Blackhawk 67405 Jack Rebuild

[BasketCase3T]

Hey all. I picked up this beast last year for scrap value, knowing it needed love. Most google searches on these jacks leads back to here, so it seems like this is my best bet for getting some advice. Got the reseal kit for it and am getting ready to dive in. The pump pistons cleaned up pretty well, considering the neglect. This was the main failure on this jack. The pistons just leaked and hissed fluid.

What do I need to know before going in? It looks like I need to find a 1" and a 2" spanner socket to get the nuts off for the pump pistons. Just take those off, replace the stack and reassemble? Are those stake marks and will they give me trouble?

For the lift piston, does it come out through the end after removing the seal? Sure looks that way from the diagram. Just pull it out, replace the seals on the rod and reassemble?

I appreciate any insight on it!

 

[paulsomlo]

Work over a tray in case any of the check balls go flying and try to note in which order they came out.

 

[BasketCase3T]

As an update, the pump nuts came out by gently putting a big screwdriver through the legs of a big pair of needle nose. They weren't all that tight. Still looking for info on how to replace the seals in the main ram. Does the ram just come out the end? There is no visible gland nut like I'd expect to see on a hydraulic cylinder.

 

[ajchien]

I found this for you:

https://media.hcrcnow.com/uploads/drawings/Blackhawk_B67405_Service_Jack_4_Ton.pdf

 

[paulsomlo]

Looking at the drawing, it appears that the ram just pulls out the end. I don't see a means for overextension limiting, but there must be a way that Blackhawk dealt with that.

 

[BasketCase3T]

Looking at the drawing, it appears that the ram just pulls out the end. I don't see a means for overextension limiting, but there must be a way that Blackhawk dealt with that.

That's what I saw too. Blackhawk handles this with a rod connected to the lift mechanism that will pull the release once it hits full extension. I did get a response in a FB group that said I will have a very hard time getting the seals in from the front, and I can fully appreciate that. I assume that I'd want to install them loose and be able to tighten the nut from the back. He said the best way is to remove the threaded barrel and that it can be a real bear. For now, I'm thinking that if it's not leaking, I might just leave it. I'll do all the balls and the pump seals and save the ram for another time if it ever starts to leak.

 

[paulsomlo]

That's what I saw too. Blackhawk handles this with a rod connected to the lift mechanism that will pull the release once it hits full extension. I did get a response in a FB group that said I will have a very hard time getting the seals in from the front, and I can fully appreciate that. I assume that I'd want to install them loose and be able to tighten the nut from the back. He said the best way is to remove the threaded barrel and that it can be a real bear. For now, I'm thinking that if it's not leaking, I might just leave it. I'll do all the balls and the pump seals and save the ram for another time if it ever starts to leak.

I'm guessing that rod is part # 75 on the drawing.

Yes, the threaded barrel (cylinder) will be very tight, several hundred ftlbs.. A large pipe wrench and cheater is needed and care needs to be taken to avoid flat spotting it, generally by inserting something solid and cylindrical inside to keep the wall from collapsing.