Loader movement delay

OneHappyPappy · Apr 27, 2007

Hello,

I'm new to the forum after just buying a 1982 JD750 with loader. Looks like a lot of knowledge being shared here. I have a question on the loader movement delay. When I raise or loader the bucket there is a delay when I change direction and I was wondering if this is normal. The delay seems to be about 5 to 10 seconds. I also have a couple of Quick Disconnects leaking. From your expierence does replacing the O rings normally stop the leaks or move than likely will I have to replace the whole QD? I'm sure I'm going to have many more questions and maybe someday I'm be able to answer some.

Thanks
OneHappyPappy

KJM · Apr 28, 2007

G'Day OneHappyPuppy - welcome!

(Hey, it feels strange for me to say "welcome" - I feel like I'm new here too

I'm no hydraulics guru, and I don't have a JD, but 5 to 10 seconds sounds like you have air in the system. So the fluid needs to be pumped in to compress the air before any action ensues. Quick check for this (for me) has always been to fully extend a cyl in both directions. On a loader, this means all the way up and then gently down. The "gently" is important because gravity assists and you can potentially create gas pockets in the suction side of the system if the pump output is not sufficient to cope. If you do this and there is now no delay - then "air" is certainly the problem. You could also have low oil or an air leak on the suction side of the pump. Basically, you're looking at some kind of air in the system in all likelyhood.

Weeping QDs shouldn't let too much air in, I would have thought. Replacing O-rings will cost next to nothing, and should fix leaking unless the male mating surface has been damaged.

1982 is approximately the same vintage as my wee Kubota B7100. I have had to replace all the cylinder seals on mine (easy) due to leaking. Put the loader up, switch off and see how long it stays. When I bought the B7100, it'd stay up for a couple of minutes. Now it stays up overnight!

Hopefully one of the more hydraulically enlightened might chip in if these comments are mis-guided.

Best of luck.

/Kevin

OneHappyPappy · Apr 28, 2007

Kevin,

Thanks for the reply. I tried the full up and down slowly and it seems to be fine. After futher checking the problem seems to be with the bucket pivot more than raising and lowering. The bucket will pivot as long as there is no resistance but for example I wanted to smooth out some ground so I put the bucket down and started backing up and the bucket was just bouncing up and down so I stopped and pivoted the bucket down and it didn't move for a while and then finally started to apply downward pressure on the ground. It was like you said air in the system and had to be replaced with fluid. I guess I need to get a manual for the loader and check to see what it says. I guess I'll replace the O rings first and see it that stops the leaking. I don't like the hydraulic fluid dripping all over.

Thanks
One Happy Pappy

KJM · Apr 28, 2007

Glad it was of some help. If the loader lifts and drops OK and it is just the bucket curl - then I hope it is the bucket curl QDs that are leaking? If only one circuit is flakey and it isn't the hoses and QDs then it is probably the spool. Which would be a bummer, because that isn't cheap to fix.

My backhoe was a PITA to bleed the air out of. The main boom cylinder needed to be moved to max/min extension. This, of course, means you need a convenient 6 foot or so deep hole to poke it down.... which is a problem if you haven't yet dug one!

Loaders are so much easier to bleed through!

If you do need to replace the spool, this board seems to recommend Surplus Center. I just bought a BRAND 2 spool with float and regen from them for the B7100. This is a joystick type setup. Cost was just over $US200 with the HPCO (Power Beyond) sleeve. Haven't yet put it on, but it looks a quality piece of work. Surplus Center was a joy to deal with (remember: I'm 1/2 way around the planet!). Usual disclaimer: I have no connection with Surplus Center, just a happy customer etc etc...

I still consider myself a hydraulics novice, but I'd suggest you have a browse for posts by the late "madreferee". I learned so much from his posts. 99% of hydraulics seems pretty straight forward, but there is a sneaky 1% to it that makes things expensive if you do the wrong thing.

Cheers
/Kevin

Soundguy · Apr 29, 2007

Get those qd's replaced or repaired.. they will be a constant source of problems, on top of any other problems you may have.. like a bypassing cyl.. or bad spool.. etc..

Soundguy

OneHappyPappy · Apr 29, 2007

I found a couple of leaks that I can work on. One question I have is will it be okay to use teflon tape on these fittings or is there some other compound I can put on the threads to help seal them.

Thanks
OneHappyPappy

Dougd · Apr 30, 2007

The counter guy at my local Parker hydraulics place told me they use teflon tape on their NPT hydraulic connections. Not neccessary or desirable to use teflon tape with JIC or ORFS fittings as they don't seal via the threads as NPT fittings do.
He also recommended against NPT fittings as "Sooner or later they will leak."

Soundguy · Apr 30, 2007

Good sealed NPT fittings are fine... I've got 2 loaders plumbed with them.. no apparent leaks. One I've had for a few years.. one I assembled myself recently. both tractors are from the 50's.. If the 'later' is more than 50 ys.. what more can you ask for????

soundguy

OneHappyPappy · May 1, 2007

Well I have 90% of my hydraulic leaks repaired. I feel good about that, a little teflon tape and 1 new quick connect. I do have one question, how do you get the o rings out of the quick connects to replace them?