1. Trailer Leaf Spring Suspension
  2. Redline
  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: $10.66
Trailer Leaf Spring Suspension
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Redline Trailer Leaf Spring Suspension - 166079
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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 Redline. Spring-Eye Bolt with Locknut for Slipper Springs - 3-1/2" Long part number 166079 can be ordered online at etrailer.com or call 800-298-1624 for expert service.
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  • Reviews (295)
  • Q & A (30)
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Redline Trailer Leaf Spring Suspension - 166079

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

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


Features:

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


Specs:

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


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

91635B





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 etrailer.com. 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:  4.9 out of 5 stars   (295 Customer Reviews)

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

- 166079
by:

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



- 166079
by:

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.



- 166079
by:

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



- 166079
by:

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



- 166079
by:

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.


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


- 166079
by:

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 etrailer.com 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!



- 166079
by:

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



- 166079
by:

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


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



- 166079
by:

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.



- 166079
by:

I have purchased a number of items from etrailer.com 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 etrailer.com has been top quality and has worked extremely well. I would come back again for any of my future trailer needs.


Comments
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



- 166079
by:

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



- 166079
by:

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.



- 166079
by:

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!



- 166079
by:

The products we receive from Pat C at etrailer are good. All the way from the easy ordering to the timely delivery the process always goes smooth. etrailer has become our choice for trailer parts. Thank you



- 166079
by:

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


Comments
Great
Rmb - 07/14/2021


- 166079
by:

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



- 166079
by:

I called back to get the p/n of the Lippert part wich didn't how the specific dimention online store which was not what I needed...your phone assistant helped me with thw OOLEN number which was not your current stock.



- 166079
by:

Good quality, just what I was looking f or.



- 166079
by:

Perfect fit replacement, high strength



- 166079
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Good product



- 166079
by:

Solid bolt and locknut design. Works as it should, to hold my trailer's slipper springs in place.



- 166079
by:

Impressed with how fast they got here. Easy to install. Thank you



- 166079
by:

PART WORKED GREAT



- 166079
by:

Just received this order. Won't be using then for a few days but they look like just what I needed.


Comments
Working good
Jim H - 05/17/2021


- 166079
by:

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.


