350C Reverser Rebuild

[BSims66173]

I have a JD 350C that has lost power. I have checked the pressure at the control valve and I am only getting about 70 psi in both forward and reverse. I have tried shimming the relief valves but that did not help. I guess it is time to pull the reverser. What parts need to be replaced? Looking at the diagram, I see a clutch disc and plate for both forward and reverse. Assuming all bearing are still goog. is just replacing these parts and any seals all that needs to be changed? Also, how can one tell if the pump is worn out? What needs to be replaced in the control valve also. I would like to get this machine back in good working order, it has been neglected for years. It has a lot of loose pins and bolts but it is still a pretty good dozer. Any advice will be appreaciated.

Barry

[jdemaris]

I have a JD 350C that has lost power. I have checked the pressure at the control valve and I am only getting about 70 psi in both forward and reverse. I have tried shimming the relief valves but that did not help. I guess it is time to pull the reverser. What parts need to be replaced?
Barry

Seems a bit unusual to get an even 70 PSI in forward and reverse at all RPMs. Are you sure the clutch pedal linkage is returning fully, and did you try opening up the rate of shift screw? Also, have you tried blocking off the pressure line that goes to the steering clutches to see if then the reverser pressure goes up? My point being, how do you know you're not losing that oil pressure in the steering clutch packs?

As far as rebuilding goes . . . generally speaking when a reverser is worn, all moving parts will have wear. Some of this also depends on the vintage of your reverser and how many times it's been repaired before. Also depends on how perfect you want it, and how many useable but worn parts you are willing to use over again.
Being a C series, the seals will be rubber instead of steel except for the forward-reverse manifold. At the least, you're going to need new rubber seals, probably a new manfold and iron rings. Pump gears and housing are easily checked just by appearance and feel. Maybe some or all clutch discs, depending if they are burnt or warped. In the control valve assembly itself, the shift-fork inside will need repair or replacement.

When a shop does a reverser and work has to be warranteed - parts that are 50% worn are not resused. When it's your own machine, it's a different story. You could spend a small fortune if making all like new, considering all the isolator parts, front pump, input and output shafts that tend to have worn splines, etc. To make all "like new" you could spend many thousands of dollars.

[BSims66173]

jdemaris, when it first lost power, I was running the machine and pushed in the clutch to shift from forward to reverse, when I released the clutch pedal, it felt like it stuck about halfway out. I used my foot to pull it out the rest of the way and it would barely pull then. I have not blocked the oil to the steering cluthes or messed with the rate of shift screw. All I have done to this point is checked pressures and relief valves. It would pull good until this happened. I thought it might be something in the control valve but I am not sure. I know very little about these machines but have the manual and am very mechanically inclined. I have had the engine out before and had it rebuilt, put a new transmission in it but I don't think the reverser has been into at this point. The previous owner did not mention anything about it anyways. I have had the machine for about 12 years now and just want to get it back in good working order without spending a fortune. I just use it around my place and have just bought a one man sawmill and will need it to skid logs. It has a winch on it that I also plan to repair.

[BSims66173]

Finally got the crawler in the shop and checked a few things. Checked the bypass valve and adjusted the restrictor valve and nothing has changed. Haven't blocked the fluid to the steering clutches yet. I am not gaining oil in the transmission or losing oil out of the reverser so I don't think it is the steering clutches, but will check to make sure. If I take the 120# relief out and start the tractor, will that put full pump pressure to the test gauge? I guess what I am asking is there a way to actually test the reverser pump output pressure. I am getting the same pressure to the forward and reverse clutches. I was mistaken when I first posted 70 psi. It is actually around 50 psi. With both the forward and reverse pressures the same, I wonder if the pump is the problem. Again, any help is appreciated.

Barry

[dirtguy34]

Have you checked your filter in the reverser? And the condition of the oil.
Make sure it's not contaminated.

