The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Rob Valdez 79 R65 on September 27, 2009, 06:11:29 PM
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I got the caps and springs out by myself, but I needed help from my neighbor when it came time to loosen the 13mm way down in there, and the big a$$ allen screw that comes up from the bottom.
We had them freed rather quickly.
Then I went to take them apart. The right leg came apart "normally", with the damper rod hanging out of the fork leg.
On the left leg, however, the top 13mm fastener came loose alright, but the allen screw on the bottom never let loose. Now I have this, with the left slider in my bench vise waiting for an idea.
And I'm hoping I don't have to worry about that buffing of the chrome.
It appears to be below the seal.
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Rob, did you attempt to loosen and remove the 6mm Allen screw before removing the top[ parts and spring? Monte
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Rob, did you attempt to loosen and remove the 6mm Allen screw before removing the top[ parts and spring? Monte
Yes. It just turned, as expected, but nothing to do with loosening.
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NEW QUESTION:
When I release the pinch bolts holding the fork legs, how do I break the fork legs free from the grip of the triple clamp?
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OLD QUESTION RESOLVED:
I turned the fork slider upside down (oil comes out!) so I could put the 13mm "fastener" back onto the damper rod, and I tightened it down pretty good.
Then I concentrated all my physical and psychic energy toward breaking the allen screw loose.
It worked!!!
Just keep fiddlin...
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To release the stanchions from the triple clamps I made some hardwood wedges and tapped them into the slots.
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To release the stanchions from the triple clamps I made some hardwood wedges and tapped them into the slots.
Very THIN, tapered wedges and do not tap any more than absolutely necessary! Monte
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If that allen head bolt refused to loosen up, what would your options be, drill the head off of the bolt ?
The allen head bolt is made from aluminum, correct ?
Maybe another one of those parts, to apply anti-seize to upon reassembly !
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Rob, a quick question for you... Did you have the sometimes present and sometimes missing "bumpers" in the damper assembly? Looks like a big, fat, flat-sided O-ring of black rubber. Replacemnts from Motobins are now fabricated of nylon. A photo would be nice ... ::)
When I rebuilt the 81's front end, there was no rubber part, just a messy collection of sludge in the very bottom of the lower legs.
Monte
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Monte,
When I was in Lowe's Home Improvement Center, a month or so ago, when you mentioned the 'wave' washers, I saw clear thick plastic 'washers' that looked like they may work in this application .
May want to check it out the next time you're in there .
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Monte,
When I was in Lowe's Home Improvement Center, a month or so ago, when you mentioned the 'wave' washers, I saw clear thick plastic 'washers' that looked like they may work in this application .
May want to check it out the next time you're in there .
I have the "bumper" parts from Motobins. Just wondering if your bike's damper assembly had them in place. Monte
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The '81, didn't have them, just the black goo in the bottom of the fork, the LS, hasn't had the forks apart yet, but with 91,000 miles on it, I'd go out on a limb, and say they aren't there either .
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Dang it! I was hoping to eliminate the occasional topping out of the forks. :-? Monte
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Rob, a quick question for you... Did you have the sometimes present and sometimes missing "bumpers" in the damper assembly? Looks like a big, fat, flat-sided O-ring of black rubber. Replacemnts from Motobins are now fabricated of nylon. A photo would be nice ... ::)
When I rebuilt the 81's front end, there was no rubber part, just a messy collection of sludge in the very bottom of the lower legs.
Monte
One leg had some goo (chunks, really) and no bumper ring, while the other leg was relatively clean and the bumper ring in it looks like it could be reused.
My new bumper rings are red in color.
I think this answers my question (never posed here, I don't think), of why my fork legs were un-even when I pulled the front axle out!
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F116712396%2Fmedium.jpg&hash=adea5225665f45c7eb950867a94d65fe26b74cc7)
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F116712509%2Fmedium.jpg&hash=e1b0ec287549690f8d953deb08ffdf74dfe66714)
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If that allen head bolt refused to loosen up, what would your options be, drill the head off of the bolt ?
Not an option. The damper rod would just spin.
The allen head bolt is made from aluminum, correct ?
NAW! Couldn't be! The one coming up from the bottom of the leg, right? Hardened steel, I'm sure.
Maybe another one of those parts, to apply anti-seize to upon reassembly !
I think I would use some blue locktite on the threads at the top of the damper rod, that the 13mm hex fastener/oil gallery/shim holder screws onto.
You could put anti-seize on the threads of the big allen screw in the bottom, but I don't think I will. I don't want that stuff getting in my oil.
I'll get pictures.
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[size=12]This is only part of the story. More to come.[/size]
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F117696499%2Fmedium.jpg&hash=1158675959485520682b418fd4fcfd5d5c150070) (http://www.pbase.com/tomfarr/image/117696499/original)
click for larger
On this one, you can see the threads that the damper rod fastens to.
The 13mm bolt face is on the "top".
The nylon washer is behind it, and the "holey" washer is lying to the right.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F117937230%2Fmedium.jpg&hash=e36003934ec2a5d3ba82459b2db5ee507e2a6ae7) (http://www.pbase.com/tomfarr/image/117937230/large)
click for larger
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Rob
Your damper valve body (base cylinder in your photo) looks to be original like mine and not the modified version. Was there a shim between it and the circlip ?
If not when you re-assemble and replace the circlip if there is any movement at all of the damper valve body you may want to fit a shim which I think is still available from US suppliers.
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A few new pictures.
Click on this one, and go forward for the sequence.
