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Clutch Slave Cylinder Bolt Stripped - Options for Repair

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I have a 2014 KTM 250 SX. While getting it ready for the year (changing clutch fluid) I found the bottom bolt on the slave cylinder is stripped.

I'm looking at my options and if anyone has had any luck fixing these before? The options I have came up with so far are below.

I could try a helicoil but there isn't a lot of meat on the case in that area and I am afraid of ruining the case if I start drilling. New case is $600 plus the cost to essentially rebuild the engine in the new case.

Loctite makes some thread repair epoxy that might also work. This bolt doesn't need a lot of torque on it so this might hold.

Another option I have considered is the threads deeper in appear to be intact. It only has about 1/8inch of good threads available, but I could put a stud in with red loctite and then put a nut on the end. Again this bolt doesn't need a lot of torque so this might work.

Any insight or help from those who have more experience with these KTMs would be appreciated.

KTM_Clutch.PNG

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You could drill a little deeper in the case and re thread it but you will have to find a longer bolt. I think it's 6mm Be careful not to drill too deep. You don't need a ton of thread for the small amount of torque on those. This isn't the best fix but it is quick and cheap.

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divot is right, give that a go first, drill another 5mm or so and make sure you dont overtighten the bolts.

other option would be to re thread it to m7.   m7 quite rare on bikes but i can assure you they exist, there will be enough room for that.

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I like your idea of a stud and nut using the threads that are left, but I would first try just using a longer bolt with some blue locktite. Drilling the existing hole to accept a larger diameter bolt seems less risky than going deeper. If it was stripped without you knowing it with no leaking of trans oil it should be fine with just a longer bolt. 

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Thanks for the suggestions. So you are pretty sure there would be enough room to drill it out to 7mm? If so would a helicoil work? Then I can keep the stock bolt and not have to drill into the slave cylinder as well. There just doesn't appear to be a lot of meat on the case and I'm afraid drilling it out might destroy the case.

Another thing a co-worker suggested was finding a welder who can weld aluminum and have them fill the hole and then retap it at 6mm. That would probably require I take the whole case apart though.

 

Anyone by chance used the loctite thread repair? I figured if I'm going to drill it out I could try that stuff first and see if it works.

Edited by Jackace

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2 minutes ago, jugnuts said:

I like your idea of a stud and nut using the threads that are left, but I would first try just using a longer bolt with some blue locktite. Drilling the existing hole to accept a larger diameter bolt seems less risky than going deeper. If it was stripped without you knowing it with no leaking of trans oil it should be fine with just a longer bolt. 

The stock bolt is M6x20. I bought an M6x25 on my way home today and it hits the threads but only gets about a 1/4 turn of good bite and sticks out a few mm from going all the way in.

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22 minutes ago, Jackace said:

The stock bolt is M6x20. I bought an M6x25 on my way home today and it hits the threads but only gets about a 1/4 turn of good bite and sticks out a few mm from going all the way in.

If you can tighten to 25mm bolt I would shorten it to use without it bottoming. A 6mm heli coil needs the hole to be increased to a 1/4 inch I believe or 6.35mm    Should be enough case to do this. The heli coil kit should give these dimensions to be certain. 

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If you are confident in your ability Heli coil is the way to go. There is 100% enough room to go to 7mm but remember you will have to drill out the cover as well as you said earlier.

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Never used a heli coil before but I went to the store tonight and got one. I will probably try that this weekend. From what I have read I should use some red loctite on it so it doesn't come out and hopefully that should hold. Just need to make sure I get everything straight. Go slow and don't get in a hurry seems to be the key.

Edited by Jackace

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9 hours ago, Jackace said:

Never used a heli coil before but I went to the store tonight and got one. I will probably try that this weekend. From what I have read I should use some red loctite on it so it doesn't come out and hopefully that should hold. Just need to make sure I get everything straight. Go slow and don't get in a hurry seems to be the key.

Sounds like a good plan. I over think things so be careful with the red locktite, it could cause the insert to come out with the bolt when removed maybe put a drop of oil or a little grease on the bolt.  

Edited by jugnuts

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4 hours ago, jugnuts said:

Sounds like a good plan. I over think things so be careful with the red locktite, it could cause the insert to come out with the bolt when removed maybe put a drop of oil or a little grease on the bolt.  

I meant put loctite on the insert when I insert it. I won't put any loctite on the bolt.

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if you look in their is a bottom to that hole and their is the possibility of blowing that out then having that scrap floating around between the centercases waiting to destroy your motor. i like the idea of run a bottoming tap then stud and stud locker compound

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Heli coil is installed and appears to be working. I was able to tighten it up like the other bolts. We will see if oil leaks and it holds though.

 

Thanks for everyone that chimed in. I appreciate the responses.

Edited by Jackace
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