I picked up a heavy stump today with my Kubota U17 excavator, and the hydraulic line on the rod end of the boom cylinder burst. I looked up the part (RA221-64113), and it costs $180 from Kubota. So I decided to look into having DiscountHydraulicHose.com make me one instead. The stock hose is Bridgestone PF2104, which is 1/4"x130" with 3000psi working load and 2" minimum bend radius. I found two types of 3000 psi hose at discount hydraulics. 1) SAE 100R17 at $1.10 per foot with 2" minimum bend radius, and 2) SAE 100R5 at $4.78 per foot with 3.5" minimum bend radius. I have no idea why the 100R5 is almost 5x the cost of the 100R17? I'm guessing the 100R17 would work fine for my application, given the bend radius is the same? How do I know which fittings to have discount hydraulics add to the line? Also, the hose runs through the inside of the boom. Are there any tricks to running the new hose. Thanks!
Tie a string to one end of the old hose. Pull the old hose out from the other end. Tie the string to the new hose and pull the string and hose back through. Use heavy string. The 100R17 should be fine. You might need to take the old hose to a local hydraulic hose shop to get the proper assenbly.
They have a thread guide to determine which size and type of fitting you need. A caliper and thread gauge will help. If you get the right male-male adapter, you can pull the new hose through with the old one. Unless it's clamped somewhere you can't reach...
The price difference of theR17 compared to the R5 hose is because the R5 has a much higher temperature rating and more reinforcing it also meets more application standards for use in different systems... but like f311fr1 said the r17 should work for you just fine.
Not sure the difference between the hoses but I would get the highest presssure rating you can for the dollars. The brochures say the system pressure is 3000 but the relief is 3250 on the u25 and I think the u17 is the same.
^^ Which is why it is generally a good idea to take your old hose to a competent hose shop and they will make the right hose for you The R5 and R17 series have the same 3000/12000 pressure ratings but like 007 says the reliefs for the U17 are higher than the working press ratings so it might be worth looking to the next tier of hose.
I removed the hose and bought a new 5600 psi hose from my local hydraulic shop. It cost $105 including tax. The guy there said the hose has British Pipe threads. There's a nipple inside the thread opening. I asked him if this was there to hold the swivel head on, and he said it's actually there because that's the part that seals. From looking online, I see no mention of this. Does the centerpiece seal the connection on British Pipe?
Does it look like the old one? That sort of internal flare is very common.
Yes, it looks exactly like the old one. I'm just wondering how I would order similar hoses online in the future. Nearest I can tell from online information, this is a BSPP female swivel fitting. "The BSPP female swivel has a tapered nose/Globeseal flareless swivel which seals on the cone seat of the male."
yes, looks like a 3/8" bspp. Metric fittings look similar but the cone doesn't protrude into the nut so far.
I'd like to thank everyone for the information. I changed the hose and all is fine with my mini excavator.
Glad you got it working again and all is good Out of curiosity how/where did the old hose burst? at an end or somewhere between that was rubbing on something? if it was from rubbing it would be worth checking all the other hoses for similar issues and do a bit of preventative maintenance to correct the rubbing issues... such as installing some heavy zip ties and rubber hose to 'armor' up any problem areas can save a lot of money and downtime in the long run.
The hose blew out at the fitting. The guy at the hydraulic shop said it was probably due to a bad factory crimping job. The stock hoses are protected with a thick rubber cover, but the new hose doesn't have any additional protection. I'm not sure what you mean by "rubber hose" to armor up any problem areas. That sounds like a good idea. What type of hose I should get?
I generally use any thing I have laying around... like old radiator hose or some of the old rubber mud flaps work if you want to go around something a couple times... old fire hose works good for some areas also, the larger sizes are great for putting a few hoses in... just slice it down the length then punch a series of holes along each side you cut... and wrap it around the hoses and stitch up like a corset with some shoelace . Or you can buy the heavy plastic spiral hose armor from hose /hydraulic shops but it gets a little spendy... Yeah, have seen quite a few blow at the fittings... sometimes probably from a bad crimp but can happen from to much flexing right at the fitting if the hose has a fairly long unsupported section or is restrained to much too close to the fitting where it is next to a pivot. If it does have a good length that is not restrained or can't be for design reason than it probably needs spring strain reliefs on the fitting... however depending on how many hours you got out of that hose it could be just fine like it is....
The machine has 95 hours on it since new. The photo below shows the new hose I installed. It wraps back and threads down through the inside of the boom and into the excavator body. I'll put some reinforcement at the contact points.
Only 95 hours!!! Wow, I would have thought a lot more... like a couple thousand