How to rebuild clutch Master cylinder

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Hellboi
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How to rebuild clutch Master cylinder

Post by Hellboi » Thu Apr 10, 2014 8:53 am

So I couldn't find any how to online but my clutch was pissing fluid so I went ahead and just went with trial and error. Took some pics along the way and decided to do a quick write up. Super easy and no need to remove it from the bike.

What you will need.

1)Magura KTM LC8/690/MX Master Cylinder Rebuild Kit
KTM Part Number: M0720499
Be sure it is the kit for the 10.5mm piston, there are a few that look similar.
2) Snap ring pliers, 90 degree version. The kind that compress when you squeeze, not the ones that spread.
3) Clutch Bleed syringe (I will show you how to make one and save money)
4) Mineral Oil (Magura sells overpriced mineral oil called Magura blood. You can use any mineral oil. I used Baby Oil. it was $1.99 USD for a large bottle and If it ever leaks again it will smell nicer. :D )
5)4mm Allen key
6)8mm open end wrench

OK first things first, Turn the handlebars to full lock right.
Next, remove the rubber dust cover at the pivot point of the clutch lever by gently pulling it towards the end of the lever and setting it aside, this will expose the lever pivot bolt and nut underneath.
Image

Next, using the Allen key and wrench, remove the pivot bolt then simply remove the lever, taking care not to drop the insert sleeve or the lever spring and set aside.

Image

Now we remove the piston dust boot by simply giving it a pinch and tug it out of it's seat.

Image

From here, you will see the snap ring exposed.

Image

Next take your compressing snap ring pliers and pop it out, the white teflon washer will probably fall out with it.

Image
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Next make sure to have a rag or a bucket below because when you slide out the piston, the oil will flow a bit. Also remember that the spring end will go in first when installing the new piston.

Image

Lastly for the disassembly I removed the reservoir cover and much more oil flowed out, and man was it dirty. I cleaned out the reservoir with a small lint free cloth and fresh mineral oil. then placed the cap on loosely to keep dust out.


Next step will be to flush the system prior to re assembly.
Last edited by Hellboi on Thu Apr 10, 2014 10:04 am, edited 1 time in total.
And where might a fellow like me find such a glorious spatula?

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Re: How to rebuild clutch Master cylinder

Post by Hellboi » Thu Apr 10, 2014 8:54 am

OK now for the flush. Time for the bleed tool. You can pay upwards of $30 USD to buy a tool or you can do as I did, I purchased a flavor injector from my local grocery for around 1USD and about half a meter of clear tubing used for irrigation or fish tank bubblers, about 30 cents. Simply attach the hose to the syringe and Violla. You now have a tool.

Image

Now dip the end in the mineral oil and draw it in to the syringe, Turn it upside down to let the air rise to the top, then expel the air back into the bottle of mineral oil, repeat until there are no air bubbles at all in the syringe or the hose.
Now carefully slip the end of the hose onto the bleed nipple near the clutch slave cylinder trying not to let an air bubble appear.

Image

Once you have the hose on simply take your 8mm wrench and turn the bleed nipple about a quarter or half turn and start to push the syringe plunger. This will expel all the old fluid out from the piston area so be sure to have your bucket or rag ready. You may want to repeat until the oil runs clear so if you need to refill the syringe, be sure to close the bleed nipple before removing the hose.

Once you are satisfied, it's time to install your new parts. Dab a bit of fresh oil on the piston seals and slide it in spring end first.

Now is a little tricky, slip the white teflon washer on the end of the piston while holding the snap ring pliers and snap ring in your hand. You will need to push the piston in pretty firmly to get the snap ring to it's seat, it will feel like it's in, but give it a firm push and it will go in a tad further. To push the piston in I used the bolt from the lever pivot point. then carefully snap the ring in place (sharp side outwards, rounded edge side towards piston).

Once your piston is locked into place, go back to the bleed nipple and push more fluid into the system until the reservoir is full and no air bubbles come out. Then tighten the bleed nipple and reservoir cap and remove the bleed tool.

Instal piston dust boot, Clutch lever, and clutch pivot dust cover.

Clean up and have a beer.
Last edited by Hellboi on Thu Apr 10, 2014 10:08 am, edited 1 time in total.
And where might a fellow like me find such a glorious spatula?

