Allis HD - 6 and back hoe question

[Tom McLaughlin]

Well I am getting the HD6 back together with a different motor (Original blew)anyways the question I have a older davis backhoe that I made a frame for to put on the tractor but it is a bit heavy and moves the tractor around a bit. Has any body put one on the back of a dozer? I see the samller dozers had them but havent seen the hd6 size. Question I have is about the hydraulic pump being big enough? any thoughts or suggestions? I am not to worried about mounting it as I have all the fabricating means just courious about the pump. Thanks Tom

 

[Anonymous-0]

I see some guy with back hoe on but did't check if they change the pump and my hd6g manual parts
pages 346 can see a back hoe and in the manual he has 2 different pump in.

 

[JDemaris]

I've seen many with backhoes. More often the HD5s that are basically the same machines as HD6s, but with Detroit 2-strokes instead of Buda 4-strokes.

HD6 basically weighs the same as a Deere 450, and there are many mid-size hoes that fit fine.

In regard to hydraulics, it all depends on what option package the crawler came with. A Garwood dozer is likely to have a smaller hydraulic pump than an HD6 loader.

For a decent running hoe, you need to size the pump to the size of the cylinders on the backhoe. It's mostly a matter of the pump's cubic inches. The bigger the pump is, the better the hoe can run at lower engine speeds. A pump rated at 10 GPM at 1000 RPM puts out 20 GPM at 2000 RPM and 30 GPM at 3000 RPM. If you want to use the hoe with the engine running a comfortable 1500 RPM, and the boom cylinder is 4" to 5" in diameter, you need a pump that is 2.4 to 3 cubic-inches-per-revolution.

I don't know what you have now. A dozer or loader? If a loader, it's likely the biggest lift cylinders will be close to the diameter of most of the cylinders on a backhoe you'd use. So, you can judge if you've got adequate hydraulics going by how fast your dozer blade or loader goes up now with the engine running at moderate speed. If, let's say your loader has 5" cylinders and it goes up painfully slow - then a backhoe with a 6" cylinder will be even more slow.