14 bolt swap for the suburban.
Regarding my soon swap of a 14 bolt into the suburban, Mike writes: Did you have to change the length of the rear driveshaft?? I need to know ASAP b/c I am considering the same swap in my 1986 K10 truck. What do you think of using a FF vs a SF rear end? I could really use some advice as I am considering making the purchase this week.
I haven’t done it yet (this weekend hopefully, finished the front axle last weekend, many post to come), but the driveshaft should be fine. The length looks the same within an inch (from the center of the axle to the u-joint) and I think the u-joint is the same (if not you can get an adaptor u-joint).
Now, full-float vs. semi-float (K5 has a lot of info). Full float is stronger, but semi is OK unless you have a big block and large tires and a lead foot. Full-float is only availible in 8 lug, whereas it is possible to find a 6 lug semi-float 14 bolt (however, only in ~’90 up heavy half/light 3/4 trucks and the spring perches will have to be moved to fit the older trucks). If you are going to install a locker, it is many times cheaper for a full-float (you don’t have to replace the carrier, unless it already has posi, so check first). The full float does use larger u-joints, so be prepared to buy the adaptor. The full float doesn’t have c-clips so if you break an axle you can drive on it. The full float is larger and heavier and will have less ground clearance. More on FF here.
I went with the SF because I just wanted bigger brakes and better towing capacity than the stock 10 bolt, and I could keep the stock rims.
I appreciate your comments….the purchase may be delayed as I am dealing with a family illness…but I thought I would respond to your comments about the SF vs the FF. After doing some more thinking, I am leaning more towards the FF. I don’t like the idea of c-clips at all. I remember seeing a mid 80’s ‘burb on the back of a flat bed wrecker with BOTH axles missing. The backing plates were just about ground down to the tubes. The pumpkin was missing a fair amount of metal too. I asked the driver what happened and said the guy was pulling a horse trailer and one of the c-clips let go. The axle worked its way loose and the other axle popped out too. Not sure what happened to the trailer, but the back of the ‘burb was burned badly - the sparks ignited a nearly empty fuel tank. A nearby fire crew was able to respond quickly, preventing the entire truck from burning up.
Now realize I have been running a 10bolt with C-Clips for nearly 235,000 miles – at 100k, the gov-lock grenaded itself and an Auburn was installed. I don’t know if the c-clips were replaced, but I know the bearings and seals were not. Only the pinion seal leaks after all this time. The left axle tube started to bending at 125k (running 31’s) at its natural hinge point (the freeze plug looking crap pressed into the tubes on either side of the pumpkin). The other started to bend at 160k (after installing 33’s) – and now the truck crab walks. The K10 never carried any serious weight (>1500 lbs) or towed anything over 1,000 lbs until 175k. The weight of the truck bent those tubes…Now the truck is equipped with 265 75R16s D rating and it is much much happier.
When it is all said and done, I will probably end up using the SF rear end – but if I had my druthers and a much stronger engine, I would use the FF. I can buy an 87 K20 ‘burb (sans front clip) for 5-700ish with a 4.10 8-lug SF and a 4.10 8 Lug Corp 10…does that sound like a good deal to you? I also need a front driveshaft as the slip joint in mine is shot…there isn’t much else I can use on the truck…
Comment by Mike — March 30, 2006 @ 8:26 am
Forgot to mention I am running 3.73, 700R4, Goodwrench 350 (with Edelbrock cam, intake and carb), and tow a 5,000lb boat.
Comment by Mike — March 30, 2006 @ 8:29 am
I guess I have a different view on the c-clip axles; I’ve lost the axle (and tire) from twice in non-clip axles and never with a c-clip. But never in a full float axle. So, semi-float axles that don’t have c-clips (either by design or from a c-clip eliminator kit) instead rely on a press fit of the outer wheel baering to retain the axle. So the axle will not fall out if it breaks, however, it can (and will) if the bearing fails. I’ve had this happen twice with the stock 10 bolts in ‘68 pontiac tempest/lemans/gto cars. Its amazing how far a tire and axle can travel and how hard they are to find. Now, if you use a c-clip eliminator kit (which basically consists of press fit bearings) you’ll have new bearings which shouldn’t fail. But another way to retain an axle is with disc brakes (this is why front disc brakes were mandated in ‘73, not for braking). The price of a c-clip eliminator kit is good piece of a disc brake conversion kit. Or if you are changing wheel bearings anyway, you might as well use the press fit bearings. Not sure if the burb is a good deal or not, if you have a good craigslist in your area, you could put in a want ad. If you do get the ‘burb, I’d be interested in the rear seat shoulder belts and 3rd seat mounts.
Comment by Administrator — March 31, 2006 @ 6:20 pm
hey i azm looking for a 14 bolt c-clip eliminators, u guys know wher ei could find any????
Comment by Ricky — October 27, 2008 @ 1:21 pm