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How to rebuild clutch Master cylinder

Post by LenFerguson » Thu Apr 10, 2014 9:59 am

Top write up Hellboi.
Current stable: KTM1290SDR(14), KTM1190ADVENTURE(14), BMWS1000RR(12), KTM690R(12), Husky TE250(13)

Previously loved: KTM990SMT(11), WR450F(10), F800GS(09), KLR650(08), KTM450EXC(05) FJR1300(04), KTM200EXC(03), XR400(03), CBR1000F(90), XR600(88), KR1(86)

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Re: How to rebuild clutch Master cylinder

Post by kevxtx » Thu Apr 10, 2014 10:52 am

Great info for the boys. :D

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Re: How to rebuild clutch Master cylinder

Post by JJay51 » Thu Apr 10, 2014 6:14 pm

Well detailed, thanks for taking the time to do it :)

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How to rebuild clutch Master cylinder

Post by Rangoonruns » Thu Apr 10, 2014 8:09 pm

Great write up
Thanks
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Re: How to rebuild clutch Master cylinder

Post by downboysit » Fri Apr 11, 2014 11:24 am

onthe subject of clutches:
on advrider forum, with regard to the problems some owners have faced with the slave cylinders failing early, one seemingly knowledgeable member wrote:

the problem is sintered aluminum + mineral oil + heat + pressure. Its called a solvothermic reaction. Swap to a synthetic fluid that's non reactive with the sintered aluminum cylinder and there is absolutely no issue with the stock unit. 60+k miles and no failures. Same for every one of my customers and friends who I've swapped over to 3w synthetic fork oil.. I could make 35% selling these replacement slave but it really isn't necessary, IMHO.

http://www.advrider.com/forums/showthread.php?t=918101

seems like sound reasoning here to me
any opinions here people? any reason NOT to use synthetic, despite the clutch reservoir explicit advice?
cheers

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Re: How to rebuild clutch Master cylinder

Post by Hellboi » Sat Apr 12, 2014 1:56 am

Hey, If it works I'm in! My bike now has 17000km on it and the thing was leaking so bad it left puddles on my driveway and the fluid was filled with sparkly grey specks as to where it looked almost black. A bit premature, but then again my fuel pump died around half that so I was just chalking it up to KTM "Quality". I think I'm off to buy some synth! Great find!!
And where might a fellow like me find such a glorious spatula?

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Re: How to rebuild clutch Master cylinder

Post by ogden » Sat Apr 12, 2014 11:52 pm

Stickied. Did we discuss having a how-to section in the past? If not, might be an idea.
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Re: How to rebuild clutch Master cylinder

Post by gefr » Tue Jan 06, 2015 8:33 am

Hello everybody.
I have a mechanic that can resleeve a worn master cylinder, with s/s sleeve. He brings the cylinder to original diameter so with a new piston and some bearings at the joints of the clutch lever, the system gets a long life span. If the master cylinder starts leaking, the piston seals are damaged. The bore looses partially its internal coating and then wears the piston seals. So seals or piston replacement as above, will probably not work for a long time.
Cheers.
Last edited by gefr on Tue Jan 24, 2017 7:54 am, edited 1 time in total.

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Re: How to rebuild clutch Master cylinder

Post by deee-blue » Thu Jan 08, 2015 9:26 am

Does anyone know where you can buy All I'm after is the clutch seals.
KTM SMT

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Re: How to rebuild clutch Master cylinder

Post by gefr » Thu Jan 08, 2015 10:41 am

The only source I know is KTM.
Part No # 50302032000
I do not know if MAGURA sells it cheaper.
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Re: How to rebuild clutch Master cylinder

Post by D-train » Thu Jul 23, 2015 11:57 am

Replacing mine this weekend. New piston ket here in Adelaide is $79....

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Re: How to rebuild clutch Master cylinder

Post by gefr » Fri Jul 24, 2015 6:52 am

Please report after a month. Very interested in the outcome.
Cheers.

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Re: How to rebuild clutch Master cylinder

Post by Kernow » Thu Oct 01, 2015 9:56 am

Good how too , very useful .
One thing to make it even simpler , don't use a syringe to bleed , just a length of the clear tube about 5 foot long hold it high and the system will get flushed as you pump it through , the air will just rise up the tube because it's hugher than the master cyl

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Re: How to rebuild clutch Master cylinder

Post by D-train » Mon Nov 09, 2015 9:49 pm

I agree. I replaced my seals but after 3 months it was leaking again. So I have looked into a replacement master cylinder and will make a separate post about it.

And here it is : viewtopic.php?f=13&t=7726

BTW, The same guys I got the new unit from do sell the 10.5mm seals for the 163 model that we have... Cost about $50 + postage.

Just didn't last long for me as I think the bore was worn / corroded.

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Re: How to rebuild clutch Master cylinder

Post by ktmnerd1958 » Mon Nov 14, 2016 10:12 pm

This is of such great help! Thanks Buddy!

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