This page is for 1970 and later BMW models, R50/5, R60/5, R75/5, R60/6,
R75/6, R90/6, R90S, R60/7, R75/7, R80/7, R100/7, R100RT, R100RS and possibly
The purpose of the rear brake is to stop the rear wheel, not to stop the
motorcycle. The tire stops the motorcycle and that efficiency depends upon the
specific tire. If you can't easily stop the rear wheel with moderate foot
pressure, then it needs some attention. This page is only a start and will
be expanded when time allows.
Removing the rear wheel from your BMW motorcycle
This procedure may vary a lot, depending upon year and
accessories mounted. A tire that is wider than specified by BMW may make
the job harder too.
Make sure that the bike is on the center stand and very
Back off a few threads on the swing arm pinch bolt. No
need to remove it.
Remove the axle nut and washer.
Use a bar to rotate and pull on the axle. It should come
out fairly easily.
You may need to back off on the rear brake adjustment wing nut
From the left side, you should be able to gently pull on the
wheel to get it off of the brake shoes. If the shoes are fairly tight
against the drum, you may need to rotate the wheel a lot while pulling it off.
What happens is that the shoes can try to go with the wheel. They get
cocked a bit and that actually makes them tighter in the drum. Now it
won't move at all. That is why rotating helps.
The wheel should just wiggle out of the area and roll between
the fender and muffler. If not, go to the next procedure.
Have a helper tilt the bike over on the right side and hold
it. Now the wheel can come out of the bottom and miss the muffler and
fender. If no helper is available, then use something to cushion the
right side valve cover and lay it over. One may have to let the air out
of the tire too.
Inspection of the rear brakes
Grab the foot brake lever and wiggle it sideways. It should only have a
slight movement. Yours wiggles a lot because of wear caused by a lack of maintenance/lubrication. Remove the
brake lever for inspection, cleaning and lubrication. First, back off the rear
brake adjustment at the final drive. Run the wing nut back several turns.
The normal adjustment should look something like this. This is about average. See the threads showing? That is about average. See the slightly less than 90
degree angle between the brake arm (vertical part) and the rod (horizontal part)
with the spring? When the brake is applied, that angle comes closer to 90 %,
which is where one gets the maximum force applied to the brake, depending upon
the cam wear. See the upper
shaft and the two punch marks at about 10 O'clock? I made those punch marks. This allows one to remove and reassemble it in the same position. The arm is
mounted on the shaft on splines. There is little variation allowed. You should
punch the marks before you remove the arm if you think that the arm is in about
the correct spot. This allows you to reinstall the arm in the correct position
the first time. This shaft is something that should be removed for cleaning and
lubrication. More later on this.
This is what is back behind the driveshaft and is hard to see.
Lift the fastener to this position. It now comes towards you. It will
probably be impossible to get out. They get rusted up and so I suggest some WD
40, or your favorite anti-seize oil. You may even have to punch it out from
the other side with something long and slender.
This is the bolt that is now ready to be removed. On the right are two flats
for a wrench. Hold the bolt by the flats and remove the nut shown on the left. It is kind of tricky at first to reach both, but it can be done. Examine this
bolt. See the hole for grease? See the rust that is to the right of it?
This is the backside. I have cleaned out the grooves for the grease so that
they show up well. They kind of "spiral" around the bolt. They are not rusted
because they had grease in them. The body of the bolt is rusty because it didn't
get greased. As soon as the grease is forced out, the water gets in. The rust
now "grinds" away at the tube welded on the frame. The rust makes friction and
some braking action is lost here. The frame tube gets larger and the brake lever
is now sloppy. You can't easily fix the part that is now worn, but you can make
sure that it doesn't wear more. The photo above shows the washers in the
This shows the head of the bolt with its grease zerk in the middle. Remove it
with a 7 mm socket. Take care not to lose it, as I have no idea where one
gets another one.
The old grease can be very hard to get out. I often start with a drill bit
and turn it by hand. The flutes allow some of the hard grease a place to
go and get pulled out.
Solvent and an old fashioned Q tip will clean the hole out.
Don't freak out, the zerk is held in the vise by the
grease gun, not the jaws. This is to test the zerk.
You can see some grease that just got pumped through.
Here the zerk has been reinstalled and tested. See the grease that was
pumped through? Don't assume that it will work unless you have tested it.
This is what the lever should look like.
This shows the adjuster bolt in about the usual position.
You might need to move the nut around to the other side to get the
adjustment. That is an unlikely option and I would be concerned if this is
needed. If one is doing something special, then maybe it is OK. On an average
bike this would only be needed if something is bent or altered. I would want to
find out why. With the adjuster bolt screwed in this much the foot brake lever
would be raised up a lot. It isn't unknown for the brake lever to get bent. It
usually occurs between the empty hole and the adjuster. They even break off. The
part can be welded back on again. The bolt/nut shown serves two purposes, to
operate the brake light switch and be a stop for the lever position. By
adjusting this bolt, one can move the lever up and down. Your preferred foot and
toe position may be improved by this adjustment. Don't be afraid to play with it
a bit. Many of these bikes have never had the lever in the best position for the
rider. You may also move the foot pegs up or down too. Any
adjustment with these parts will require some adjustment of the wing nut at the
I will be adding more text and pictures to show the rear brake shoes,
final drive, wheel and splines. See
my other page related to this topic.