Introduction: How to Repair a Snap-on YA700 Floor Jack
The YA700 has a 2 1/2 ton capacity. I'm going to present a lot of photos with a few comments. I hope the photos are detailed enough to give you an idea of what tools and techniques I used to tear the jack down. The steps I give are the exact order that I used to disassemble the jack. This same procedure can be used on the 2 ton YA642C and also the Lincoln/Walker 93642 series C service jacks. The only difference being the heel plate and u-cup on the end of the ram.
- 201733 Plug, Expansion 5/8" PLN
- 201802 Ring, Retaining 5/8 Open
- 201828 Packing, V 11/16 OD x 3/16 ID Leather
- 203196 Ball 5/32 GR25 CRM Alloy Steel
- 203198 Ball 7/32 GR25 CRM Alloy Steel
- 203201 Ball 5/16 GR25 CRM Alloy Steel
- 204842 Gasket, ring 9/16 OD x 7/16 Copper
- 216143 O-ring 3/8 ID x 1/16 BUNA A70
- 218043 Valve, Release
- 221318 Screen 65 x 42 Mesh .26 OD BRS
- 221748 Ring, Quad 1 1/2 OD x 1 1/4 ID
- 226351 Washer 5/8 OD x 1/4 ID Rubber
- 228256 Packing, U-cup 1.521 OD x .258 Thick
- 230301 Plate, Heel
- 233917 Spring, Plastic Celcon
Step 1: Remove the Front Wheels
Using snap ring pliers, remove the clips and washers from both wheels and then slide the wheels off the axle. This step isn't really necessary, but as I have pressure washed the entire jack I want to make sure to clean and lubricate the axles before I reassemble.
Step 2: Remove the Casters
The casters need to be removed to gain easier access to the hydraulic unit mounting bolts, and also they need to be re-lubricated.
Step 3: Releasing the Side Plates
First step in getting the hydraulic unit out of the jack is to remove the 2 nuts and lock washers on either side of the main fulcrum pin and also the 4 bolts securing the hydraulic unit to the frame. The side plates on this model are welded to the front axle but it is not necessary to do anything further at this point.
Step 4: Separating the Side Plates Just Enough
In order to free the block of the hydraulic unit from the side plates it will be necessary to pull the side plates to the outside just enough to allow the hydraulic to drop free. I do this by tapping on the inside of the side plates until I see that the protrusions on the sides of the hydraulic that extends through the side plates are out far enough so that it can be moved out. Once this is accomplished, the handle yoke assembly and the thru pin will fall out.
Step 5: Dropping the Hydraulic Unit Out
At his point it is just a matter of technique. Basically, just grab a hold of the end of the lifting arm and jerk it upward with enough force to free the hydraulic and push it out the rear. It can all be done in one swift motion. The first two photos show the frame coming up and the hydraulic pivoting toward the rear.
Step 6: Release the Return Springs
It's easier on this model to release the springs off the pins in the pillow block. This is not always the case on other models. These springs are fairly long and weak and I just grab them with my hand and pull them forward enough to raise them up off the pins. Other techniques I have used on stronger springs is to lock needle nose vice grips on them at the hole where they go into the base of the hydraulic and then twist and rotate them out of the hole.
Step 7: Releasing the Tip of the Ram
The cotter pin on this model is usually long and easy to bend, so it's not much of a problem to straighten it enough with a pair of pliers and pull it free.
Step 8: Securing the Hydraulic for Disassembly
I can't stress enough how important it is to secure the jack in such a way that it has no movement. You will see why when you go to remove the tank nut. Do NOT hold the hydraulic in any way that involves the oil reservoir, that's the round tank you see with the air vent in the top. This is relatively thin metal and can be crushed in the process of putting it in a vice.
