My buddy is unhappy with the sag he gets when hooked up to his 33' fifth-wheel (2002 D/A EC LB). We don't know the pin weight but I'm sure it's typical. He's had air bags before and doesn't want them again. Parts guy says GM doesn't sell the 3500 3rd. stage spring separately.
I tried search but nothing applicable came up. Any ideas on how best to reduce the sag?