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  1. Trailer Leaf Spring Suspension
  2. ABS Fasteners
  3. Suspension Bolts
  4. Spring Mounting Hardware
  5. 3-1/2 Inch Long
  6. 9/16 Inch Diameter
Spring-Eye Bolt with Locknut for Slipper Springs - 3-1/2" Long

Spring-Eye Bolt with Locknut for Slipper Springs - 3-1/2" Long

Item # 166079
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Our Price: $7.63
Trailer Leaf Spring Suspension
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Shipping Weight: 0.35 lbs
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166079 - 9/16 Inch Diameter ABS Fasteners Spring Mounting Hardware
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9/16" Diameter spring-retainer bolt is used to mount slipper spring inside front hanger. Includes locknut. Lowest Prices for the best trailer leaf spring suspension from ABS Fasteners. Spring-Eye Bolt with Locknut for Slipper Springs - 3-1/2" Long part number 166079 can be ordered online at or call 1-800-940-8924 for expert service.
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  • Reviews (312)
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ABS Fasteners Trailer Leaf Spring Suspension - 166079

  • Suspension Bolts
  • Spring Mounting Hardware
  • 3-1/2 Inch Long
  • 9/16 Inch Diameter
  • ABS Fasteners

9/16" Diameter spring-retainer bolt is used to mount slipper spring inside front hanger. Includes locknut.


  • Suspension bolt attaches leaf spring to front hanger
  • Included locknut secures in place on bolt


  • Diameter: 9/16"
  • Length: 3-1/2"

166079 Spring Eye Bolt with Nut - 3-1/2" Long


Video of Spring-Eye Bolt with Locknut for Slipper Springs - 3-1/2" Long

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

Video Transcript for Review of Trailer Leaf Spring Suspension - Spring Mounting Hardware - 166079

Jeff: Hello, everybody. This is Jeff at Today, we're going to take a look at the 9/16th diameter, 3 1/2 inch long spring eye bolt with the lock nut for slipper springs. Now this 9/16th diameter spring retainer bolt is used to secure the slipper spring to the front hanger of your slipper spring trailer suspension. The 3 1/2 inch long bolt is common on trailers that have a 6,000 pound or 7,000 pound axle and uses 2 inch wide leaf springs.Now, the bolt itself is a grade five bolt. The way we can tell that is, if you look at the head, you'll see three lines on it.

That'll indicate that that meets the grade five designation. The length on this is 3 1/2 inches, and that's measured from under the head to the end of the bolt, so there's your 3 1/2 inch length. Diameter of this bolt is 9/16th of an inch. The thread size on the end here that the lug nut or the block nut attaches to is 9/16th by 18 threads per inch. Now the bolt head size is a 13/16th of an inch, and let's show you here's a 13/16 socket.

Oops, wrong one. Here's the 13/16 size socket. You can see it fits securely on there.And the lug nut size uses the 7/8th inch size socket, and that's the first one here I pulled. And you can see that fits exactly on there. And this included lock nut is what will secure this bolt to the spring eye.

But that should do it for the review on the 9/16th diameter, 3 1/2 inch long spring eye bolt with the lock nut for slipper springs.

Customer Reviews

Spring-Eye Bolt with Locknut for Slipper Springs - 3-1/2" Long - 166079

Average Customer Rating:  4.8 out of 5 stars   (312 Customer Reviews)

9/16" Diameter spring-retainer bolt is used to mount slipper spring inside front hanger. Includes locknut.


Great products from e trailer. They work as expected and hassle free. Even better prices.

The trailer springs and brackets have been great no issues at all. Very pleased with etrailer products.
Matt - 04/10/2022


Great Experience!

When I noticed
that the leaf springs on my 44 year old boat
trailer had cracked I thought I would never find replacements.
I fully expected to have to have something custom built.

I was amazed when I found the fantastic diagrams/descriptions
dimensions for replacement springs on

The phone support person was wonderfully helpful in confirming
if items were in stock and ready to ship. The replacement springs
arrived on time and everything bolted up perfectly!

Thanks for such a great site!


