646-75lbh Restoration

[Spike188]

Sep 20, 2022

The engine has been dropped of at a machine shop for boring and a wish list sent to Boomer. In the meantime the hoe will get some attention. After reading Harry's post of issues with his bucket not curling, it was the motivation and encouragement needed to give the hoe a proper rebuild.

The 646L hydraulic system was used to stretch out the hoe for pressure washing and joint pin removal. The center pin was seized and took a lot of persuasion to remove. At one point consideration was given to drilling and tapping the pin for using a hollow core cylinder to pull the pin out.

2 items added by a PO were found after removing the center pin. A 2X4 block was wedged under the 4 hard lines and a clamp made of steel had been used to support??? the lines. The clamp bolts were bent over and nuts damaged beyond turning. Because the bolts were tapped into the frame they turned out of it easily. Time has not been taken to see if there is a proper pipe clamp that is missing from the joint area.

The 2 long cylinders came apart much easier than expected. The Davis manual says the the gland nut is torqued to 200 ft/lb's. The end caps were not much more than hand tight and the gland nuts broke loose with a cheater.

There was quite a bit of filth inside the cylinders, probably 45 years worth. The 646L was used for testing the hoe so it will definitely need an oil and filter change before doing any work.

The gland guide on on barrel has a lot of gall marks. The barrel is also scored. The barrel will hone but no decision has been made on whether to reuse or make a new rod end.

The crushed hard lines were taken to a local hydraulic shop and duplicated with a 24 hour turnaround. The price was roughly 3 times the price of a same length hose.

Still digging in,

Eugene

[Spike188]

Oct 7, 2022

2 out of 3 cylinders cleaned up very nicely.

This one has deep scoring so it will be paired with a slightly pitted ram. Since this cylinder will be a candidate for replacement it will be used as the bucket cylinder so that change out labour will be minimal. The good cylinder twin will be used in the boom position.

The first 2 cylinders came apart with very little effort but...

Over 3 hours was spent removing the ram and cap from the dipper cylinder. After removing the snap ring, the end cap would only move just past the snap ring grove. Remembering the problems that Lionel ran into with one of his rams a different approach was taken. The cylinder bottom was pinned to heavy wall tubing which the forklift was parked on top of and the ram end was tied to the forklift mast. After 2 attempts of lifting the mast forks and bending the 2" X 1/4 wall tubing it was time to rethink what was binding. On close inspection the snap ring grove was hammered and mushroomed. Using a Dremel and grinding burr the mushroom area was removed. The ram pulled out by hand with with 3 good pulls.

Keep digging

[Spike188]

@Eugen These are the types of cylinder and glands used on my D100.

[Spike188]

Oct 12, 2020

After replacing glands and o-rings, the end caps needed persuasion when clearing the bore end. A welding clamp did just the job.

With 3 cylinders completed, it was tempting to carry on without opening the swing cylinder or outriggers.

The Swing cylinder removed very easily because it was all that was left connected to the valve bodies. This was where the biggest surprise came. The double ended ram is also a reservoir, hollow through to a valve on the other end.

That end is solid and has a cushioning valve in it.

The hollow end was full of sludge

and the valve end full of debris.

Debris in the valve could have became and issue and maybe where system crud migrates to.

The debris appeared to be hose lining and maybe some o-ring or gland.

Eugene

[Spike188]

Nov 7, 2020

Today's project, $90.00 worth of o-rings. 4 between each valve, 2 on each spool and 6 on relief valves.

There is a stop missing on one of the spools but it can be replace with the unit assembled. The spools do show a bit of wear in the od but no scoring. This job was made a simple by taking a valve body to a local supplier so that he could measure the recesses and cutouts for the proper size. Of 46 o-rings in 6 sizes, all but one size was in his stock, and his order was here overnight.

Sorry, I forgot to take pictures.

Eugene

[Eugen]

This is great help @Spike188 ! Very timely too! Thank you! Look, your tips allowed me to get the first rod out!

[Eugen]

Nov 7, 2020

Today's project, $90.00 worth of o-rings. 4 between each valve, 2 on each spool and 6 on relief valves.
backhoe valve rebuild.jpgThere is a stop missing on one of the spools but it can be replace with the unit assembled. The spools do show a bit of wear in the od but no scoring. This job was made a simple by taking a valve body to a local supplier so that he could measure the recesses and cutouts for the proper size. Of 46 o-rings in 6 sizes, all but one size was in his stock, and his order was here overnight.

Sorry, I forgot to take pictures.

Eugene

But did you keep track of the sizes?

[Toolslinger]

I just checked... Apparently I didn't keep track of the sizes when I had my 1.5 year long battle with the stack valve on my machine... I really thought I did... Perhaps on another computer, or in a file I've lost track of... I do love the computers, but there's something to be said for a clipboard with all the details of each machine's history in one place like all the machines at the farm have had my whole life... I've got the details, and prices of parts back to the 70's on those machines.

[DavidBarkey]

@Spike188 Wow Eugene thats coming along . Hope you get your strength and stamina back . Covid long haulers is not nice.

[Spike188]

All repair parts were sourced locally. The supplier measured the glands and cylinders to match up o-rings, backer rings, wear rings, and seals. All of the paperwork had his own part numbers on them making cross referencing to size difficult.