Step 9: Remove the U-Joint and Release Stem Assembly
Nothing special here, just unscrew it from the base of the hydraulic unit. It's rare to see any thread damage on these or even the o-ring damaged. This model has what's called a plastic spring in the end of it (that little white dot in the center of the threaded end.) The spring is worn on this one to the point that it no longer functions and I know from experience that it is going to be difficult to get out, but more on that later on as I will show you what I do to remove it. By the way, it's purpose is to keep a little spongy feeling when you close the release valve and it prevents the two metal surfaces from sticking together. When they are worn out, the release can sometimes be hard and "pop" loose as opposed to smooth and easy. Such quality engineering in jacks has all but disappeared in import jacks.
Step 10: U-Joint Removed
I should add that there is a special valve still down in that hole so don't lose it. I will take this one out a little later.
Step 11: Pump Clip Removal (part 1)
Obviously not everyone has the vice and tools I use. I apologize for that, but the main point here is to show you what has to be done. There is a spring inside the pump assembly and you have to hold it down so that you can safely remove the clip securing the top pump cover.
As you can see from the photo, I have levered a metal plate with a hole in it in such a way that I can hold it down with one hand while I remove the clip with the other.
Step 12: Pump Clip Removal (part 2)
Using a pair of modified snap ring pliers, I can grab and expand the clip to take it off. Without holding the spring down at this point, you can imagine what may come shooting up at you. BE CAREFULL!
Step 13: Remove the Pump Covers and Spring
By keeping pressure on the spring, I slowly release the tension until I have all the pieces separated.
Step 14: Remove the Pump
I use a socket and breaker bar, but you could use a hand wrench or impact wrench.
Step 15: Pump Removed
The pump is out and I will take it apart later. I still have things to do with hydraulic while it is locked down in the vice.
Step 16: Remove the Release Valve
I use a magnet to pick the valve out of the release stem hole.
Step 17: Remove the Expansion Plugs
I center punch the expansion plugs, drill a hole in them, and then use a modified punch to lift them out.
Step 18: View After Expansion Plugs Removed
The first view is off the overload valve. You can see an adjustable screw toward the bottom. The other side with the screw near the top is a pressure plug. It is not adjustable.
Step 19: Loosening the Screws
I just loosen the screws at this point and leave them in place. I use an impact screwdriver to remove the the pressure plug. One or two heavy blows with a hammer usually breaks it loose and then I unscrew it until it is completely loose.
Before loosening the overload screw, tighten it down (clockwise) and see how many turns it takes to reach bottom. It is generally about one and one half turns. I loosen it completely and leave it in the hole.
Step 20: Loosen the Tank Nut
I just loosen the tank nut at this point and I don't unscrew it. There is still oil in the reservoir that will spill out if you back it off to far.
I use a 3/4 inch drive socket and a breaker bar to remove the tank nut. In some cases I have to put the pump handle on the end of the breaker bar for more leverage. It is at this point that you will find the importance of having the hydraulic firmly held in place.
Beware that this may break loose with a sudden snap that can jar your back or neck it you are not prepared. Once it breaks loose it will usually unscrew by hand the rest of the way, but I as I mentioned, I leave it as is to prevent oil leaking.
There are no seals at the front or the back of the oil reservoir. This is a metal to metal seal. If never service before, this may be extremely tight.
Step 21: Remove the Tank Nut
An old cake pan serves me well for this size hydraulic. I set the hydraulic up on end and can usually unscrew the tank nut the rest of the way by hand. Be prepared for a mess!
Step 22: Remove the Oil Reservoir
Like I said, it can be very messy in these old jacks that have never been serviced before. Somewhere in this mess will be a filter screen. A few of the internal parts may have fallen out at this point, so gather them up.
Step 23: Removing the Internal Pieces
At this point in the repair, I wipe off some of the gunk and oil so that I can get a grip on the ram cylinder. After I grab the cylinder, I turn the hydraulic upside done on my vise table and give it a good rap on the table to get all the internal parts to fall out. It is generally the overload assembly that comes out last. The parts on the valve side should fall out pretty easy (if they are not already out.) Make sure on the overload side that you continue until you retrieve a small ball that is the last piece to come out of the hole. If it doesn't come out after rapping it on the table, you can use a small magnet. Occasionally, the ball can be stuck on the seat at the bottom of the chamber. If this is the case, you will have to break it loose with the tip of a screwdriver before it will drop out.
