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Grease Cap, 1.988" OD Drive In - Qty 2

Grease Cap, 1.988" OD Drive In - Qty 2

Item # RG04-020
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Trailer Bearings Races Seals Caps
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TruRyde Caps - RG04-020
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TruRyde Trailer Bearings Races Seals Caps - RG04-020

  • Caps
  • Standard Grease Cap
  • 1.98 Inch O.D.
  • TruRyde

Trailer Hub Grease Cap, 1.988" OD Drive In

  • Quantity: 2
  • Commonly used on 3,500 lbs. trailer axles

Video of Grease Cap, 1.988" OD Drive In - Qty 2

Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.

Video Transcript for Trailer Bearings Races Seals and Caps Rebuild

Speaker 1: Today we're going to take you through the rebuild process on a couple of hubs. We've got an idler hub, and here we've got a hub and drum assembly. Works with electric rigs, but this can also work for just standard discs, if you've got a disc brake style setup.Basically what we're going to show you is how to get all of the bearings out. How to remove the seal. How to remove the race's if they're damaged, then get them replaced in the proper manner. We'll show you how to use an easy loop hub, which we have here.The first thing we are going to need to do is, get the grease cap off the end.

It can have either a rubber plug in it like this one does, or it can be a solid metal cap.These are pressed fit in there, basically by tapping on them on the back side. To remove them, a deadbolt hammer is typically what we're going to use. We're just going to start tapping as we go around. You'll see a little separation start right here, and slowly it'll work it's way off.Now the next step's going to vary a little bit depending on your axle setup. Do you see this is going to have a keeper that goes around the nut.

And that prevents that from being backed off, or removed. A lot of times you'll have a castle nut, which will have just little tabs that stick off, and there will be a cotter pin that passes through it. Just depending on your application, you need to get the keeper for the nut off. This style we just kind of pry out. A cotter pin you would just remove of course.Once we have that off ...

We'll start to take off the nut here, and the washer that's in behind it. Now yours should look a whole lot more dirty than this. There should be a lot of grease packed in, and through the hub, this one's brand new. We thought it'd be nice to show you the components before the grease was on .. Of our washer that comes off.And then here we're going to have our outer bearing.

