Boom dropping on Industrial-600 backhoe on HD4

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   I posted recently about my "new-to-me" HD4 crawler with loader and backhoe. I've started some work removing some stumps and she's worked great so far. However, I'm a bit concerned about the boom dropping on the backhoe.

I knew from the previous owner before buying it that there was some slight drop on the boom over time (i.e. if it's up when you park it for the night, it'll be on the ground in the morning). I played around with it a bit and noticed that it was a bit quicker than that, but not so much as to be concerning.

Yesterday was my first time really doing some work with the backhoe though, and as time progressed the boom drop got worse and worse to the point that I was having to constantly raise it while doing the other controls because it was dropping too fast. I'm thinking where before if it was raised it might take about a half hour or an hour to fully drop, now it would be fully dropping after a minute or two.

Looking at the troubleshooting section of the manual I found the following:

LOAD DROPS WITH SPOOL IN CENTERED POSITION
1. Damaged cylinder packing: Replace cylinder packing

2. Line to cylinder leaking: Tighten fittings or replace hose

3. Leaky circuit control relief valve: Remove relief valve and clean with solvent and air pressure. If this does not correct problem, replace with new circuit relief valve.

4. Damaged O-ring in "circuit control chamber": Remove assembly in "circuit control chamber" and replace O-rings and back-up washer in chamber.

5. Damaged lockout poppet: Remove lockout plug and replace poppet.

6. Foreign matter under poppet: Remove lockout plug and clean poppet and seat.

7. Damaged O-ring on lockout seat: Remove lockout plug, poppet, and seat. Replace O-ring on seat.

So that gives me 7 potential areas to look.

My questions, then, would be what the best way is to go about eliminating these options to narrow down the problem source. Things like removing plugs and poppets sound to me like they'd be much easier jobs than "replace cylinder packing" so I'm wondering how to potentially eliminate that as being the problem.

Any help on how to go about narrowing it down is greatly appreciated!

Edited by Daelric - 29 Sep 2021 at 10:39am

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Daelric Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 22 Sep 2021 Location: Terrace BC Points: 70	Post Options Post Reply Quote Daelric Report Post Thanks(0) Quote Reply Topic: Boom dropping on Industrial-600 backhoe on HD4 Posted: 29 Sep 2021 at 10:38am
	I posted recently about my "new-to-me" HD4 crawler with loader and backhoe. I've started some work removing some stumps and she's worked great so far. However, I'm a bit concerned about the boom dropping on the backhoe. I knew from the previous owner before buying it that there was some slight drop on the boom over time (i.e. if it's up when you park it for the night, it'll be on the ground in the morning). I played around with it a bit and noticed that it was a bit quicker than that, but not so much as to be concerning. Yesterday was my first time really doing some work with the backhoe though, and as time progressed the boom drop got worse and worse to the point that I was having to constantly raise it while doing the other controls because it was dropping too fast. I'm thinking where before if it was raised it might take about a half hour or an hour to fully drop, now it would be fully dropping after a minute or two. Looking at the troubleshooting section of the manual I found the following: LOAD DROPS WITH SPOOL IN CENTERED POSITION 1. Damaged cylinder packing: Replace cylinder packing 2. Line to cylinder leaking: Tighten fittings or replace hose 3. Leaky circuit control relief valve: Remove relief valve and clean with solvent and air pressure. If this does not correct problem, replace with new circuit relief valve. 4. Damaged O-ring in "circuit control chamber": Remove assembly in "circuit control chamber" and replace O-rings and back-up washer in chamber. 5. Damaged lockout poppet: Remove lockout plug and replace poppet. 6. Foreign matter under poppet: Remove lockout plug and clean poppet and seat. 7. Damaged O-ring on lockout seat: Remove lockout plug, poppet, and seat. Replace O-ring on seat. So that gives me 7 potential areas to look. My questions, then, would be what the best way is to go about eliminating these options to narrow down the problem source. Things like removing plugs and poppets sound to me like they'd be much easier jobs than "replace cylinder packing" so I'm wondering how to potentially eliminate that as being the problem. Any help on how to go about narrowing it down is greatly appreciated! Edited by Daelric - 29 Sep 2021 at 10:39am