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Show More Reviews

Ask the Experts about this Redline Trailer Leaf Spring Suspension

  • Where is the Length of the Bolt part # 166079 Measured
    The 3-1/2 inch length of the bolt part # 166079 is measure from below the head of the bolt to the end of it. Based on what you mentioned this should work well for you.
    view full answer...
  • How to Determine Correct Slipper Spring Replacement for 1,500 lb Axle
    What happens to slipper springs is that over time they elongate and flatten out, particularly if your springs are considerably older. The most important measurement you mentioned was the 26 inches from the center of the spring eye to the end of the spring. Based on that the closest slipper spring we have that could work is the 3-Leaf Slipper Spring w/ Radius End for 1,500-lb Trailer Axles - 24-5/8" Long # SP-178275, which would work if you had a tandem-axle trailer. There are no slipper...
    view full answer...
    Image 1 for Image 2 for Image 3 for
  • Recommended Slipper Spring for Custom Kayak Trailer
    Thanks for the photos with measurements. The 2-Leaf Slipper Spring w/ Radius End for 1,000-lb Trailer Axles - 24-5/8" Long # SP-177275 are rated for 500lbs each for use with a 1000K axle. This will work with the inside to inside measurement you are seeking. You will simply need the 9/16 inch bolt # 166079. If there is any extra space in the hanger it won't be an issue with the bolt and bushing.
    view full answer...
    Image 1 for Image 2 for Image 3 for
  • Correct Bushing and Bolt for 4-Leaf Slipper Spring # SP-264275
    The 4-Leaf Slipper Spring # SP-264275 that you referenced actually comes included with the nylon bushing but if a replacement is needed then the 9/16 inch # TRBU11561 that you mentioned would be the correct size and will work perfectly. The correct bolt for this setup is the Redline Spring-Eye Bolt # 166079 that features a 9/16 inch diameter and 3-1/2 inch length.
    view full answer...
  • Replacement Trailer Suspension Parts for Trailer with 2 Square Axle
    It looks like you've got a pretty good grasp on all of this and thank you for the detailed information; it looks like most of the parts you've mentioned will work for you. For the leaf springs, the 26" long # SP-051275 will be the best option for you since springs stretch out over time and they're right around the capacity of what the axles likely is. The next closest size would be the 25-1/8" # SP-212275, but I would be hard pressed to believe that your old ones have stretched out over...
    view full answer...
    Image 1 for Image 2 for
  • Replacement 30" Long Slipper Spring for Boat Trailer
    It sounds like you're looking for the 4-Leaf Slipper Spring w/ Flat End part # SP-040275 which is a slipper spring, 30" long x 1-3/4" wide, with four leaves. It can then be mounted on a 2" square axle with the CE Smith U-Bolt Kit part # CE23103. For the suspension bolts, we have the Spring-Eye Bolt with Locknut for Slipper Springs part # 166079.
    view full answer...
  • Replacement Slipper Leaf Spring for Triton PWC Trailer
    The best slipper spring option for your Triton PWC trailer is going to be the Slipper Spring part # SP-039275 as it's for up to a 2,900 lb axle, is a 3-leaf setup, and is 1-3/4 inches wide. It does have a flat end though and not a radiused end but that shouldn't be an issue.
    view full answer...
  • Replacement Suspension Components for 6,000 Lb Axles with 25-1/4 Inch Long Leaf Springs
    Thanks for the photo! I have everything you need to get your trailer back on the road. I have attached my recommendations on the following parts for you trailer as well as the quantities needed. Leaf Springs: part # SP-111275 (4) Equalizers: part # TREQ310 (2) Shackle Straps: part # 115208GALV (8) U-Bolts: part # APUBR-8 (2) Eye Bolts: part # 166079 (12) I have also attached a few review videos on the above products for you as well.
    view full answer...
    Image 1 for
  • Will Putting Axle In Backwards Cause Trailer Brakes To Not Function?
    The reason your brakes are no longer functioning, is that they are actually directional with the front and rear pads being different. Since the axle is backwards meaning the brakes are backwards the brakes will not function. To fix this you will need to remove the axle and turn it around. As long as the shackle bolts are not rusted, you will have no issues reusing them. If they have any damage though I would go ahead and replace them for peace of mind. If you need a replacement...
    view full answer...
  • Are there Bolt-On Hangers for Trailer Leaf Spring Suspension
    We do have a couple of bolt-on spring hangers # CE14017G and # CE14016G but they are designed for slipper springs and not double-eye springs like # SP-124275. Its not likely that professional welder would charge that much. You might be able to find one locally via an iron workers union near you. For u-bolts for your 1-1/2 inch square axle you can use # SP01-120 for 2 u-bolts and 4 nuts. For a u-bolt plate you can use # 115983. For a hanger kit you could use # APS1. Now what you could...
    view full answer...
  • Bolts Needed To Install Slipper Springs
    For the spring eye you would use the Spring-Eye Bolt with Locknut for Slipper Springs - 3-1/2" Long # 166079, but slipper springs don't have the second spring eye, so a bolt is not used on the back end. You can also use a wet bolt like # 126B2, for less friction. The Shackle Bolt with Locknut for Double-Eye Springs - 3" Long # 166081 are for use with the spring and shackle straps used with a shackle straps on a tandem setup with an equalizer but it could be used for the springs and the...
    view full answer...
  • Comparing Lippert Never-Fail Bushings to the Bronze Bushings and Wet Bolt Option for Tandem Axles
    The bronze bushings and wet bolts are a great option but they still do require maintenance especially under the conditions you referenced. There really isn't any new information in comparing it is basically the difference between maintenance required and zero maintenance. The Never-Fail bushings # LC279685 are maintenance free and self-lubricating so they will be a better fit for you. This kit comes with the bushings for 4 springs and two equalizers for a complete tandem axle trailer....