Step 24: View of the Valve Parts
Here I have placed all the internal parts and in the order that they would be in the hydraulic block. Make note of this now.
Step 25: Remove the Ram From the Ram Cylinder
Here I secure the unit by the cylinder in my pipe vise. Once secure, I slip a small strong steel rod through the hole in the tip of the ram. Next I pull (or yank) until the ram comes out of the jack.
I was very fortunate that things went smoothly on getting this ram out. The nylon heel plate could have been swollen to the point that I would not have been able to pull it out by hand. If this is the case, I jig up a slide hammer to bump it out. If the u-cup is brittle, it may break into several very small chunks that will present a problem cleaning. I make sure they don't get into the hole at the bottom of the ram cylinder. Now if the ram comes out, but the heel plate doesn't (happens more times that what you might expect), I have another jig for that.
Step 26: Remove the Ram Parts
In the first photo it is not real obvious, but as the second photo reveals there is a split in the u-cup. I see this all the time in older jacks where the u-cup is brittle and it has either cracked or broken up into several very small pieces. Behind the u-cup is the heel plate and behind that is a steel backup washer. If you look carefully at the heel plate before you remove it, you will notice that there is a top and bottom to it. The rounded edge should be facing up (away from the u-cup.)
Step 27: General Cleaning and Inspection
At this point in the repair I do some general cleaning of the parts so that I can get a better look at the ram cylinder walls, valve seats, etc. I just use 100% mineral spirits and air pressure to do the general cleaning. For more intense cleaning, I use a wire brush, wire wheel, flex hone, and emery paper.
I can see from this inspection that the ram cylinder is going to need some very light honing. Although you can't see it in the photos, I get a much better look at the valve seats by using an otoscope (such as an ear doctor would use.) What I am looking for are nice clean and round surface areas where the valve ball sits in the impression on the hole it covers. Sort of hard to explain what a bad one looks like as it can be anything from rust, pock marks, or the hole wobbled out over time. All of these things can be dealt with by making a clean new seat which involves drilling the old seat out. These seats look good so I am going forward.
Step 28: Inspect and Clean the Oil Reservoir
It is very important that the top and bottom edges of the tank are round, flat, and clean. Like I mentioned before, there are no seals to make up for imperfections or even improper tightening. Years ago I saw a drawing that indicated the factory probably put varnish on the surfaces before assembly. The recommendation on the drawing now is Loctite Gasket Eliminator 515. I use a very thin coat of Versachem Super Blue Silicone type 613 on the bottom edges only (more on that later.)
Now on to a more intense cleaning.
Step 29: Cleaning the Ram
The ram sides have nothing to do with the performance of the jack since all the pressure is on the end. It is important to keep the sides clean and smooth so that the seal in the tank nut stays in good shape. The tank nut seal keeps the oil contained inside the reservoir. The only time there is pressure inside the oil tank is when the jack is being released and it is refilling with oil coming out of the ram cylinder. This pressure should be quickly dissipated by the air filter/vent.
Step 30: Clean the Base
I use a wire wheel to clean the threads at the top of the ram cylinder and clean the base.
Step 31: Cleaning or Honing the Ram Cylinder
This cylinder needed a little more than just cleaning with a rag, it wasn't pitted or corroded yet and I caught it just in time. Generally what happens is, that the jack goes bad while sitting in a corner for months or years without use. I personally think it might be a good idea to pump a jack up and down every so often (good or bad), so that the oil doesn't have a chance to sit in one place and cause damage. I'm pretty sure this would help, as most of the damage I see to the inside and outside of the ram cylinder appears to be from oil that may have pooled up and set too long. I have seen corrosion on the outside of a cylinder so severe that it ate a hole thru to the inside of the ram cylinder.
