Help
Posted 23 May 2005 - 03:27 PM
I originally only wanted a good lap belt since the shoulder harness were not really going to get much use for the cost involved in proper attachment points. After thinking about it a bit and how I was going to do it without going to crazy with cost I decided to go forward and do the proper 4 point.
Discussion on a prior thread Lap Belts & Harness helped me make a lot of my decisions.
Below were my personal goals:
1. Keep OEM stock Belt for normal use.
2. 4 point harness 2", both lap & shoulders. 3" too uncomfortable, 2" just as good.
3. Keep Stock OEM Seat.
4. If buying a seat keep away from the high sides for easy entry/exit. IMO due to the speed of our sport on the trail this side support are not really needed.
5. Keep a proper Shoulder Harness attachment point.
Since I was hoping to see if I can modify the stock OEM seat (saving money) I decided to splurge and get a good quality harness. As discussed on the above link that I listed above... there are cheaper alternatives. I called Schroth and talked them into breaking up a combination that was not part of their catalog. They also offered me an account for this type of setup in the event of future sales. We started with one of their basic setups to fit my needs (especially with the 2") & we modified from there.
Profi II-6H
By looking at the above picture you will notice how the shoulder harness starts a 2" & ends at 3". I did not order the 5 point which is at the crotch area. The 5th point prevents submarining at high speed impacts. Since I am not racing a mustang at the track I found no need for this.
The next item was the cam buckle, I wanted the SL11 Aviation Buckle. The difference is that is has a release tab on top of the buckle that allows the release of the shoulder harness while still keeping the lap section connected. I found this to be very useful for my application.
Below is a close up pic of the buckle which are made out of high impact resistant composite material.
Take note of the tab on top of the buckle that releases the top shoulder section only.
If you rotate or twist the buckle at any time they will all release at once.When I got the package and saw the quality & workings of this belt I was very satisfied with the quality of this product.
I'm glad that I took this route as I was comparing it to other belts that I have seen in the past.Below you will find a few close up pics of the lap belt.
You will notice on the pic below how one of the metal tabs are bent, I will explain this later as they are normally straight.
Seats: Seating options that were available and what I personally decided to do.
There is a proper way to buy or modify a seat that will properly make the shoulder section work to hold you in place. A picture is worth a thousand words:
I first started looking at the different seats that were available from a few manufacturers to properly attach the harness... many to choose from. After spending a few days on and off speaking to different manufacturers, looking at different model seats & most importantly speaking & corresponding with other Jeepers that had seats I came to this conclusion....
Two Types: High & Low Sides.
If your buying a seat, keep away from the high sides for easy entry/exit. IMO due to the speed of our sport on the trail, the side supports are not really needed. We get in and out way too much while on the trail and this will eventually get to be a bear. This was expressed to me by a few Jeepers I corresponded with that had the high sides, they all stated that if they had to do it again, they would purchase a low side.
Most after market seats that you will purchase will have a straight or non swivel back. It will also require an adapter bracket or a full replacement to make it fit in your Jeep. Plan to pay around $300 to $500 for a seat by the time is all said & done. I have to say that out of all the seats that I looked (if I was to purchase a seat), the Daily Driver made by PRP was my choice. They also made an adapter bracket for the Jeep instead of replacing the entire bracket system.
With all this in mind I decided that the stock OEM seat was not too shabby.
I thought to myself... what's the worst that can happen... ruin the seat... I guess I would have to buy one if I did. 
I wanted to save some money along with knowing that what I already had, worked well for me all these years. I tried to find info all over the place to see if anyone had modified the seat for this application, could not find anything. Someone advised that they saw one at a show that was modified but had no pics nor information on it. 
Modifying the stock OEM seat to accept a shoulder harness:
I looked at the shop manual to see what I was getting into. It showed a picture of the back rest frame being of tube with (what it looked like) sheet metal covering the entire area of the head rest, not much else was said on how to remove or install. This meant I had to take it apart to cut the sheet metal instead of just cutting the material & foam support from the outside.
