TC24DA birthday breakdown Hydraulic system

tedf · Sep 16, 2012

Hello all,

TC24DA,2005, 260hrs, FEL, HST

Today when trying out my new birthday gift, Dolmar PS-510 chainsaw, I was moving my tractor to load up the FEL with the wood. I went over some branches on the way and started to move the FEL when I heard a weird sound. The hydraulic system was making a bad noise. I quickly moved it out of the spot and into a clearing to take a look. I see some fluid dripping from the bottom (stomach drops) so I bend over and take a look. The one rubber fitting has part of a branch sticking in it. The fitting looks like it slipped back off of the solid hose and has a crack in it. Looked at fluid and it is bubbly 紡ir! Took it slow back to the shed. I have attached some picks. Looks like Part # 44 on the part list, three way (T) HYD connector.

I have a few questions (and my opinion).

1 Does anyone have any experience with this type of repair? It looks like it should not be very bad as long as there is some play in the three hard HYD lines feeding the fitting.

2 Will lose all of my HDY fluid? I think yes/most from the location and the fact that it is still dripping 6 hrs after it happened. Is this a good time to change all my HDY/HST filters? I am not due until 300hrs and even though that is only in 40hrs it may take some time to get to 300!

3 After the repair and fill do I / how do I bleed the air out of the system? I replaced I 90deg fitting in the HYD system this year and did not have any air in the line issues. Does the system bleed itself?

4) Anything else I should know about the repair and start up?

Thanks,
Ted

jinman · Sep 19, 2012

Ted, I don't know if you've already done this job, but I'll take a stab at helping. I'm not sure if the lines will flex enough to to get the "T" boot replaced, but I'm guessing you may have to remove the pipe going to the main pump or at least loosen support brackets to allow some flexing. As far as your system leaking out all the oil, this should not happen. The big pipe input to the "T" is from the top of the filter. The reservoir level is below this point and you can change the filter without draining the reservoir. However, since the "T" is below the level of the reservoir, you may have developed a siphon that sucked out all the fluid already. To defeat the siphon, just loosen the filter so air can get into the line at that point. You'll probably also get drips from some fluid flowing backwards through the main pump, but not too much.

I would be prepared to remove the line going to the top of the main pump. By prepared, I mean I'd have a new o-ring seal purchased in case I have to remove that pipe to get the boot on. Since this is a suction line, it is never under a lot of pressure. The front of the "T" is the inlet to the main pump, and the top is the inlet to the HST transmission's charge pump.

EDIT: Oh yes... From the looks of that fluid flowing out of the transmission, it is still very clear and has no water in it. It's probably fine. The only thing that bothers me is how much fluid you have left in the reservoir since you said the tractor started making funny noises. The noises may have just been the pumps sucking air at the busted "T", so your reservoir may still be at a nearly full level. If it is, I'd say you could go either way with changing the fluid. If it is half empty, I'd just go ahead and replace the fluid since you'll be buying 1/2 the full reservoir quantity. Either way (refill or drain and refill) I think you'd be just fine.

EDIT2: Happy Birthday! My birthday is Sept. 14th, so we are really close. However, this last birthday was 65 for me, so now I'm qualified for Medicare.

tedf · Sep 22, 2012

Jinman, thanks for your response. I am still waiting on the part from my dealer. I took a quick look and you may be correct about getting the “t” on without removing one of the lines. I may stop at the dealer today and check on the o-ring. Hope they have it in stock as they seem to be on a 1+week timing for parts. If I have to remove the line, are you referring to line # 5 or #6 in the drawing?

I lost ~ 1.5 – 2.5 gallons of fluid. I see there are two filters (both look the same) behind the rear right wheel. I assume one is for the HST and one for the hydraulic system (only one is on the pic I posted of the parts, the other must be on another page). Can I change both filters without losing all my oil? I still have not decided if I will drain all 4.2 gallons and change both filters but I am leaning this way. The reservoir was close to full when I got back to shed so I think it was just air in the lines that caused the funny sound when using the FEL.

Happy Birthday to you! Hope you enjoyed your day and have many more!
Thanks again for your help.
Ted

jinman · Sep 22, 2012

Yes, you can change filters and only loose a very small amount of oil. I think line item #5 is the easiest to remove for ease of replacement. I don't have any detailed experience with the TC24DA though. Good luck and be sure to let us know how it turns out.

tedf · Sep 23, 2012

I took a good look at the options yesterday. Both sides look to be difficult to remove. Pipe #6 may be better (still not sure), do you know how the joint labeled B on the diagram connects / seals into part #25? Is this a press fit that is secured when you bolt down the top? I do not see any other way it connects.

I am discouraged with this repair before I even start. The access is bad on both sides and even if I can get to the area that #5 and #6 terminate there are hard pipes on the mating fitting that go to areas that do not have any access without taking apart a lot a stuff. I guess I don’t have any choice at this point.

