Hydraulic Line fittings on Dump Trailer hoist cylinder

tamarack · Oct 18, 2021

My son has a Forest River 6x12 10k Dump Trailer and the pump failed. The trailer has a KTI Hydraulic system and he was able to purchase a direct replacement pump from KTI. He has run into a couple of problems and I was hoping that someone in the Hydraulics could help resolve these. The first problem has been when he went to assemble the suction screen assembly to the pump. The screen assembly consists of a pvc street ell which is attached to the screen on one side and the other side of the street ell attaches to the pump with a 3/8 inch pvc close nipple and an O ring. He attached the screen assembly but when he tightened the assembly to the nipple, he needs to make a 3/4 additional turn on the screen assembly in order for the screen to be properly oriented when the tank is installed. He is hesitant in trying this as he thinks that he will break either the pvc nipple or the pvc street ell. Any suggestions? Now to the next problem! He talked with a hydraulics shop in town and they said that if he would disconnect and drain the hydraulic lines from the hydraulic cylinder that there would not be enough residual fluid left in the lines to be a problem when using an approved hydraulic fluid specified by KTI. He attempted to remove a hydraulic line from the cylinder yesterday and he ran into a problem as there does not appear to be a swivel hydraulic fitting on the line attached to the cylinder. I have attached KTI blueprints of the KTI system on the trailer as well as pictures of the pump, o ring, pvc nipple and the pvc screen assembly. I have also attached a picture of the hydraulic line attached to the cylinder and the fittings. Sorry about the length of this post, but I reside over 300 miles from our son and I would hope that someone on this site would be able to provide some helpful information. Thank you, Tamarack

oldnslo · Oct 18, 2021

No help on the inlet elbow but picture 3 of the cyclone appears to have JIC 37 degree swivel type fitting.

Leejohn · Oct 18, 2021

You could get you electric fitting lock nut and use that to put it in the place .

LouNY · Oct 18, 2021

If I'm understanding correctly he has tighten the threaded PVC so tight that he is afraid that 3/4 of a turn more will break something.
If correct unscrew it use some pipe dope and retread together stopping before it gets too tight.

LD1 · Oct 19, 2021

Great advise above.

In pic 3, that certainly is a swivel fitting.

The middle hex that you put a wrench on is the one you loosen. The one closest to the hose is where you use a backup wrench to keep the hose from twisting and let the swivel fitting do its thing.

The elbow, its not under pressure, just a suction line. And if he is already so tight he is worried about breaking he probably went too far. One pic shows an o-ring and the other shows none. IS that something HE added? The nipple on the pump almost looks like straight threads....not saying they dont exist....but I have never seen a grey PVC fitting with straight threads....they are usually NPT. SO if the elbow is indeed NPT....A few careful wraps of teflon tape and try again stopping before it goes too far. Or even stack another o-ring on there. Again, its suction side and not under pressure

tamarack · Oct 21, 2021

oldnslo said:
No help on the inlet elbow but picture 3 of the cyclone appears to have JIC 37 degree swivel type fitting.

I want to thank everyone that provided answers to the questions. I have forwarded all of the replies to my son and he is working on resolving the issues based on the information provided by the members. Thank you all.

tamarack · Oct 21, 2021

LD1 said:
Great advise above.

In pic 3, that certainly is a swivel fitting.

The middle hex that you put a wrench on is the one you loosen. The one closest to the hose is where you use a backup wrench to keep the hose from twisting and let the swivel fitting do its thing.

The elbow, its not under pressure, just a suction line. And if he is already so tight he is worried about breaking he probably went too far. One pic shows an o-ring and the other shows none. IS that something HE added? The nipple on the pump almost looks like straight threads....not saying they dont exist....but I have never seen a grey PVC fitting with straight threads....they are usually NPT. SO if the elbow is indeed NPT....A few careful wraps of teflon tape and try again stopping before it goes too far. Or even stack another o-ring on there. Again, its suction side and not under pressure

tamarack · Oct 21, 2021

I want to thank everyone that provided answers to the questions. I have forwarded all of the replies to my son and he is working on resolving the issues based on the information provided by the members. Thank you all.