[BSims66173]

I hope like hell that was not it. I have the engine pulled, the blade and blade frame off and the operators console off of it now. I will pull the reverser this week. I plan on going through nearly the whole machine while it is apart. I have a lot of worn pins and bushings that I am going to replace. The engine probaly has less than 300 hours on a major rebuild, New injector pump less than a year ago. Both finals have been rebuilt, transmission has less than a 1000 hours on a total rebuild. I hope to have everything in good shape when I finish. I am not going to do anything to the under carriage at this time. I know some of the bottom rollers need to be changed. The tracks and pins and bushings are not that bad so I will wait a while on that. Overall its a good little machine and I plan on putting a new paint job on it while its apart. I doubt I would ever sell it and it should last a long time no more than I use it. Wish me luck. I will try to take some pics and post later.

Barry

[RANDY Fay]

Be sure and take hydraulic reverser accumulator housing apart
This is where oil flow --forward -- reverse--and nutrel is controled.It is also where dump valve for foot clutch is located--This is where your problem could be have fun Randy

[BSims66173]

Well, I got the ole girl down to the bone. All thats left bolted together is the tracks, trans and finals. I have the reverser apart and cannot find anything obvious that was causing the low pressure. I am waiting on some parts from Deere and will reassemble everything. I was suprised at how little wear there was on the clutches and plates measured against new ones. Nothing was burned or warped. After I get it all back together, is there a way to test the pressure before reinstalling. I have other work to do on the machine that will take a while, but would like to know if it is going to work. I thought I read some where that you could spin the pump with a drill, if I can find a chuck big enough to fit the shaft. I thought about making a simple coupling to fit over a few of the shaft splines that will fit a 1/2 in drill. Will this spin it fast enough to get any pressure? Is it possible to lose pressure in the steering clutches and not gain oil level in the transmission? I was not losing any oil from the reverser or gaining any in the transmission. The only thing I have found at all is the tubes from the control valve to the manifold were somewhat loose, but not sure if they could be leaking. Thanks in advance.

Barry

[CatD8RII]

To me it sounds more like a control valve problem than a clutch pack problem, especially since you had a problem right after pushing the pedal in. Have you inspected the control valve yet? Especially the clutch pedal valve.

[BSims66173]

I have been in the control valve and didn't see anything wrong. The clutch piston had a little scoring that I buffed out. The clutch valve looked good with no scoring at all. I replaces all the seals and gaskets and put it back together. One thing I noticed today after getting it back together is the arm on the clutch shaft does not go all the way to the stop on the valve body in the released position. I didn't notice if this was the case before taking it apart. I guess I will pull it back apart and inspect it very closely. I can see the clutch valve move looking in from the back side. It looks like it moves about a 1/4 inch. From that point on I can tell it is compressing the spring. Does that sound about right for the valve travel? Anyway, I am still waiting on the rubber washers for the reverser pistons and I will put it back together. Still haven't gotten any answers on some of my previous questions, but I will try the drill to see if I can get it to build pressure. Thanks for your replies.

Barry

[BSims66173]

The first pic is of the clutch valve lever. You can see it has a recessed area on one side. Is that supposed to be there or is it worn that much from the pin? If it is wear, I will weld it up and mill it back down smooth. The next pic are just showing whats left of the ole girl. Can't wait to get her fixed, painted and everything tight. It will be nice to run a tight machine.,

[CatD8RII]

Thats wear on the lever ,it should look the same on both sides. Looks like youre going all out too.

[CatD8RII]

BTW the drill will work too as long as you can get the speed fast enough , you just need to loop the cooler lines.

[shinnery]

Nice looking shop at least, I'm impressed. Is that a lathe and two milling machines? Looks like a fun job on the crawler.
Bryce

[BSims66173]

Bryce, yes, I have an old Bridgeport, a tormach CNC and a shopfox 13x40 lathe. I am by no means a machinest but like playing around with them. The Bridgeport was given to me by my uncle who has two machine shops full of CNC equipment. I bought the Tormach because it was a great deal off Ebay. I just recently bought the lathe to replace an old Atlas lathe my uncle had given me. For many years, the only place I had to work on stuff was in an old run down chicken house with a dirt floor. About five years ago I finally built a 40 x 60 shop and now my wife says says I should just move my bed out there because I spend so much time out there. It's just nice to be able to drop a nut on the floor and not have have a shovel to find it. The pictures don't show it, but at the other end is the wood shop with all the saws, planer, CNC router table and all the other junk I can cram in there. When I built the shop, I thought a 40 x 60 would be plenty of room, but it filled up very fast. Anyways, thanks for the compliment.

Barry