First: I ordered rectangular slots so it would not chew up the belts. I found them from a company called Corbeau. They originally quoted me $20 but when I go the bill it was $35. They are of two parts, front & back locking into each other. I made sure I had these in hand before undertaking stock seat modification. Part# GT7GT7 Harness Slots.
Before you start any of this... sit on the seat, take a ruler, lay it on top of your shoulder, measure and mark your shoulder height, you don't have to be exact but do try and get as close as possible.
1. You will need to remove the seat, four bolts with one star at rear passenger. Disconnect the electrical plug for the stock buckle sending unit.
2. Remove the pivot bolt that holds back rest to the bottom of the seat located on the passenger side. If you don't do this you will not be able to slide the zipper over the main bar.
3. Slide the entire back rest cover & foam support off the back rest frame. Your back rest frame is now completely exposed.
4. Measure the inserts (purchased or made), get as close to the shoulder height you previously measured, make a cut (larger than inserts, about 1/4 to 1/2" to allow spacing and alignment at the final install) on the sheet metal to the most outer part of the tube frame to create as much space in between the two cuts as possible.
Below are back and front pics of the cut:
Notice that the cuts are not the most straight ones you have ever seen but as long as you get close enough and allow a gap, the inserts will align, give you support & adjustment for the inserts at the final stage.
5. Install the foam cushion back on the frame. Feel around, have patience and insert your favorite sharp object through what you think is the middle of both slots. Take a small scissors and start cutting away slowly making the hole bigger.
NOTE: Cut enough just to be able to push cushion out of the way with your hand and provide pressure to the insert as it is being installed. Make numerous try fits with the actual insert as often as possible until it slides all the way through. If you cut too much, your inserts will slide around, you then will need to go to the junkyard or buy a new seat.
All cuts need to hug the insert and must not be larger than the outer lip.Below are front and back pics of the cushion cut:
6. Install seat cover over cushion, make the cut following the instructions listed on #5.
7. Install the inserts from both the back and front side until the smaller bottoms out into the bigger one. Technically you are supposed to glue these so they do not pop out. I choose not too do so that I may install these over my seat covers allowing me to change out the seat cover in case it gets old & ripped.
Not gluing them created a problem because they would pop out (at least one did). I shaved a wooden dowel with a knife creating a wedge. I slid two of them between the corners of the inserts and they locked perfectly. Now I can remove & re-install the inserts anytime I wish.
Below are pics of the finish inserts on the seat cushion & on the seat cover:
Picture of the finished stock OEM seat back on the TJ:
Installing The Lap Belt Section:
Attachment points must provide optimum geometry to minimize movement of the lap belt. Lap belts perform best when they act at an angle between 45° and 55° relative to the longitudinal axis of the vehicle. This angle permits the lap belt to react to the upward pull of the shoulder harness. A system installed with a shallow belt angle, permits the shoulder harness to pull the lap belt up off the pelvic area and into the abdominal region with the likelihood of injury to internal organs. Using the stock point of attachments insured me of this. If you are going to have other attachment points, please make sure to follow this rule.
Below is a pic of the graph outlining more detail.
1. Remove the Star bolt located at bottom of the stock belt housing near the inside driver side rocker panel.
2. Remove housing, all should come out in one unit.
Take note and look down at the slots on the stock tube frame to get an idea how to re-install the housing.
3. Install the lap belt driver side belt piggy back on the stock bolt bracket mount. The lap belt mounting tabs usual come straight. As you can see on the pic below I put a bend on them so that they clear & don't rub against anything.
4. Install belt housing back on the vehicle. Notice the clearance of the stock & lap belt. They do not interfere with each other nor rub against anything.
5. Remove the OEM driver seat buckle bolt located underneath the seat on the right side.
6. Piggy back the lap belt mounting tab on the same bracket using the same OEM bolt. You will notice that I also bent the mounting tab of the lap belt for better positioning and clearance.
Below you will see the finish lap belt which is what some people just want to do rather than the additional 4 point harness. I forgot to mention that the cam buckle will stay on either the left or the right side (depending on how you ordered it) of the lap belt when released.
Choosing the Proper Shoulder Harness Attachment Point.
