450c 6-way fittings?

Post support questions about your JD350 and newer crawler here
jjgurley
420 crawler
420 crawler
Posts: 37
Joined: Wed Nov 15, 2017 12:47 pm

Re: 450c 6-way fittings?

Post by jjgurley » Tue Apr 21, 2020 10:26 am

Will reveal all next week. My gauge is 5000psi.

I may not go to the 2250 value since it IS an '81 with mostly original glands - hate to blow one out just to get faster operation. This machine is basically used for driveway maintenance and fire lines as required. Doesn't have to work very hard.
1981 450C
6405 #355834

gaspumpsam
440 crawler
440 crawler
Posts: 161
Joined: Sun Sep 22, 2019 8:56 am
Location: Quesnel, BC, Canada

Re: 450c 6-way fittings?

Post by gaspumpsam » Tue Apr 21, 2020 10:51 am

Ok. Good luck

User avatar
Lavoy
Site Admin
Site Admin
Posts: 10936
Joined: Sun Apr 03, 2005 8:32 pm
Location: North Dakota
Contact:

Re: 450c 6-way fittings?

Post by Lavoy » Tue Apr 21, 2020 11:55 am

Pressure is lift capacity, not flow. Higher pressure will not make anything function any faster as you have not changed flow, which is speed.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com

jjgurley
420 crawler
420 crawler
Posts: 37
Joined: Wed Nov 15, 2017 12:47 pm

Re: 450c 6-way fittings?

Post by jjgurley » Tue Apr 21, 2020 3:25 pm

It will affect speed if all the flow is diverted by the bypass. At higher RPM, the flow increases enough to create a little more pressure and flow to the right place.
1981 450C
6405 #355834

User avatar
Lavoy
Site Admin
Site Admin
Posts: 10936
Joined: Sun Apr 03, 2005 8:32 pm
Location: North Dakota
Contact:

Re: 450c 6-way fittings?

Post by Lavoy » Tue Apr 21, 2020 4:23 pm

That's like saying it will affect it if you take the bypass out altogether. You are not going to do that, so that is a pointless example. What I said is correct, pressure is pressure, flow is flow. Obviously flow increases with RPM, I never disputed that, but your comment that you are going to set it at a lower pressure to reduce flow is incorrect. Flow will remain constant at a given RPM, ultimate pressure will be reduced, and therefore so will lift capacity.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com

User avatar
DrLoch
1010 crawler
1010 crawler
Posts: 382
Joined: Thu Jul 04, 2013 6:39 am
Location: Mebane NC

Re: 450c 6-way fittings?

Post by DrLoch » Wed Apr 22, 2020 7:07 am

Flow = speed
Force/pressure = restriction of flow,
Reduced pressure = reduced force
If you want to reduce the flow the correct method is to replace the pump with one that is smaller, i.e. less cu/in pre rev equals less flow for a given RPM with a gear pump.
450C Track Loader
291457T

jjgurley
420 crawler
420 crawler
Posts: 37
Joined: Wed Nov 15, 2017 12:47 pm

Re: 450c 6-way fittings?

Post by jjgurley » Wed Apr 22, 2020 7:28 am

I only said I might set the bypass to a lower than spec pressure because I don't want to contribute to failure of old cylinder glands.

Until my repair is complete, and I'm proven wrong, I'm going with the problem being the bypass was open all the time, and I was only able to develop enough pressure to lift the blade when the RPM generated enough flow to overwhelm the "leak" the bypass represented.

If my repair of the bypass is ineffective, then I'll look for a pinch in the pump output line or maybe an acorn in the supply line. The mechanic lifted the dozer to replace the 6-way pins and remover the tracks, so he might have put a chain in a bad spot. Without a flowmeter, it's working a little blind. I'm pretty sure the pump didn't wear out suddenly.
1981 450C
6405 #355834

gaspumpsam
440 crawler
440 crawler
Posts: 161
Joined: Sun Sep 22, 2019 8:56 am
Location: Quesnel, BC, Canada

Re: 450c 6-way fittings?

