Tire Carrier Pivot Pin, 1" Grade 8 Bolt?

[B y r o n]

I'm researching a tire carrier build and wondering if anyone has built their pivot(s) using a Grade 8 1" bolt? If so what were your results?

I'm thinking of making a double swing and sleeving the swing bar and mounting bar with 1-1/2" x 1/4" wall DOM which would leave 1" hole. Bars will be 2" with 1/4" wall which leave 1-1/2" inside dimension.

I know a lot of you are using specially built pivots or adapting trailer axle spindles. Just looking at alternatives.

 

[handcannon]

Use bronze bushings inside the tubing, and then a grade 8 bolt (maybe 1/2" dia will work inside the bushing) as a pivot pin. Not only will it reduce the size of pivot pin needed to a much more reasonable size, it will make the assembly pivot much better.

Don

 

[B y r o n]

Don, Since the factory pins are about 1/2" and they used 2 I figured I would need a beefier pin in a single configuration. I'm just not sure that a single 1/2" bolt, even grade 8, could withstand the stress of about 70 plus or minus pounds trying to twist it.

For easier movement I was thinking of a hardened washer between the two pieces along with grease added by a zerk fitting mounted to the swing arm joint. Bronze would be better but finding the right size bushing could be an issue unless you know of a good source.

Like many, my body has been torn because of the weight of the spare and additional gas cans. I haven't mocked it up yet but I'm going to try and transfer some of the weight to the factory bumpers to reduce the stress on the pins.

 

[handcannon]

I was thinking of two pins like the stock carrier. So, if you use a single pin then 1/2" definitely will not be enough.

Don

 

[B y r o n]

Well, I'm almost to the point of being able to mock up my idea for a pivot pin using a 1" bolt. This may give you an idea of what I'm working with.

Don't pay attention to the tool steel and small block at the top of the receiver they are only there to hold the receiver in position since it is not welded yet. The 4 spacers next to the 1/2" mounting bolts will go inside the 4"x2" rectangular tube to keep it from crushing. I originally was going to go with 1/4" wall tube but I couldn't find any remnants at the metal yards. I ended up with two pieces of 0.120" wall. I'll be joining them in the middle under the hitch. The 2"x2" square tube above is also 0.120" wall and will be used for the swing arms.

 

[B y r o n]

So I was finally able to find the DOM tubing I needed for the pivots.

I lucked out and my HF lathe/mill tool was just large enough to allow me to face the spacers after cutting them to length. I cut them 1/2" longer than the width of the mount so there would be 1/4" stick-out for weld clearance.

I've learned a few things during the process so far. Trying to be precise with mounting hole placement can drive you mad. You need to drill the hole large enough to allow some wiggle to get things to bolt together. I used 3/8" holes for the M8 bolts. I also made spacers for these bolts and discovered it's harder to get them in the pivot end if you have already tack welded the bushing stock in place.

I also learned that it is time to see a frame straightener before I go any further with this build.

It may be hard to see because of the camera's focus but past pulls have bowed the rear frame member. It's about 1/4" out at the bottom center. This will prevent me from being able to mount my receiver hitch unless I make more compromises which I'm not ready to do at this point.

I tried to use my hi-lift jack to pull it in but didn't have any luck. Not enough ground clearance to work the handle without causing the jack to slip off the frame. I had the top chained to the rear leaf front spring hangers on both sides of the frame. Once the frame is back in shape I'll report more.

 

[Howard705]

In this picture it looks like your bumper tube is bent

 

[B y r o n]

In this picture it looks like your bumper tube is bent

The tube itself isn't bent, the material I'm working with was actually two equal length pieces that meet in the middle. The bend you're seeing is caused by the bend in the rear frame member where it is pulled out at the bottom. I'm hoping a frame shop can push or pull things back into alignment. Once that is done I will weld the tube into a single straight piece.

 

[Howard705]

Back it into a tree going at 1-2 mph at the exact spot of the bend. Clamp a 2 x 4 or something similar to distribute the load and space it from the body. Have a (good) helper watch.

 

[B y r o n]

Based on what I've pulled off the old ball hitch, 1-2 MPH against anything solid is not going to bring the frame back to where it needs to be. I went to a shop this morning and $50 got me what I wanted.

I didn't bother with a side/overhead shot because of the way the camera focuses. Trust me when I say it is straight, at least on one plane. Lay a straight edge on the back edge and it is straight now. However, when I mounted up what you see in the photo it now peaks upward ever so slightly in the middle. I assume this is from jacking under the old ball hitch for various reasons over the years. You might be able to detect that the gap in the center is less than the gap at the ends. I'm OK with this as it will cause the pivots to be leaning slightly out. I had to clearance the holes again for the 4 mounting bolts of the receiver hitch I'm making. I apparently also mis-calculated the length of bolt I needed for mounting it. Instead of 3-1/2" long it looks like I will be needing 4" bolts. This may be due to a slight indent caused by the HD hydraulic jack used to push the frame back into alignment. Once things are tightened up for the final assembly I may have pulled the dent out and 3-1/2" bolts will work but for right now I can only get about 1 thread to engage and that is not enough to try and draw things together.

 

[B y r o n]

Making progress, but need to buy some more supplies.

 

[B y r o n]

Well, I'm getting closer. Went out to pick up some more supplies and ended up with some 0.188" wall 2"x2" tube. It should resist twisting better.

Tubes are not welded yet, just mocked up.

My current plan is to weld a spacer under the top two hitch bolt spacers. I'm going to weld a 1/2" nut to the bottom of this spacer so that I can run a 1/2" bolt down through the swing out arms. There will be a spacer above the hitch so the swing outs will sit level and the bolt will hold them together. That is why the 45 degree angle cut. With everything tight it should be rock solid.

The reason for going with 1/2" bolt is because it will use a 3/4" socket which is also 19 MM which is the same as the lug nuts. No extra wrenches and plenty of strength.

 

[Bigcity25]

Sorry if I missed it, but did you attach this to the existing bumper? I am in the same boat with my 40 and not sure if removing the old bumper is gonna open a can of worms for me.

 

[B y r o n]

The existing "bumper" is the two small bumpers, one on each side. These are bolted to the rear frame cross member. I used the existing mounting points in the rear cross member and bolted my 2" x 4" square tube to those existing spots. The small bumpers are mounted in their original location with longer bolts passing through the new piece. I have 3/8" thick spacer plates between the rear frame member and my new tubing.

Here is a close up picture showing the rear cross member, spacers and new rectangular tube.

 

[Bigcity25]

Nice, I need to look closer at my setup (7/70 fj40) I thought the spring perches were part of the whole rear bumper/frame setup. So wasn't sure if removing the rear bumper would be a bigger task than thought. Thanks for the info