Step 32: Pump Teardown and Inspection
This style of pump comes apart easy. To disassemble it, all I do is push the pump piston out the bottom. Once the piston is put, I remove the seals on the end of the piston. The parts are a lock nut, steel washer, rubber adapter/washer, and 3 leather v-packing. I clean and inspect the inside walls of the pump cylinder. I have occasionally had to use a flex hone to clean it up.
Step 33: Pump Cover Issues
Notice how the top pump cover is concave instead of being flat on top. It also has a small dent dead center on the side. The bottom cover was okay. A large enough dent in the top cover will cause it to rub or stick on the bottom cover when the pump is compressed. I large enough dent on the bottom cover will cause the spring to snag as it compresses. That is why I like to deal with these dents right now and prevent further issues.
Step 34: Repairing Dents in the Pump Covers
The procedure is simple. To smooth out the sides I pound a pipe that barely fits into the cover. You can see the dent in the side before I drove it all the way in. To flatten the top I basically drop a large steel rod into the top a few times until it is flat.
Afterwards I lubricate the spring so that there is less friction on the cover (see what I use for lubrication later on in the repair.)
Step 35: Clean and Inspect the Tank Nut
There is a quad ring inside the tank nut near the top. I use a modified dental pick to remove the quad ring and then clean the nut. In the last photo, notice the lip on the tank nut when it is turned over. This is a metal to metal sealing surface with the front of the oil reservoir. It must be clean with no nicks in it or else it will leak.
Step 36: Remove the O-ring on the Release Stem
Nothing special here. The u-joint that is attached to the release stem on this jack is in good shape, but they are not always that way. The u-joint must be inspected for freedom of movement. If it catches in any direction it may give the operator the feeling that the release is closed off. If the pins are in danger of falling out, they can sometimes be re-peened. If the pin cannot be re-peened, I have seen some come in with a small nail through the body and then bent over. I usually put a small metal screw through the body and then peen it near flat. The head of the screw can be slightly ground off to remove the slot. It makes a nicer looking job than a nail.
Step 37: Plastic Celcon Spring Removal in Release Stem (part 1)
I made a special step of this because it doesn't always go as easy as it may seem. First of all, if it is long enough to grab, I just pull it out using my finger nails. Yeah! If that doesn't work, I try blowing a small stream of air right directly at it. About 25 percent of the time that actually works and it goes flying across the room (safety googles!)
So at this point, neither of these things worked. Now I get out my propane torch (see part 2.)
Step 38: Plastic Celcon Spring Removal in Release Stem (part 2)
The procedure is simple enough and doesn't involve much time, it goes like this. Heat up some wire until it is red hot. Don't lollygag around, stick it in the end and hold it there for about 30 seconds. Pull it out (sometimes hard to pull out.) I have found that two pieces of twisted wire works better than one.
Step 39: Parts Used in Repair of Snap-on YA700 2 1/2 Ton Jack
At this point in the repair, all pieces have been cleaned and inspected,
all old seals etc. have been removed, and all valves and orifices have been cleaned. With the cause of the malfunction identified (a cracked and brittle u-cup,) I can now proceed with confidence installing the new repair parts.
201733 Plug, Expansion 5/8" PLN
201802 Ring, Retaining 5/8 Open
201828 Packing, V 11/16 OD x 3/16 ID Leather
203196 Ball 5/32 GR25 CRM Alloy Steel
203198 Ball 7/32 GR25 CRM Alloy Steel
203201 Ball 5/16 GR25 CRM Alloy Steel
204842 Gasket, ring 9/16 OD x 7/16 Copper
216143 O-ring 3/8 ID x 1/16 BUNA A70
218043 Valve, Release
221318 Screen 65 x 42 Mesh .26 OD BRS
221748 Ring, Quad 1 1/2 OD x 1 1/4 ID
226351 Washer 5/8 OD x 1/4 ID Rubber
228256 Packing, U-cup 1.521 OD x .258 Thick
230301 Plate, Heel 233917 Spring, Plastic Celcon
Step 40: Installing the Repair Parts in the Hydraulic Unit Assembly
The 1st picture is from Step 23. It shows the proper order to replace the new and used items. The 2nd picture shows the hydraulic after the parts have been installed. The pressure plug on the right is tightened with the same impact screwdriver I used to break it loose (see step 19.) The overload adjustment screw I tightened down all the way to bottom and then backed it off 1 and 1/2 turns. This gives me a general starting point for the overload valve to pop off at.
