Any one want to help out a newbie with an old Link Belt excavator?

Hi guys! Long time lurker and thanks to anyone who takes the time to answer any of my questions! The machine is an 1989 LS2650 C11...bought it with the hopes of getting 200 hours out of it doing some stump clearing and ditching around my place and all was going good until about 120 hrs.

Issue #1. Last fall the hydraulic cooler developed a leak so I had it repaired. The 2 hoses that connect the cooler to the piping ended up being in less than desirable shape and actually leaked a tiny bit. So I called my Link Belt dealer and gave them the SN# of the machine and they ordered up the hoses..well I finally got around to putting them on last month and they were 4" shorter than the ones I took off...They do connect the cooler to the pipes but are barely on there . Originally it was double clamped and now I can only get one clamp per connection...I called back the dealer and they say that Link Belt says they should be 16" , not the 20" I had and they didn't have any kind of solution for me other than try to source the hose locally...the real problem is that it's a 34mm id hose I cannot for the life of me track any down..have any of you ran into this before or know a place that would have 34mm id straight hose?

Issue #2 I didn't notice it last fall when burning stump piles but now this summer the couple times I've been able to use it ( 6 day a week job and the rainiest summer I can remember have limited me) after about 45 mins of hard use, I get what sounds like air in the system...especially when I say curl the bucket and then swing ...when I slow the swing down and open the bucket I get a very loud sound of air in hydraulic noise...I've been using aw46 in this machine and it had a new pump shortly before I purchased it but was wondering if I should be using 68 oil?

Thanks again!

p.s. I've owned at one time a Case backhoe and payloader but this thing is by far the funnest to operate! I think I might be looking for a career change

I'm wondering if someone changed to a different model cooler to make the 4 inch difference, you can find yourself a hydraulic hose shop, some places like Napa that service heavy trucks will have hose making capibilities beyond 3/4 inch, If its just bulk hose with clamps, low pressure type then you'll just need something longer made.

McMaster Carr carries bulk hydraulic hose if you know the type and ratings you need.

thanks for the reply fast_st...It's very possible that it was replaced...I have tried NAPA and just about everyone else I can think of including some Case dealers (because of their association with Sumitomo) and pretty much the entire internet, but NOBODY lists 34mm id hose...they have plenty of 1 1/2 and 1 1/4 id but this is 34mm (just shy of 1 3/8) and I've yet to find any oil resistant hose in that size...I tried pushing 1 1/4 on it that I got from NAPA but I couldn't get it over the first barb of the pipe....I'm now considering 2 options 1: drill new holes in the cooler mounting flange and lower it by 2"...2nd option is to buy some solid aluminum bar stock and have it turned down to proper od and then bore out the center and use as a splice in the middle of each hose(kinda hokey but it should work). I double checked today with Link Belt and the parts guy told me that it is indeed 34mm and my measurements confirm that. Old machine problems I guess

Item#2: Shouldn't need 68 oil in Minnesota I would think. Might check to see if the hydraulic tank is overfull, as the oil heats and expands you lose airspace in the tank and as cylinders go in and out the air instead of compressing and expanding has to go in and out through the breather. Just a thought.

As to the hose fitting over the first barb, what's the pressure expected to be? perhaps the napa hose was a double braid high pressure and didn't have enough flex?

lantraxco said:

Item#2: Shouldn't need 68 oil in Minnesota I would think. Might check to see if the hydraulic tank is overfull, as the oil heats and expands you lose airspace in the tank and as cylinders go in and out the air instead of compressing and expanding has to go in and out through the breather. Just a thought.

Click to expand...

Well I greased and checked all the fluid levels about 4 operating hours ago as per the service manual and my hydraulic level was right in the middle of the low/full marks...pardon my ignorance but could I check to see if what you're suggesting is happening, by just removing the cap from the hydraulic reservoir when I start experiencing this or will I end up taking a bath in oil?

fast_st said:

As to the hose fitting over the first barb, what's the pressure expected to be? perhaps the napa hose was a double braid high pressure and didn't have enough flex?

Click to expand...

Not sure on that..I can tell you that the hose that was originally on it, didn't have any wire in it at all...more like a fiber sandwiched between to layers of rubber similar to a radiator hose...I'm just guessing but I doubt that it sees more than 125 psi.


edit: the Napa hose I tried was just a single wire hose that they said was for return hydraulic.

any pressure spec on the new short hose?

fast_st said:

any pressure spec on the new short hose?

