Radiator Cap on my 955H won't screw back on

[spikesantee]

Greetings,

I put a new set of hydraulic hoses on my 955H SN 60A09195 and started the unit back up, and all went well!

However, I wanted to check the water level in the radiator. I unscrewed the cap, checked the level, and then attempted to put the cap back on.

However, the threads of the cap don't engage the threads of the metal post in the radiator. It's very perplexing because the threads in the cap and the threads on the radiator post seem to be in good shape. The cap just spins and spins, the threads don't engage. It was definitely screwed on in the first place because I could feel it threaded on when I went to unscrew it.

A bolt will thread into the cap, and a corresponding nut will thread onto the radiator post. It doesn't make sense.

Does anyone have any suggestions on how to figure this out?

Thanks in advance.

 

[Nige]

Post a photo of the top side of your radiator cap please.

 

[spikesantee]

Dear Nige,

Thanks for responding. I'm on a trip right now, but when I get back, I will.

The cap has a female shaft in the middle, and the inside of the shaft is threaded so that it comes down on a threaded male bolt which is attached to the inside of the radiator.

I'll take pictures when I get home.

thanks for your help.

 

[kshansen]

Post a photo of the top side of your radiator cap please.

Yes a picture would help!

I wondering if this cap is one of the anti-vandalism caps where you pull up on a "tab" and install a padlock? Or is it like this one:

This is what I see on SIS for that machine.

Did you or someone have the cap apart?

 

[sawmilleng]

Take a tap and run it into the female side. Take a die and run it down the threaded stud. You'll find the dingleberry on the thread that is gumming up the works.

Jon.

 

[Nige]

I wondering if this cap is one of the anti-vandalism caps where you pull up on a "tab" and install a padlock?

Our minds work the same way.........

 

[spikesantee]

Hi Friends,

Sorry, this took a while, I was on a business trip.

I went to the hardware store to find a bolt that matches the threads on the radiator cap.



It is a 1/2 - 13.

I got a corresponding nut to try on the 955H stud part #2M9033. It is way too big for the stud.



It is way too loose. The nut will thread on the stud but loosely. The radiator cap just spins on the nut, it doesn't catch a thread at all.

It really seems like the stud and the cap are different sizes but when I went to check the water level this time, it unscrewed, but wouldn't screw back on.

I don't have all of the parts listed in the part diagram above, I just have the cap, a washer and a retainer.



Does the stud unscrew from the internal part of the radiator so i can replace it with the part listed in the diagram?

Any insight is appreciated.

Thanks.

 

[Nige]

Corrosion has f**ked the stud in the radiator.......

Does the stud unscrew from the internal part of the radiator so i can replace it with the part listed in the diagram?

Yes the 2M9033 Stud is a separate part. The big challenge will be removing the old one out without breaking it. In Cat terminology it is a taperlock stud which in this means that the deeper it is screwed into the threaded hole in the radiator tank the tighter it grips. It's been in there for maybe 60 years.....

To add insult to injury it has been discontinued which means that the measurements can no longer be accessed. I'm sure that there will be something available aftermarket though.

 

[spikesantee]

So the stud is a part of the "assembly." Is the assembly discontinued or just the stud? I wonder if I could use something like JB Weld to fill in the threads and then tap it to size?

 

[Nige]

So the stud is a part of the "assembly." Is the assembly discontinued or just the stud?

The stud is available separately to the assembly under P/N 2M9033 which has been discontinued by Cat but appears to be available via aftermarket suppliers. https://offroadeq.com/parts-search/2M9033/
TBH it wouldn't be that hard to make one from a 1/2"-13TPI bolt with the head cut off.

I wonder if I could use something like JB Weld to fill in the threads and then tap it to size?

I wouldn't recommend it. What happens if a piece of JB Weld breaks off and gets stuck in a critical coolins system part.?

 

[spikesantee]

When I was feeling around the base I couldn't feel anything like a hex for a wrench to grab on too. Would a socket wrench be the tool?

The stud is available separately to the assembly under P/N 2M9033 which has been discontinued by Cat but appears to be available via aftermarket suppliers. https://offroadeq.com/parts-search/2M9033/
TBH it wouldn't be that hard to make one from a 1/2"-13TPI bolt with the head cut off.

I wouldn't recommend it. What happens if a piece of JB Weld breaks off and gets stuck in a critical coolins system part.?

Ha! My JB Weld idea is my amateur suggestion. Thanks for setting me straight.

I was sitting on the loader drinking some coffee this morning and I had the same idea of putting a bolt in there too. Thanks for the suggestion. I'm going to drain out some fluid so the stud can dry out, then try and put some rust penetrator on it and let it soak while I look for a part or a bolt.

I appreciate you guys for looking at my post and giving me some suggestions. It's crazy how this little part is keeping me from using the loader.

 

[spikesantee]

Ha!

Looks like someone already tried to fix this stud. I drained some fluid out of the radiator so I could see it better and it looks like someone put a bolt in there and welded it on.




One thing leads to another doesn't it? Now I need to figure out how I'm going to cut that piece out.

I think a carbide blade for my oscilating tool might do the trick, cut at it from different angles to get rid of the welding material and then extract the bolt with an extrator tool.

On a side note, I was so bummed out because I couldn't find my 1/2 tap, I looked everywhere for it. It was sitting on the loader where I left it. So, that's one bright spot about this project. I didn't lose my tap after all.

Any ideas?

Thanks again for the attention. It makes this journey more enjoyable.

 

[kshansen]

IF you do manage to get that stud out and can see good threads for a new stud I might be tempted to see about finding a stainless steel bolt to cut off to replace it.

Also not sure if parts are available to rebuild your cap or if buying a new after market one would be better. And while your at it I would polish up the sealing surface for the cap. Might as well get the system to hold pressure for better cooling.

Just in case you don't know the pressure cap is under that round cover next to the large cap you have off. There are, if they still sell them, parts under it that you can replace to rebuild it. If you need part numbers let me know.

 

[Nige]

Just in case you don't know the pressure cap is under that round cover next to the large cap you have off.

You mean pressure relief valve I think.

 

[spikesantee]

Update Pictures

I was able to clean up the old stud today.







I ordered the whole radiator cap kit, not just the stud, to make it all good when I'm done.

I'm going to wait until the kit arrives before I rethread the opening to make sure I use the right tap.

Thanks for the guidance.

 

[Nige]

The surface where the rubber seal of the radiator cap seats is going to need a fair bit of smoothing to get the cap to seal correctly.

 

[spikesantee]

The surface where the rubber seal of the radiator cap seats is going to need a fair bit of smoothing to get the cap to seal correctly.

View attachment 313468

Thanks for the advice! I'll tackle that today. It's going to take a day or two for the kit to arrive.

 

[spikesantee]

Here comes the dumb question of the day. I have never tapped a hole for a bolt before. If I have a 1/2 bolt, how big of a hole do I drill, 1/2 inch? It seems like I should drill it slightly smaller so there is material left for the threads. Can you give me some advice?

 

[Nige]

Google "tapping drill sizes". The required hole for a 1/2" - 13TPI UNC thread will certainly be less than 1/2".
My table says 10.8mm.

 

[Bumpsteer]

27/64 on this side of the pond

Ed