Step 41: How a Jack Works and Symptoms of Bad Valves
The 1st photo is a general representation of how most service jacks work. The 2nd photo shows a comparison of good and bad ball seats. It's important at this time to feel confident about the valve seats. If you experience the following symptoms after the repair, these illustrations may help.
1. If the jack handle drops down of it's own accord - there is an issue with the suction valve. This is the valve on the bottom with the smaller ball.
2. If the jack handle raises on it's own accord - there is an issue with the discharge valve. This is the valve on the top with the larger ball.
Step 42: Install the Quad Ring Into the Tank Nut
Nothing special about installing the quad ring, but notice how it has more sealing surface than an ordinary o-ring. Put a thin coat of hydraulic oil on it.
Step 43: Recheck Mating Surfaces
I had done general cleaning of this earlier, but now it's time to get "picky." Everything must be cleaned and rechecked. A tiny piece of debris in the valve chamber can cause a failure to lift and/or hold.
Step 44: Install the Ram Into the Cylinder
Place the steel backup washer on the ram end first, and then the heel plate. The heel plate has a front and back. One edge of the heel plate has a sharp edge and the other is slightly rounded over. Mount the heel plate so that the sharp edge will fit against the back of the u-cup with the rounded edge pointing up out of the cylinder. The u-cup just snaps in place, but it may be hard to push on. I usually lay the u-cup on a flat surface and then push the the ram into the u-cup. After the parts are installed on the end of the ram, I put a light coat of oil on the entire ram. I squirt extra oil on the u-cup before inserting it into the cylinder. I also coat the inside of the cylinder with oil also. Obviously, extreme care is taken not to damage the edge of the u-cup while inserting it into the cylinder.
Step 45: Check and Fit the Filter Screen
The filter screen pushes into the hole on the underside of the cylinder. It only pushes in about 1/4 inch and nothing holds it in place other than friction. I like to expand the end of the filter by pushing a small tapered punch into the end of the filter just prior to pushing it into place. This isn't always necessary, but if it feels like the screen went into the hole too easy, I take it out and refit it.
Step 46: Install the Oil Reservoir
As mentioned earlier, both ends of the tank are metal to metal mating. Thanks to the fine engineering and quality control that went into these old American made jacks, I can't remember any of them leaking in this area. In lieu of varnish, I put a very thin coat of sealant on just one surface of both ends. You can barely see the sealant on the tank nut.
I place the tank so that the air vent hole will come back into position while I am tightening the tank nut.
Step 47: Tighten the Tank Nut
It's a simple job that would be much harder had I not a way to secure it tightly. I use an old jack handle on the end of a 3/4" breaker bar to tighten the nut. Notice how the vent hole is now aligned on top center. I did not just stop at that point once I saw that it was lined up. It is a trial and error process that ends when I can not tighten it any further.
Yes, I have broken my breaker bar in the past by misusing it this way, but it's welded and stronger than ever!
Step 48: Install the Seals on the Pump Piston
I saturate the 3 leather v-packing with oil before inserting them on the mounting stem. The rounded side of the rubber washer fits into the bottom packing. Next comes the steel washer and locknut. I don't tighten the nut very much at this point so that it is easier to slip the assembly into the pump cylinder.
Step 49: Assemble the Pump Piston and Cylinder
I use a 3/8" nut driver to push the piston into the cylinder. Once inserted I tighten the packing down. As a general rule, I tighten the packing down until I can't turn the nut any further and then back it off about 1/4 turn. If the packing is too tight, the pump spring will not be able to pull the piston back up once it is depressed.
