Banjo Bolt Torque

[Willie G.]

I was given a very well taken care of Kubota BX235D. This tractor has a hydraulic leak on the bucket control valve banjo bolt fitting. They use orings on the top and bottom of the fitting where the banjo bolt screws into the control valve. It's leaking where the line is welded to the fitting, not the orings. The banjo bolt has a 1" hex head and 3/4" x 14 or 16 tpi on the bolt that screws into the control valve. I would like to know if anyone can give me the torque for the banjo bolt. I read on another post on another site that used orings in the fittings were torqued to 38ft lbs, but didn't give a bolt size, any help would be appreciated. If there is an administrator on this site you can email me an answer, or point me in the direction to find the torque. I have a shop Manuel for this tractor, and can't find any information about this.

 

[Seven Gables]

I've never encountered a banjo bolt that used o rings, they've all used either copper or aluminum washers. I just snug them up good by feel and they've always remained leak free. Are you sure the orings aren't the source of your leak?

 

[RickB]

O-rings are often used to seal banjo bolts. They typically don't start leaking unless they have been disturbed somehow.
I don't know that you will find a torque spec for that application if it is not in the workshop manual for that machine. 38 ft/lbs would be adequate.

 

[TractorGuy]

See if this helps.

https://www.hoseandfittings.com/banjo-torque/

 

[BeezFun]

I'd go on Messick's parts diagram and see what they call out for that fitting.

You can tell if the bolt was designed for an o-ring by looking for a relief space machined into some part of the assembly. An o-ring should only be compressed a small percentage of it's thickness, it can't be squished like a flat washer. So there has to be a groove or some machined space for it to squeeze into to prevent over compression. On a banjo bolt that would mean there needs to be a chamfer on the top and bottom edges of the line fitting, or a groove cut under the head of the bolt, or some combination of the two. I have not seen a banjo bolt sealed with o-rings, I've only seen the type that have soft crush washers. So as @Seven Gables mentioned, it's possible someone didn't have the right washers and tried to substitute an oring.

 

[RickB]

I'd go on Messick's parts diagram and see what they call out for that fitting.

You can tell if the bolt was designed for an o-ring by looking for a relief space machined into some part of the assembly. An o-ring should only be compressed a small percentage of it's thickness, it can't be squished like a flat washer. So there has to be a groove or some machined space for it to squeeze into to prevent over compression. On a banjo bolt that would mean there needs to be a chamfer on the top and bottom edges of the line fitting, or a groove cut under the head of the bolt, or some combination of the two. I have not seen a banjo bolt sealed with o-rings, I've only seen the type that have soft crush washers. So as @Seven Gables mentioned, it's possible someone didn't have the right washers and tried to substitute an oring.

Kubota BX2350D (4WD TRACTOR W/ROPS) Parts Diagrams

Kubota Parts Catalog Lookup. Buy Kubota Parts Online & Save!

www.messicks.com

There's a bunch of banjo bolts on a BX2350 loader valve, all sealed with o-rings.

 

[Willie G.]

Kubota doesn't give a torque. Chart helped, thanks. May call messics. There are relief cuts for the Orings to seat in. All Orings we're good but will replace them anyway. Orings cheap, preventive maintenance.

 

[LD1]

You need to see if it is leaking at the o-ring or where the tube is welded.

Obviously if its leaking where the tube is welded, the o-rings wont help and just replace the tube.

 

[RickB]

You need to see if it is leaking at the o-ring or where the tube is welded.

Obviously if its leaking where the tube is welded, the o-rings wont help and just replace the tube.

But if tube replacement is necessary it is good practice to replace the o-rings as well.

 

[LD1]

But if tube replacement is necessary it is good practice to replace the o-rings as well.

Agreed.

IF it were mine, Id confirm where the leak is and do the job once.

No point in buying o-rings, replacing them...only to take it back apart because it wasnt the o-rings.

And whatever is on the other end of the tube....likely another banjo bolt that needs o-rings as well. Get it all and be done if it is the tube leaking.