Thanks for watching! (pBase is having issues, right now)
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.suraklyn.com%2Fr65_forum_gallery%2Falbums%2Fuserpics%2F10021%2Funtitled1.jpg&hash=cbd7b47c2af2e68ca95d975e8c116021d73f6f8a) (http://www.pbase.com/tomfarr/forks)(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.suraklyn.com%2Fr65_forum_gallery%2Falbums%2Fuserpics%2F10021%2F7.jpg&hash=533d1a7e1d197ce7c608dbcb638b456e551d722c)
Left to right:
Bottom support for damper pipe [18]
Lock Ring [19]
Valve Housing [21] (I have no clearance shims [20])
Valve washer [22]
Flat washer 23] (holey washer)
Ring [24] (bumper ring)
And they all fit over the damper pipe, which is capped by that fitting with the 13mm head on it. These two are listed as one in RealOEM (http://www.realoem.com/bmw/showparts.do?model=0363&mospid=47851&btnr=31_0297&hg=31&fg=10).
Close up of bottom dismantled:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F117717254%2Fmedium.jpg&hash=d3f26e9c75465dfd882020a9a6e8f9821a9d3bc6)
This is the bottom of the damper pipe support.
This sits against the bottom inside of the fork slider, and the big 14mm allen head screw [17-above] goes in there, to hold them together.
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F117717265%2Fmedium.jpg&hash=927abfccda4c7bc8b019d577bdf87805f800bf1e)
This is the fitting at the top, which is intended to stay in place when you dismantle the forks.
I plan to blue Loctite this fastener. Maybe even red! [smiley=shocked2.gif]
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F117717130%2Fmedium.jpg&hash=0d79598458a280ee2d3d728c16a085582c844361)
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I got the fork legs out of the triple clamps a little bit ago. I used my heat gun on high for just a couple of minutes on each clamp, and I was able to twist the tubes out!
Bad news, the left leg (impact side) is significantly bent.
The right one looks O.K.
MAX BMW quotes a new one at $460!
I hope I can get this one straightened to my satisfaction.
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I am putting my forks back together! :)
These are the bumpers I got from Max BMW:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F119147808%2Fmedium.jpg%3Cbr+%2F%3E&hash=149d2f7871de53513c5004212ccf707284a4c898)
These are the ones Motobins sells:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.bmwr65.org%2Fhtdocs%2Fyabbfiles%2FAttachments%2F29020_001.jpg&hash=41c6807afb79c2f46bb5a257b95f275a1ad38581)
I noticed the inside diameter of my new ones is slightly larger than the old one I pulled off. (The one in the other leg was no where to be seen)
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The '81, didn't have them, just the black goo in the bottom of the fork, the LS, hasn't had the forks apart yet, but with 91,000 miles on it, I'd go out on a limb, and say they aren't there either .
Dang it! I was hoping to eliminate the occasional topping out of the forks. :-? Monte
Perhaps I misread/misunderstood previous posts. RealOEM for my '81 shows the same exploded view of the front fork innards as the diagram in your post. Item #24 is the rubber/nylon "ring" above the perforated disc.
I'm going to fit the Motobins rings in the '83 as the fork legs are currently off for the steering stem bearing replacement.
Monte
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Yep - #24.
When I was sliding the damper rod assembly into the fork leg I knocked off two of the three thin shims that sit in a groove on the top piece:
(https://bmwr65.org/smf/proxy.php?request=http%3A%2F%2Fwww.pbase.com%2Ftomfarr%2Fimage%2F117717130%2Fmedium.jpg&hash=0d79598458a280ee2d3d728c16a085582c844361)
The fact that they are brand new tubes that never had oil in them may have made it a little tougher. I just put them back in place and tried again, pushing around on different sides as I slid it up.
Good cir-clip pliers are essential.
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Rob
I dont know if it makes any difference but I spaced the gaps on the damper piston rings 120 Deg apart just like you would on an engine piston to get a better seal. They'll probably move around anyway. I also found it easier to put the damper rod in from the top of the stanchion so that the tapered bottom edge of the circlip groove compressed those little rings gently into the bore of the stanchion.
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... I also found it easier to put the damper rod in from the top of the stanchion so that the tapered bottom edge of the circlip groove compressed those little rings gently into the bore of the stanchion.
This is a very good idea! I have also used two 0.002-inch feeler gauges leafs as insertion guides when refitting damper bits into the fork legs. Monte
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OK - anyone have a torque figure for tightening the damper rod and the great big allen bolt that goes up the bottom of the fork slider?
How about the same for the fork tube clamp bolts?
Thanks! [smiley=thumbup.gif]
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I confess I didn't use a torque wrench for the bottom Allen bolt. [smiley=embarassed.gif]
For ease of removal next time I just tightened it enough so that it didn't leak. The bolt isn't going anywhere with the wheel spindle in place and an oil leak is going to tell you if it comes loose. I've done it this way several times and not had a problem. This suggests you could get away with using the low side of any torque values that you find.
I can get figures for the clamp bolts when I get home from work. I know I went on the low side of the reccomendation again. These bolts in alloy always scare me as they seem to keep turning more than I expect before the torque wrench clicks.
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OK I'm home after a cold not much above freezing ride in the fog.
The fork yoke clamp bolts are 29.5 - 33 lb/ft
and the bottom allen screws 22 - 29.5 lb/ft
Can't see a figure for the damper piston itself. I Guess it should be a little higher than the bottom allen screw.
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Thank you!
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The allen hex head bolt in the lower fork leg can be remove with an impact driver after compressing as much as possible the whole setup, just push the top of the fork down to your feet, with the legs upside down, then whack with the impact driver.
I have only done this on three bikes, but it worked three times, so I thought I would pass it on.
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The allen hex head bolt in the lower fork leg can be remove with an impact driver ...
Just don't re-install it with the impact tool. Danger, Will Robinson. Danger.
Monte