Steamer

[tracksntreadslou]

Looking very good rob..that brute will be able to haul twice as much as Regs Uclit lol ..Hey I hope you can forgive me about the trash talking..

[RCP57]

What? That's it...I'm building a 797 in 1/10 scale! Haha

[steamer]

Wow Reg that things going to be huge. You will almost be able to sit in and drive it. Been working building the two stage cylinders and they now are finished. Still haven't tried them yet but I think I have all the bugs worked out. Will try to get pictures up tomorrow.
Rob

[Espeefan]

Nice work on the Mammoth, Rob. The new rims are nice. The Aeromax looks like a really nice truck too. The dump trailer fits it well.

[Dairyland Trucker]

The dump looks better with the new planitary hubs and painted, the dump trailer is awesome as well love it looks like what we have used a Clements bridger trailer...

[steamer]

Well here's the latest on the cylinders. First picture has one cylinder in pieces and one together. First big problem I had was I was trying to hold too close a tolerance on the rod guide bushing and this caused them to bind up.

So I took everything apart and polished the piston rods down another 2 thou and they seemed to work better but still hung up coming back down. Should say these are single acting so are supposed to fall when the pumps are reversed and remove the oil.

What I think is happening is the oil is creating suction when the pistons bottom out in the bores as there's no way for the trapped air and oil to escape.

So I think the next job will be to drill an #80 drill out through the end of the first stage guide bushing and the end of the second stage guide rod. It's a long shot and I'm hoping that it will break the vacuum to stop the hangups.

One thing I must say is that there is no lack of lift with those small wedico pumps. With the large bore of 3/4" and the small one at 3/8" it will lift a 11 kilo bag of lead up like crazy. Even tried the bag out on the rock lid and it didn't change at all. From box down to full up about 10 seconds.
Thanks for looking
Rob

[RCP57]

Lookin real good Rob!

[Lil Giants]

That looks awesome Rob, I'm sure it works super slick!

What's your closed vs open lengths?

Pics of them installed open & closed would be a treat!

Is there a procedure you do to bleed the cyl when 1st oil is pumped?

The rule of thumb I have always done with the wdc & Leimbach telescopes to remove all the air was to turn the cyl upside down, so the entry of oil is at the top. Then extend the cyl with pumped oil, keeping some resistance pressure by holding base in my hand - other end against my knee till its fully extended. Relax, wait a few minutes for air bubbles to rise to entry/exit fitting. Then with some force by my own hand 1st & then activating pump to reverse oil flow with constant hand force too till cyl is fully retracted. Repeat process 2 more times to ensure every last air bubble is out of the system and hopefully telescope works smoothly.

[RCLogger]

Nice work Rob. Thanks for the photos

[steamer]

Here's a picture and a couple of Video from the Trains show yesterday in Campbell River
Good comparison of the 966 and 980 side by side.

Vid

Vid

Vid


More to come after todays show.
Thanks for looking
Rob

[Lil Giants]

More to come after todays show.
Thanks for looking
Rob

It's great to see what you posted thus far Rob.. I was waiting to comment after you posted the rest of the eventful wkend.

[steamer]

789C is finally cosmetically finished. Just need to build the radio rack and do some more work on the hydraulic cylinders and she's ready to haul dirt.



I have to modify the lift cylinders because the tolerances were too tight and won't come back down properly. I think if I change from o rings to cup seals it should work better.
Thanks for looking
Rob

[Espeefan]

That looks really nice! Way better then the Tamiya Mammoth it started out as. Nice job.

[RCP57]

Looks sweet Rob! Hopefully I will get to see it soon!

[RCLogger]

The frame looks good with that fresh paint. Looking forward to getting it dirty.

Greg

[Old Guy]

Rob

I had the same problem witn my telescoping cylinders I found the solution was to add a ring just above the piston seal about 1/2" wide this eliminated the binding problem. I was lucky with the rear dump as I had more stroke than I needed and could add the 2 1/2" stops
Hope this helps.
Earl

[steamer]

Earl. thanks for the great suggestion. When I get back on the project I'll give that a try. I also thought about putting in return springs on the piston rods inside the cylinder. There's lots of room inside and more power from the pumps than needed to lift the body full of dirt. I'm hoping that the spring action will start them down.
Thanks Rob

[Old Guy]

Rob
Like you I was getting frustrate with the slow down on the 2 stage cylinders on my rear dump, so I fixed it Ij ust reverse the hydraulic pump it comes down as fast as it goes up, I could do this as the pump I built and I knew I could reverse it and the pump is only connected to the lift cylinders, just a thought

Earl

[steamer]

I'm using Wedico pumps on this one and they're designed to run both ways forward and reverse. My problem is when the cylinders are full stroke the pumps pull all the oil out and create a vacuum. You can imagine what happens then, the box slams all the way to the bottom because there's no oil cushion left in the cylinders. I thinking with the internal springs there should be enough return pressure to start the box down when the pump reverses. At least that's what I'm hoping for.
Rob

[RCP57]

So Rob, Are you coming to Duncan or what?