A tiny brake/clutch fluid leak

[kiva667]

This has been bothering me for the last year. Every few months I have to add a tablespoon of brake fluid to the reservoir.

 

At first I thought the brake cylinder needed a rebuild ( I have a kit from West Germany) but then it occurred to us that the clutch slave cylinder had a leak. And as long as I am doing that, I might as well replace the clutch master  cylinder. 

 

Am I being obsessive or is this the route to follow?

Edited January 4, 2023 by kiva667

[NickVyse]

Does your NK have one reservoir for both brake and clutch? If so just replace/rebuild the clutch MC as that's obviously leaking. Or is the brake MC leaking too, can't tell from the pic?

 

[kiva667]

13 hours ago, NickVyse said:

Does your NK have one reservoir for both brake and clutch? If so just replace/rebuild the clutch MC as that's obviously leaking. Or is the brake MC leaking too, can't tell from the pic?

it's a stock '67 with two reservoirs - at first I thought it was the brake MC but close examination revealed a tiny leak only from the clutch slave. I've read that replacing the clutch MC can be difficult. And the parts book has different part numbers for all of the above. Any thoughts on which slave and clutch master would be correct ?

K

Edited January 13, 2023 by kiva667

[kiva667]

Of the various options for a 100% stock 67 2000?

[kiva667]

Here is what I found :

 

 

BMW OR ATE GERMANY NEW Repair Kit Output Cylinder Clutch 1500 2000 21521103737

WWW.EBAY.COM

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BMW OR ATE GERMANY NEW Repair Kit Output Cylinder Clutch 1500 1600 1800 2000tilux...

 

BMW 1600 1800 2000 Clutch Master Cylinder Repair Kit FAG 19mm 1963-1971

WWW.EBAY.COM

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Part Manufacturer: FAG. Fits Year(s):1963 - 1971. Fits car MAKE(s): BMW.

 

[NickVyse]

You simply need to match what you have in the car and only you can tell us that - a lot can happen over 50 years. But you've not said why you've diagnosed the MC as faulty other than having to top up the reservoir with a teaspoon every once in a while. Could just as easily be a seeping caliper or rear wheel cylinder.

[kiva667]

Thanks, Nick

 

im no mechanic but when I took the car to my guy with the repair kit for the brake MC he told specifically he traced the leak to the clutch slave. He's an old school guy whom I have learned to trust. He suggested that I change the clutch MC because in his opinion when the slave fails the MC may be close to follow.

 

btw he flushed the brake and clutch fluids that same day so had a good look at everthing. And he said the calipers, which I had rebuilt in 2018, were still in perfect shape.

At the same time I replaced the rear wheel cylinders, too. They are in excellent condition too, he said

Edited January 14, 2023 by kiva667

[kiva667]

Anyone know what might be the part # for this slave cylinder? Just got around to taking a photo yesterday.

 

[Schnellvintage]

It looks like the standard slave cylinder for a 2002 with a hydraulic clutch. 

 

Matt

 

Clutch part number.pdf

[kiva667]

2 hours ago, Schnellvintage said:

It looks like the standard slave cylinder for a 2002 with a hydraulic clutch. 

Matt

Thanks, Matt!  But realoem gives different part #s for the NK slave cylinders. I did find a repair kit on eBay with a similar part # but the dust cover is different, as we see in the photos already in this thread.

 

21521103737

 

The search continues.

 

Best,

Kit

Edited March 17, 2023 by kiva667

[Schnellvintage]

Here is an early parts book page with a superseded part number.  Unfortunately, it utilizes the early part numbers too.  Hope this helps.  I would image BMW supersedes many part numbers as they update and improve he parts for later cars.  

 

Matt

slave nk.pdf

Edited March 17, 2023 by Schnellvintage
added info

[NickVyse]

seem to recall I used a standard 02 cylinder. I think the only difference is the location of the exit is slightly diferent, but no big deal.

[kiva667]

It only costs $25 USD to deliver the repair kit to my door from Athens. I will buy this kit and see if it works. If it doesn't I can always try to sell it here on the forum 🙂

[kiva667]

So I bought the repair kit and no, it doesn't work. If someone wants it I'd be happy to send it to them no charge in an envelope.