1/2" Diameter Greasable Hinge Pin, 4-1/2" Long

1/2" Diameter Greasable Hinge Pin, 4-1/2" Long

Item # HP412G

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HP412G - 1/2 Inch Diameter Redline Doors
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Hinge pins are welded to either the outer frame or the gate/door and then inserted into the welded hinge pin nipples to create custom, heavy-duty hinges. Greasable pins feature a grease zerk for lubrication. Call 800-298-8924 to order Redline enclosed trailer parts part number HP412G or order online at etrailer.com. Free expert support on all Redline products. Guaranteed Lowest Price and Fastest Shipping for 1/2" Diameter Greasable Hinge Pin, 4-1/2" Long. Enclosed Trailer Parts reviews from real customers.
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Redline Enclosed Trailer Parts - HP412G

  • Doors
  • Door Hardware
  • Hinge
  • Hinge Pin
  • Redline
  • 4-1/2 Inch Long
  • 1/2 Inch Diameter

Hinge pins are welded to either the outer frame or the gate/door and then inserted into the welded hinge pin nipples to create custom, heavy-duty hinges. Greasable pins feature a grease zerk for lubrication.


  • Build your own hinge
  • Great for trailers and agricultural applications


  • Outer diameter 1/2"
  • 4-1/2" long

HP412G, Hinge Pin Greasable 1/2" OD 4 1/2" Long

Video of 1/2" Diameter Greasable Hinge Pin, 4-1/2" Long

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

Video Transcript for Redline Enclosed Trailer Parts - Doors - HP412G Review

Today were going to review part number HP412G. This is the Redline 1/2-inch diameter Greaseable Hinge Pin. This hinge pin is welded to either the outer frame of the trailer or the gate and door and then this is inserted into the welded hinge pin nipple to create a custom heavy duty hinge. This is used when building your own hinge, its great for trailers and agriculture applications. This is a grease-able hinge pin which means it has a Zerk fitting right here on the very end and basically what that means is you can attach your grease gun to the end of this fitting and pump grease into the inside which will come out this hole right here and spread all along the length of the hinge pin which will lubricate the total hinge. Ill give you a few measurements on this, total length of this pin is 4-1/2 inches, the outer diameter is going to be a 1/2 inch.

And that should do it for a review on part number HP412G.


Ask the Experts about this Redline Enclosed Trailer Parts

Do you have a question about this Enclosed Trailer Part?

  • Can the Ramp Spring # RS16933LH Be Installed on a 1-1/4 inch Diameter Pin
  • The inner diameter of the Ramp Spring # RS16933LH that you referenced is 1-1/2 inches, you could easily use this spring on a hinge shaft that is 1-1/4 inches in diameter. I spoke with my contact at Redline to confirm this.
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  • Replacement Trailer Ramp Springs
  • We have several hinge pins like # HP412G that I have linked for you, but it sounds like you need actual springs. We have some heavy duty ramp springs like # RS16933RH and # RS16933LH if you happen to have a heavy duty equipment trailer like what they haul tractors and other large equipment on. For an open utility trailer you may be able to use a tailgate assist like # RA-27C. Or for an enclosed trailer we have springs that are similar to garage door systems. I have linked those as well....
    view full answer...

  • Trailer Ramp Springs for a 20 Ton Tandem Axle Trailer
  • That sounds like a very heavy duty trailer. For heavy duty trailers there are special ramp springs, # RS16933RH for right hand side and # RS16933LH for left hand side. They fit a 1-1/2 inch diameter shaft or hinge pin. We do not have a pin that large. I have included a link to a video review of the springs for you. The other springs we carry are all lighter duty for enclosed consumer trailers and probably would not be strong enough to fit your 20 ton trailer.
    view full answer...

  • Ramp Spring Weight Capacity and Left or Right Hand Orientation for a Horse Trailer
  • The right hand ramp spring, item # RS16933RH, and the left hand spring, item # RS16933LH, are differentiated by paint on the springs from the manufacturer. The springs with green paint on them are right side springs, left side springs are unpainted. Right side springs will go on the right side of a ramp and left hand springs go on the left side of a ramp. Both right and left hand springs deflect in the same direction the designation of right and left has to do with orientation of the stick...
    view full answer...

  • Ramp Spring Recommendation for a 20 ft x 7 ft Equipment Hauler with Adjustable Width Ramps
  • Yes, the Ramp Spring - 2K Torque for 1-1/2" Shaft - RH # RS16933RH would work on the right side of your trailer and the Ramp Spring - 2K Torque for 1-1/2" Shaft - LH # RS16933LH would work for the left hand side of your trailer. Both of these springs are designed for use on 1-1/2 inch diameter shafts so they would fit very well. I attached a picture we got from a customer who used these springs on an adjustable width ramp just like you plan on doing.
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  • Trailer Ramp Spring Assist Recommendation for a 44 inch Wide Trailer Ramp
  • The best ramp assist spring recommendation I can make for you would be the Enclosed Trailer Ramp Spring # ERS80S66. Check out the review video I attached to the right. The installation instructions for this product are recommended for individuals who have experience winding torsion springs. If you have not worked with a torsion spring system before, we recommend contacting a local garage door company to install this system.
    view full answer...

  • Can All Left or Right Heavy Duty Trailer Ramp Springs be Used to Replace 2 Ramps with 1 Long Ramp
  • Since you are removing the 2 ramps and putting in a single ramp then you can use all left or all right ramp springs as long as they engage the ramp like they are supposed to and there is room to mount them. Regarding your follow-up question, yes, that is correct. The spring tension will occur when the ramp opens. That tension will help support the weight when lowering and when lifting the ramp. It sounds like you have a good handle on this already!
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  • Rear Ramp Door on Pace Enclosed Trailer Does Not Open or Close All the Way with Hinge Springs
  • It sounds like there could be something bent either on the ramp itself, the body of the trailer or the spring or hinge pin. You could replace the hinge type springs with an enclosed ramp spring system such as # ERS120D81 at 81 inches wide and 120 pound capacity but if something is bent then it will still have the same issues. We also have the enclosed springs in different sizes: # ERS160D96 is 96 inches wide, 160 pound capacity # ERS80S66 is 66 inches wide, 80 pound capacity # ERS80S96...
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  • Removing Rusted Hinge Pin on Trailer
  • You can try heating the nipple with a torch and then using a punch to drive out the pin. Be gentle with the heat, as the idea is to get the nipple to expand without heating the pin to the extent that it expands as well. When driving the pin out, be careful not to mushroom the end of the pin. For multiple hinges, you might have to remove the pins a little at a time. If that does not work, you will have to use an angle grinder to remove the nipple and pin completely, then start over with...
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  • Rear Door on Circle J Horse Trailer Has Play in It when Closed
  • From what I could find the Circle J horse trailers use a sort of cam-lock design similar to what you might see on a big rig trailer # 383200 or a side door bar lock like # 305736. These designs work fine until something gets knocked out of alignment. The most likely cause is damage to the door or a hinge problem. If the door is warped or if you are able to wiggle the door at the hinges then that would be the issue. Straightening out the door or repairing it as needed and repairing the...
    view full answer...

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Info for this part was:

Expert Research:
Robert G
Expert Research:
Michael H
Expert Research:
Jameson C
Installed by:
Jeff D

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