Continue to pull that. We're gonig to have our inner bearing here. That sits in the backside of the hub. And we didn't put it in yet, we will show you how to put it in. But a seal would typically be covering the backside here. We'll show you how to use a seal removal tool, or another tool. To get that pried up and out. To get an access to that inner bearing.Now for a drum style like this, that process for disassembly is going to be just the same. One thing to keep in mind if you're using a disc brake setup. You'll have to remove the caliper before the disc is going to come off.Now once we have the spindle exposed, as we said this is going to be really greasy. We want to get all the grease removed, and the first thing we'll do is inspect it. We want to make sure that it looks just like what we have here. Everything's nice and smooth. We don't see any kind of discoloration, or any marring on the metal. Indicating that our bearing's got hot.If you do have any of those symptoms, at this point it's time to replace those bearings. You don't want to repack them. Get new bearings, and put in there. You might have a bearing that's come apart in here. Another surface to ensure is in good condition, is where your seal is going to go. That helps seal all the grease inside of our hub. With a damaged or broken seal, that grease is going to seep out. Either out of the hub, or in this case into our brake assembly.Now if your axle has brakes, we're also going to check the disc. Make sure it doesn't have any issues, or your hub. And this is going to be a hub and drum assembly. The brakes are going to ride on this machine surface. You're going to check that for signs of excessive heat, discoloration, or cracking. And this is our magnet surface. We'll check that surface for the same issues.Now inside the hub regardless if it's a disc brake, it's a drum brake like this. Or just a standard idler style hub. You're going to have an outer race. Would be right here, it's a small tapered piece of metal your bearing sits in, and rotates on. That's basically the outer portion of the bearing.You have the same thing here on the backside. This is called the inner race. Now if those show any signs of wear, overheating, or cracking. Those are also something we'll need to replace, which we'll show you how to do in just a minute.Now, with your brake assembly exposed, if you do have electric brakes like we have here. It's a good idea to check all the components for wear, cracking, maybe missing pieces. Check your pad thickness to make sure those are in good shape. Basically if you have a non working brake assembly and you put everything back together, you're just going to have to take it apart and do it all over again to get back to the brake assembly. This gives you a really good option to be able to change them out.And most applications are going to use a four, or maybe a five bolt flange to hold them in place. And you'll just remove the lock nuts, or sometimes you'll have a hex nut with a lock washer. You want to remove those, and then simply slide your assembly off after you cut the wiring.The friction material itself should also be checked for any kinds of cracking, or overheating. If you have any grease inside the system at all, it's likely it's gotten on those pads. It's a good idea to get those changed. Now as far as the removal of the races go, it's going to be just the same whether we're using an idler style hub like we have here. A drum brake like we have here. You can basically see where the idler is, here in the middle of the hub. It's going to go all the way around there, and we just have this extra material here to provide our braking surface.Now if you're doing a disc brake style job again, it's going to be just the same here with the races living inside of the actual hub portion. You'll just have the discs there for the brakes to make contact. We're going to use this little bit smaller one, it's a little bit easier to manage to show you how to get these out. We've talked about where the races are. The outer here, the inner being closer to the inside, but on the backside of the race there's a little lip. That lip's meant to stick out just a little bit further than the hub, and provide us an area to put our tool on, and help to drive that out.If you look all the way through there on that inner race, you'll see that little lip that sticks out just from the hub slightly, and it gives us enough area to use our tool on. Now generally to remove these you're going to use a punch, similar to this. Some guys will use a screwdriver. Or a piece of pipe. If you have a piece of pipe that's small enough to fit inside of that diameter, you can take that down through and allow it to rest on that lip.Use our punch, and then just need a hammer. And we'll start working that out. We're going to tap all the way around. Kind of equally, and evenly apply the force to get it to come on out of the bottom for us.You can see now as it starts to come out there's going to be a little gap created between the hub and the race. And we can just keep going, bringing it on out. Then you can inspect the inside of the hub surface there. Make sure no damage or anything has occurred, and repeat that same process for the outer race if you plan on removing and replacing that one.Now in the outer flat edge, you can see we're going to have our tapered edge on this side. If we roll our race over to the flat side, typically there's going to be a manufacturers part number on there. That will help you identify which race it is, that you need to go back in your system. If those are rubbed off, worn off, if you can't read them. You can measure the outside, to outside diameter of the race here. It's a good idea to use a micrometer to get it exact.Now here's your basic micrometer. And again, the outside of the race is what we're going to need to measure. You want to go . I set the thickest point there. Looks like this one's going to be about 1.98. That's going to be the measurement you'll want to supply.Now while we've got this out, let's also look at the proper way to measure our bearing. Instead of the outside for the bearing, we need to measure the inside diameter. That's going to be pretty simple. Let's pull that out, find the largest measurement we can. Which here, looks like it's going to be 1.03. With that information, we'll be able to get the correct bearing, and the correct race, so they'll fit together properly and make a full bearing kit for us.Now here's the race, we're going to show you how to get this put back in. Basically just going to press fit inside of our hubs. We need to get it down on there. Kind of like that. And you'll have a couple options. A lot of times you're going to see do it yourself or at homer, just going to use a wooden block. Just place it on there. That's going to get you started, but at that point you'll struggle in getting it to go all the way down into it's seat.Now to take care of that problem, there are several seal drivers that are available. Seal and race drivers that are available out there on the market. It's designed to fit down inside of our race, inside of our hub and get it down there where it needs to go. This is part number ptw83020, has several different sizes, even if you have multiple trailers it's going to do the job.Now the side with the angle on it, is designed to fit down inside of our race. If we use the other side, that's going to be for driving your seal into place. Just want to hold it, and take it on in with your hammer. You'll see, you just want to insure that our race is all the way up against that line on the hub where it's supposed to mate to.Now when it comes time to