Blackhawk SJ3 Floorjack

[Billybdakota]

I am rebuilding my old Blackhawk SJ3 and have replaced all the seals, etc. . It now seems to pump OK but the lift arm falls back when I bring the handle back to the start position. Obviously something is wrong but before I start tearing things back down, I’d like to know if there is an obvious answer to curing the issue. Is there a manual posted online? Is there a troubleshooting thread or post I can check? Any help is much appreciated. Thanks.

 

[paulsomlo]

That sounds like "handle feedback" - I don't know that jack specifically, but there may be something going on with the balls in the working valve.

 

[paulsomlo]

I just took a look at the drawing - that's a two speed. Make sure you have all the parts in the speed and power circuits in the right order.

 

[RTM]

. Is there a manual posted online? Is there a troubleshooting thread or post I can check? Any help is much appreciated. Thanks.

I’d start here, all the GJ knowledge on SJ3

blackhawk sj3 jack site:www.garagejournal.com - Google Search

 

[paulsomlo]

https://media.hcrcnow.com/uploads/drawings/Blackhawk_BSJ-3_Service_Jack_2_Ton.pdf

 

[Billybdakota]

Thank-you all for the helpful replies. Paulsomlo may have hit the problem on the nose as the drawing showed different parts than what came out of the two chambers I rebuilt (I didn’t want to muck with the bypass chamber). The speed chamber did not have a small ball bearing as shown on the drawing. I put one in and it is entirely possible that there was one stuck at the bottom so that could easily be the problem. I don’t have a tiny magnet to fish out the chamber and I will get one and re-install in accordance with the drawing. I will report back. Thanks again!

 

[Billybdakota]

I emptied the chamber for the Speed Circuit and it contained the piston, gasket and two springs and two balls as shown in the drawing. I carefully replaced them and tried the handle - same as before. It pumped up but when I brought the handle back the lift arm fell down.

I then removed the screw cap from the Power Circuit and oil shot up, violently emptying the chamber. I can’t say for sure but I think only two balls and one spring came out with the piston and the gasket (That’s what I recovered on the floor). I replaced them in the order shown on the drawing and replaced the screw cap and added oil to the reservoir. Now no lift at all. All I can think of is the spring was not set correctly when I dropped it in. Does the large end of the spring go in up to meet the end of the piston?

Any other ideas as to why it doesn’t pump up?

Thanks!

 

[paulsomlo]

I emptied the chamber for the Speed Circuit and it contained the piston, gasket and two springs and two balls as shown in the drawing. I carefully replaced them and tried the handle - same as before. It pumped up but when I brought the handle back the lift arm fell down.

I then removed the screw cap from the Power Circuit and oil shot up, violently emptying the chamber. I can’t say for sure but I think only two balls and one spring came out with the piston and the gasket (That’s what I recovered on the floor). I replaced them in the order shown on the drawing and replaced the screw cap and added oil to the reservoir. Now no lift at all. All I can think of is the spring was not set correctly when I dropped it in. Does the large end of the spring go in up to meet the end of the piston?

Any other ideas as to why it doesn’t pump up?

Thanks!

My intuition says all springs small end down in both circuits. I think it's worth it at this point to open up the bypass circuit where part numbers 56, 57, and 58 are located.

 

[Billybdakota]

Well, I emptied the Power chamber again and Lo and Behold, there was a second small ball bearing stuck at the bottom of the chamber. When I removed it and placed the correct components back into the Power chamber (small ball, bigger ball, spring and piston) the Jack pumped up! But, back to the earlier problem. When you pump the handle down, the Jack cylinder lifts the lift arm but when you pump the handle back down, the cylinder retreats and the lift arm falls. I double-checked the Speed chamber and it seemed to be in order (small ball, small spring, bigger ball, bigger spring and piston).

I hesitate to touch the Bypass chamber since it does not appear to be leaking and the Jack worked fine (except for leaks) before the repairs started.

I was able to “override” the problem by pumping fast and at the end of many strokes the lift arm reached full height. Whether at full height or part full height, the lift arm appears to be stable.

