What is wrong with our car seats?

[emelsea]

DH and I both replaced our cars in the last year.  I currently drive a  2008 Volvo XC70 (station wagon) and DH drives a Kia Optima.  Prior to this, I drove a Dodge Dakota extended cab truck and DH had a Hyndai Elantra.  

Our son rides in a Graco Nautilus in DH's car and an original Britax Frontier in my car (both used as BPB's, NOT with the 5-point harnesses), in the passenger rear seat in both vehicles.  Both are installed using the LATCH, and the tether.

In both cars, when DS gets in, the seat belts are already "locked", and he cannot pull them forward.  Either DH or I have to go back, remove the seat belt from the belt guides in the seats and push the belts back "up" to then release them.  And that doesn't happen right away.  It sometimes takes 5 minutes to get the belt to release and pull out.  I'd say that this happens 90% of the time in my car.  DS and I rarely ride in the other car, so I'll be generous and say it happens 50% of the time in that car.  

The first thing we did was take our cars back to the dealers to see if there is something wrong with the belts in the cars.  I feel that at both dealers, they really did thoroughly check, and I feel reassured that there is nothing wrong with the belts, and it has to be something about the way we are using the seats in these vehicles.  

This NEVER, not even once, happened in our old vehicles.  And I asked many friends, and it doesn't happen to any of them, either.  

We're considering buying new booster seats, to see if these seats just don't fit our cars correctly.  

Any ideas?  Does this happen to anyone else?

[LaughingHyena]

Our seat belts lock only when pulled out to the full extent, after that you can feed them back in but not pull extra out. The kids have managed to lock them a few times when they have pulled out too much belt, either being silly or because they got it somehow tangled. Even I've done it when pulling loads out to fasten my youngest in.

If we had short belts I'm sure it would happen a lot more.

Once locked you have to feed all the belt back in to unlock it, so like you we have to take out the booster as the belt loops through it but after that they release straight away.

[emelsea]

I think you're right, and my son is pulling them all the way out in order to fasten it himself.  

I wonder if regular boosters (as opposed to these larger seats that converted from 5-point harness seats to BPB) would be better because they have a slimmer profile?  Perhaps they don't stick out so far and he wouldn't have to pull out so much belt to get around the seat?

My husband is voting to just get some backless boosters, but I feel like DS would be so exposed in one.  I think we both have side curtain airbags in the backs of our cars, but still...

DS is 8.5, about 53 lbs and around 50.5" tall.  

[mama2soren]

At 8.5 I would have no concerns with a backless booster, assuming there was adequate support behind your son's head (headrest to the top of his ears at minimum).  I have a Frontier 85, and I can barely buckle the belt around it in booster mode,  it almost always pulls out far enough to lock.  A slimmer booster might be your best bet!