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U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts

U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts

Item # APUBR-9
Our Price: $48.47
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Mount your round, 3" diameter axle to your trailer's leaf springs with this U-bolt kit. U-bolts, plates and nuts included. Great Prices for the best trailer suspension parts from Redline. U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts part number APUBR-9 can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (286)
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  • Videos (2)
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Redline Trailer Suspension Parts - APUBR-9

  • U-Bolt Kits
  • Camper
  • Car Hauler
  • Utility Trailer
  • Round Axle - 3 Inch
  • 7-1/16 Inch Long
  • 5200 lbs - 7000 lbs
  • 9/16 Inch Diameter
  • Redline

Mount your round, 3" diameter axle to your trailer's leaf springs with this U-bolt kit. U-bolts, plates and nuts included.


  • Attaches trailer axle to leaf springs
  • Includes:
    • (4) 7-1/16" Long U-bolts (176500)
    • (2) U-Bolt plates for 1-3/4" or 2" springs (117521)
    • (8) 9/16"-18 Hex nuts (916N)
  • Spring seats required for mounting axle to leaf spring sold separately


  • Axle diameter: 3"
    • Typical 5,200-lb to 7,000-lb axle
  • Spring width: 1-3/4" or 2"
  • Dimensions: see below

U-Bolt Diagram

APUBR-9 U-Bolt Kit for 5,200-lb to 7,000-lb Round Trailer Axles

Video of U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts

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

Video Transcript for Redline Round Trailer Axles U-Bolt Mounting Kit Installation

Today on our fifth wheel trailer we'll be installing the Red Line U-Bolt Kit for mounting 5,200 pound to 7,000 pound round trailer axles. This is part number APUBR-9. Here's what our kit consists of. We have the two flanges here that will go on top of our axle which will secure our u-bolts to the top and hold our axle in place to release springs. We have the necessary two, one per side and then the necessary four u-bolts, and then the eight nuts to secure it. The reason you want this is in case you ever need to replace a bent or damaged u-bolt or hanger assembly, or if you ever need to remove one a lot of the times they have a nylon lock nut on and you cannot remove the nut easily without causing damage to the threads of the u-bolt.

As you can see here ours rusted and bent and they had to be cut to be removed. If you have a situation like we did here today, this is the perfect kit for you to replace this. Now that we've gone over what's included in our u-bolt kit, we'll go ahead and show you how to install it. As you can see here we just have our axle sitting atop of our release spring here, and it's not secured. This is where the u-bolts come in play, and they'll secure our axle to release spring. We'll take our plate here, notice it's got these ridges.

These bridges need to face up. Here's our centering pin on our release spring, it goes in the center hole here on our plate. We'll drop that over, as you can see that holds it in place. I have our two u-bolts here and our four nuts. We'll start with one u-bolt, come up from the bottom, take two nuts ... We'll take our second u-bolt just like we did on the outside edge, come up and place our nuts on.

Now we use a 7/8ths socket and a ratchet and we'll snug these down. See, now that they're snug we'll torque them down. When we do our final torque we'll do it like the lug nuts on a wheel, in a star pattern, just to make sure the torque is evenly applied to your bolts. With that done we'll do the same on the other side now. That completes our installation of the Red Line U-Bolt Kit for mounting 5,200 pound to 7,000 pound round trailer axles.

Part number APUBR-9 on on our fifth wheel trailer.

Customer Satisfaction Score:

Customer Reviews

U-Bolt Kit for Mounting 5,200-lb to 7,000-lb, Round Trailer Axles - 7-1/16" Long U-Bolts - APUBR-9

Average Customer Rating:  4.7 out of 5 stars   (286 Customer Reviews)

Mount your round, 3" diameter axle to your trailer's leaf springs with this U-bolt kit. U-bolts, plates and nuts included.


Ordered a lot of parts for a dump trailer rebuild in Sept. Didn't install some of the final parts until Christmas break. THEY SENT COARSE THREAD NUTS INSTEAD OF FINE. I ruined 2 u-bolts and need all 16 fine thread nuts. I'm outside 60 days so I was told I'm on my own. I've spent $5k+ on etrailer. I'll find some place else.......

Etrailer Expert

Brooke M.


Hmmm...I dont like this either. I am going to send this to a customer service team lead to see what we can do. I am sure they will have a better solution for you! Hang tight!


U-Bolts and hardware seem to be good quality. Package was delivered when promised. Very satisfied with purchase. Will be buying from E-Trailer again.

Robert T.


They are working great. No problems or issues with them.


Exact replacement for original parts, easy install


Axels are a perfect fit for my trailer and are working great.


Everything arrived quickly and as descr ibed.



Put the suspension kit on my dump trailer about a year ago and has held up very well.

Etrailer Expert

Jerred H.


@Michael Happy to hear that! Thanks for the feedback!


3 weeks late box was completely destroyed and missing bokts

Etrailer Expert

Brooke M.


Gosh that is frustrating, I am so sorry! I will make sure our customer service team reaches out to you about this.


The ladies at etrailer are awesome! Unbolts work on the new leaf springs , they know there products. I will buy from them for all my projects!
Thank you


Great product haven’t had any problems yet ands it’s been about a year


Excellent Help.


I chose this particular kit mainly for the 9/16" u-bolts. I could have easily used the 1/2" kit but it was a nice upgrade and not much difference in cost. These u-bolts and plates fit my car trailer perfectly without any modifications. Everything in product description was just what it said when I received them. Shipping was faster than I expected!


What I ordered. Got to me quickly.


I had rusted old bolts and leaf springs, these were great replacements. No issues look great work well and fast shipping.


Very wonderful and knowledgeable about parts and got parts ordered and paid for and received them very quickly , very happy this place is open on sundays and will use this company again!! Again thank you !!!


Delivered as promised and installed as required.
No problems with service and the product.
Excellent company to do business with. Always glad to have etrailer available for go to supplies at lowest cost.


Excellent parts for the project I was working on. I installed a 1997 Chevy axle on a 1950 International box trailer. With a few “adjustments”, I made it work!


As described


Ordered new leaf springs for 2020 Grand Design 303RLS. Replaced OEM 4 leaf spring with 5 leaf spring. Perfect fit.


I finished installing my new springs on my trailer today. Every thing went together without any problem.i am very pleased with your product.


Customer service went above and beyond, had a problem with a bolt missing and they shipped one to me no problems.



Working Great!


Got what i was looking for and got great input from Customer Assistance.


Replaced the 4 leaf leaf springs on my 5th wheel with the 5 leaf leaf springs and the mounting kit, so far it seems to have solved the problem of the springs breaking. The trailer handles better then ever on the highway and the back roads. Couldn't be happier.

Robert S.


Couldnt be happier with the mounting kit and etrailer


The parts arrived quickly and were an exact fit, thank you!


Arrived as advertised. I would have liked to have locking washers or any kind of washer for that matter! That would be an opportunity for improvement. Otherwise very good product.


U-boats were OK, and the correct length. However, the plates were soft and basically junk.
there were no washers. You should never install U bolts without washers.


The products from etrailer are great quality and received on time and have been very reliable

Show More Reviews

See what our Experts say about this Redline Trailer Suspension Parts

  • Material Grade and Torque Spec of the U-Bolt Kit part # APUBR-9
    The U-bolts of the U-Bolt Kit part # APUBR-9 are Grade 5. The torque specs for 9/16 diameter U-bolts like this is 65-95 ft lbs.
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