Advice on flushing hydaulic system on 1702D

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oldbrownhat
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Advice on flushing hydaulic system on 1702D

Postby oldbrownhat » Tue Jan 21, 2020 2:51 pm

I've had problems with milky hydraulic fluid, which suggests water getting in somehow, although it has never caused a problem in operation. Recently the temps. dropped to about 10ºF and I had no hydraulics until I put a heater under the reservoir, but even then the performance wasn't quite up to par, so I didn't push it and used my small excavator instead for dealing with the snow. In the past I've replaced the fluid (AW-32) every fall, although last year I did it in the spring.

Now that things are thawing out I'm thinking that I should completely flush the system, rather than just draining it and cleaning the filter. Any suggestions on the best way to do this? I've read about using diesel + ATF and/or 90% isopropanol but am a little leery about using diesel, which ignites under pressure, although perhaps not a problem at the pressures generated by the hydraulic system. Any solid advice on how to do this properly and thoroughly would be appreciated.
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Re: Advice on flushing hydaulic system on 1702D

Postby Aaron » Tue Jan 21, 2020 4:34 pm

We usually just drained the oil, added a few gallons of diesel, rocked the tractor around for a while to slosh the diesel around, drained, cleaned the screen, replaced the filter, refilled with oil. I've never had one so contaminated that it took more than that to clean out. Water usually gets in through a cracked shifter boot.

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Re: Advice on flushing hydaulic system on 1702D

Postby oldbrownhat » Tue Jan 21, 2020 5:50 pm

Thanks, Aaron. I'll just use straight diesel and then drain. My shifter boot isn't in the greatest of shape but I usually keep the tractor covered as much as possible, latterly under the extension I built off the basement, but once I get it all fully cleaned out and replaced, I'll see what happens.

Should I also disconnect the hydraulic hoses and lines from the front end loader and blow them out, or will some gentle hydraulic activity do that for me?
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Re: Advice on flushing hydaulic system on 1702D

Postby Aaron » Wed Jan 22, 2020 1:42 pm

If you are just looking to get out some condensation then just draining the oil & refilling would probably be sufficient. Blowing the lines out would certainly not hurt anything though. I would not start the tractor with diesel in there.

oldbrownhat
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Re: Advice on flushing hydaulic system on 1702D

Postby oldbrownhat » Wed Jan 22, 2020 2:23 pm

Thanks again, Aaron. I think I need to do a full flush out and get as much of the old fluid out as I can. No way of rocking the tractor around, though. (I'm way too old for that kind of stuff!) May have to come up with way to agitate the diesel.

Unfortunately, I recently had to do a repair on the shifter and carefully applied gasket seal to the top of the shifter box but I guess I'll have to re-do all that. But I want to get the whole hydraulic system as clean as possible before putting in new fluid.

It's barely hitting 40ºF here at the moment so may wait until things warm up a little. Probably doesn't matter much to the tractor, but a bit easier on me :)
If a politician found he had cannibals among his constituents,
he would promise them missionaries for dinner. (H.L. Mencken)

oldbrownhat
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Re: Advice on flushing hydaulic system on 1702D

Postby oldbrownhat » Fri Jan 24, 2020 12:52 pm

Given that I'd like to flush out the whole system as thoroughly as possible, is there any way to circulate diesel through the system w/o actually running the engine? I'd like to flush out the pump as well, but being mechanically operated off the motor it's lilely impossible to "run" without the engine operating, or removing the pump, which appears to be quite a bit of work.

Or maybe I'm just overthinking all this.....
If a politician found he had cannibals among his constituents,
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winston
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Re: Advice on flushing hydaulic system on 1702D

Postby winston » Fri Jan 24, 2020 1:27 pm

If I were going to that extent I would use something like this for first flush. Some use it as final fluid and it probably meets your specs. Little higher than diesel but if I were going to circulate this would be my choice. Just an opinion, not fact. https://www.tractorsupply.com/tsc/produ ... _vc=-10005

oldbrownhat
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Re: Advice on flushing hydaulic system on 1702D

Postby oldbrownhat » Fri Jan 24, 2020 3:27 pm

Interesting... so this could be used both to flush with the engine running and then a second batch for the proper fill? I'll see if it or an equivalent is available up here.

I was wondering about thining some of my AW 32 (since I have it on hand) and using that as a flush, bit the question is what to thin it with, as I don't want to damage any seals. It would only be running for a few minutes before being drained in any case. I've read of using ATF to flush a system, too. But doing a littie online research just now, others have suggested just using. thinner hydraulic oil than usual, as you suggested.
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winston
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Re: Advice on flushing hydaulic system on 1702D

Postby winston » Fri Jan 24, 2020 6:28 pm

I don't think using your aw32 as a flush would hurt anything. Sure not going to hurt your seals. Only thing is it seems to be a 10w so you might have to use some extra final fluid to get it all flushed out of your cylinders and lines. Otherwise, I would think you might be getting away from the gear protection additives found the combination fluid.

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Re: Advice on flushing hydaulic system on 1702D

Postby oldbrownhat » Fri Jan 24, 2020 8:23 pm

Doing a little moe digging online has found recommendations for using Seafoam TransTune as an additive to a thinner hydraulic oil. The reason for asking about thinning the hydraulic oil is that I'm not sure what I have available reasonably locally.

