4720 Hydraulic fittings/hoses

Ladew · Nov 9, 2017

Been awhile since posting here and need some help. I shredded a hydraulic hose under my 4720 ('04). It's controls the BL 20 FEL. Think it's the return -- goes out the side of the controller, snakes under to near the left rear wheel onto a metal line. Ordered a replacement from dealer but the fitting to the fixed line side (and elbow fitting) was wrong size and type. It was 15/16" nut with flat nipple rather than 1 1/16" flared nipple. Kinda mad (!) I had another one made at a specialty hose shop in town and returned the branson one. The one I had made was 3/4" rather than 5/8" - didn't think that would be a problem. Finally got it hooked up (no small feat) but it leaks when under load. Idle and above it's fine - no leak. Just when working bucket the hose and fitting are moving up and down under pressure and causing the fitting to seep. Believe me this fitting it TIGHT but since it's moving around it's tweaking the connection. Should I go back to the 5/8" (which is a lot easier to work with) or try to secure/bracket the new hose and fitting so it doesn't slop around?? I never noticed before if the fitting moved (up/down) when under pressure since it's fairly well hidden behind the rear tire. Any thoughts out there? thanks.

oldnslo · Nov 9, 2017

If you are putting strain on the connector it will fatigue and fail over time.

Cougsfan · Nov 10, 2017

I don't think the fitting should be moving and would secure it as it may eventually fail. However I don't think that is your immediate problem with the leak. On my old Ferguson, some of my fuel lines on the high pressure side of the injection pump developed leaks after 50 years of service. I tried tightening them to to the point I was afraid I would break something. All to no avail.
Finally and old mechanic friend suggested I loosen before I tighten them. Maybe even do it several times. Sure enough, it worked. Might try that.

LD1 · Nov 10, 2017

If by flare fitting you mean JIC, over tightening can damage the sealing surface and cause leaks just the same as not tight enough.

oldnslo · Nov 10, 2017

Not sure on your 4720 but on my 2400H the flare fittings are 30 degree metric & not std JIC. Are you sure that you have the proper hose ends?

Ladew · Nov 10, 2017

thanks for the replies so far. The fitting should be correct as I had the old hose with me when getting the new one made. Loosening slightly sounds worth a try - I cranked that thing pretty tight! I'll also try to secure the fitting somehow so it doesn't move/pinch under pressure.

LincTex · Nov 14, 2017

oldnslo said:
Not sure on your 4720 but on my 2400H the flare fittings are 30 degree metric & not std JIC. Are you sure that you have the proper hose ends?

This is my first thought - - - I'll bet the guy who made the hose has the wrong degree flare on that end.

There are 45*, 37* and 30* flares.

They don't interchange.