Front tow hook replacement: Receiver tube install

 

The front tow hooks on the ZR2 are not as strong as we would like them to be. There are quite a few stories about them breaking or bending under load. Since I do take my ZR2 off-road and occasionally pull other people out, I knew that I'd need something beefier.

I had seen a few folks over at ZR2.com had installed 2.5" square tubing in the front frame horns that allowed them to use class 3 receiver inserts. I thought that was a good idea and so I decided to do this modification too.

NOTE that I'm writing this up about a year after the install, so I don't have as many pics as I'd like and maybe some of the smaller details I'll forget. But I'll have enough info here that it'll be clear how I did it.

First off, though I'd seen other peeps had actually gone to the store and purchased class 3 receiver tubes and inserts, I'm a cheapskate and I have a few tools, so I decided to build my own. I went to the local iron & steel shop and told them what I needed - they went to their scrap bin and pulled out exactly what I needed. They sold me about 5 feet of 2.5" square x 3\16"  tubing for $7 and 6 feet of 2" square x 3\16" for $5. Good deal!

First off, I removed the OEM tow hooks. Some peeps take of the plastic valance for easier access but I have skinny arms and fingers, so I left the valance on. Also take off the front skidplate.

I cut off two 12" lengths from the stick of 2.5" tubing. I put each length into one frame horn so that about 4.5" extended out of the frame horn. Then I marked where I need to drill to use the existing bolt holes on the bottom of the frame horn. You know, 4 on each side (2 from OEM hooks, 2 from front skidplate).

I was originally going to drill and tap all 4 holes in the 2.5" tubing and use the OEM bolts to bolt it in. However, I wasn't comfortable with only having a few threads for the bolts to grab as the thickness of the tubing (3/16") only allowed for 3-4 threads.

So, I drilled the threads I had tapped out of the holes used by the OEM tow hooks and cut the threaded "tab" off of the OEM hooks. I then used those tabs as backing plates since they are much thicker and have like 10 threads for the bolt to grab. Check out the pic below and you can see what I mean. The holes on the left side of the pic are tapped in the tubing while the holes on the right side of the tubing do not have threads (the threads being in the "backing plate", which is the OEM tow hook tab).

Before I bolted the 2.5" tubing in, I drilled out holes to allow for the "hitch pin". You can barely see the holes in the pic above, the two vertical holes to allow for the pin to go in horizontally.

At this point, most people who have done this modification have installed the 2" sq. insert with a clevis attached to the end. They've either purchased one ready made or have made their own.

Instead, I made my own. I bought the biggest clevis I could find and cut a 10" length of the 2"x2" tubing and drilled the appropriate holes and assembled. The tubing was inexpensive but the clevis was close to $15.
Sorry that I didn't take a pic when it was new, it's all beat up now but still functional!

I had intended to make 3 of those inserts, one for the back and two for the front. Well, I didn't want to spend another $30 on two more clevis, so I use the one I did make in back...

But in the front, I did something different. I purchased a 4' piece of the biggest log chain I could find and two 1/2"x3.5" grade 8 bolts and bolted the chain in. Really, the clevis insert is a better, stronger solution but I've grown to like the chain on the front and I haven't had any trouble with it yet, so it remains.

I will make a disclaimer here though. Some people have told me that pulling with a chain installed like that creates large stresses due to the angle of the chain where it bolts into the receivers. I did a little research and this is a true fact, though I couldn't come up with any #'s (like 4x the stress per degree, 10x, whatever). So, though I have pulled out one truck and one tree with it, I go easy on it. Hopefully, I'll never have to do one of those "multiple yank" extractions with it. If I absolutely do have to get crazy with it, I'll post the results here and on the ZR2 BB's.

 

Hmm, a few other notes:

 

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Here's a few other write up's of other people's receiver modifications. Everyone makes it the way they see best and they all do a great job. (well, only one so far, I'll find the other links soon)

http://www.zr2.com/frequently_asked_questions/modifications/hitches/hitches.html