In order to choose & install the proper attachment point we first need to understand a few things.
Look at the picture below.
Shoulder harnesses should NOT be anchored more than 1 through 4"s below shoulder height. Mounting below this height may cause additional spinal compression.
In an accident situation, the shoulder belts pull down and back on the torso as they resist the forward motion of the driver. The resultant restraint force compresses the spinal column and will add to the stresses in the spine already caused by the force of the crash impact.
The end attachments of the shoulder harness must also be installed at appropriate angles. The ideal position is anywhere between 5° below and 30° above the drivers shoulder. If the trailing ends of the harness are too far above the shoulder (greater than 30°), then two problems can occur. First, tension in the shoulder harness is increased and undue stress is applied to the harness and its structural attachments. Second, excessive angle will cause excessive motion. If the harness belts are too far above the shoulder, they will provide little resistance to forward motion of the drivers upper torso. The result is impact with the steering wheel and the possibility of neck injury. The shoulder straps should also be 3 to 6"s apart behind the driver's neck to prevent slippage off the shoulders.
With this in mind, below you will find some pics of Proper and NOT so Proper attachment points. Some are being sold without knowing.
1. Here you have an install spreader bar on the top rear ears, I actually thought this would be too high but when I measured it with an angle finder I was 28 degrees which makes this an acceptable method since we are not exceeding the 30 degrees above shoulder.
2. This is the perfect bar in my opinion made by Rock Hard 4x4. If you have a tube bender you can probably make one yourself. I choose not to since I did not want to do any trial error with the angles and the Rock Hard had beefy clamps (shown later on the install) allowing me not to have the bar welded to be removed at any time.
3. The next one is also made by Rock Hard 4x4. This IMO is incorrect and will NOT provide a correct attachment point even though the shoulder harness can be attached. I don't believe they actually know this and are selling them to please some of the people that want to still have an easy entry to the back seat.
I decided to do the number the #2 option. The #1 option would have been cheaper since I already had this brace but would have left things dangling a bit getting in the way of passengers along with a continuing concerns of the kids playing around in the back seat under normal situations. One quick note: When I received & installed the #2 option it was not bad at all getting to the back seat as I though it would be.
On to the #2 Attachment Point Install:
Before I install anything on the TJ I usually make sure everything fits. I truly believe there is no such thing as bolt on. I have to say that this has to be as close to bolt on as I have ever seen. The clamping ends were of good quality and the bar fit well around the tubes with some help from the hammer and a small wooden block. Let's just say that I will be selling this bar on my Cyber Store currently under development.
1. Remove passenger seat belt attachment point at the top of the stock bar, 3 star bolts. You need to do this because of the angle that you must bring the bar in will not permit the clearance needed.
2. Make sure everything fits and aligns properly. Measure the height, get it as close as you can to the slot inserts on the seat. In the picture below, it still needs to come up a bit.
3. Remove, prime & paint. I used about 4 coats of a Cold Galv spray for priming after I cleaned and Acetone the bare metal. Used about 4 good coats (hour a part) of the final black spray paint.
You will notice from the above pics my excellent paint booth.
4. Install the bar after a few days of drying. Notice the quality of the end clamps with 6 bolts. This thing is not going anywhere.
Check out the angle and the spacing from the front seats.
5. Install both the shoulder harnesses. Make sue that the buckle clip is fastened properly, there should be no movement.
Picture from below. Notice that I rolled the excess of the belt and wire tied to the bottom supports of the bar. Did not want to cut them in case I ever sell them or decide that my needs have changed and need to install it a different way.
Side view from the opposite side so that you can see the angle coming into the slots.
Finished back view.
Shoulder harness belts lay nicely on the sides of the OEM seat towards the rear. They don't move nor are in the way of anything when not in use.
Below is a pic of everything connected.
Overall this was not a hard install by no means, I'm sure there is plenty of other ways of doing it, let's post up if you have some additional info. I do have to say that I probably have the only pics on the net with regards to modifying the stock OEM seat, I really tried to find info on this but came up empty. Feel free to share with anyone in hopes of helping someone putting this to use.
