Hi, I recently purchased a 1960’s era D grader (in NSW, Australia). It originally had the Allis petrol engine in it, but has had a little Cummins four cylinder diesel fitted later. I am loving running it. 

It’s a pretty tired old machine, so my expectations are low, but there are a few things that I would like to fix up if I can. I’d appreciate any advice anyone can give.

Biggest issue: the hydraulic ram that lifts the left side of the blade wont hold. Raise it up and it just wants to slowly drop again. The ram is leaking oil a little, so I figure the first step is to fix the seal and see if that helps. Can anyone point me toward a resource on how to rebuild these rams? Is it something I can do myself, or should I just pull them off and send them to some one to do for me?

Did any of these graders have an hydraulic steering booster? The steering is a real bear (of course) - not helped by the front wheels being “floppy” left and right as I have a feeling the wheel tilt mechanism was removed once upon a time (the piping for its hydraulics is still there on the nose).

Anyway, thank you in advance for any assistance. It’s greatly appreciated.

Langdon

The most likely cause of the dropping is the packing on the inside piston. A simple way to test, feel the temperature of the cylinder with you hand after lifting up and letting it fall several times. The pressure of the bypassing oil will generate heat in just several cycles. If the cylinder is not heating, it is most likely the control valve.

Hi Ray, thank you for the reply. That's a good trick to test whether it's the ram packing or the control valve.  I'll give that a go on Monday and see what it tells me.

In your case where are you going to find a AC dealer, or someone to change AC part numbers to generic. So just be prepared to have it sitting until the parts show up.

I had a D grader at one time and believe it must have been designed by someone that had never operated a grader. You need four arms to operate it. I modified mine so one hand controlled both sides of the blade operation and the other hand on the steering wheel. I created a heel and toe foot throttle for one foot and the other foot operated the clutch and brake. I also rigged up power steering that could steer the steering wheel with one finger. Now it was a great machine.

Hi Don, yes I'd expect that a hydraulics shop will be able to do the rebuild, it's just a question of cost then.

You are not wrong about needing four arms for this grader! I'd be pretty happy with mine though if the blade didn't leak down and it was a bit easier to steer.  I'm considering adding an hydraulic power steering booster to it.  It will be a simple enough upgrade and make it a *much* more tractable machine.

You don't have any photos of how your D was set up do you?

I have not really learned much about picture posting. But have found there is only so much storage space for pictures on this site. Once you have used it up delete older pictures if you want new ones. Or place them elsewhere and put in a link. All takes me finding a helper.

Update: I have pulled all three of the rams off the grader and due to time limitations I have sent them off to a local engineering company to refurbish. 

When I pulled the ram off the ripper frame I found that the rod has some pretty bad scoring on it (no idea how that could even happen, but there you go!).  So I'm thinking that I might just replace it entirely if the cost of refurbishment is too high.

I picked up my remanufactured hydraulic rams this week!

They have been fully rebuilt - new rods, pistons, glands, and seals. It cost $700 per ram, but given the amount of work involved and the expected life span of the rams now (not to mention the ease of servicing in the future) I think that was a more than fair price.

I'll be getting them back on the grader this week coming and hopefully getting into some work with it.

So I got all of the rams back on the grader and hooked up.

I've been running the machine for a few days and it's been working well. Only issue is I haven't managed to get the hydraulics bled properly yet. There are bolts on top of each ram for bleeding the top side of the rams, but can anyone tell me the best way to bleed the bottoms?