings operate closer to the dirt &  gunk that works it's way  down the tube past the seals so you can probably get by with just the uppers.

 

The lower bushings are fully oil bathed so probably less chance of finding wear on them. 

[Dann]

This is not me on the video

His name is Chris Harris. He used to run a BMW repair shop.

I just followed his procedure when I changed my fork seal

[David13]

Well I'm almost ready to order the parts, but first I wanted to review the rep rom which does call for 450 ml of fluid.  I found the Liqui Moly 10 at Revzilla.  Beemer Boneyard was out ot it.

 

In reviewing I have come across some odd notes titled "Attention" 

 

The first is half way straight which is don't remove a screw in the bore of the quick release axle, that it is not a drain, but is to secure the ... displacer.  Whatever that might be.

 

That the slider tube will develop an irreparable leak if that screw is slackened.

 

Ok, I probably would not have gone in there anyway, if I could.

 

But the next one "If the fixed fork tube is pulled out of the slider tube past the limit of it's 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."

 

What are they talking about?  It seems to be to be saying don't take the two parts apart. 

 

Like I say I have yet to figure out how these forks work.  Having had German cars before and worked on them I have an idea of the convoluted ways in which German engineers sometimes do things. 

 

Can anyone interpret that for me?

 

Thanks

dc

[David13]

The reprom also does not give any information about the handlebar stubs as they call them.  And the BMW data sheet doesn't give any torque spec for that.

 

Any ideas?

Thanks

dc

[dirtrider]

11 hours ago, David13 said:

Well I'm almost ready to order the parts, but first I wanted to review the rep rom which does call for 450 ml of fluid.  I found the Liqui Moly 10 at Revzilla.  Beemer Boneyard was out ot it.

 

In reviewing I have come across some odd notes titled "Attention" 

 

The first is half way straight which is don't remove a screw in the bore of the quick release axle, that it is not a drain, but is to secure the ... displacer.  Whatever that might be.

 

That the slider tube will develop an irreparable leak if that screw is slackened.

 

Ok, I probably would not have gone in there anyway, if I could.

 

But the next one "If the fixed fork tube is pulled out of the slider tube past the limit of it's 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."

 

What are they talking about?  It seems to be to be saying don't take the two parts apart. 

 

Like I say I have yet to figure out how these forks work.  Having had German cars before and worked on them I have an idea of the convoluted ways in which German engineers sometimes do things. 

 

Can anyone interpret that for me?

 

Thanks

dc

 

 

Morning David

 

The displacer is just a piece bolted into (inside) the bottom of the lower fork leg with a SEALED bolt coming up from the bottom. I think the warning is to make sure that tecs don't  mistake that sealed bolt as a fork drain.

 

But the next one "If the fixed fork tube is pulled out of the slider tube past the limit of it's 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." -- This one is a bit more confusing as it doesn't seem to apply to all the forks. It is basically telling you to install the fork seals AFTER the upper tube is slid back into the lower slider.  On s-o-m-e fork upper tubes there is a machined ring & a hole on the side (I haven't don't enough to figure out what ones have that & what ones don't) --I'm pretty sure this is a 41mm tube thing but again I just haven't done enough to have any sort of full understanding.

 

So for me-- (or at least how I handle it) is (IF) the upper tubes have the hole & machined ring then install the seals AFTER the upper tubes are slid back in.

 

If like most 1200 forks that have smooth upper tubes (no hole or machined ring)  then you can install the seals first, then lube the upper tube bottom, then slide it into the lower & bleed.  

 

    

 

[David13]

Thanks dirtrider.

 

I found a torque spec according to those at BMW Luxury of .. 19 lbs.  Which seems a bit light for such large torx head bolts.  But, I still have time on that.

dc

[dirtrider]

29 minutes ago, David13 said:

Thanks dirtrider.

 

I found a torque spec according to those at BMW Luxury of .. 19 lbs.  Which seems a bit light for such large torx head bolts.  But, I still have time on that.

dc

 

 

Morning David

 

Is this what you are referring to?

 

19nm  not  19' lbs?

 

 

[David13]

Yes, dirtrider, 19nm.  It's 19nm that seems like a little loose on those large torx head bolts.  But I guess it doesn't hold much in terms of weight or anything.

 

I also found on top of the right fork is a clip.  It holds two cables and clips onto the top of the fork.  Basically to hold them off the fork.  I'll call Max BMW today to see if they can add that to my order.  I couldn't find it on the fiche.

 

Thanks for all the help.

dc

[dirtrider]

1 hour ago, David13 said:

Yes, dirtrider, 19nm.  It's 19nm that seems like a little loose on those large torx head bolts.  But I guess it doesn't hold much in terms of weight or anything.

 

I also found on top of the right fork is a clip.  It holds two cables and clips onto the top of the fork.  Basically to hold them off the fork.  I'll call Max BMW today to see if they can add that to my order.  I couldn't find it on the fiche.

 

Thanks for all the help.

dc

 

 

Morning Dave

 

Is that the double clip with the cable tie attached?  If so then look up part #  (  32737675754 HOSE CLAMP, DOUBLE) --- Only BMW would call  a cable clip a hose clamp?

 

On the bolts holding at 19nm, personally I only use 3 bolts on each side with very thin stainless steel  shim washers under the stubs at the  3 bolts, then use a thicker sealing "O" ring between the stubs & upper tree (takes some of the bar buzz out in addition to using heavier bar end weights). Never had any of the 3 bolts come loose in many miles of riding.  

[David13]

Thanks again dirtrider.

 

I have now found 3 similar clips on the Bowden Cables pages.  Which I looked before and didn't see them there.

 

I still haven't found these alleged o rings that go under the handlebar stubs.  I'd like to get those also.

 

But I will call Max BMW on Monday to have them add that to my order of yesterday.  Their email said some of the items are not in stock and they should get them in 1 to 2 days.  I'll see about that.  I know if they have to back order from Germany it will take longer but I can still ride, and am still riding the bike with a little leak in the fork.  I don't think it matters. 

 

If it wears to front wheel funny it doesn't matter as it's old and I have a new one anyway.

dc

[dirtrider]

12 minutes ago, David13 said:

Thanks again dirtrider.

 

I have now found 3 similar clips on the Bowden Cables pages.  Which I looked before and didn't see them there.

 

I still haven't found these alleged o rings that go under the handlebar stubs.  I'd like to get those also.

 

But I will call Max BMW on Monday to have them add that to my order of yesterday.  Their email said some of the items are not in stock and they should get them in 1 to 2 days.  I'll see about that.  I know if they have to back order from Germany it will take longer but I can still ride, and am still riding the bike with a little leak in the fork.  I don't think it matters. 

 

If it wears to front wheel funny it doesn't matter as it's old and I have a new one anyway.

dc

 

 

Evening David

 

I   t-h-i-n-k  it is   (  07119905179  O-RING - 30 X 2.65 -N- NBR70), 30 mm sounds about right for "O" ring size.  

[David13]

That's it.  I finally found it under Upper Fork Cross Brace under Suspension, rather than under Steering.

 

Thanks again

dc