pack your bearings you're going to have several different ways of doing this. You can just use your hand, is the traditional method. That's going to be the method probably reserved for the very occasional trailer work kind of situation. If you do it once or twice a year, probably get away with it that way.Next you would go to a, kind of a sandwich funnel style almost. If you look inside of there, you can see the bearing. It's located between the two pieces. Just use a grease gun. Start filling that with grease, and that's going to fill our bearing for us. And the third, with this one you're just going to place your bearing down and in. It should be pretty close to center. And then we've got our cone her that's going to go down and secure that.Now I think this style, wastes a little bit more grease than what this style will. This has a dust cap. You can see, you can keep your grease in there, put your dust cap on there and save it for later use. This will be if your going to do it every couple years. And this particular style would be if you're a more regular user.Let's start by showing you how to use a bearing packer. Similar to this. Again, we've just got our grease inaudible 00:11:07 here on the top. And then just slowly start to fill it. Now I like this style quite a bit. I think even regular users might enjoy it, because you can get a really quick visual look at that bearing. You're not going to have to overdo it, or have to much grease.You can kind of see in there now, we're starting to get grease to come out of it. Couple more pumps, we'll be good. You can see we've got grease coming out all the way around. Where all of our bearings are. Got a little bit of excess there. Just take that around the outside of it. And then we should be able to lift it off. And now you can see what we we're talking about. Just a little bit of excess there, that you're just going to wind up wasting.Now we'll take our bearing, we're going to place it right down in our race. And then we'll cap off the back with our seal. Right now our seal's going to fit in just like our race did. It's going to have a little bit of a pressure fit to it. Now very often in this situation, I see people using the four by four method. Kind of here, just placing that on and tapping it. As an option though, if you do have one of these. You can see that's designed to fit right on the top of the seal. And help drive it in.The biggest thing here is, just going to be getting it driven in squarely. You can see, this side's in a little bit further than this side. I'm going to start this side first. Now since we didn't have the opportunity to show you before, we're going to take a look at pulling a seal. Now this is a seal puller, we carry this on our website part number ptw1219. This is meant to hook underneath the seal. And then you kind of pull up on it, and just like our race you'll have to work all the way around that edge. Just bringing it out a little at a time.If you don't have that available. Another option would be a screwdriver. You just kind of get that under the seal, and turn it. And see, that'll allow you to also pop that out. We've taken care of our race. Our inner bearing. Our seal. The last component, before we put our hub back in place is going to be our outer bearing. Now with this bearing, I'll show you the hand packing method.This is definitely . Slightly dirtier method than the bearing packer. When we get grease on our hand we want to look at the larger side of the bearing. This is the smaller side. We have a larger side In between the inside and outside there's a gap. We can see our rollers in there. We want to grab that, and use that gap and shove grease inside of it. Now this is going to take a little bit, you want to work in the same spot until you get the grease pushed all the way through. We can see on the top there we've got a little bit starting to come through.And once we push it in the bottom, and you see it start coming out the of the top in those little drips, it's going to indicate that, that section's fully packed. Just need to work all the way around their outside edge now and do the same thing. Alright, once that's all the way around . The bearing will be ready for use.Now one more thing I like to do. We can see our inner bearing there, and our outer bearing. Well between the two, got a pretty big gap in there. If you'll take a . Pretty good amount of grease. We're just going to go all the way around. See how we can go all the way around the inside and just line that really well. The more grease we have in here, the less chance we have of any moisture getting in there, which can cause corrosion, rust, pitting. Pretty much things we do not like when it comes to bearings, races, and hubs.Put plenty of grease in there. And then this one does have the easy lube spindle, that'll even fill it in more. Now we can get our assembly slid on. I like to keep my thumbs on that outer bearing, just to prevent it from . inaudible 00:15:28 pushed off there. Now we can put on the original hardware that we removed, in taking off our hub the first time. In our case, we had our washer and our nut.Now most commonly you'll see pliers similar to this being used. We basically want to get that tightened down. Once it's fully tightened down you'll feel some resistance in the hub. We back it off just slightly. That'll give us a little bit more freedom of motion there. Something you don't want however . Is any movement in, or out on your hub. You want to be sure that everything is compressed, and you don't have what's called end play. Which would be the play in and out.Once we've got that set, then you'll put on whatever tight keeper yours came with. Get that put back in place. Now with an easy lube style hub, you're going to place your grease gun on the end, and then you can just fill the remainder of that hub up.Now for your typical applications, you're either going to have a solid cap, or a cap that'll have a rubber plug in it. A solid cap's going to be for an axle without the grease inaudible 00:16:51 here on the end. Goes on there. Just knock it on with your rubber mallet. Same with the one with the plug. Just gives you a removable area there, be able to cap that off.We'll show you how to put that on. Now as alternatives as well, a lot of times on boat trailers and marine kind of situations. You'll see a bearing buddy. This is going to apply a little bit of pressure on the grease, you'll fill it up. This kind of comes out just a little bit. That applies constant pressure on the grease to make sure we don't have any air, or anything like that. Then there is also an oil bath hub available. Now this is going to be for use with seals that are going to be designed specifically for oil bath use. You'll have to change that seal.We're using a double lip seal. There are also single lip seals available. Of course a double lip seal is going to give you just a little additional security. Keep that in mind when you order. But let's get this knocked on there now so you can see how that works. We just want to take the cap, we're going to center it. This is going to be very similar to what we did with the seal. And then just gently start tapping it around the outside. And it'll seep down on there for you.It's really going to be the same thing that you'll do with any of the end caps. Now with this side done, it's a good idea to take care of all the other hubs. Get them all on the same maintenance schedule. And as long as you'll periodically check the grease, take your trailer out for a trip occasionally. Just to keep everything lubricated. It should extend the life of these parts, and give us years of good service.

