I would look into the release valve, something is awry.
Overseas Jack Rebuild Help Tutorial.
- Thread starter Hiball
- Start date
I would look into the release valve, something is awry.
It can’t hurt, especially since your Ucup was in pieces. Yes I would get the current setting prior to disassembly. It’s possible it’s got something holding it open, but without knowing what you disassembled, I started with the release valve. I would add that you look at the working valve also, if there is **** in there, it will cause it’s own issues. The main problem I see when people reinstall the release is they don’t get it installed in the locking washer correct and it prevents it from seating correctly. Or they bottom the outer hex portions down before the release stem/needle can get to where it needs to be. It’s a give and take when reinstalling, as you tighten the assembly you need to spin the gear to retract the internal mechanism all while tightening the assembly till it bottoms out.
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Ok, I'll pull it out tomorrow & see what's what
I dont suppose you know what brands the orange ones were sold under?
Be nice to properly restore it, got an 80's blue point engine hoist which is still 100% working, madness how modern equipment isnt even in the same league as the old stuff
I dont suppose you know what brands the orange ones were sold under?
Be nice to properly restore it, got an 80's blue point engine hoist which is still 100% working, madness how modern equipment isnt even in the same league as the old stuff
RTM
Well-known member
Overseas Jack ID
Hey gang
Can anyone ID this jack manufacturer? I bought it used, and am in need of the universal that connects the handle to the valve, (rivets broke), and want to see if I can just buy the part (will add dimensions here later, with a pic). I may need to do some work on the valves, as the fast / power lift doesn't seem to switch right, was a bear to lift once it contacted the axle of the truck. I have not checked it for holding ability yet, just refilled it, and used it to move furniture out of a pod, so nothing challenging yet. More pix here
Thanks HiBall for starting and maintaining this thread over the years, and to all the participants who contributed knowledge.
Hey gang
Can anyone ID this jack manufacturer? I bought it used, and am in need of the universal that connects the handle to the valve, (rivets broke), and want to see if I can just buy the part (will add dimensions here later, with a pic). I may need to do some work on the valves, as the fast / power lift doesn't seem to switch right, was a bear to lift once it contacted the axle of the truck. I have not checked it for holding ability yet, just refilled it, and used it to move furniture out of a pod, so nothing challenging yet. More pix here
Thanks HiBall for starting and maintaining this thread over the years, and to all the participants who contributed knowledge.
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Well the label says 3000 lbs. So it 1.5 ton jack. As for the rivots, you may be able to match the rivet size with those in a hardware store, or take it to a machine shop for them to replace them. What does it say in the scratched area? Is there a model number or some product name in this area?
Re: Overseas Jack ID
The smaller aluminum floor jacks all seem to have the same behavior once the load is reached, at that point the speed portion bypasses and power side works alone. The overall handle feedback increasing is a combination of the jack now against the load and the size of the pump piston in comparison to the cylinder. Who knows what brand of sticker was applied, Tons of resellers including HF, Arcan, NOS or Larin to name a few. In regards to the universal joint and a broken rivet I suspect you could fix the old one with a small bolt or new rivet?
Hey gang
Can anyone ID this jack manufacturer? I bought it used, and am in need of the universal that connects the handle to the valve, (rivets broke), and want to see if I can just buy the part (will add dimensions here later, with a pic). I may need to do some work on the valves, as the fast / power lift doesn't seem to switch right, was a bear to lift once it contacted the axle of the truck. I have not checked it for holding ability yet, just refilled it, and used it to move furniture out of a pod, so nothing challenging yet. More pix here
Thanks HiBall for starting and maintaining this thread over the years, and to all the participants who contributed knowledge.
The smaller aluminum floor jacks all seem to have the same behavior once the load is reached, at that point the speed portion bypasses and power side works alone. The overall handle feedback increasing is a combination of the jack now against the load and the size of the pump piston in comparison to the cylinder. Who knows what brand of sticker was applied, Tons of resellers including HF, Arcan, NOS or Larin to name a few. In regards to the universal joint and a broken rivet I suspect you could fix the old one with a small bolt or new rivet?
Hiball
Thanks for the help, stripped it out & flushed with bit more oil & there was a fair bit of crud that come out
Now fully working but I have a new leak �� on the pump rod
Out of interest is the sears 328.12001 main seal 40x22x10?
Would be good to know so I know which rebuild kit to order to get everything easier
Thanks again
Thanks for the help, stripped it out & flushed with bit more oil & there was a fair bit of crud that come out
Now fully working but I have a new leak �� on the pump rod
Out of interest is the sears 328.12001 main seal 40x22x10?