Post by gaspumpsam » Wed Apr 22, 2020 8:08 am

You will find problem. I think with hyd systems acting up, right after someone that shouldn’t have been working on the system, because of lack of knowledge, is like playing with a jig saw puzzle with pieces missing or in the wrong spot!
Proper parts books, and shop service manual, put all jig saw pieces in right spot!!

You just have to do repair/ fix the valves as you come to them. ie- the relief valve, repair it to specs( as you are doing) and keep going and pretty soon , all will work properly.
Our hyd instructor used to stress-1- be careful of preconceived ideas, 2- don’t over think problem.

A machine set up to specs is “fun” to operate, if you have to fight or compensate, because a system won’t do what it’s supposed to, becomes pain in ass pretty quick.

Jim B
350 crawler
350 crawler
Posts: 2080
Joined: Sun Nov 05, 2017 11:36 am
Location: western Maine

Re: 450c 6-way fittings?

Post by Jim B » Wed Apr 22, 2020 10:48 am

Get your relief valve repair done. By the sounds it will currently prevent anything from working or checking out right. As I posted back in November your JD service manual should give you cycle time specs for the dozer functions. Set the main relief pressure and engine rpm as the book calls for them to be at when doing the tests; then time the movements. Those tests will give you a good idea of how well the pump is functioning, without needing a flowmeter. If you want to reduce the pressure to take it easy on the glands, do it after you check cycle times.

jjgurley
420 crawler
420 crawler
Posts: 37
Joined: Wed Nov 15, 2017 12:47 pm

Re: 450c 6-way fittings?

Post by jjgurley » Mon Apr 27, 2020 2:42 pm

The T10649 (I might have washer measures 0.10 inch, so that's quite the error in the pressure setting. I'm optimistic this will fix my problem when I get a break in the weather and my todo list. I bought two of them if anyone ever needs one..
1981 450C
6405 #355834

gaspumpsam
440 crawler
440 crawler
Posts: 161
Joined: Sun Sep 22, 2019 8:56 am
Location: Quesnel, BC, Canada

Re: 450c 6-way fittings?

Post by gaspumpsam » Mon Apr 27, 2020 5:35 pm

Is that washer thicker than .010”? The thin washers are .010” the washer should be close to .050”.

jjgurley
420 crawler
420 crawler
Posts: 37
Joined: Wed Nov 15, 2017 12:47 pm

Re: 450c 6-way fittings?

Post by jjgurley » Mon Apr 27, 2020 7:09 pm

sorry my prior post was typo filled. the T10649 washer called for is 0.100 thick. The shims in my valve are all 0.010. The part I bought is in its original JD packaging with part number.
1981 450C
6405 #355834

gaspumpsam
440 crawler
440 crawler
Posts: 161
Joined: Sun Sep 22, 2019 8:56 am
Location: Quesnel, BC, Canada

Re: 450c 6-way fittings?

Post by gaspumpsam » Mon Apr 27, 2020 7:19 pm

That sounds better! Yes install the washer and your 3 thin shims, then let us know what your pressure becomes!

jjgurley
420 crawler
420 crawler
Posts: 37
Joined: Wed Nov 15, 2017 12:47 pm

Re: 450c 6-way fittings?

Post by jjgurley » Tue Apr 28, 2020 4:01 pm

Maybe I'm getting dumber by the day, but when I inserted the proper washer along with the four shims, I was unable to manually compress the spring enough to catch the threads on the cap. I tried until my hands were tired, so I know why the mechanic left it out!

Is this normal? I think I can get it if I move to a vice and find some leverage, but I'm surprised. Definitely not something I want to attempt while the valve is in the machine.
1981 450C
6405 #355834

gaspumpsam
440 crawler
440 crawler
Posts: 161
Joined: Sun Sep 22, 2019 8:56 am
Location: Quesnel, BC, Canada

Re: 450c 6-way fittings?

Post by gaspumpsam » Tue Apr 28, 2020 5:07 pm

Yes. Some valves are like that

Post Reply

Who is online

Users browsing this forum: No registered users and 50 guests