Customer Reviews

Grease Cap, 1.988" OD Drive In - Qty 2 - RG04-020

Average Customer Rating:  4.8 out of 5 stars   (213 Customer Reviews)


Inexpensive, arrived fast and work well. Thank you etrailer !


Purchased to repair/replace Bolen's HT-20 tractor front wheel bearings.
Easily installed by driving into hub with scrap wood and hammer.
Affordable, relatively quick repair completed in between snow storms.
Thank you again eTrailer!

Worked great for my 1980 Bolens HT-20, thanks
Christian - 02/11/2022


This product was exactly what we wanted. The ordering was easy and simple. Great product. We will order from again.


Very pleased with ordering process. Package arrived as promised. Will order from etrailer again.


Their just grease caps that cover your spindle nut, nothing special


Not the same quality as the OEM caps. 1/16” too big and they dented easily when attempting to drive into place with a rubber mallet.


I was having a hard time finding this item and I am glad I looked on line.


Caps are fine. A little banged up installing them but they are doing the job.


No problems, great price for the produc t.

After a year, I have no complaints on the product based on the price. I should have painted them, but that is on me. Still holding tight after several thousand miles of use.
Cole - 03/28/2022


The etrailer team is always a pleasure to deal with and follow up after the sale is world class.


Fast shipping, part was exactly as desc ribed.


they do not fit. please give me a new part number

These caps are 1.988 inch OD. You will need to measure the inside diameter ID of the cap mounting surface on your hub to match the outside diameter OD of the grease cap. You will then be able to the proper style cap with the proper OD for your trailer hub.
-- Etrailer Expert Sierra K - 10/14/2021


Perfect fit. Thanks!


These caps match the OEM caps on the other hubs of my trailer. They are good quality. Just a little brighter than the other three, but time will change that.


Thought these were right for the 3500lbs. drop axle with the EZ lube hubs but they were just a hair too big, had to bend the flange in a bit and then beat the hell out of 'em but they work. My old dust covers from my old axle were not deep enough and the EZ lube grease zerks would hit the inside of the cap.


I'm very pleased. The item was shipped and received quickly, and the diameter of the dust caps' diameters measured exactly what they were nominally listed as (1.98"). They were also cheaper with etrailer than anyplace else, in my online search.

