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Old 06-22-2010, 04:18 PM   #45
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Joined: Nov 2006
Location: Bowling Green, Ky
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R80 G/S ring gear bearing replacement

Replacing final drive bearings on a R80 G/S.

BMW Part #’s
5) p/n 33121241938 shaft seal (85X110X10)
4) p/n 33121242210 out put ball bearing (85X120X18)
2) p/n 33121241682 needle bearing dive bearing (35X50X20)
13) p/n 33112311097 gasket
p/n 07119906328 (two) brake pivot o-rings

Fig 1

Fig 2

Fig 3
First clean mud (this is a G/S) from final drive, rear wheel and mono lever. Loosen three nuts holding rear wheel and back off adjusting rod to the brakes, then remove wheel. Remove brake shoes and just to make things easier keep springs on shoes, also remove circlip (#18). Put these in a safe spot along with other parts, which will be removed later. It’s helpful to put parts in relative location for ease or reassembly.

Fig 4
Remove drain plug (#9) for drain final drive. At this time clean off the drain plug magnet. Now clean the inner part of the final drive with brake cleaner and a small brush. Remove the brake rod adjuster (wing nut). For the brake arm, make a scribe mark on the brake arm pivot pin where the arm is split. This will aide in relocating the arm and pivot pin on reassembly. Remove pinch bolt and pointer. Then tap the brake cam out towards the left side of the bike (while sitting on the bike) again make sure to keep parts grouped together so no to mix them up later.

Fig 5

Fig 6

Final drive cover removal-The remove the 8 final drive cover bolts and wave washers in Fig 5, and then insert two 5x30mm bolts as pictured in Fig 6. Then heat up the housing cover around the perimeter of the oil seal with a heat gun, this is to make removing the cover easier as the out put bearing is press fit into the cover.
Tighten each of the 5x30 mm bolts, equal amounts, don’t over tighten one side over the other, as you want to pull the housing cover off square and not angled. The bolts will be tightened down almost to their full length before the cover is released from brake pivot tube (fig1, #25). Make sure to keep one hand on the cover at all times to catch it when the bearing is released.
In order to remove the large roller bearing (fig 1, #4) from the outer cover screw in the tap lightly with a copper hammer around the perimeter of the flat ring gear surface (Fig 6) until the cover is free of the ring gear and bearing. Once free remove the cover and ring gear from final drive. Again make sure to hold onto the cover and be careful not to damage the spacers inside the outer cover.

Fig 7

Be careful as the driven bearing has a shim (Fig 7) for the ring gear. It is a brass like ring, DO NOT BEND OR LOOSE THIS. Best and safest place for it is in it’s current location.

Fig 8
Seal removal-Look inside the cover plate and be careful not to loose or bend the shims (fig 8) for the out put bearing. Remove shims and store in a safe place. Clean the cover in mineral spirits and scrape gasket, leaving the flange clean. Note that seal (Fig 1 #5) protrudes slightly from the face of the cover; make a mental note of the amount. Then remove the large seal with a hammer and punch. Once removed clean and oil the sealing surface.
Put cover gasket side down on a flat clean surface and lightly oil outside edge of seal,
put it in place on outer cover and around the circumference GENLTY tap new seal in place. DO NOT force, the key is to work it slowly, as not to bend the seal. Keep tapping seal until the amount of protrusion is the same as noted earlier and equal all the way around.

Fig 9

Fig 10

Out put bearing removal- Note I don’t have the appropriate three jaw bearing puller for this so be patient on this. Heat the inner race with a heat gun, then with a set of chisels work on hammering the race off. Work the chisels at 180 degrees of each other, then at 90 degrees. Keep tapping the chisels in place working them opposite of each other, you may have to get larger chisels or add metal shims next to the ring gear (Fig 10) as the spacing between the race and ring gear gets larger. Be very careful not to mar the ring gear surface. Don’t do this on concrete, or where you may drop the gear as it might be damaged. Removal will take time but it will come loose.

Fig 11

To remove the inner driven bearing race (Fig 1#2) on the ring gear a dremel tool and small cutoff wheel works very easily. See small cut in Fig11. Just make sure not to cut completely though bearing race, as you don’t want to damage the ring gear surface. Proceed slowly in cutting but stop when almost through the shell. Then tap the cut with a chisel and the race will spring open for easy removal. Save the inner race for reinstallation of the new race. Clean ring gear thoroughly.
Remove the brass shim and protector plate from the drive housing (Fig 7).

Fig 12 Note small hole in bearing shell

Fig 13

I found it easier to remove the needle bearings and cage first, and make note of the small hole in the outer race. Use an inner bearing removal tool to remove outer race of the driven bearing (Fig 13), which is inside the housing. Remove any remaining gasket and sealant with a scraper (be careful not to mare the sealing surface) and solvent. Wipe down and clean inner housing of all oil, also inspect gears for wear.

Fig 14

Fig 15

Chill ring gear in freezer and with a heat gun heat the inner race of the driven bearing. Lightly oil the surface of the ring gear. Tap race into position, and use the old cut race (fig 11) to tap it completely home as in Fig 15. Make sure the race is seated completely on the ring gear flange.

Take note of the hole in the bearing race and line up as in Fig 12. Use bearing driver tool pictured in Fig 14 to install outer race and needle bearings in the final drive housing. Use appropriate size tool that rest on the outer race, as you don’t want to damage the needle bearings or cage. Install protector plate (Fig 7), Lightly oil brass shim and place in position.

It is best to use a hydraulic press here, because if the bearing isn’t seated fully the endplay will not be adjusted correctly. Place ring gear in freezer and heat the output bearing (Fig 1 #4) with a heat gun, lightly oil ring gear surface, then press bearing into place. Make sure it is fully seated.

Now all the hard things are done, the rest is easy!!!!!

Lightly oil ring gear where it contacts the outer cover seal. Place ring gear in housing make sure that the driven gear bushing (fig 7) is in the correct location. You don’t want to damage it. Put a light coat of Yamabond (Harley Davidson High-performance grey or Permatex #2 works well too) to both sides of outer cover gasket (fig 2 #13). Place gasket in housing, put cover in place and tighten cover bolts slowly and evenly tightening alternating bolts (make sure to rotate the ring gear as the gear teeth need to mesh tot he pinion gear and not get press on two gears, teeth need to slide past each other) until cover bottoms out, torque bolts to 13 ft.-lbs.

Oil and replace two rear brake cam pivot o-rings, install brake lever arm making sure that the split section of the arm lines up with the scribe mark made earlier. Don’t forget the pointer, which goes between the socket head bolt and arm.
Install circlip (fig 2 #7) onto the left brake pin. With an clean cloth wipe brake shoes and sand with sand paper (100 grit works fine), just enough to scratch off the surface. Then install springs to the shoes then shoes to the final drive. Install rear brake arm. Replace wheel and torque three lug nuts to 62 ft.-lbs. Then adjust rear brake rod so rear pedal travel is 25mm.
Fill final drive with 350cc GL5 SAE 80w/90. Now take your G/S for a test ride and double check your work, checking brakes for adjustment, listening for any noises and or vibrations. You might want to check after 20-30 miles the final drive for leaks, just in case.

2004 BMW R1150RS
1984 BMW R80G/S
(wrenching index)
2003 Suzuki DRZ 400S (TAT Prep)
One More DRZ does the TAT (Ride Report)

One Less Harley screwed with this post 06-22-2010 at 04:24 PM
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