Would be good to know so I know which rebuild kit to order to get everything easier
Thanks again
That’s the problem with only fixing 1 problem, generally you will always be time ahead if your strip the entire hydraulic unit and replace all seals/components. In regards to sears jack in question, I’m not 100% sure. It’s a common size in 10 and 12mm thickness for jacks from the era. The best advice is to measure the pump piston diameter, get a rough cross section for the Oring and talk to the supplier of choice, same goes for the Oring inside the tank nut.
ericlar80
Well-known member
I’m sure this has been asked, but is it ok to use hydraulic oil for a tractor to top off a floor jack?
In regards to seal compatibility, Sure... depending on the oil weight etc it can possible slow things down depending on the operating temps etc.
jalmbe5
Member
I'm trying to repair my floor jack which will not raise a load anymore. It's an MVP G-630WM. There are no visible leaks. I've taken it apart and found a crack in u-cup seal. I measured the seal with calipers and it looks like a 24mmx40mmx10mm (or 8mm) is the closest match. My seal seems to be kind of unique. It has a notch or step on the OD of the bottom (flat, not cup) side. This stepped section sits down in a mating backup washer. All of the seals and backup washers I see are flat and don't "mate" together like mine. Is this important? If I get a regular u-cup seal should I get a new regular flat backup washer and not reuse the stepped one?
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The majority of Ucups that I’ve seen like that are made of BN and that stepped washer serves as a backup to prevent extrusion. If it was mine, I would replace the entire seal/washer with a Poly Ucup in the correct size and thickest seal I could fit between the steel guide and Snap ring.
I suppose if you where wanting to retain the use of a backup washer you could attempt to source one or modify the current one to accept a flat Ucup.
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On the stepped washer and seal, my 3ton Sears jack had an outside edge like yours on the backing washer used in the pump check valve and then the oring. Since I was not able to find a replacement stepped washer, I just went with a regular backing washer and oring as-is done nowadays. I wonder if all Chinese jacks use green main pump seals - the color of jade for some reason. But I haven't seen aftermarket ucups in this green color.
Back around page 22 on the forum there was discussion on removing the stepped edge of the main RAM shaft since it causes drag. However, I wonder if one can put two different ucups in series in floor jacks. That is ucup #1 has one inner diameter, followed by ucup #2 that has the inner diameter of the step and then one doesn't have to remove the step and also get twice the benefit of the ucup. The same could be done for the backup washers too in combination with these ucups. This should work since various hydraulic system diagrams show ucups in series (2 or more) not to mention stacked V cups. In this case, it is U instead of V! 
Back around page 22 on the forum there was discussion on removing the stepped edge of the main RAM shaft since it causes drag. However, I wonder if one can put two different ucups in series in floor jacks. That is ucup #1 has one inner diameter, followed by ucup #2 that has the inner diameter of the step and then one doesn't have to remove the step and also get twice the benefit of the ucup. The same could be done for the backup washers too in combination with these ucups. This should work since various hydraulic system diagrams show ucups in series (2 or more) not to mention stacked V cups. In this case, it is U instead of V!
Yeah I wouldn’t back to back “piston” application Ucups, that’s asking for problems, A Ucup won’t provide a solid or uniform base for the stacked Ucup to work properly.
Not sure.. Tracking down leaks isn’t overly difficult, not to mention that due to some seals inherit design, it’s common for some seals to allow a “small” film of oil to coat the rod surface. It would be like taking a black light to your local No-tell Motels comforter.
jalmbe5
Member
Thank you Hiball! The shaft has an additional step at the the backup washer so I think I'll keep it and just trim the washer to be flat. Thanks again for your assistance and the wealth of information in this thread.
Yes, If there is a step on the Ram, it will either need to go or trim the washer.
jalmbe5
Member
I trimmed the washer and got everything back together. I think I got the air bled out but I'm not sure. It will lift a load now, but it won't start lifting on the first stroke of the handle. I have to stroke it once then on the next stroke it will lift. That's if I'm able to bring the handle all the way up then down. If I'm in a situation where I can't bring the handle all the way up, such as trying to jack my truck under the rear axle differential and the handle hits the bumper, then it takes several pumps before it'll start lifting. Do you think it still needs to be bled? What other issues could I have?
Thanks,
Jarrett
It’s kinda the nature of the beast of any jack that uses a 90 degree pump piston, it’s why Walker created the angled pump to allow more stroke under vehicles. It could also be a weak pump seal or rod surface issue in that particular sealing zone.
