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Easy way to find hyd. leaks?

Welder Dave · 2022-10-19 22:18

I have a slow leak on my 931B that isn't shooting fluid out and there are several steel lines in the area of the leak. I sprayed some degreaser and pressure washed the area and lines as best I could and then dried them with compressed air. I don't have a black light and dye so wondering if there's a simple way to pin point the leak? I've read you can put flour on the lines but thought someone who's done lots of repairs might have a simple way way to find a small leak among several steel lines. Can JIC fittings suddenly develop leaks? The leak is somewhere in the bottom of where there's 4 or 5 steel lines. It's harder to locate because all the lines were wet.

Replies26
  1. #1DB22022-10-19 22:44

    Some leaks sure can be tough to find. Can you get someone to stall out each circuit while you observe the area ? Just my 2 cents.

  2. #2Coaldust2022-10-19 22:49

    Just don’t use your hand. High pressure injection injury’s are no joke. Just a random picture from the interwebs.

  3. #3Simon C2022-10-19 23:29

    I have wrapped a Kleenex tight to the line or nut and held it on with tape. Short run and one of the Kleenexs will have oil in it. Have wrapped a sensor the same way to find oil or even antifreeze leak. That is one of my tricks. Simon C

  4. #4Welder Dave2022-10-20 00:06

    I know not to use my hand. I had thought about wrapping the lines with tape or some kind of paper. When I go out again I'll see if a line leaked while sitting. Maybe I can run it a bit and see which line is leaking. If all the lines are dry the kleenex idea sounds like a great idea.

  5. #5Cat9772022-10-20 02:12

    Spray on developer for finding cracks in steel, its like spray on baby powder. Normally used on a solvent cleaned surface, then spray dye, whip it off. Then spay the developer, it then pulls the dye out of the crack.

  6. #6Welder Dave2022-10-20 15:17

    Just the developer would probably work to show an oil leak. I've used dye penetrant before. I think I read baby powder has been used too. I've got a few good ideas I can try. It's one of those things you initially think is going to be a beeatch to figure out but then someone else gives you a simple solution of how they've solved a similar problem. Thanks for the great suggestions! I just had an idea. I'll run a kleenex under the lines when I go back out and see if one has oil on it. I think even a very slow leak should still weep a tiny bit when it's been sitting for a couple days.

  7. #7Mbar2022-10-20 19:05

    Brite dyez. I think is what it’s called. I always get it at calt when I’m getting parts. It’s not uv and can change color of fluid as dark as you want. It’s nice when you have trans and hyd running very close together

  8. #8Cat9772022-10-21 04:15

    I couldn't find it on a google search. Could you check on the name?

  9. #9Old Doug2022-10-21 08:18

    There is a guy that left the Amish i saw him and he had his hand all rapped up. I ask what happen he said he was filling for a hyd leak. He about lost his hand over the deal. I dont remember what he did before that but that was the 3th thing within a short span he had did.

  10. #10Mbar2022-10-21 09:59

    Was incorrect on my spelling of it.

  11. #11Welder Dave2022-10-21 19:42

    Found the leak. It wasn't one of the lines directly under the control valve. It was a line from there going to a bulkhead fitting for loader lift cylinders. It loaked shiney just behind the nut and sure enough was wet on the bottom. It makes sense now that I think about it. That line was black the full length from collecting dirt due to the miniscule leak. The oil ran down it and eventually dripped on the other lines under the control valve soaking the dirt underneath everything. I tightened it very slightly and used the machine for about an hour but it got wet again. I drove back to the shop and took the bulkhead fitting out. I remembered hearing/reading about sealing washers for flare fittings so called my favorite hyd. shop and they had them. I raced to get their before they closed and they had a display of the washers on the wall. They didn't notice anything wrong with the bulkhead fitting. They said maybe the nut split but it was fine. They said the washers are a 1 time deal so if it still leaks I'll have fix or repair the line. They didn't charge me for the 1 washer. They are called Flaretite seals. I'm very confident it will solve my tiny leak. The leak was at the back fitting in the pic. Flaretite Seal

  12. #1292U 34062022-10-21 19:56

    Never heard of those before. Pretty neat!

