cracked oil pressure switch port

[PaulC 342]

Hey guys I have a kt17 on a 417-A that I noticed the oil pressure switch was leaking. Unfortunately when I got the new switch and installed it I ended up over tightening the switch and fitting and putting a small crack down the side of the port on the engine block! its got such a small amount of material around the port that im surprised kohler didn't have issues of cracking them when tapping them at the factory, or at least that's what im telling myself to make me feel better about my stupidity. Either way im looking for opinions on the best and easiest way to fix this. I have the ability and access to equipment to tig weld or braze it and have also had someone suggest to 5 minute epoxy/JB weld it. I have the tins off so I can access the area pretty good so I think I can get in there with whatever I need without removing the engine. Im thinking I can even do this without draining the oil but im wondering if the oil will try to wick into the crack when I add the heat.

Epoxy would be an easy try but I don't expect it would have great success and then it would complicate the next attempt and repair.

Tig welding I think is a good option because I just need to repair the crack not hold 2 pieces that require great strength together. Do I need to "V" it out? and I would plan to just use stainless filler

Brazing is also a good option I have thinner wire here with a flux coating on the outside. I worry about having less control of the "flow" with this method though. Would I need to "V" it out for this method? I also had the idea with this approach to braze the small fitting right into the port so then the fitting becomes part of the engine but I don't know if its necessary and if im asking for more trouble by doing so?

Please give me suggestions on which way you think I should go and especially if you have attempted a repair like this before. Thanks Paul

[mikekot3 93]

When welding aluminum cleaning the area is very important. Take the engine apart prior to welding. Drill the end of the cracks to prevent further cracking and v-out the crack area. Depending on the material the metal may need to be preheated also.
 

[slammer302 2,156]

the JB water weld seems to work very well 

[PaulC 342]

When welding aluminum cleaning the area is very important. Take the engine apart prior to welding. Drill the end of the cracks to prevent further cracking and v-out the crack area. Depending on the material the metal may need to be preheated also.
 

Mike this is a cast iron block. Im hoping to not even remove the motor from the machine let alone completely disassemble it. This is not any sort of stress crack on anything structural so further cracking should not be an issue. I cracked it by over tightening the 1/16" NPT fitting.

the JB water weld seems to work very well 

JB water weld? ive never heard of water weld. Are you suggesting that would be a good fix for this?

[slammer302 2,156]

its worth a try! Another member turned me on to it and i was very surprised on how well it works  

[pfrederi 18,452]

When welding aluminum cleaning the area is very important. Take the engine apart prior to welding. Drill the end of the cracks to prevent further cracking and v-out the crack area. Depending on the material the metal may need to be preheated also.
 

Mike this is a cast iron block. Im hoping to not even remove the motor from the machine let alone completely disassemble it. This is not any sort of stress crack on anything structural so further cracking should not be an issue. I cracked it by over tightening the 1/16" NPT fitting.

the JB water weld seems to work very well 

JB water weld? ive never heard of water weld. Are you suggesting that would be a good fix for this?

When welding aluminum cleaning the area is very important. Take the engine apart prior to welding. Drill the end of the cracks to prevent further cracking and v-out the crack area. Depending on the material the metal may need to be preheated also.

KT 17s do NOT have cast iron blocks( crankcases)  The are Aluminum alloy of some type. 

[PaulC 342]

KT 17s do NOT have cast iron blocks( crankcases)  The are Aluminum alloy of some type. 

Really?! I never even considered it would be anything but cast iron, I thought all the older kohlers were. That would have been interesting firing up the tig welder on DC- trying to use stainless filler  Im glad I asked here. I have done some research on JB welding and am thinking of giving that a try. Now im wondering how it would tig weld considering its aluminum  
 

When welding aluminum cleaning the area is very important. Take the engine apart prior to welding. Drill the end of the cracks to prevent further cracking and v-out the crack area. Depending on the material the metal may need to be preheated also.
 

Mike sorry I replied to your post saying it wasn't aluminum

[PaulC 342]

Well the JB weld route worked!! Last Wednesday before leaving for an out of town wedding I grooved the crack with a small cutoff wheel, cleaned it with brake kleen, and put the JB weld on it. I put a piece of masking tape over it and let it sit for the weekend while I was away. After removing the tape and cleaning a few sharp edges that formed I reinstalled the switch and you can hardly even tell anything was done. I used the tractor for about 2 hours yesterday mowing and dragging my sweeper and did not lose a drop of oil. I was a bit skeptical but as of now I am very pleased and if it holds up long term this will turn out to be the best fix. It was really easy only took me about a half hour without removing a drop of oil or anything else(I do already have the tins off since they have been for a few weeks now since dealing with this issue) and like I said its hardly noticeable that a repair was done.

[mikekot3 93]

Glad it worked out for you. I gave you worst case scenario without being there to help you.