RTM
Well-known member
Turns out I had thought of this, but didn't remember why it didn't work. The universal is some type of Cardan Joint, and the rivets that broke don't go through, the cross shaft is in the way.
Some type of blind rivet or expansion plug was needed, so I just bought a new joint for $15 (more than the jack itself). It needed a 12mm bore, should be here in a week. New one rated for 26Nm, so probably much stronger than the old POS. Had to press out the old pin shaft (face up on right piece), and got to play with the Dake 001 press, and it worked easily the first time (little victories)
The area in the photo obliterated by scratches is just min and max heights.
Poked through all the "racing" "1.5T" manuals at HCRCnow, and didn't find any with the odd set up of ports mine has. Will look harder later.
But, should be back in business next weekend.
Thanks all
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See weblink below on calculating spring load. I'm trying to determine what the max load for the safety/overload valve to open up is for my jack. Since my spring is black coated, I'm assuming the material is oil tempered. The Sears jack is 3ton (6000 lbs). The spring height unloaded and measured outside of the jack is 18.75mm. It is closed and ground flat. The outside diameter is 10.20 or 10.25mm. The approx coil cross section is 3.2 to 3.25mm since I can't get the calipers on the coils wire cross section to measure it more accurately. The number of coils is 5, but if using the extra 1/2 turn it would be 5.5 turns. Mean diameter calculated to be 8.6mm.
So I'm not sure if the stress load or the load at solid is the value that the safety valve opens at. If one calculates the pre-load value to be the max height minus some compression distance of the spring that is equivalent to putting 1.5 turns on the set screw, one would think that the stress and/or load at solid to increase so that the safety valve opens at a different higher or lower value.
https://www.newcombspring.com/springulator/compression-spring-calculator
I selected the "dimensional" calculator part and not the 1, 2 load or the variable load calculator since I didn't know the P1, L1 values to enter.
stress limit=680, corrected stress @solid height=600, Load @solid height=536.88
tensile strength=1510 max % allowed at tensile strength=45 thus 1510*.45=679.5 or 680 the stress limit.
Although the above stress/load numbers didn't specify a unit of measure, from what I've searched on stress they are typically in MPa (mega pascals) which can be converted to PSI via google.
Thus 680 MPa is 98,625.7 psi then dividing 2,000 lbs/ton = 49.3 tons
Using load@solid height of 536.88 it is 77,867.86 ps and is 38.934 tons
Hence the spring range is 0-38.934 tons . I don't think I could turn the set screw enough to max out the maximum tonnage for the spring, and count the number of turns while doing it.
One could create/determine a scale that is a relationship between number of turns and tonnage. So the "turns" scale is 0-(max turns needed for 38.934 tons).
Now to determine the number of turns needed to open the safety valve at 3 tons, one would calculate the % as 3/38.934= 7.7% and multiple by the (max number of turns) on the "turns" scale to determine the number of turns needed to open at 3 tons. Hopefully it would be 1.5 turns.
Since x*(0.077)=1.5 turns then x is 19.48. Hence the (max turns needed for 38.934 tons) would be 19.48 turns.
Any more insight on the above info?
So I'm not sure if the stress load or the load at solid is the value that the safety valve opens at. If one calculates the pre-load value to be the max height minus some compression distance of the spring that is equivalent to putting 1.5 turns on the set screw, one would think that the stress and/or load at solid to increase so that the safety valve opens at a different higher or lower value.
https://www.newcombspring.com/springulator/compression-spring-calculator
I selected the "dimensional" calculator part and not the 1, 2 load or the variable load calculator since I didn't know the P1, L1 values to enter.
stress limit=680, corrected stress @solid height=600, Load @solid height=536.88
tensile strength=1510 max % allowed at tensile strength=45 thus 1510*.45=679.5 or 680 the stress limit.
Although the above stress/load numbers didn't specify a unit of measure, from what I've searched on stress they are typically in MPa (mega pascals) which can be converted to PSI via google.
Thus 680 MPa is 98,625.7 psi then dividing 2,000 lbs/ton = 49.3 tons
Using load@solid height of 536.88 it is 77,867.86 ps and is 38.934 tons
Hence the spring range is 0-38.934 tons . I don't think I could turn the set screw enough to max out the maximum tonnage for the spring, and count the number of turns while doing it.
One could create/determine a scale that is a relationship between number of turns and tonnage. So the "turns" scale is 0-(max turns needed for 38.934 tons).