    view full answer...
  • Replacement Slipper Spring for Boat Trailer 1000-lb Axle
    Well-worn leaf springs can become elongated and actually measure longer than their length when new. It is not uncommon for a leaf spring to get as much as 3/4-inch to 1-inch longer from years of use. If your spring measures 25-1/4-inches long then chances are that when new it was indeed the 24-5/8-inch length of the Redline # SP-177275. This 2-leaf spring is rated for 1000-lb trailer axles; you can check the sticker on your axle to confirm it's weight rating. This spring does indeed...
    view full answer...
    Image 1 for
  • What Size Bolt Is Needed for the 4-Leaf Slipper Spring 3,700 Lb with Flat End
    The 4-Leaf Slipper Spring w/ Flat End part # SP-040275 is designed for 9/16" bolts only, the Spring-Eye Bolt with Locknut for Slipper Springs part # 166079. There isn't any way to use a 3/4" bolt with this leaf spring nor do we have an option that will in this size.
    view full answer...
  • Bushings, Shackle Straps, and Wet Bolts for Tandem Axle Trailer
    The bronze bushings with 9/16 inner diameter come as a single, # D014-077-00, or in a pack of four, # K71-291-00. The closest shackle strap we have to that length is 3-1/8 inches. I've linked our selection for you. We do carry a heavy-duty strap that's 3-3/4 inches long, part # 018-026-05. We have wet bolts that are 3 inch, # 126B2, but the 3-1/2 inch long bolt that will fit the 9/16 inch bushing is not a wet bolt, # 166079. All of the prices can be seen on the linked product pages.
    view full answer...
  • Recommended Bolt On Hangers For Aluminum Frame Trailer
    Since you've got an aluminum frame trailer, I understand why you're looking for a bolt on solution. The only available bolt on hangers we have available would be the # CE14017G and # CE14016G but they are designed for slipper springs and not double-eye springs like # SP-124275 you were looking at. If you went this route you would want to use something like the # SP-040275 as your springs, which have a 3700-lbs capacity. This would be the best solution available for your new aluminum...
    view full answer...
  • Correct Track Alignment Replacement Hanger Bolt Recommendation
    What you'd want is the replacement suspension bolt part # 166079. This is 9/16 inch in diameter like you need and is 3-1/2 inches long too. It comes with matching nut as well.
    view full answer...
    Image 1 for
  • How to Determine the Correct Slipper Spring for 6,000 lb Axle
    The slipper spring we carry for 6,000 lb axles is the 5-Leaf Slipper Spring w/ Hook End # SP-160275. To figure out if this spring is going to work for you there is a measurement you will need to take. If you look at the accompanying diagram you can see that "C" is 27 inches. This is the length from the center of the eye to the end of the spring with the slipper; you can measure your current slipper spring to see if you have a similar measurement, keeping in mind that the current spring...
    view full answer...
    Image 1 for
  • Axle Spacing When Using Slipper Spring Equalizer Kit # APT6SE with 26 inch Long Leaf Springs
    Based on your leaf spring length the axle spacing you'd have with the hanger kit part # APT6SE would be right at 33 inches. This kit is designed for use with 9/16 inch bolts like the # 166079 and we would not recommend drilling out the kit to fit a wider bolt.
    view full answer...
  • Hanger Bolt Recommendation for a 3-Leaf Slipper Spring # WIE3
    You need to use a 9/16 inch bolt for the front eye of the 3-Leaf Slipper Spring that your referenced part # SP-178275. For that I would recommend the Spring Eye Bolt with Lock Nut part # 166079. The correct rear hanger is part # 115706S if it's a single axle trailer. Since the spring does not have an eye on the back of it you do not need to match a 9/16 inch bolt to anything.
    view full answer...
  • 9/16 inch Diameter Shackle Bolt Longer than 3 inches Availability
    We have the # 166079 which is a 9/16 inch diameter shackle bolt like you need that measures 3-1/2 inches in length.
    view full answer...
  • 12 Inch Slipper Spring Equalizer Kit Recommendation
    The only 12 inch slipper spring equalizer we offer is the part # E4541-Z. For shackle bolts you would need the part # 166079, for equalizer bolts you would need # TRFA71063, cotter pin part # 165649, and for spring keeper bolts part # 7-7. We do not have all of this in a kit though.
    view full answer...
  • Single Slipper Spring for Tandem 6000 Pound Axles 2 Inches Wide
    To determine the appropriate replacement slipper spring you would need there are a few measurements that are crucial. In order to get these measurements the current spring cannot have a load on it. If you have already removed the slipper spring from the trailer that works great. Or you can measure while it is on the trailer, just make sure that when you jack the trailer up you do so by the trailer frame. Also, make sure it is safe and secure before taking your measurements. The...
    view full answer...
  • Bushings for Slipper Spring with 1/2-Inch Inner Diameter
    The nylon bushing is included with Slipper Spring # SP-178275. The bushing has an inside diameter intended for a 9/16-inch bolt like # 166079. I linked a page showing all suspension bolts in this diameter. For a bushing with a 1/2-inch inner diameter and the 11/16-inch outer diameter required for this spring you can use # TRBU11506.
    view full answer...
  • Shackle Bolt With Nut For 3 Inch, 3-1/2 Inch, And 3-5/8 Inch Length
    Shackle Bolt with Locknut for Double-Eye Springs - 3" Long, # 166081 and Spring-Eye Bolt with Locknut for Slipper Springs - 3-1/2" Long # 166079 both come with a nut. The Step Wet Bolt for 1-3/4" Double Eye Springs # 34007-187-00 does not come with the nut, however we have confirmed a fit with nut # 192600
    view full answer...

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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

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