  13. #13Simon C2022-10-21 20:57

    I have a set of copper seals that are the same, made by Caterpillar . They fit over JIC fittings nicely and do a good job. They use to be in Caterpillars One Safe Source catalog. If I find mine I will post the part numbers. Simon C

  14. #14Welder Dave2022-10-22 01:01

    I remember reading that Cat had them. No idea what they're called? I called my favorite hyd. shop because if they had something would be much easier to deal with than going to Finning. They have a service counter you can just walk up to and tell them what you need. No need to go through a parts guy that has to look them up to get a part number. Not that Finning would be bad but what if the parts guy has never heard of them? The shop I go to not only knew of them, when I walked in immediately noticed the display on the wall. It's great that they pop on over the flare. I'm not sure but thought the Cat ones were just a cone shaped washer and was wondering how you hold it in place. I'm also not sure if the Cat seals have the ribs and Loctite on them. Hopefully it's not raining tomorrow and I can test it out.

  15. #15gwhammy2022-10-22 07:02

    I've never seen those but a great idea. Are they available in sets over the internet?

  16. #16Nige2022-10-22 07:05

    I found the Cat ones in the "Seals and Miscellaneous Products" section of the Hose & Coupling Guide.

  17. #17kshansen2022-10-22 08:11

    Yep those are handy little parts. Just have to wonder if who ever is doing maintenance at the quarry has any idea of what those things are in the box on the shelf in the shop!

  18. #18Simon C2022-10-22 10:23

    Thanks Nige for Showing where I got that idea from. I only have 2 0f each, but very handy if you need. Hopefully someone else can use as well. Simon C

  19. #19Coaldust2022-10-22 14:55

    Those copper seals do come in handy, occasionally. Sometimes they save the day. I need to restock my collection.

  20. #20Coaldust2022-10-22 15:01

    I see a kit on Amazon. A little pricy.

  21. #21kshansen2022-10-22 18:41

    Just out of curiosity checked on SIS about prices on a few of those seals: 6V7333-$3.22 6V7330-$4.24 6V7327-$9.02 Might be a lot of money for a thin little piece of copper, but if it fixes a leak with out needing to replace a JIC fitting or maybe a very expensive hose that would take hours to replace would be a good deal!

  22. #22Simon C2022-10-22 20:50

    I only have 2 of each size. Not a big inventory, but useful as ( kshansen ) said. What can $40.. buy now adays especially after hours. It got me out of a bind 1 time and was worth it. Simon C

  23. #2392U 34062022-10-22 21:40

    You folks run into JIC fittings leaking regularly? I can't honestly say I've ever had a JIC fitting leak on me before.

  24. #24Welder Dave2022-10-23 00:26

    The one I got is 304 stainless with some type of Loctite on it. It seems to have fixed the leak! I was looking and Flaretite has many different types of seals, 304 stainless, copper, coated, uncoated, 316 stainless for marine etc. I think they are a little pricey but sure beats having to get a new line and even worse figuring out how to get the old line out and the new line in. According to Flaretite they seal better than O-ring boss fittings. Would cost a bunch to do every connection on a machine though.

  25. #25kshansen2022-10-23 15:56

    Not often but when we did it was handy to have a quick fix. Probably only needed half a dozen of them over the years.

  26. #26Welder Dave2022-10-30 00:23

    The Flaretite washer solved 1 leak but using the loader more rather than the backhoe I'm slowly losing oil again. I noticed it was wet on the opposite side under the left side floorboard. It was getting dark fast so I didn't try to cycle the hyd's. to pin point the leak. There are 2 hoses going to the loader lift cylinder that were wet and frame of the machine had oil soaked dirt. The outer hose was wet going further down than the inner hose so I figured it must be the one with a tiny leak. The inner hose was more covered in built up oil soaked dirt. The hose looks OK but it was too dark to inspect very much. It does appear to be a non Cat hose with Cat reusable fittings. It kind of looked like the outer sleeve of the fitting slid back if that's even possible? Being tomorrow is Sunday I'll have to go Princess Auto to get a hose made. Their hose assemblies have been fine in the past and the Cat reusable fittings aren't used anymore. I'll try to clean the hose and inspect it more in the morning but if I can't see anything obvious, I'll keep it just in case the other hose is the leaking one. I think they are identical length. Just when you think you have all the leaks stopped another one shows up. It gets a little frustrating and adds up when have to replace hoses and oil everytime.