Now to determine the number of turns needed to open the safety valve at 3 tons, one would calculate the % as 3/38.934= 7.7% and multiple by the (max number of turns) on the "turns" scale to determine the number of turns needed to open at 3 tons. Hopefully it would be 1.5 turns.
Since x*(0.077)=1.5 turns then x is 19.48. Hence the (max turns needed for 38.934 tons) would be 19.48 turns.
Any more insight on the above info?
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Hello Everyone,
I will start working on a Norco 71230A jack in the near future (currently working on a Hein-Werner WS) and I have a couple questions.
Background:
The jack lifts as it should but it will go down slowly when under load while the handle goes up proportionately. No visible leaks or other issues.
The jack was rebuilt a little over 2 years ago, I called the shop that rebuilt it
and told them about what was happening hoping they would guide me to perhaps a minor adjustment but they told me that the jack needed to be rebuilt again. The guy was very nice and he didn't seem surprised with the jack failing after only 2 years of being rebuilt.
Questions:
1.- I believe the usual guarantee on a hydraulic pump rebuild job is often for just months or 1 year tops, but isn't 2 years too short of a time for the seals to fail? Of course, who knows how the jack was used (abused) and the quality of the rebuilt, but my next question is, if 2 years is how long is going to last, is it worth rebuilding? For those of you that have rebuilt a similar unit, how long did it last?
2.- From what I've read in this forum, the issue could most likely be either the working valve assembly order (more specifically, the bigger upper bearing ball not sitting correctly) or the ram seal not sealing properly and letting oil sip through, am I correct?
If so, the ball that I should check more closely is the bigger upper ball # 9 in the diagram below?
Thank you again to everyone in advance for all your help, I really appreciate it!
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I will start working on a Norco 71230A jack in the near future (currently working on a Hein-Werner WS) and I have a couple questions.
Background:
The jack lifts as it should but it will go down slowly when under load while the handle goes up proportionately. No visible leaks or other issues.
The jack was rebuilt a little over 2 years ago, I called the shop that rebuilt it
and told them about what was happening hoping they would guide me to perhaps a minor adjustment but they told me that the jack needed to be rebuilt again. The guy was very nice and he didn't seem surprised with the jack failing after only 2 years of being rebuilt.
Questions:
1.- I believe the usual guarantee on a hydraulic pump rebuild job is often for just months or 1 year tops, but isn't 2 years too short of a time for the seals to fail? Of course, who knows how the jack was used (abused) and the quality of the rebuilt, but my next question is, if 2 years is how long is going to last, is it worth rebuilding? For those of you that have rebuilt a similar unit, how long did it last?
2.- From what I've read in this forum, the issue could most likely be either the working valve assembly order (more specifically, the bigger upper bearing ball not sitting correctly) or the ram seal not sealing properly and letting oil sip through, am I correct?
If so, the ball that I should check more closely is the bigger upper ball # 9 in the diagram below?
Thank you again to everyone in advance for all your help, I really appreciate it!
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I’d definitely check the upper ball #9, handle feedback is a dead giveaway that pressure from the Main cylinder is back flowing into the pump piston chamber, thus raising the handle.
In regards to the longevity of the Jack rebuild, If all the cylinder surfaces and rod finish was good the jack should perform well past 2 years. Secondly.. if the shop is requesting that the jack be rebuilt again based off the symptoms you described, I’d probably take my business elsewhere.
In regards to the longevity of the Jack rebuild, If all the cylinder surfaces and rod finish was good the jack should perform well past 2 years. Secondly.. if the shop is requesting that the jack be rebuilt again based off the symptoms you described, I’d probably take my business elsewhere.
Hiball,
Sadly, those were my thoughts in regards of the local shop as well. I had read your posts about the possible causes of the jack not holding load and the handle feedback and I was hoping they would guide me through the process of checking the valve assembly parts or even offered to look at the jack for me but... that was not the case.
I will check the valve assembly order, triple check ball #9 and report back. Hopefully ball #9 is just stuck or out of place some how and is an easy fix. If everything looks right with the valve system (hopefully I can tell whether it is or not hahaha, that's the tricky part), would the second place to look be the ram seal? Thank you again for all your help Hiball, I sincerely appreciate it!
Sadly, those were my thoughts in regards of the local shop as well. I had read your posts about the possible causes of the jack not holding load and the handle feedback and I was hoping they would guide me through the process of checking the valve assembly parts or even offered to look at the jack for me but... that was not the case.
I will check the valve assembly order, triple check ball #9 and report back. Hopefully ball #9 is just stuck or out of place some how and is an easy fix. If everything looks right with the valve system (hopefully I can tell whether it is or not hahaha, that's the tricky part), would the second place to look be the ram seal? Thank you again for all your help Hiball, I sincerely appreciate it!