Step 50: Install the Pump Into the Hydraulic Unit
The process of tightening the pump usually leaves the pump piston in the down position. I pull it back up in preparation to installing the pump covers.
Step 51: Install the Pump Covers
Installing the pump covers is pretty much the same as removing them. The cover and spring has to be held down in such a way that allows retention clip to be installed.
Step 52: Install the Release Stem Parts
Sometimes I have a problem inserting the new plastic spring into the hole. The hole can get peened over once the spring wears out. I use a round file to get rid of the edge that builds up on the inside rim of the hole. The spring should protrude out of the hole about 3/16".
Step 53: Installing the Release Stem and U-Joint Assembly
First be sure to drop the cone shaped release valve into the release valve hole. Double check to make sure it did not turn sideways or flip completely over before inserting the release stem into the hole. I put some oil on the o-ring and the plastic spring prior to insertion.
The hydraulic unit is now ready to be remounted into the frame assembly.
Step 54: Install the Hydraulic Unit Into the Frame
This is just a repeat of the disassembly process. Install the cotter pin, springs, handle yoke, thru bolt, and all the frame bolts and nuts that were removed.
Step 55: Install the Casters and Wheels (with a Word on Lubrication)
So for many years I have mixed up a 50/50 blend of 120W oil and STP oil treatment to use as a lubricant for every moving part of the jack (except for the ram and u-cup.) There are upper and lower caster balls, wheel holes and axles, pump roller, handle end and socket, handle retention bolt, and any moving part or friction area I can find. Yes, the oil is still pretty fluid and will drip off, but what stays behind last for a long while. It silences the caster bearing noise and makes the rolling around feel very smooth.
Step 56: Filling the Oil Reservoir on a Snap-on YA700 Jack
This model holds about 10 ounces of hydraulic fluid (or about 1 squeezable plastic ketchup bottle.) Start with the lifting arm in the down position and with the release valve open. If you look through the vent hole you can see the ram cylinder. Add just enough fluid to cover the ram cylinder and then stop. Too little oil and the jack will quit lifting after the oil runs out. The jack will still hold a load but the pumping action will feel spongy due to the fact that it will be pumping air into the cylinder instead of oil. Too much oil and the oil will try and squirt out the vent hole when the air in cylinder is displaced by the returning oil. This leads to the next step, which is the job of the vent plug.
Step 57: Clean, Inspect, and Install the Vent Plug/Filter
The vent plug on this model does more than just keep the oil from squirting out. As you can see from the 2nd photo, there is a piece of felt below the cross arms followed by a rubber tube attached to a stem. Design engineers must consider several factors when the ram cylinder is being filled up and then released. They generally do not want a vacuum to build up as the oil is being sucked out of the reservoir and filling up the ram cylinder, or too much pressure to build up in the tank as the oil returns. It would appear that on this particular vent plug, the rubber sleeve serves this purpose. If it is missing or brittle, things go wrong. I have seen some that do not release the pressure at all and then oil starts to come out the overload chamber when too much pressure builds up in the tank.I have also seen some that spews oil when the lifting arm comes down (especially when it comes down fast.) In the latter case, it wasn't that there was too much oil, the problem was that the rubber sleeve no longer served it's original purpose.
Step 58: Testing
I have a means to test service jacks such as this, and make sure the the overload is set properly. If anyone is following along with this, I have a word of caution. If you reset the overload to where you found it, you are more than likely okay. On this particular model (it is just my observations and personal opinion) that the length of the ram is too long and will bend slightly if overloaded. If the overload is set properly you will not have any problems. I have seen several of these with a bent ram. Symptoms would be the lifting arm stopping part way down (without a load) and then continuing with a little assist. Worst case scenario, the lifting arm won't come down at all. Also, I have seen the pump handle bent. Keep this in mind, if you are lifting something and it gets too hard too pump, the overload should have gone off BEFORE you got to that point!