Rebuilding The Hydraulic System on A TerraTrac Crawler

[Iplayfarmer]

I've decided that it may be easier to consolidate my progress and questions by making one thread about rebuilding the hydraulic system on my TerraTrac GT30 crawler. Thank you to all for your input on my other two threads here in the Hydraulics forum. In keeping with the status quo on TractorByNet you've helped me to spend more money than I had originally planned. I ordered two double acting 34" stroke cylinders that should arrive sometime next week.

The attached picture is of the culmination of an entire days work. I took yesterday to measure, mark, and calculate what the bracket would need to look like in order to mount the new hydraulic pump so that it AND the alternator can both be driven off the fan belt. It doesn't look like much, but I consider it a masterpiece. I'm sure I'll have to modify something on it by the time this project is over, but for now it's great.

I had some questions about the size of my valve, but I think I've resolved them. The pump I bought says that it's rated for up to 10 GPM, and the hose size guide says that I need larger hoses for that kind of flow. But, the pump's suction and pressure openings are the same size as the fittings on the valve I have to use, so I'm going to go with it.

What has filled my idle thoughts today has been where and how to mount a filter. I'm sure I want it after the tank before the pump suction port. The most likely place is out on the front of the crawler. Is that a bad idea? Do these filter have to be mounted right side up, or can I mount it sideways?

The other challenge I'm going to face is routing hoses for the lift arm cylinders. The older cylinders were single acting, and the new cylinders are double acting. I'm going to need a place for another two hoses. The current configuration includes a hard line plumbed across the front of the operator station. I may try to add a second hard line since I think that would look the best. Can good old galvanized pipe be used on a hydraulic system?

 

[oldnslo]

Do not use galvanized pipe or fittings for hydraulic lines. The galvanize coating will come off destroy your hydraulic components.

What speed - RPM are you spinning the pump? Take RPM times displacement in cubic inches and divide that sum by 231 to arrive at GPM pump flow.

For pump inlet line size do not exceed flow velocity of 4 feet per second preferably less to prevent pump cavitation.

Filters can be mounted horizontal but be sure to protect it from branches, etc.

 

[Iplayfarmer]

I知 not exactly sure what speed it will spin at yet. First I need to find the speed of my engine. Then I can calculate based on the ratio of pulley sizes. I知 assuming I値l be in that 2,000 rpm range.

 

[WranglerX]

I would avoid any galvanized fitting and/or any "pipe" fittings..... Only buy high pressure approved fittings from hydraulic equipment supplier....

Dale

 

[Iplayfarmer]

Some updates on my progress. I got the bracket painted and installed. I was right in predicting that I'd probably have to do some modification. The pump mounts fine and clears everything, but the pullet interferes with the radiator hose. I raised the bracket up so that it mounts on just the two upper bolts, but now I need to fabricate some a new mount for the alternator because it too must go up. I may end up back at the drawing board completely. If I can't get the alternator to play nice I may end up swapping and putting the hydraulic pump on the top and the alternator on the bottom.

I did measure my crankshaft pulley last night, though. It's 6" diameter. My pump pulley is 4" diameter, so that puts my pump speed at half again the speed of the engine. At 1600 rpm engine speed I'll be spinning the pump at 2400 rpm. In the end It may work better to get a larger diameter pulley to slow down the flow.

The attached picture is of the pump mounted in the engine bay BEFORE I saw the interference and raised it up.

 

[Tinhack]

When I built the "Kenbota", I put the filter line on the output port of an open center valve. Plumbed to a convenient location, of course. The outlet side of the filter went to the tank. You could also put a cooler in this line as it's low pressure at that point. The tank is expected to always have clean oil. You also don't want anything (except maybe a strainer) restricting the suction of the pump. A soft suction line will collapse. That's what was happening to my JD dozer with an old 1 1/2" suction line. The old rubber just got soft. Pretty pricey replacement too.

This shows the location of my Kenbota hydraulic filter.

 

[Iplayfarmer]

The tank for this machine is actually the inside of the loader frame pipes, and it hasn稚 been used for a while. (The crawler came to me with a dump trailer style electric over hydraulic system.). I may mount the filter between the tank and pump temporarily until I?m confident that any dirt and debris have been cleaned out. Then that system with the filter between the valve and the tank makes a lot of sense.

 

[Iplayfarmer]

On another note, I decided to add an idler pulley to my configuration. When I got the alternator and the pump set in place the belt was only engaging with about an eighth of the pulley. Adding an idler will get more belt to pulley contact AND give me an easier way to tension the belt.

 

[Iplayfarmer]

I have a few updates to this TerraTrac project. I took a few weeks off of work for Christmas, and carved out some time to work on it.

First of all is the final bracket assembly for the pump and alternator. In the end I feel like a GM engineer... I over-complicated things and managed to have bolts that are almost inaccessible. But, everything fits, and the belt has pretty good engagement with the pulleys. I still haven't run anything yet to make sure the belt stays where it's supposed to be, but things look lined up and secure when I poke my head in there. I have included a few pictures of the final bracket assembly. Between the two pictures hopefully you can see the details of how it all goes together. You can also see from these pictures that I am not working in any kind of heated shop like some of you have. I do have a roof over me, but there's no shortage of snow and ice that ends up on the machine in between working on it.

The other tidbit relevant to the engine bay installation is that I received the bearing for my outboard pump bearing. This is the bearing that I had to order from the UK. To my relief it fit pretty well. I did add a little locktite to the outside race of the bearing just to give a little extra security. It seems like it's going to work how I need it to. I plan to be careful about tightening the belt too much. This is as much for the lower crank bearings on the engine as it is for the pump. I guess if I have issues with slipping I'll troubleshoot when it happens.

 

[Iplayfarmer]

I'm breaking the progress report into a few posts to make it easier to see what pictures go with what part of the description.

While I had the engine bay all torn apart I decided that there would never be a better time than now to rewire the whole machine. With the exception of the main battery cable, I replaced every wire on the machine and ran it all through plastic looms. It really improved the look of things, but primarily it should prevent problems that were inevitable with the old, frayed, brittle wiring that was in there. Part of this process was to add headlights to the front as well. These are vintage fixtures that I've had on my shelf for years. My hoarding tendencies have, once again, been validated.

I added new switches, new gauges (including oil pressure and coolant temperature lines), and I added a fuse block. As a side note, I also replaced the carburetor with a new Kipa carb from Amazon. I had to do a lot of measuring and researching because there's no cross reference table for these old TerraTrac crawlers, but I ended up getting one that fit "mostly". I had to keep my old throttle and choke linkages to maintain compatiblity with the controls on the dozer, but the rest of the carb matched up just fine. I still have not tested anything because I don't have any hoses run to the pump, and I don't want to run it while it's dry.

The new headlights on the crawler make it look like a snail in my opinion. Another guy said it looks like the shrimp off of "Finding Nemo". The second picture is of the new gauges, and you can kind of see the wire looms underneath the dash plate.