These parts were back ordered but I really appreciate the communications from Etrailer to let me know the status several times without an inquiry from me. Excellent customer service! I will install this coming weekend. Thanks everyone


Customer Service was / is excellent. Timely delivery easy ordering process. Correct parts and easy to install Great Company and would use again when I need to


I will be disassembling and do a further visual coming up. But what I did see while on the trip is that it definitely looks as the rollers (gold colored like a grade 5 - 8 bolt, I'm assuming they are hardened) that are in the system to roll on the slipper springs are showing wear.


I used etrailer during my restoration of my 1965 Travler Comet runabout boat. The trailer was in poor shape requiring all new suspension and hardware. etrailer had everything I needed. Easy to find and order. Great service and quick shipping.


This leaf was a different size from my original but I was happy it still fit. I had to sacrifice the fenders because of the difference in length but it was OK. I will shop etrailer for all my future needs.


Super service getting all the right parts. I received the parts in just two days it took about one hour to change both springs .everything fit grate back on the road.thanks


I have bought many different products from Etrailer and the staff have been more than helpful and I would recommend this company.

It’s been a year already! How time flies. Every things still working great thanks again.
David - 11/30/2019


The original spring bolts were 1/2" these are 9/16" and I had to enlarge mounting bracket holes but satisfied with these stronger bolts. The springs and all other hardware high quality at a very good price.

Great. Quiet, firm ride. Handles great.
Patrick M - 04/17/2021


Everything worked awesome and order was delivered on time and we rebuilt it yesterday! Thanks Carol C


I have purchased a number of items from such ans leaf springs, axle and hub assembly, and other items as well, I recently finished the trailer and it is now on a cross country trip. The trailer has just finished a 3,000 mile leg of this trip and I am told it was so smooth that it could not be felt by the towing vehicle.

Every product I have ordered from has been top quality and has worked extremely well. I would come back again for any of my future trailer needs.

The trailer has since been on a second cross country trip and it is still working just like it was the day I finished it.
Robert H - 06/27/2018


Fortunately, one spring broke a leaf so I naturally replaced both. I could feel the difference and all the noises were gone. Just like plumbing, replace everything involved, bolts, washers, etc. I don't think I will ever have to replace them again.


Replaced this good deal with a new one. The bolts were too expensive but the springs were right and shipped fast.


Awesome bolt and nut.


The bolts are a heavy grade 8 bolt and have the ridges by the head of the bolt. These are handy as the dig in and help the bolt from slipping as you tighten it. Even though it is listed as an add on item for the 1 3/4 leaf spring set, the bolt is slightly to long for this application. You will need to put washers on so the nut will tighten.


The box was delivered w leaf springs hanging out and hardware missing. They sent new hardware asap. Great service and committed to quality service.


I bought these to use on a bracket I was building for the slipper end, but they didn't measure a full 3-1/2" so they were to short. They only measured 3-1/4". I did end up using them on the eye end, of which they were a touch long, but I just added a washer to take up the excess and they worked fine.


They are holding up nice. I rinse the trailer every time it gets dipped in the Gulf, keeping the rust at bay. Thanks for checking. Have a good one!


good job i wish i bought all of my suspension parts from you


Great replacement


Excellent product and is holding up very nicely, I would recommend this to everyone who needs this

Rmb - 07/14/2021


Spring was good, fit as expected. I wish the paint finish was a little more durable but we're talking about a trailer leaf spring here, that's just the way they are. I had to flip the center pin for my application which was easy enough.

The most disappointing thing is the way these were packed, like everything else I have ever ordered from etrailer they were literally just thrown in a giant box with a single sheet of packing paper. The box was of course destroyed by the heavy springs bouncing around in the box. You can tell that at some point at least one spring fell out of the box and the shipping company had to put it back in.


Good quality, just what I was looking f or.


Very happy with service and speed of this order

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Info for this part was:

Employee Jeff D
Installed by:
Jeff D
Employee Randy B
Installed by:
Randy B
Employee Jameson C
Expert Research:
Jameson C
Employee Kathleen M
Video by:
Kathleen M
Employee Wilson B
Updated by:
Wilson B
Employee Eric H
Updated by:
Eric H

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