Does anyone know off hand what the thread type/size of the Power Beyond and tank ports on the front hydraulic block? Thanks.
Thread/size used in L series front hydraulic block
- Thread starter domigold
- Start date
Hi, I just got a new L2501 this year. I installed my own 3rd function valve from summit and dealt with the hose for that between the loader valve fittings under the step on the left where the filter is? I believe I found them to be JIC 8 as it is often the corresponding number stamped on the nut so check for that too.
I'm not sure, are you asking about hose size? The hose On mine I think is 3/8. One of the hoses i have laying around after has JIC6 on one end and JIC8 on the other end and it is 3/8 hose. So you can get different size on the same hose. Any help at all or clear as mud?
I guess in clearing what i am referring to is the size of the JIC style fittings on the block by the filter, the part that looks like a common flare fitting.
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
On my new L3901 the PORTS appear to be 3/8 NPT. The loader hoses have JIC-8 female swivels on the ends and NPT to JIC port adapters are used to make the port to hose connections.
Dan
Attachments
![20210530_112357[1].jpg](/forums/data/attachments/60/60733-59a23f8eaaffa457211e9a2cef1d0a3a.jpg)
Last edited:
Interesting. My buddy thought that his L3301 port was NPT and found out that it's actual JIC. Did you actually open and inspect it?
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Forty plus years in the engineering world have taught me to be careful with my words. Notice I said "appears to be NPT". I have not taken one apart to check but I have never seen a JIC port and the male threads are wrapped in PTFE thread tape. Unless the dealer mechanic that installed this loader is a total numb nuts that rules out BSPP, and SAE ORB leaving BSP or NPT.[*]Using a caliper I measured the root diameter of the male threads at the top of the block and get .625 which is consistent with NPT. The block is spot faced at all four port locations which started my Spidey Sense tingling when when I first looked at the connections. I can not rule out the possibility the block is (or perhaps I should say was) BSPP (BSPP ports are used extensively in Asia and Europe) and the dealer mechanic installed an NPT fitting rather then the proper BSPP fitting with sealing washer. Seems unlikely since I expect the fittings come with the loader package. So since you ask I did the obvious and looked at the online parts listing for the LA520 loader package. I found:
040 75594-63680 - Adapter (NPTF)
050 75540-64190 - Elbow #190-08-06
So based on that it seems very likely the ports are 3/8 NPTF (06) and the hose ends are JIC female swivels (08)
Dan
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Thank you.
Thank you for the clear diagram. The ports on the block are NTPF but the hoses are JIC and they just use adapters between them.
Yup, and by their (NPTF) design, any time you’re taking NPTF connections apart, you may as well plan to be changing both that block and the adapter fitting since once those are separated, the threads aren’t likely to ever make good seal a second time.
whitetiger
Moderator
Staff member
Equipment
Kubota tech..BX2370, RCK60, B7100HST, RTV900 w plow, Ford 1100 FWA
Why on earth would you think that????????????? You just put some thread sealant on the fitting, tighten it to the prescribed torque. I have done it hundreds of times and do not recall ever having a leak at the threads.
when I see the seal takes place by ‘deformation of the threads’, that kinda speaks to an old service guy (35 years) such as myself that worked on instrumentation that went as high in (liquid) pressure as 28,000 psi and as low in vacuum as 2x10-7 torr.
To each his own...
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Precisely. Pardon me for preaching to the choir but i will add this.
Not only does the seal deteriorate every time you remake the connection it gets tougher, even impossible, to properly clock that elbow. The make-up distance on NPT(F) joints is a carefully engineered distance that cannot be maintained across repeated assemblies.
The NPTF thread form also has both root and flank interferences and is designed to seal without the use of sealant. Those sealing surfaces will not survive repeated makeups and will get sloppier every time the joint is reassembled.
Soft materials like aluminum make the problem worse.
Dont throw your block away. Send it to me and I will recut the ports for SAE 8 adapters like they should have been to begin with.
Dan
Attachments
In theory you guys are likely correct. Granted, any NTP of NTPF joint if separated and reconnected many times will reach a point where it does not function correctly anymore. But I do not think in this case we are discussing such a situation.
So in the real world I will go with whitetiger's experience...
Ah, the age-old question as to “...why does a dog lick his balls?... “. (And just because he can, doesn’t mean he should).
Since I work for myself on my own tractor, I can take the time to do it slowly and meticulously, unlike the poor tech at the dealership whose boss gives him the stink-eye if he wants to replace a $2 fitting or use proper thread sealant (that costs more) than PTFE tape. Yes, it will work, but I refer you back to the dog and his hobby.
Whitetiger is clearly an experienced tech, but the shortcuts taken by some other techs working for the dealer aren’t likely the same ones they would take when working on their own tractor.
I keep hearing about Kubota and how they’re cracking down on warranty but yet I keep seeing pictures of people’s hydraulic blocks, cylinders and other NPTF fittings just slathered in PTFE tape (I refer you again, back to the dog).
That’s the point at which I decided I myself would add my three rear remote valves.
Let’s just leave it at ‘stylistic differences’ and move on.
Since I work for myself on my own tractor, I can take the time to do it slowly and meticulously, unlike the poor tech at the dealership whose boss gives him the stink-eye if he wants to replace a $2 fitting or use proper thread sealant (that costs more) than PTFE tape. Yes, it will work, but I refer you back to the dog and his hobby.
Whitetiger is clearly an experienced tech, but the shortcuts taken by some other techs working for the dealer aren’t likely the same ones they would take when working on their own tractor.
I keep hearing about Kubota and how they’re cracking down on warranty but yet I keep seeing pictures of people’s hydraulic blocks, cylinders and other NPTF fittings just slathered in PTFE tape (I refer you again, back to the dog).
That’s the point at which I decided I myself would add my three rear remote valves.
Let’s just leave it at ‘stylistic differences’ and move on.
TheOldHokie
Well-known member
Lifetime Member
Equipment
L3901/LA525, B7200DT/B1630, G2160/RCK60, G2460/RCK60
Not theory - real world experience. NPTF fittings suck for hydraulic connections and I avoid them like the plague. Female pipe swivels are a pig of an entirely different grunt since they do not seal by deformation of a taper thread.In theory you guys are likely correct. Granted, any NTP of NTPF joint if separated and reconnected many times will reach a point where it does not function correctly anymore. But I do not think in this case we are discussing such a situation.
So in the real world I will go with whitetiger's experience...
That said unless whoever installed them over tightened them to the point of burying the thread up to the hex the straight adapters should go back in without issues. The elbow may be more problematic. You will need to go a full turn deeper to get it properly clocked and tight. Real world experience says that depending on the random position of the thread starts in the mating parts you may find that requires some serious over tightening. But of course the third time will be easier and a replacement block is only $21.
Dan
I think that was the point I was trying to make...no doubt if you can replace something much better if there is any question. Sometimes not easily done...That said unless whoever installed them over tightened them to the point of burying the thread up to the hex the straight adapters should go back in without issues.
Dan