Jazz1
Well-known member
I have not had any luck removing this brass piece on S14 Blackhawk. Heated jack and latched onto brass with lathe jaws,,won't budge. Soaking daily with Screwloose. You ever run into this?
Either patience or cut the brass out but don't know where I'd find a nut like that. I'm assuming its threaded in and not pressed
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I get it... there not in the business of handing out free information and trust me, I’ve made plenty of enemies from people I considered friends for doing such favors. If the jack stops dropping under load once the handle peaks, I’d say that’s your main issue and definitely the first place to look. I would elevate the jack in the rear and disassemble the valve looking for anything preventing the upper ball from seating. If nothing is visible and the fluid looks good, I would reinstall the ball and grab a punch sized as close the ball as possible and give it a couple whacks to possible reform the seat.
Do you have a adjustable face pin spanner? It definitely threads out, standard thread. I would be Leary if using any punches in those holes as I can already see some deformation and that normally makes them out of round in the middle and causes rod finish damage.
I guess I should clarify, while a face spanner will easily remove that backing ring. Upon installation you will need a face spanner that will fit the holes and clear the Main Ram. I have speciality sockets to fit the common Blackhawk models and have introduced a couple face spanners to the grinding wheel to allow for clearances. I suspect you will need to clean those pin holes up to accept the proper sized pin.
Hiball,
So...a cheap face spanner like the ones on the link on my previous post won't work?
How about something like this one?
Much more expensive but it looks solid, does it look like it will have enough clearance once the main ram is on? Could it also work to loosen the main tank nut?
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So...a cheap face spanner like the ones on the link on my previous post won't work?
How about something like this one?
Much more expensive but it looks solid, does it look like it will have enough clearance once the main ram is on? Could it also work to loosen the main tank nut?
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It would probably do the outer ring, but there is generally a deeper compression nut that sets the Vee packing preload, it’s looks a little wide and probably not long enough.
Jazz1
Well-known member
That's a very nice adjustable face spanner. We had no luck with a homemade spanner and thats what damaged the holes. Going keep soaking it, possibly drill a couple new holes. Also made a tool with 1" round stock, about 6" long, two pins inbedded into it to undo another part inside the jack but again it failed. I can't believe these are so tight and unwilling to part ways. More soaking before the jack is deemed a boat anchor. Thanks for response
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That's a very nice adjustable face spanner. We had no luck with a homemade spanner and thats what damaged the holes. Going keep soaking it, possibly drill a couple new holes. Also made a tool with 1" round stock, about 6" long, two pins inbedded into it to undo another part inside the jack but again it failed. I can't believe these are so tight and unwilling to part ways. More soaking before the jack is deemed a boat anchor. Thanks for response
At this point, prior to drilling new holes I would probably grab my brass punch. I can see that the hole’s are elongated both directions so my guess is at sometime in its life it’s been beat on, probably in a effort to control a leak. Once you break it free, it will probably come loose with your homemade tool.
Jazz1
Well-known member
Punch and hammer worked. I had been trying to avoid the hammer. The damage I can deal with. Next is the one same as piece beside the brass nut. It’s deep inside the jack and tool I made not budging it yet even with 1/2” impact
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Jazz1
Well-known member
Hi Y2K600F4,
Do you have the contact information of the person with Shinn-Fu that helped you with the rebuild kit?
I tried to order a kit from them because I read here at the forum that their prices were very very affordable. The sales/customer-service person that helped me told me that they only sell to people with an account and I would need to be "a certified service center or do 10k to 20k a year (purchases)" to open an account with them. When I told him that I was just a customer he informed me that they don't sell directly to customers and referred me to an online company I will not do business with.
Anyone else had luck ordering a replacement kit from Shinn-Fu? Please, let me know. Thanks!
I checked the bearing #9 on the Norco jack and didn't find anything unusual. Most likely I don't know what I'm looking for. I thought there could be some debris or something obstructing the checkball but I did not find anything. I did tap the checkball to help it seat but it did not work, the jack still lowers until the handle peaks.
Any suggestions on what to look for and how to address the checkball issue?
Could it be some other issue besides the bearing not sitting properly? Looking at the diagram, I did not check the condition of the #8 Oring, could that be the issue?
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Any suggestions on what to look for and how to address the checkball issue?
Could it be some other issue besides the bearing not sitting properly? Looking at the diagram, I did not check the condition of the #8 Oring, could that be the issue?
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