420 hyd. Issue

General help and support for your Lindeman through 2010 John Deere crawler
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theshanmand1!
430 crawler
430 crawler
Posts: 58
Joined: Wed Sep 11, 2013 9:41 pm

420 hyd. Issue

Post by theshanmand1! » Mon Feb 13, 2017 3:09 pm

Hello all,
Wont let me post from my laptop for some reason, but will from my iphone.
So here goes again!
When i freshened up the crawler i had the hyd. Cylinders completely gone through. Replaced all of the broken bolts on the hyd pump, inspected the gears & leather seals, all seamed in good order. & it stopped leaking!
I had new lines made up, cleaned the hyd tank & filled it with AW46 hyd.
I did not go through the single remote cyl. Valve, other than the 6 times taking it off trying to get the pick up tube to stop leaking, double stacked the cork o-rings as per Lavoy & wallah! No more leaky.
My issue is that when im plowing snow & want to raise the blade a little, it sometimes wont move & i can hear the hyd pump cavatating, making a eeoorr sound. Then if i stop, lower the blade, put down pressure on it, then pull up it will come right up, it also does it when im in float back blading.
I have not put a pressure guage on the single remote yet.
But my suspicion is its either that or the hyd. Pump is due for a overhaul
Any advice is greatly appreciated.
yard dog
1958 4 Roller 4 speed Holt Blade Holt Winch
420 C
Industrial Yellow

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Lavoy
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Post by Lavoy » Wed Mar 01, 2017 11:28 am

If the sound you hear is the bypass howling, your hyd valve linkage is out of adjustment, or accumulated wear is too great. If they are nit adjusted correctly, the one valve is opening before the other valve and it is dead heading the flow and forcing the oil through the bypass valve, hence the squealing.
Lavoy
Parts and restoration for antique and late model John Deere crawlers.
Owner and moderator www.jdcrawlers.com

theshanmand1!
430 crawler
430 crawler
Posts: 58
Joined: Wed Sep 11, 2013 9:41 pm

Post by theshanmand1! » Wed Mar 01, 2017 11:40 am

I suppose I had better open my manual & get busy educating myself on that aspect of my crawler.
Thank you Lavoy.
yard dog
1958 4 Roller 4 speed Holt Blade Holt Winch
420 C
Industrial Yellow

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Stan Disbrow
350 crawler
350 crawler
Posts: 2894
Joined: Fri Jul 15, 2005 3:13 pm
Location: Raleigh, NC

Post by Stan Disbrow » Wed Mar 01, 2017 1:59 pm

Hi,

Yeah. It is important to have the linkages between the lever and the two hyd valve control pistons correct. There is a buzzing-like sound when the bypass opens up. Sorta like a game show Thank You For Playing error buzz....

I was working with mine today, and was backing up, steering and raising my blade all while having a swivel head like a WWI Flying Ace. When....Buzz!! Oh. Yes. I ought to let go of the blade lever *before* it raises full up! :P

Stan
There's No Such Thing As A Cheap Crawler!

Useta Have: '58 JD 420c 5-roller w/62 inside blade
Useta Have: '78 JD350C w/6310 outside blade
Useta Have: '68 JD350, '51 Terratrac GT-25
Have: 1950 M, 2005 x495, 2008 5103 (now known as 5045D)

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