jason74

So, I have the Britax Roundabout in the passenger side rear seat of my 07 C2 with backrest and bottom cushion removed. The upper LATCH is secure and the seat belt has been threaded through the car seat properly after being pulled out to end and is as taught as possible.

The bottom of the car seat can still move around (forward) a lot. The top stays secure, but I am alarmed and concerned about the movement of the bottom as his legs would be easily crushed on the front seat back in a head-on collision. It can move forward 4-6" easily.

Has anyone considered or developed a system to remove the lower anchors of the factory seatbelts and attached the child seat directly to these? After removing the plastic covers for the lower anchors, there is a simple bolt holding each lower seat belt point in place. Has anyone replaced the bolts with a hook type system that could more securely attach the lower portion of the child seat? Kind of like creating a lower LATCH mounting system. This seems to be a very simple fix to a potentially major problem.

Kuhan

I have the britax roundabout also - I assume you have removed the base from it?

I find that mine also moves a little - the seat belt buckle is higher than the path through the seat so you don't get great tension. My daughter is 3 and I make sure that the front passenger seat is far enough forward that there is not much chance of her hitting it with her legs.

By the way, there are red seat belt clasps on the child seat in the area that the seat belt passes through. Make sure you use these - they do limit the movement. I didn't study the manual too much but it didn't look like they were mentioned.

jason74

I didn't remove the base. I will look at this tonight. Maybe this is where I've gone wrong.

There is still the possibility to develop a simple bolt on piece to attach here.

Thanks for the feedback

808997

Try putting the bottom and back cushions back in. It sacrifices a bit of leg room but should be tighter.

holden997

I also have the britax roundabout and the base was removed for the installation. I also found the rear seat belt did little to secure my child car seat. So I fabricated 2 brackets (see pictures) and fastened them to the existing anchor points.
To make your own brackets, you will need 2 strip of metal about 1/8” thick x 1” wide x 4” long.
Drill ½” hole for the car seat latch and another hole for anchoring it to the existing seat belt point (see pic). The size of this hole should be a bit larger than the diameter of the bolt. Final step is to bend the strip to about 45 degrees at the center.
To install, remove the back and seat cushions. Remove the anchor bolt, place the bracket on top of existing seat belt anchor and fasten both bracket and seat belt anchor with the existing bolt. Bolt is long enough. Do the same on the other side. Torque bolts to 30 ft lbs.
Now you can use the child car seat latch system to fasten the bottom portion and use the seat belt to secure the top portion.
My child car seat is now rock solid in place. The wife is also happy with this. (a happy wife is a happy life).
Hope this helps.
Holden

jason74

I did remove the seat base which didn't help at all. He may have a bit more leg room and sits lower in the car, but still way too much movement. Holden, this is exactly what I was thinking about. I'll fabricate one up soon to solve the problem. I can't believe that you and I are the only to notice this or have this problem.

gshap

Holden thanks for the write up I have a few questions for you. How far are the holes from the edge of the bracket on both sides and how large is the hole that attaches to the car side seat belt bolt?

TIA

jason74

I did make the attachments on Saturday. They work well, but there is still a little bit of movement in the seat, but much more secure.

I did make the extension on the central tunnel a bit shorter so that the LATCH device was a little bit more taut. I used a 1/2" bit to make the holes into a 1" wide piece of metal. That leaves about 1/4" on each side after I ground down the corners. The LATCH clips just fine onto that.

Probably could have used aluminum to save a few ounces....

UNC Nick

I've got a 2 yr old and 4 yr old that ride almost daily in the back of my 996 cab (getting ready to buy a 997, but that's a different topic). The ONLY way that I could get either of their seats to be firmly attached without movement was to use on of the seat-belt ratchets that let's you crank away until there is zero extra belt to allow any motion. I can grab my son's seat with both hands and violently shake as hard as possible and I MIGHT sway the car a little- the seat goes nowhere.

Kuhan

I bought some 1" steel strip over the weekend and will give this a go also. Does the 1/2" hole for the belt bolt leave any play or is this the right size? Anyone know the exact diameter of this bolt?

jason74

I don't know exact size of the bolt, and I don't remember which size ratchet I used to remove it... When drawn down tight, there was no movement of the extension. You can get exact size when bolt is removed if you prefer.

I like the idea of the seat belt tensioner. I didn't consider this.

Frontside720

I have a 911 C4S on hold for me until I can figure out this child seat issue. I just sold my truck and am sitting carless with cash in hand.

For those of you that have Cab's. How are you mounting the rear child seat latch strap? (the one latch that usually anchors to the back of the car seat)

I was thinking of using of making a bracket like the one above but possibly having a dog bone shaped end so I can have two holes with two straps.

Thanks for your help and great idea!

pabafree95

i have the recaro prosport for our 2.5 yo (30lbs) and had similar issues with some movement. I removed the seat cushion but left the seat back intact - in my opinion, you want the seat back, it can also absorb some force so that the car sear is not just abutting the carpeted frame. Anyway, this is what I did to make it more secure - loosen the upper latch, then harness the kid into the seat, then open rear hatch and tighten the upper latch as much as possible and what it does is secure it more squarely, with significantly less play of the carseat bottom. I am much more comfortable with it now, minimal movement.

thejoee

I have a Britax Marathon in mine right now. I removed the seat bottom and seat back/shelf. I had a little bit of movement at the bottom until i rolled up a towel and placed it underneath before I did my final tightening. it doesn't move anymore. Now I gotta buy another Britax seat for my other child so I can drive them both to school everyday

Frontside720

I'm getting my car tomorrow and will start on this modification.

The issue with the tightening is that there is no cushion to compress to assist with tightening. I will make the brackets but I also plan to use foam mats that you see people use for kids mats or laundry room mats (puzzle peice around the edge to join them together) and put one or two underneath the seat. This should allow me to to put a little tension on all harness'.

I will decide if I'm going to put them on the back of the seat because I plan on removing the seat backs as well (cabriolet = steeper back rest)

Still not sure about the rear tether but I will sort that out when I get there.

I will post pictures for the cab drivers out there.

Thanks again for the amazing solution!