rear brakes

[MrRiden]

Yes looks like he has the '81-on shoes. The '79-'80 show this. Wouldn't a 10/1980 manufacture date make his bike a '81 model though?
rich

[nhmaf]

Yes, the production of the model year starts in late Sept/early Oct of the year before, so they should be '81 shoes and cam, etc.   But, maybe there was a leftover part or two in the bin when the production line started up?  OR maybe a PO substituted some parts?   I don't see how that rear brake cam could get so worn down under normal conditions unless the bike was ridden 100K+ miles and/or the rider loved to lockup and skid the rear tire at every stop sign/intersection?

[trolle]

Hi

This is a picture of my rear brakes from the '81-'84 model. Neither shoes nor cam are worn, as they are from a rear drive from an R45 with a low milage. They are identical with the R65 brakes.

greeting from a 90% clouded normal temp. 50 F north

[Ed Miller]

Good picture, Trolle, thanks.  But flipping back and forth between Darwin's pics and yours, all I can think of is Darwin has the shoes in wrong, probably on the pivot end that isn't in his pictures.

Hmm, he hasn't posted again to this thread.  Is it fixed?

[Darwin_R65]

It's not that it's fixed, but sometimes work sends me away.
I been in Gove working, (A small mining community in remote Northern Territory) so haven't had the chance to come back to the bike. Nice to see so many interested people. I put the rear wheel back on because I've got little kids and I don't want bikes falling over. I'll try and pull it off again this afternoon and have another look.

I have made sure the pivot is seated correctly, that was my first thought. When I pull it off later, I'll measure a few more things.
Because of the distinct difference in shoes, I'm definite I have the 1981 shoes. I guess it could it be possible my bike was made with the 1980 drive unit, or a PO has changed things. My Valiant has shown me that PO's can be very creative in producing non standard repairs that simply don't work, but that's another story.

John

[Darwin_R65]

p.s. Living in Darwin I'm unaware of any other R65's here, and parts are 4000 kms away in either Perth (new parts ) or Melbourne (wreckers). Unless Aussie can tell me of some BMW goldmine in Adelaide.

[Darwin_R65]

Right I've pulled the rear drive apart.

following are some photos with measurements

but first one to show the shoes are on the pivot correctly, I've removed springs in this photo so I can show the cam in it's operating position.

the second photo shows I've measured from the outside of the pivot side of the shoes.

The third photo shows my measurements. (camera angle is a bit off causing parallax error)

the smaller shoe measures 150mm inner edge to 156mm outer edge.
the larger show measures 180mm to the inner edge and 186 to the outer edge.

my pivot post measures 12.8mm diameter.

[Darwin_R65]

And my brake cam measures 30.3 mm x 19.3 mm


If anyone could measure theirs it would be much appreciated. I have a had a thought it is possible the previous owner may have replaced something with the wrong year.

And from the centre of the pivot post to the centre of the brake cam is 155mm

[Darwin_R65]

And the rear drive unit plate has the part number on it 1238834
and has a circle with an 81 above an 80, which i assume refers to the year, so I guess the plates the right year. It's just the cam I don't know about. So if anyone has a post 81 model bike and you could measure your brake cam that would be fantastic.

John

[MrRiden]

Measurements of my LS won't help BUT I am finding multiple part numbers for the brake cam. The plot thickens
http://www.webparts.com/diagram.php?btnr=34_0599&mospid=47851&hg=34&fg=10

[Bob_Roller]

The part number that ends in -261, is for the '78-'80 model year bikes.

The part number that ends in -836, is for bikes made 09/80 and after.

After 29 years, and multiple owners, it is possible that incorrect parts could be installed !!!

[MrRiden]

I am so far unable to nail down the part number shown on the cover. What it looks like in the pic is 1238834 along with 11 and 225 below. no matter how I try I cant make a valid part number out of these but I'm no wizard at changing part numbers. Ive also found multiple listings for the pivot pin and cover. still trying to werk this puzzle out. All I do know is that pre '80 drives don't play with post '80 drums but there is a mod. Need to nail down the hub cover & drum year then figure out the right shoes $ other bits. The cam may be only part of the puzzle.
rich
 [smiley=wall.gif]

[Bob_Roller]

Not uncommon to have what appears to be a part number cast into the metal, that doesn't correlate to any available part number.

Most likely it is the company that produced the part, has their own numbering system, that has nothing to do with BMW part numbers.

[Justin B.]

A lot of the time these esoteric numbers are date codes, shift codes, etc., so someone who know tyhe code can tell exactly when it was cast.

[Darwin_R65]

Just to let you know I finally got around to getting new brake shoes and putting them on today, and yes there's about 5 mm difference in diameter of the shoes.

Why has it taken me so long?

I renewed the spline on the rear drive at the same time, had to order it, Freight to Darwin is by camel I'm sure.
Engineering shop took two and half weeks to replace spline in crown wheel.

Then had to find some time in between work, kids and the wife all demanding time.

So today I dedicated to returning Norma back to the road where she belongs and I get it all together and go to put oil in the rear drive and the level plug is stripped.  BUGGER.

Pull it all apart again just to get the plug out with a punch, hammer and unscrewing the bolt all at once.

Sunday on a long weekend, off I trot to Independant motor mart, any helicoils? what size? I say metric 8mm, and can't remember the pitch I say it's the fine metric, well this confuses the girl who asks if it's a special thread that's a cross between metric and UNF.

I look at the sample bolts on the display and correct my statement to M8 x 1.0. She's still lost. Feel like banging my head on the floor.

She looks up the catalogue and says "we have M8 x1.25 if that's close enough." Impulse to headbutt wall gets greater. I actually thank her for her help and walk out. Try supercheap autos and they don't even stock helicoils. Aaarghh, the frustration of trying to fix bikes on weekends.

So a day spent putting the bike together driving around in the car, headbutting walls and pulling the bike apart again, and me wondering just what did I achieve today. Bike is in same condition as yesterday except I now know I have a thread to repair.

John