Click to expand...

Unfortunately , no...plain black hose with nothing on it, like it was cut from in house made bulk stock..came in a sealed plastic bag with 2 tags on it..first one said "Sumitomo genuine parts...pn#KNJ1040 ...parts name Hose....made in Japan" ...second tag was a fedex shipping label mostly in Japanese with a shipping address to LBX company in Lexington Kentucky...I'm going to try a different LB dealer and see if I can get a guy that wants to investigate a little for me...They must have a spec book somewhere that would list the lengths of those hoses for various machines and find one close or longer than I need...they emailed me the bucket pin and bushing specs last summer that were very detailed so I would assume they have a data base somewhere they can tap into...been a good machine but this seemingly small issue is very annoying.

Perhaps its just a standard rubber hose without a pressure rating? If its low pressure, perhaps the one clamp on each end is just dandy.

Aw 46 is the correct oil for you're machine and climate, is the breather cap in good shape? LBX runs a pressurized hydraulic system relying on the tank cap to control system pressure

Daft question but what sort of shape is the hydraulic return filter in and is the oil heating heating up at all ,not over familiar with this machine but it sounds as if the oil is cavitating some where most machines will split the oil for the cooler and return circuit so it means not all of the oil is going through the cooler trace your lines on the return to tank back and see if any valves in the return pipe work hindering flow just a thought ,you should have a positive tank pressure.
Does the oil look frothy as its got air in or does it just sound noisy you could check to make sure all the suction side of the inlet from tank to pump are tight and not drawing air in.

Update: Thinking about Lantraxco and his suggestion I went home yesterday on my lunch hour and removed the cap to get a better look at both the fluid level and condition. Well when I removed the cap , there was plenty of pressure in there so I didn't think that was correct ( maybe it is, just didn't seem correct to me...I'm still learning about these machines...I've spent almost 20 years as a light truck diesel mechanic so I do have some mechanical experience, just not on these kinds of machines.) Anyway I brought the cap back with me to work and disassembled it...inside I found what appeared to be a chunk of grass stuck in between the 2 plastic "pistons" that appear to be the pressure release device? anyway I cleaned that and the filter , which was dirty but didn't appear plugged..anyways I got home and put the cap on it and used it pretty hard for almost 2 hours and NO NOISE! I had completely serviced the machine about 80 hrs ago with all new hydraulic filters, oil,fuel etc, but was going to refilter the hydraulic as a next step.

Mueller marine hit the nail on the head....assuming this has not turned into some sort of intermittent problem , which it hadn't been the last 4 times I used it, then I believe it to be fixed...I plan on using it over the holiday weekend quite a bit and will report back with a for sure answer...AGAIN, I appreciate all the advice and suggestions as I was really worried I would be looking at an big $$$ repair or if I continued to use it, break down and be unable to finish my projects

Gas Grass or hydraulic oil, nobody rides for free Good job on the repair.

Regarding your hose size problem. I have a 1991 LS2700C11. I had a similar problem with the main suction line from the tank to the pump inlet. I wanted to replace the hose and when I measured it was something like 65 mm. I couldn't find anything even close to the proper ID at a local hydraulic shop and I even tried a couple of dealers in the area (CAT & JD). Had no luck until someone suggested that if I used marine exhaust hose, it could had in oddball SAE sizes. So for 65 mm I ended up with 2-9/16 marine exhaust hose. It is a solid non-collapsable hose that is a little stiff to install with but it worked perfect for my application.

Well I used her for over 10 hours over the weekend and no issues! T_Gunn...the closest I can get with the marine hose is 1 3/8" which is 44 thousandths larger than the 34mm I need...do you think I should be able to clamp it tight enough for it to seal ? I was thinking instead of worm gear clamps like it has now , I could use some sort of banded exhaust clamp or something similar.

I took a closer look at my suction hose. Looks like it was a 60 mm = 2"-3/8". This link shows that there are 2 sizes close to 34mm

http://www.hbdthermoid.com/images/industrial_hose/coolant_7910_bellowsflex_a.pdf

I wonder if the 1" - 5/16 - 33.34 mm could fit? Also, in my experience, the t-bolt clamps pictured are far superior to a worm gear clamp.