I ordered the wrong size. I just tried to install them, and found that the bore is substantially larger. I have a Haul Master trailer from Harbor Freight. Do you have the right grease caps?
Steve M - 06/07/2017


I replaced all the bearings races seals and brakes on a small travel trailer. Bill etrailer took my order and three days later I had everything in my hands. Great job Bill ! All the parts were exact replacements and the install went very smooth. There is video help on their website to show how to make the install easier. I have been dealing with etrailer for several years and have never had a bad experience. I was completely blown away by the pre assembled brakes . Backing plate, shoes, actuators, self adjusters and wiring all ready to bolt on. How much easier can it be? With the best prices, fast shipping and great help on line etrailer is the way to go.


Hub caps are good quality and well fitt ing.


Exact fit, my old ones were rusty on the inside because no one ever coated the inside of them with a layer of grease to prevent rusting. Thank you for another great product.


Can't say enough good things about etrailer knowledge, service and speedy delivery. It's a regular encyclopedia for trailer parts. Ricky knew exactly what I needed, me being a first-timer on wheel bearing replacement and repacking. These grease caps took some pounding (with a rubber mallet) but went on my 8-91A Dexter hubs nice and tight without a dent.


Replaced the existing caps that had access to the grease fittings with a rubber grommet for a cover. I don't think greasing the bearings from the end of the axle is the way to go. I took some steel wool and roughed up the outside and painted them with black paint to match the hub.


I ordered new wheel bearing kit’s, extra cotter pin’s and hub end cap’s because one fell off going down the road. All the parts were right and came in good condition I just installed them part yesterday everything went really good and easy. Thank you for having all he parts I needed.


The grease caps had a very snug fit on my trailer, so it took a lot of tapping to get them on, but that is a good thing. The old grease caps were apparently loose enough that one fell off. Great product, thank you!


This was my first time ordering. This site was recommended by a friend. I loved the email updates of my confirmation, shipment, tracking and this follow up. My parts all have great fitment. The package arrived intact. Thank you Etrailer.


I found the personnel to be extremely helpful in getting me the correct parts...My order was delivered ahead of schedule and appears to be correct...I am extremely satisfied with the pricing as I couldn't find the same components at a lower cost by any of the local vendors; thanks again and I will definitely continue my business

havent had any problems thanks I will buy more from you at an unspecified future date
mike b - 05/03/2018

