Replacing hoses?

[chesterspal]

I want to replace some, if not all, of the twelve hydraulic hoses on my M371. They are all standard 18" (3/8" female JIC x male NPT) flex hoses that can be had for around $22 each. The ones on there now appear to be the originals judging from the old, frayed braiding. At least one has a leak due to a cracked hose fitting.

My question has to do with the replacement process.

1) Can I expect to get air into the system and what is the best way to purge it?

2) Best to replace a bunch of them at the same time or will this make the air purging more difficult?

3) Should I use Teflon tape or some kind of goop on the treads?

Thanks!

 

[FJRDarksider]

Based on the looks of those and your report of a leak, I would replace them all. Yes there will be air in the system but it will self purge once you start it and ensure the fluid level is topped up. When I did several hoses and filter change on my 853, I topped the reservoir up, ran it for about 15 seconds. Topped it up again and then slowly operated the hydraulics to purge remaining air, then re-check the level. I always pre-fill the filters before screwing them in.

The fittings don't need Teflon tape or goop, the seal is achieved at the flares inside the fitting. If they leak, then they have either been over tightened too many times and the NPT has stretched, or there is a deformity or damage to the male or female flare (or both). Should be fine with new hoses.

 

[chesterspal]

Based on the looks of those and your report of a leak, I would replace them all. Yes there will be air in the system but it will self purge once you start it and ensure the fluid level is topped up. When I did several hoses and filter change on my 853, I topped the reservoir up, ran it for about 15 seconds. Topped it up again and then slowly operated the hydraulics to purge remaining air, then re-check the level. I always pre-fill the filters before screwing them in.

The fittings don't need Teflon tape or goop, the seal is achieved at the flares inside the fitting. If they leak, then they have either been over tightened too many times and the NPT has stretched, or there is a deformity or damage to the male or female flare (or both). Should be fine with new hoses.

Much obliged for your help.

Question: Is fuid running through the arm and bucket hoses all the time (perhaps at a reduced rate) or only when you activate something?

I ask because I saw a video with the engine running and the NPT's loosened up (to bleed them) and they were leaking both air and fluid... however, the bucket was down.

 

[chesterspal]

Can anyone identify the fittings used on my M371 skid steer? Appears I did not order the hoses with the correct fittings at least on one end.

The threads are 9/16" at the widest point and it appears the two ends will make with each other.

All the hoses are the same length at 18" long and all with these male and female fitings.

Either they are JIC or NPT but not both on the same hose.

Thanks!

 

[Phil314]

Can anyone identify the fittings used on my M371 skid steer? Appears I did not order the hoses with the correct fittings at least on one end.

The threads are 9/16" at the widest point and it appears the two ends will make with each other.

All the hoses are the same length at 18" long and all with these male and female fitings.

Either they are JIC or NPT but not both on the same hose.

View attachment 4653

View attachment 4654

Thanks!

Those hoses would be 3/8 (-6) JIC fittings.

Also don't use PTFE tape on hydraulic. You don't want the tape threads getting into the hydraulic system and getting stuck in valves and such.
Use paste if needed only on NPT threads. JIC doesn't need anything, it's a compression seal.

 

[chesterspal]

Really appreciate your taking the time to clarify this. Now I can re-order the correct hoses.

Thanks

 

[chesterspal]

After calling around to locate a supplier that could make up a dozen replacement hydraulic hoses for me, I found a small local outfit that did a great job at a very reasonable price. All they do is make up hoses so they must know what they're doing.

I had quotes as high as $60 each for an 18" long hose with 3/8" male and female JIC fittings.

The firm I bought them from charged $12 each.

Just a suggestion to others to call around.

 

[BoBoV8]

Based on the looks of those and your report of a leak, I would replace them all. Yes there will be air in the system but it will self purge once you start it and ensure the fluid level is topped up. When I did several hoses and filter change on my 853, I topped the reservoir up, ran it for about 15 seconds. Topped it up again and then slowly operated the hydraulics to purge remaining air, then re-check the level. I always pre-fill the filters before screwing them in.

The fittings don't need Teflon tape or goop, the seal is achieved at the flares inside the fitting. If they leak, then they have either been over tightened too many times and the NPT has stretched, or there is a deformity or damage to the male or female flare (or both). Should be fine with new hoses.

Hello, do you know if an old (revolving 1980s) bobcat (Clark) 632 also has a self bleeding hydraulic system? I also had the pump out and I replaced 5 hoses and the tilt cylinder. So the system is pretty empty... ...I don't want to damage anything running it with now or low oil. The filter is new and was filled with oil before I put it on.
Many thanks in advance.