Hello I have a Cat 950H that is leaking oil through a plug at the top of engine . The ORING was bad as you can see in the picture however I changed the ORING and possibly used either the wrong ORING or I pinched it or the temperature is not compatible with the black ORING I used . Any help would be appreciated much
How about a photo showing the plug actually installed in the engine so we can see where it’s supposed to fit.? Also the Serial Number of the loader would help. Lots of different 950H’s out there.
Nige I will send you a video clip that I have on it however I need your email . I cannot send a video only photo on the site . I will tear it apart on Monday and I will post the serial number and the location . If you want to send me a email so your not posting yours on the site mine is [email protected] Thanks Nige
Serial number
Looks like that oring is too thick to me. It’s getting cut when you install it.
Is this a high pressure oil rail plug?
Take a screen shot from the video where the offending article appears and post it up here..?
That is the high pressure oil rail plug, one at the front of the head and one at the rear. I am not where I could look it up for cat p# but I believe it is a standard boss oring that should be in any hydraulic oring kit.
Parts and service , you are correct, yes one at the front and one at the rear of the head . The ORING in the picture is the old ring and I installed a black one from my kit . I got about 8 hours before she blew out again . Makes a hell of a mess of the engine when it leaks . I will post more once I tear the plug out again . Thanks guys
I believe that is a special o-ring and that plug is installed with thread locker, check your service manual. Bob
Not sure what program or computer you are working with but on my Desktop running Windows 10 all I have to do is watch a video and when I see something I want to grab a picture of hit the "Print Screen" button. Then open the standard "Paint" program and when that is open hit the "Paste" option up ant top. Then it is a simple thing to crop to what detail you want to save and save it to desktop or where ever you like and use that to post here. Just for a quick example I opened a video of a Cat dozer and did just that and cropped to just the dozer. Simple as that! If you want to get fancy you could use Paint to draw an arrow to point to the offending plug!
That all said I'm thinking this is the plug and oring you are dealing with: Seal number 238-5084
Thank you Ken . Thank all of you guys .
When we got the machine it never came with a service manual or a parts book . I should have used a loctite on the threads it may have even lossend off ! Thanks for all the notes guys
Green color of the ring probably indicates it is HNBR. Looks like an ORB plug, which supposed to be 900 series sizes, which does not share the size with anything else in AS568. So either order by CAT part number, or select the right size by measuring plugs thread and looking up in AS568 900 series size chart, for contact with air and other aggressive compounds, NBR ( or Buna N) will not last long, HNBR ( mostly green, sometimes brown or dark red in color), or even more resistant material have to be used
Those green seals are high-temperature FKM (flouro-elastomer) material that are designed to resist higher temperatures than a normal seal. If you get a genuine Cat one you may find that it comes with a blue coating on it. This is a lubricant to assist with seal assembly and prevent tearing the seal. Don't remove it. The 238-5084 seal is an FKM replacement for standard black 7M-8485 90 Duro nitrile seal. As above, I'd recommend you get a genuine Cat seal for this application. Use Loctite if you feel the need for an additional level of security against loosening.
Well I just ordered the both the plug and the seal from Caterpillar . 12.50$ for the seal and 12.75$ for the plug . I feel might as well replace the plug as well for that price . 26$ is a hell of a lot cheaper than a engine
I had this exact problem on a 7.3 Powerstroke recently. After 200,xxx miles the o-ring gave up. No problem right, we put a new one in. Made it about 3 days and looked like yours, all shredded. The answer on that was to go to Ford, $12 gets you both a plug and the strangest o-ring seal you ever have seen. Greenish blue and cross section looks like a flying saucer. Anything that strange must mean they had problems with the original design. The parts guy said the original plugs were different or something like that. Anyway I agree going to Cat and getting the current plug and o-ring is the best bet.
Nige . You were correct ! There is a blue coating on this seal . I can feel it while carefully handling . I will start on the removal and install hopefully tomorrow.
Here is a picture of the plug currently in. If you zoom in you can see the split ORING
Question / advice . When I install Should I use a high flex gasket maker or Blue loctite or the Red loctite ?
The one for the Ford Powerstroke came with a blue color ring that same color. The blue had smeared all over everything in the box a little bit. I did not realize it was a coating, I thought it was the color of the ring.
I wouldn't use gasket maker personally. There is no mention anywhere of using thread lock on that plug, even in the specifications. I did find the torque spec for it though - 146 ± 14 lb ft - aka ***kin tight.......!!
Thank you Nige . Not much room in there and to getting a torque wrench in there . The first time I removed it ... yes ******g tight .
I mentioned the torque figure for no other reason that it’s unusual for an o-ring plug to be tightened that hard.
I would tend to go with German torque "Guten Tight"
Use the blue loc tite on the first 3 threads. Bob
Thank you Nige Ken and Bob .
Guten Morgen . Well she’s running good . Thank you all for the help , advice , friendships and discussions . Sincerely Cameron Swan River , Canada