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Eric B Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 09 Feb 2012 Location: British Columbi Points: 887	Post Options Post Reply Quote Eric B Report Post Thanks(0) Quote Reply Posted: 29 Sep 2021 at 12:35pm
	If each morning or 'cold machine' start up you have the longer duration for boom drop and as the oil warms up you're back to quick boom drop, the problem is primarily the seals inside the cylinder. If it was my machine the boom cylinder would go in for re-seal or if you want to try it yourself. The first thing they'll tell you at a hydraulic shop (once the cylinder is apart) is that a big part for bleed down is from the 'barrel' being scratched and worn on the inside so that if they re-seal it you will still have boom drop. At this point you have to start comparing costs. I used to deal with an 'owner operated' hyd. shop and he was very reasonable. Once he made and machined a new barrel so cheap I couldn't believe it. Other shops quote so high it's better to buy a new or good used cylinder. However, on the H3 I used to have the loader would bleed down so fast it was unbelievable but I just went for the re-seal only and that fixed over 90% of the problem and I was satisfied with that. If bleed down is fast right from cold start that's when you start checking valve banks and relief valves.
	Currently- WD,WC,3WF's,2 D14's B. Previously- I 600,TL745,200,FL9,FR12,H3,816 LBH. Earth has no sorrow that Heaven cannot heal!

Daelric Members Profile Send Private Message Find Members Posts Add to Buddy List Bronze Level Joined: 22 Sep 2021 Location: Terrace BC Points: 70	Post Options Post Reply Quote Daelric Report Post Thanks(0) Quote Reply Posted: 29 Sep 2021 at 12:44pm
	Ok great, thanks for that. I just went out and checked it cold and sure enough, the boom drop is as slow as it was when I first got it. So it appears the increase in drop is caused by the oil warming up. So this makes for my next question... just how difficult is it to remove the guilty cylinder and take it into a shop? Also, is cylinder re-sealing/repair pretty straight forward and standardized with readily available parts, or would I be likely to run into issues due to the fact that this is a ~50 year old backhoe? Edited by Daelric - 29 Sep 2021 at 1:09pm

Eric B Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 09 Feb 2012 Location: British Columbi Points: 887	Post Options Post Reply Quote Eric B Report Post Thanks(0) Quote Reply Posted: 29 Sep 2021 at 1:25pm
	To remove that cylinder turn the hoe fully to one side and stretch it out with dipper extended to get the boom as low as possible. Fo the weight of the cylinder you need some 'muscle help', another machine to lift or make a simple tripod and use a come-along. Two guys can handle the weight of the cylinder but the heavy end is inside... if you manage to get it out reasonably easy, to reinstall gets tricky without 'lift help'. I'm sure you'll soon see how best to go about it once you get started. Another thing I should mention about older worn equipment... don't use the thinner/lighter grades of hydraulic oils, such AW32 or AW46. They become thin like water when hot and of course leads to faster bleed down. I know it's cold around Terrace in the winter but you might not run your machine too much in the real cold weather when thinner oils help. Here in BC I try to use at least Hydraulic 68 as I have run mostly older, used equipment for decades. If the previous owner of your machine always used thin hyd. oils, let's say, it's not a quick fix to change to thicker hyd. oil as all cylinders and hoses retain the oil even if you drain the tank and put in thicker oil there. Thicker oils also give your pumps longer life. The long and short of it is to keep this in mind when you buy more oil for the hyd. system. If you get a good deal on 10W30 engine oil you can use that. Walmart has a good price on that if they don't have hyd. 68.
	Currently- WD,WC,3WF's,2 D14's B. Previously- I 600,TL745,200,FL9,FR12,H3,816 LBH. Earth has no sorrow that Heaven cannot heal!

Eric B Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Joined: 09 Feb 2012 Location: British Columbi Points: 887	Post Options Post Reply Quote Eric B Report Post Thanks(0) Quote Reply Posted: 29 Sep 2021 at 1:31pm
	QUOTE: Also, is cylinder re-sealing/repair pretty straight forward and standardized with readily available parts, or would I be likely to run into issues due to the fact that this is a ~50 year old backhoe? unquote Seals are not hard to find as they are common to many cylinders. They may need to be visibly matched up to get the correct ones.
	Currently- WD,WC,3WF's,2 D14's B. Previously- I 600,TL745,200,FL9,FR12,H3,816 LBH. Earth has no sorrow that Heaven cannot heal!

DMiller Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 14 Sep 2009 Location: Hermann, Mo Points: 29459	Post Options Post Reply Quote DMiller Report Post Thanks(0) Quote Reply Posted: 29 Sep 2021 at 5:16pm
	Take it to a reputable hydraulics shop, you may be able to replace the piston seals and packing gland but cannot hone the barrel or at any stretch loosen or tighten the piston nut without a lot of grief. The guys at a shop can do these repairs and inspections in Minutes not hours or days as we being individuals end up doing.

DiyDave Members Profile Send Private Message Find Members Posts Add to Buddy List Orange Level Access Joined: 11 Sep 2009 Location: Gambrills, MD Points: 50514	Post Options Post Reply Quote DiyDave Report Post Thanks(0) Quote Reply Posted: 29 Sep 2021 at 6:01pm
	If you just want to use it a while, chain up the boom...
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