hydraulic filter leaking

[mfruhbeis]

Seems like I can attempt to do this. I noticed that the kubota brand filter I have only has about a 1/2" of thread and the nipple has about 1 1/2". Are there other brands of oil filters that have more thread that would help grip more surface in the nipple?

 

[200mph]

For what it is worth, I looked at Kubota's parts drawings to confirm the threaded nipple is part of the transmission case. No individual part is called out for the threaded nipple. I hope the threads can be repaired!!!

Using wix filters as reference:
Thread Size: 20X1.5 MM

I wish the OP luck in fixing this by simply chasing the threads, but I'm very concerned this may not be so simple of a fix.

Just to brainstorm other ideas in the event plan B or C is needed.
I didn't look at the details to see if it would work dimensionally, but if this doesn't work I'd consider a thread adapter (likely custom piece) with 20x1.5mm threads on inside and 3/4-10 (or other) on the OD. It would require a nonstock filter, but one could be found that works using Wix filter (or other) website.

 

[Jim L.]

Maybe build up the damaged thread by brazing. Kind of worry about that because of oil in that area. Then use die to recondition.

Or, attach a build-up ring on outside diameter. Then can add more nipple using a coupling. Assumes enough room for removing/replacing filters.

Just guesses.

 

[North Idaho Wolfman]

Just out of curiosity, considering the nipple looks like it's not a replaceable part, how would one (or a shop) fix something like this if the threads are beyond rescuing? Cut it off flush then weld on a new nipple I'm guessing?

You replace the case
P/N HK250-1110 ~$ 910.00

 

[North Idaho Wolfman]

Maybe build up the damaged thread by brazing. Kind of worry about that because of oil in that area. Then use die to recondition.

Or, attach a build-up ring on outside diameter. Then can add more nipple using a coupling. Assumes enough room for removing/replacing filters.

Just guesses.

Aluminum case, your going to do some damage putting any heat to it.

 

[100 td]

I've own and use metric die nuts, a word of caution, mine generally cut/clean a little deeper than standard pressed threads. Different brands may also cut different depths, since your spigot is already galled, in preference I would buy an adjustable thread tap to carefully clean your existing threads without cutting any deeper if possible, of course that also depends on what damage and burrs there are to be removed. The galling may have happened from thread deformation due to a filter being over tightened, very easily done on aluminum spigots. Filter finishing in my opinion is very poor these days, swarf/burrs being left on the threads, and malformed threads seeming to be a common occurrence and may have also caused the initial galling. Thoroughly inspect your filter threads before using. A couple of other options for longer term repair, use of epoxy thread building materials and release agents, cleanliness is essential, multiple washing with acetone/other cleaning fluids to remove any traces of oil impregnated in the spigot is essential. As previously mentioned, the installation of a threaded bush, loctited to the existing spigot and selection of a suitable filter to replace the original, or the installation of a remote filter housing adapter, or filter spacer, locked in place, so that you are not utilizing the damaged spigot when changing filters anymore. Good Luck
EDIT: Forgot to mention the possibility of aluminum solder/weld rod to build the thread up then re-cut it, fairly low temp repair I believe. You would have to research.

 

[Jim L.]

For $910 plus labor, permit me to try another guess.

Take an adapter for engine mounted filter to remote mount base. The nipple now doesn't hold tight. Either add to threads with adhesive, or bolt the adapter to the case at the outside circumference. Very cobbled together fix, if do-able, maybe less $ than original equipment. Maybe lots of adjustments to make it work.

Edit: Oh, see that 100 td was thinking close to this line before I posted.

 

[North Idaho Wolfman]

For $910 plus labor, permit me to try another guess.

Take an adapter for engine mounted filter to remote mount base. The nipple now doesn't hold tight. Either add to threads with adhesive, or bolt the adapter to the case at the outside circumference. Very cobbled together fix, if do-able, maybe less $ than original equipment. Maybe lots of adjustments to make it work.

Edit: Oh, see that 100 td was thinking close to this line before I posted.