So I think what I 'll do is to warm everything up and let it drain. Flush out the case & screen with diesel as you suggested, blow out the lines, replace filter, then fill to minimum level with a lighter (or thinned?) oil + Seafoam and give that a good run through the system before flushing that, then putting in another new filter and fill up as usual with AW32. That will probably be "good enough for government work" on this old workhorse.
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winston
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Re: Advice on flushing hydaulic system on 1702D

Postby winston » Sat Jan 25, 2020 5:23 am

Are you sure the aw32 has the correct additives for your geared transmission? I don't believe it does. You need transmission/hydraulic fluid as final. Again, just my opinion.

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Re: Advice on flushing hydaulic system on 1702D

Postby oldbrownhat » Sat Jan 25, 2020 8:07 am

Hi Winston,
.... Ignore previous nonsense :oops:

The AW32 I have is for my small Takeuchi excavator. I do in fact have a 5 gal/20L tub of gen-u-wine Trensmision-Hydraulic fluid. And the Super-S hydraulic/transmission fluid Aaron suggested is available at a nearly-local TSC in Ferndale WA, so I'll pick up a tub of that when I'm down across the line in Bellingam WA on Tuesday as I'd like to use a less-expensive product for the flush cycle. Even with the Cdn. $ exchange, it's less expensive than anything I can get here. So it looks like it's all good :)
If a politician found he had cannibals among his constituents,
he would promise them missionaries for dinner. (H.L. Mencken)

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Re: Advice on flushing hydaulic system on 1702D

Postby Threeweight » Sun Jan 26, 2020 3:17 am

When I bought it, my Yanmar 1500 had a totally shot seal on one rear axle, which had been that way for a long time and had let water in to tranny/hydraulic system (I assume from plowing rice paddies somewhere 20 years ago). That in turn had frozen the piston for the 3 pt lift. I tore the rear end completely down to get everything working right again, and found quite a bit of gunk stuck in low spots in the rear end area.

I first cleaned the those areas I could access w/ the lift off as best I could with carb cleaner and rags. Then I re-assembled and went and bought a 5 gallon pail of the cheapest 303 tractor hydraulic fluid I could find (SuperTrac), and used half of it to flush the tractor. I filled it up, then drained it into a pan, then drained the fluid through a strainer funnel to remove the gunk then repeated the process. After about 3 goes of this I changed the hydraulic filter, re-filled with the 2.5 gallons of clean fluid, then started the tractor and operated the lift and front end loader for 10-15 minutes, then shut it down and drained again. Cleaned filter then gave it a final fill with good quality fluid from Tractor Supply (their John Deere Hyguard equivalent).

Diesel would have been cheaper, but I am pleased with the results. Hydraulics worked great all summer long, and I worked the tractor HARD. Cleared and leveled a building site for a 30x60 shop, built a driveway, moved and spread 75 yards of gravel, etc...

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Re: Advice on flushing hydaulic system on 1702D

Postby oldbrownhat » Sun Jan 26, 2020 7:09 am

@Threeweight... these Yanmars are TOUGH! Fortunately I've not actually had any problem with the hydraulics until this uncommonly cold weather hit us recently. We're now into Serious Drizzle Mode out here in The Pacific "Northwet", with the occasional foray into Bibllical/Torrential, and daytime temps around 40-45º. We might even get a day or two of sunshine early next month, at which time I'll feel more like tackling the cleanout. The tractor is kept under shelter but I'm going to wait a bit as I don't need to use it for a while. Hopefully when I fire it up the hydraulics will still be OK and I can proceed without any other worries.

Your explanation of water getting in via a shot seal on the rear end is something I should look at, because it seems it is getting in somewhere. I don't use the tractor a great deal in inclement weather aside from clearing snow from my & my neigbours's driveways a few times each season. Once I get everything cleaned out I'll keep a close eye on the condition of the hydraulic fluid, esp. if I do use it in the rain or slush. As metioned above, I've found there is a TSC in Ferndalw WA so I'll pick up a tub of SuperTrac on Tuesday. At $32.00 it'll be about $15 USD cheaper than anything I can get locally, which is good as the 1702D takes 15.3 qts.

I have a fair bit of diesel on hand, as I have a 100L/25 gallon tank for my old Onan generator, plus 3, 5 gal. containers for filling the tractor and excavator. I refill them from the big tank, then top it up and add Stanadyne. (We're ion the edge of a potential earthquake zone out here, so if The Big One hits and the house is still OK, I figure between the battery backup system and the gennny, I should be good for about 15 days on the fuel I have.)
If a politician found he had cannibals among his constituents,
he would promise them missionaries for dinner. (H.L. Mencken)

Threeweight
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Re: Advice on flushing hydaulic system on 1702D

Postby Threeweight » Tue Jan 28, 2020 12:23 am

Before I got into it, mine appeared to just be leaking a little oil/hydro fluid from one of the rear axle seals. Just a little wet weeping there. My brakes were sketchy, so I decided to remove the axle stubs while I had the wheels and 3 pt lift off and service them. I found both brakes wet with fluid, and the left side was caked in ancient mud/oil/grit combo from the shot seal and bearing. The right side had a leaking seal, but no damage beyond that.

I don't know if it is possible for rain water to collect inside those axle stubs and get into the case via the brake and axle seals, but if your brakes are sketchy it might be worth a look.

You are not kidding about how tough these old tractors are. The bull gears on mine were ridiculously overbuilt for the HP rating of the tractor... beefier than the rear end on my 1 ton pickup. Mine is so loud it is physically painful to stand around without ear protection, but my neighbors 2017 Kubota BX is built like a big box store riding lawnmower by comparison.


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