Oil Leak at Gear Selector (R75/6)

[RPGR90s]

Please let us know how the repair went.

[MDchanic]

One note:

I just did this job on my bike (I'd changed out the shifter screw for a stainless one, moved nothing but the screw itself, and it leaked like a sieve afterward - go figure!).

1. I had to change the oil anyway, so I drained the oil and just laid it on the jug on the ground.
Not draining the oil would probably have been fine, but it was a good excuse to do it.
I've also used AGM batteries for the past 25 years or so, so no acid spills.
It's very easy to just put the bike on a jug, especially with the tank off, and easy to lift it up (I just grasped the handlebars, and I'm 60 and not built like the Hulk), so there's no need to be concerned about exactly how far to lean it.

2. For the early /6s (I've got a /5 with a '74 /6 engine and trans), the seal has a 24mm OD (the 75ish and later bikes have a larger OD), and there are TWO shifter seals that are sold: 24x15x7 and 24x16x7.
Both sizes will fit, and both sizes will probably work, but since the 15mm ID seal will fit fine, without tightness or binding, there is no reason to get a seal with a 16mm ID.
If you have a '74 transmission, you can just buy the seals on eBay or Amazon, but if you buy them from a M/C supplier, make sure they're selling you the 15mm ID seal and not the 16mm.

- Eric

[damienbove]

Hello Guys, well i got the seal and managed to lean the bike, remove the gear selector and remove the old seal without loosing any oil, so far so good however when i compaire the seals the old one is slightly larger than the new one and the new one is not a snug fit, so i abanded the change and reinstated the old one, any comments, i have gone back to the supplier. also in the techncial manual the seal is not even on the technical drawings (which i find supprising)

[damienbove]

i have just re-read erics post on this subject and i can confirm that i have the 15mm seal, so that makes sense, the outer diameter is 24 and inner is 15mm, i will have another go and swap it out. cheers

[Kurt in S.A.]

It is shown in another diagram...#9 in this image:

https://www.realoem.com/bmw/enUS/showpa ... Id=23_0256

Interesting that it shows two different seals. One is from 9/74 which should be the right one.

Kurt

[damienbove]

thanks Kurt

[SteveD]

It is shown in another diagram...#9 in this image:

https://www.realoem.com/bmw/enUS/showpa ... Id=23_0256

Interesting that it shows two different seals. One is from 9/74 which should be the right one.

Kurt

09 Shaft seal 24X7X15,7 1 23111006124 $11.30
09 Shaft seal 26X16X7 1 09/1974 23121338740 $10.87

[MDchanic]

Code: Select all

09 	Shaft seal 	24 X  7 X 15,7 	                                23111006124 	$11.30 		
09 	Shaft seal 	26 X 16 X  7          1 	  09/1974 	23121338740 	$10.87

Note that these are essentially the same seal, with different ODs. For some reason they change the order of the dimensions.

You have 24 x 7 x 15.7 and 26 x 7 x 16.

There is no difference between 15.7mm and 16mm in a flexible rubber shaft seal.
In fact, as noted, vendors sell both 15mm and 16mm ID seals for these, and both sizes seem to work fine (though I see no reason not to use the 15mm, which should make a tighter seal).

Both are 7mm tall.

So, an early bike will use the 24mm, and a later bike will use the 26mm, and you can measure this dimension with a ruler if you need to.

You can buy these on eBay for half the RealOEM listed price (which may be even less than a vendor's price), with free shipping.

- Eric

[damienbove]

i forgot to come back on this, i purhased a seal but when i removed hte old one it was a bit larger than the new one, so i put the old one back in, later on i realised it was bigger because it had been squahed into shape when the gear selector was tightened. however the good news is taking the seal off and putting it back on has resolved the leak.

thanks for the help guys

[MDchanic]

"... it was bigger because it had been squashed into shape when the gear selector was tightened."

So long as it works, then all is well, but that seal should NOT change shape when installed, and should not have any pressure on it from the shifter lever, so either something is very wrong, or we are talking about different seals.

Glad you got it fixed!

- Eric