We have kubota's not (pick you own off brand junk), cobbling it up is a lousy suggestion, I think we can offer better advice!

 

[100 td]

We have kubota's not (pick you own off brand junk), cobbling it up is a lousy suggestion, I think we can offer better advice!

I don't think repairing or modifying is a lousy suggestion, and I don't believe replacing the front transmission cover is better advice if a reasonable and cost effective repair can be achieved.

 

[William1]

If... the filter threads on with enough threads to hold it solid well before it contacts the housing, a disk of aluminum (think massive thick washer) could be cut and have a recess for a oil filter gasket. This would space the filter out 1/4"-1/2"and have it sit on solid threads.

 

[Russell King]

I would suggest you fix it in steps

1 chase threads see if that resolves problem

2 use a locktite thread repair kit using a nut or old filter as the thread form you will require. May need to cut filter down to the base and clean it like crazy or just sacrifice a new filter

3 get a machine shop to look at it and see if they can replace the nipple somehow. This may require the removal of that case/housing

4 glue a filter on and use it for the hours allowed

5 replace the housing




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[RWey56]

I wouldn't be opposed to trying a fix if the alternative is $900 + time and labor to replace it.

Just for discussion: If this were mine and the threads were unrecoverable, I'd consider cutting off and drilling out the existing nipple (if space allows), machine another nipple with a step that press fits into the hole ( easy for my to say, I have a lathe ), and then TIG it into place ... assuming its an alloy that will accept welding. Changing the tempering in that area would affect what? I doubt it's a point of stress other than holding the filter on. What would you have to lose?

Admittedly, the above is just my arm chair musings and reality is a different case, but I'd sure try to exhaust all possibilities before replacing the whole ca$e.

 

[RWey56]

If... the filter threads on with enough threads to hold it solid well before it contacts the housing, a disk of aluminum (think massive thick washer) could be cut and have a recess for a oil filter gasket. This would space the filter out 1/4"-1/2"and have it sit on solid threads.

A collar to move the filter out to good threads. That's a very clever solution and at least worth consideration IMO.

 

[100 td]

If it will fit.............
https://www.circuit-sports.com/products/oil-filter-sandwich-adapter-m20-fitting

 

[Jim L.]

So the key words are oil filter sandwich adapter. Normally used to add oil instrumentation such as oil temperature. Clever.

Now to see if there is room for it.

And the right adapter for this particular filter fitting.

 

[Ramos]

If an adaptor of the right diameter can be found, it would be a simple job for a machine shop to mill it to the needed thickness. only one side needs to have an o-ring. Still, I would get the threads cleaned up and just try a filter as my first move.

 

[mfruhbeis]

The oil filter sandwich adapter is an interesting idea. I did some research and it may work. I will try cleaning the threads up first and if that does not work, I see if the oil filter sandwich adapter option will work. I don't want to spend a grand for new case.

How does the locktite thread repair kit option work? Are you applying the "putty", then put a nut or filter on the threads so it forms new threads, then let it dry?

 

[100 td]

I've only used Devcon and loctite on internal thread repairs when I haven't had a suitable helicoil, worth doing a bit of research on what would be best in this situation. Release agent would be applied to a suitable nut. The only problem with this type of repair is the displaced product, it will be pushed out behind the nut and may need to be removed with a dremel/carbide burr or similar. If you can fit(& find a suitable) adapter, personally I would try cleaning up the existing thread and loctiting (or similar) the threaded adapter in place, as there appears to be enough existing thread area to get a suitable bond. YMMV

 

[Thorny]

Could you build the threads up with weld, and then cut them back down to size with a die? Seems a lot simpler than sourcing new adapters.

 

[North Idaho Wolfman]

How does the locktite thread repair kit option work? Are you applying the "putty", then put a nut or filter on the threads so it forms new threads, then let it dry?

Yes that's the concept.
One word of major caution to any repair like that, if one piece of material comes off that is not caught by the filter and you will destroy your HST, then you won't only be buying a $900 case cover you'll also be buying a 5K HST unit!