Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!

JoeVR

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  • / Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!
Hello, everybody,

New member - first time poster. I have a Simplicity Cobalt 27hp 61" zero turn mower. I love it. It has been good to me for many years now.

It threw a belt yesterday, and I realized that this was caused by hydraulic fluid dripping down from the reservoir (part #5061712sm) -- a $100 part!

It looks like the plastic hydraulic fluid reservoir behind the seat got so hot that it sort of warped the grommet at the bottom where the lower hose comes out, and it leaked out much of the fluid onto the deck, getting onto the belt, which caused the thing to fly off.

I was wondering if this reservoir might be repairable -- what would have caused this? (other than the heat, obviously)

The fluid is very hot, I did a filter and fluid change at the beginning of the season (used universal premium hydraulic fluid from Farm & Home). Could this have caused the reservoir to overheat and warp at the bottom?

Is it possible for me to remove the reservoir and press a new grommet into the hole? Has anyone experienced the plastic fluid reservoir on these simplicity zero turn mowers leaking from the grommet on the bottom?

Any help or direction would be greatly appreciated. If need be, I can order another reservoir, but I would like to avoid spending the $100 unless I totally have to.

Thank you all,

Joe
 

BlazNT

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  • / Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!
You put the wrong fluid in it. Per your manual, you should have Mobil 1™, 15W-50synthetic oil or Castrol Syntec™ 5W-50 oil. It does not use hydraulic oil. I an assuming this is what caused the overheating and melting of your reservoir.
 

JoeVR

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  • / Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!
Thank you! Wow . . . I only had about 6-8 hours on the new fluid and filter change. I'll drain everything and change it out.

I guess there probably isn't much hope in trying to fix the current reservoir . . . I'll clean it off really good and try some black RTV to see if it will hold at the bottom

But in either case, I will do a full fluid change.

Can I put in any 5w-50 synthetic blend motor oil?

Or any 15w-50 full synthetic motor oil?

I was looking at this:

https://www.amazon.com/Motul-Synthe...ie=UTF8&qid=1496906732&sr=1-2&keywords=15w-50

I'm not sure how much oil it takes, but at $18 per quart for the Mobil 1, I'd love to see if there is another option that won't kill my motor.

Thank you!
 

BlazNT

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  • / Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!
It says full synthetic. I would not use blend. Yes any brand make or model full synthetic will work. I purchased Valavine full synthetic 20w 50 at Oreillys for about the same price.
 

reynoldston

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  • / Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!
Seals-all is the only thing I have had any luck with fluid repairs. The repair spot needs to be clean and dry. You can buy it in most auto parts or hardware stores.
 

JoeVR

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  • / Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!
Ok guys,

Thank you all for the help. Here's what I did:

I removed the reservoir and emptied out all the oil.

Cleaned up the bottom of the tank and used a heat gun to warm the plastic up. I very gently rolled it flat again as best I could. The grommet seemed to seat properly, but just to make sure, I cleaned the surfaces with alcohol and used black RTV gasket maker to seal it in. I think that once it dries, it should be good to go!

As for the hydraulic fluid . . . I tried to drain it all out. Blew out the lines and drained the filter completely.

I'm going to put Mobil 1 15w-50 full synthetic in after it's all put back together.
 

JoeVR

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  • / Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!
Thanks, everybody.

You were correct. I bought some Mobil 1 15w-50 Full Synthetic, drained the system as best I could, blew the lines out as best I could, and then filled it up again with the correct oil. The newly repaired reservoir seems to be holding up just fine.

It runs great now. No overheating of the reservoir. No warping. Score!

Should I try to change the fluid out again to make sure I get out all the hydraulic fluid, or am I ok?

Thank you all!
 

BlazNT

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  • / Simplicity Cobalt 27hp - Fluid reservoir leaking? Help!
My personal thought on this is you did all the damage with the hydraulic oil. Now that it is changed I think the little you have in there will be fine.
 
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