One more observation, when I took the clamps off to see if I could slide the T on / off the clamp #23 on the #5 side was very loose and the support bracket that holds all the lines was twisted off pretty far (you can see it in the pictures). I wonder if the branch pushed the rubber T and support bracket hard and loosened the line causing the leak and that the T is OK. I think this is wishful thinking do to the fact that the picture shows the fluid coming from the top of the T. What do you think, should I tighten everything fill it back up and see what happens? I guess if I have a clean bucket to catch the fluid if it leaks again I can reuse it if I have to replace the T. Any other down / upside that I am missing?

Ted

jinman · Sep 23, 2012

Ted, it seems obvious to me from your picture that the "T" slid down the pipes and may have loosened. If you wipe the "T" clean using some diesel fuel or rubbing alcohol, you should be able to see any physical damage. If you see none, I'd slide the "T" back into position on the pipes and tighten the clamps. Also, there is nothing wrong with getting new premium clamps and putting them on there too as a double clamp if needed. I thought you knew for sure that the "T" was busted. If not, I would certainly try to refit it and go. You do need a good seal, but this point is always under suction when the tractor is running.

As far as the fittings on the filter spin-on adapter. I think you just put an o-ring inside the adapter, apply some lube to the fitting and gently press it into the adapter. The Repair Manual for my TC45D shows a similar fitting and just says to remove the pipe after taking off the bracket holding it in place. Again, since it is a suction filter, you don't need high pressure seals or fittings at this point. That's also why I suggested removing pipe #5. The fitting on the hydraulic pump's suction port is just not as critical as a pressure fitting. All it has to do is seal so that air isn't drawn into the system. That would show up as foamy hydraulic oil in the reservoir and cavitation sounds in the pump and HST.

I'm gonna keep my fingers crossed that your "T" is fine and you can re-do the clamps and only be out the price of replacing your hydraulic fluid.:thumbsup:

tedf · Sep 26, 2012

Jinman, finally got my part from the dealer (no o-rings in stock). Talked to the mechanic about the repair and he agreed with you on pipe #5. Went out tonight and checked the “T”. It was bad, big cut at the joint of the T. I pulled off the old one without removing any lines. Could not get the new one on just as you thought. Removed the 3 bolts from the top of the pump and then the two from the side of the other pump (I think). The pipe lifted off nice and easy! Still had a tuff time getting the “T” on the remaining two pipes, just gentle force. Slid #5 back in place and then the worst part of the job, putting the three top bolts back on. Not much room for my big paws. Got it all back together and will cross my fingers on the o-rings.
Changed the Hyd and HST filters and will drain and fill tomorrow or Friday (out of energy tonight).

A few questions:
1) After filling up the Hyd fluid is there a startup procedure I should follow? I am guessing I should start the tractor and let it run for a few minutes, shut it down and check the fluid. Add more if needed then re-start and slowly operate the HST and FEL and check for leaks. Does that sound correct?
2) I have been told the system bleeds itself (getting air out) is this correct?
3) Any other considerations when bringing the tractor back on line?

Thanks for all your help. I really consider myself lucky that you responded to my post!

Ted

jinman · Sep 27, 2012

Ted, glad to hear of the great progress. When you refill the reservoir, start the engine and let it run for a few seconds at low rpm (30 seconds should be plenty or 1 minute maximum). Shut it down and then crawl under the tractor to look for seeping leaks. Your pump will take a few seconds to prime. The delay is so that the main pump and HST can draw fluid into the filter and into the pipe until it is full. Since there is no fluid in the pipe, it will take a few seconds for the pumps to self-prime by drawing all the air out of the lines. If you find no leaks, start the engine again. You may actually hear noise in the piping as fluid and air mixed will cause cavitation in the pumps until all the air is out. Since you have an open-center hydraulic system, it self-bleeds just as your dealer said. All the air will end up back inside the reservoir and escape through the vent pipe. You can work your 3PH and FEL and drive to see that the HST is working normally. Any remaining air will be expelled when you do that. After running for several minutes and testing for normal operation, stop the tractor and look for leaks again. To check the o-ring seal at the pump and while the tractor is running, spray some WD-40 or light lube oil around the base of the fitting to see if it gets sucked in. If there is no sign of air leaking inward or your fluid being sucked in, your seal is fine. Good luck!:thumbsup:

tedf · Sep 30, 2012

Jinman, I finished the job Friday. All new fluid and as of now no leaks or issues! I used the tractor for about 1 hour getting a few loads of wood moved around. Used the 3PH, FEL, the HST in high and low and the 4x4 / 4x2. Everything seems to work fine. Parked it back in the shed and checked for leaks over the weekend (none). Feels really good being done with the repair and even better having my tractor running again! Thanks again for all your help. Ted