I think the Jack oil is topped up but could it need bleeding? Any other ideas? Thanks again for the help!

 

[paulsomlo]

I hesitate to touch the Bypass chamber since it does not appear to be leaking and the Jack worked fine (except for leaks) before the repairs started.

OK - exactly what repairs and what parts of the jack were you into?

 

[Billybdakota]

I started out with a working Jack. It was leaking badly. I ordered the full rebuild kit and replaced the main cylinder seals. When I put the Jack handle on, I put the disc on the wrong side of the bypass lever so the lift arm didn’t drop when I turned the handle cap. It dropped overnight however because the power unit pistons leaked.
I then rebuilt the power unit pistons by replacing the seals. I also replaced the Power circuit chamber components and the Speed Circuit chamber components. I didn’t touch the Bypass circuit because I read that it was factory set and you had to be careful to reset the depth of the cap. Since the circuits had been working fine, I only rebuilt the Power and Speed circuits.
So now, after correcting a mistake in the replacement of the components in the Power circuit (I didn’t remove the small ball) it is working except that when you return the handle after the power stroke, it releases. But if you pump vigorously, it will raise the lift arm and it holds.

So I just need to figure out what is causing the power to release on the return stroke.

Thanks.

 

[Hiball]

It sounds like an issue with upper ball/seat on the speed side. How are you determining that it’s the “power” side that is releasing on the return stroke? It sounds like the power side is sealing, hence the pressurized oil released when you pulled the valve cap. I’m assuming the lift arm was up? <—- Bad idea for future reference.

What are you calling a “Piston” in the Valves? The metal spacer/weight?

I double-checked the Speed chamber and it seemed to be in order (small ball, small spring, bigger ball, bigger spring and piston).

Make sure the spring orientation is such that it won’t allow the spacer to go inside the spring on the speed side. Probably not a bad idea to pull components and double check to make sure there isn’t (2) small balls down there, if the stack height is too tall, it won’t allow the upper ball to seat and cause the teeter totter that you have described.

Also make sure the orientation of the small spring between the smaller ball - bigger ball is oriented to not interfere with the lower ball seating.

 

[Billybdakota]

Full credit to Paulsomlo and Hiball. You were correct that the problem resided in the hydraulic circuits. Bonus points to Hiball who nailed it as an extra little ball in the speed circuit! I had dumped the contents of the power circuit carefully but when I loosened the cap on the speed circuit it was under load and everything erupted. I did not find the small ball that was supposed to be at the bottom of the chamber. I assumed that it had ejected and was lost somewhere on the garage floor. I did turn the unit upside down and tapped it with a hammer just in case but it appeared to be empty.
So I replaced the components with the new ones in the rebuild kit and then experienced the teeter totter problem. After the wise advice provided here, I removed the components and just to be sure, I hit the chamber with a blast of air. Nothing else seemed to come out. I replaced carefully everything in the correct order and “Bingo”, it works like a charm. And when I moved the jack there it was. A tiny ball underneath. The air had forced it out!
Anyway, thanks again from the proud owner of a Blackhawk SJ3!

 

[Billybdakota]

Oh. The piston I referred to is a single component which presumably replaced the cap and spacer in the diagrams. My unit just has a piston (cap with slot head and about an inch and a half long smooth section that butts up against the spring.

 

[TxSteve]

Sounds like you found the option, but check here for FAQ info on those style of jack

How To | Lazzar's Floor Jack & Hydraulic Cylinder Repair Center

Lazzar's HCRC is a leading supplier of repair parts and seal kits for floor jacks, air hydraulic pumps, hand pumps and rams. We also sell Metric and Standard Seals.

www.hcrcnow.com

Also - if it's a quick lift, there's a document somewhere on that page on how it operates and how to adjust it

It was very helpful when I rebuilt my old Craftsman jack.

 

[Hiball]

Or you could just find all that info here, where he simply copy/pasted and passed it off as his own knowledge.