Show More Reviews

See what our Experts say about this TruRyde Trailer Bearings Races Seals Caps

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    A grease cap like # RG04-020 is primarily intended to keep grease inside your hub bore and keep contaminants like dirt out. They are not totally water-proof by any means but they certainly do provide a degree of water-resistance. Mostly what keeps water out of your hubs is the full level of grease inside them. That is why folks like EZ-Lube spindles since they make it so much easier to ensure your hubs' grease level is always full.
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    In order to gain access and inspect the bearings on your trailer, you will first need to remove the hub itself. Older hubs like what you have that have accumulated a nice coat of rust can definitely be a bit harder to remove, likely requiring some tough love. To knock the dust cap out of place on your hub you will want to spin the hub around while you use a mallet or hammer to tap the cap in a few different places. Hopefully doing this a few times will let you remove the cap the rest...
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  • How To Find the Correct Dust/Grease Cap for a Trailer Axle
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  • Grease Dust Caps Abnormal Size 2.11"
    That size grease cap is obsolete. You will need to look at replacing your hub assembly to go with a new cap. I recommend disassembling one of your hubs to check your spindle measurements. With those measurements and a condition inspection we will be able to determine if it best to replace your hub assembly. Or if the spindle dimensions are obsolete or damaged a new axle may be necessary. Please let me know what you find and I can help you with finding the new parts.
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  • Dust Cover for Trailer Hub with 1.98 inch Diameter
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  • Looking for Grease Cap With OD Slightly Larger than 1.98 Inches
    The next largest size is # RG04-040 which has an OD of 1.99 inches. If you can provide me with the reference number from your outer wheel bearing, I'd be happy to check into the availability of a suitable grease cap.
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  • Need a Grease Cap / Hub Dust Cap to Fit Dexter 10 Inch Drums
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  • Recommended 2" Dust Caps for a 1994 Coleman Destiny Trailer
    From what I could find out about the part number 4714A0621, it looks like it is a 2 inch diameter standard grease cap. So with that being said, the TruRyde 1.988" OD Drive In Grease Cap # RG04-020 will be what I suggest. These will fit your hubs nice and securely.
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  • Dust Cap Recommendation For Trailer Hub With A Diameter Of 2.44 Inches
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  • Purpose of Grease Caps and How to Measure to Get Correct Size
    The purpose of the grease cap is to protect the bearing and the axle from any dirt getting into the bearing, which would then damage the bearing, hub and axle. So it is a good idea to have caps on your axle. To get the correct size cap you would need to measure the inside diameter of the cap mounting surface on your hub. Then that measurement would match up to the cap size outside diameter. The sizes of caps only vary by a small amount so the measurement has to very accurate. Some of the...
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  • How to Measure a Trailer Hub or Dust Cap to Find the Right Replacement Dust Cap
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  • How to Pick Out Replacement Dust Caps for a Trailer that Previously Had Bearing Buddies
    If the bore you measured on your hub measures 1.980 inches then the correct cap would be to use the RG04-020. You will need to use a more exact measuring device than a ruler though like the caliper part # PTW80157 since it has to be an exact fit. Once you have an exact dimension check out the link I attached that will take you to a page that has all of the grease caps we offer. The filters will allow you to select the correct caps.
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  • Grease Cap Recommendation for Hub Bore of 1.96 inch
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  • Comparing TruRyde and Fulton Grease Caps for Trailer Hubs with 1.988 Inch Bore
    There is basically no difference between dust cap set # RG04-020 and single cap # F001518 other than # F001518 is a single unit and # RG04-020. They otherwise have the same dimensions just from two different manufacturers.
    view full answer...
  • How to Measure a Trailer Hub for the Correct Size Grease Cap for a 1993 Coleman Pop-up Camper
    You would need to measure the inside diameter of the hub opening to determine which cap size is needed. You would want to choose a cap whose outside diameter matches the inside diameter of the hub. Some of the most common sizes are 1.980 inch, 1.986 inch, 2.441 inch and 2.717 inch. As you can see the sizes can differ by very small amounts. To measure accurately to two or three decimal places, I'd recommend using a digital caliper like part # PTW80157 so that you can be confident you are...
    view full answer...
  • Grease Cap with Diameter Close to 3-3/8-Inches
    We have grease caps in many sizes that appear on the linked page and the nearest size to your specified 3-3/8-inches is Fulton part # F106122 which has an outer diameter of 3.358-inches.
    view full answer...
  • Replacement Dust Cap For Haul Master utility trailer model 90154
    I am happy to help you figure out which dust cap you need for the Haul Master utility trailer model 90154 however, I was not able to find any information about the wheels on your utility trailer. To get the correct sized dust cap you can simply measure the inner pilot hole diameter of your wheel (where the cap goes). You may find it helpful to use a digital caliper like part # PTW80157 to get the measurement as accurate as possible. For example: the diameter of the grease cap part # RG04-020...
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  • Possible Dust Cap to Fit Hub Bore on Trailer that is 2 inch in Diameter
    51 mm is right at 2 inches. We have caps that have an outer diameter of 1.98 inches like the # RG04-020 that you referenced but this would be too small to really fit your hub. You might remeasure with a digital caliper like the part # PTW80157 to verify the size you need.
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  • Will Fulton 1.96 Inch Grease Cap Fit Hub and Drum for a 3,500 Pound Trailer Axle
    I tested a Fulton Grease Cap # F001610 in a standard 3,500 pound axle hub and drum assembly out in our warehouse. The cap just drops right in and would fall back out immediately. You will definitely need the 1.98 inch caps # RG04-020. They are about 1/4 inch (0.26 inches) taller than the Fulton caps.
    view full answer...

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