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GM 10.5 14 bold questions

the general

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:bow: i,m thinking of buying a 14 bold rearend for my 75 k5(now have a 12 bold+dana 44 combo with ARB lockers)
A guy here(i live in The netherlands) who sells Army k5 blazers/k30 pick-ups said if you put that k30 axle under your k5 you will have to change the Masterbrake cilinder because the brakebalance is different ,is this correct? a 14 bold has bigger brakes/thus more brakepower.is there a difference in 14 bolds(for Chevrolet ) and what are the weak points?i now have 4.88 diffs is there a standard ratio for this axle?:confused:


Boebboeb blazer!

regards Patrick.
 
from my knowledge i have never heard people having to do anything with the brakes, only with a rear disc swap because of how much fluid the calipers need. and about the ratios, most come with 4.10s, but militarys have 4.56s in them, and most military ones are locked. hope this helps!
 
No brake changes as long as you stay with drum brakes.

And there are no weak points to a 14-bolt. :waytogo:

The only differences in any of them is if it's either full-floater or semi-floater and different widths and spring spacing. They'll all bolt on, some just need modification.
 
When I swapped my 14 bolt into my 86 K5 I made no changes to the breaks what so ever.

Another thing to think about is your front axle. If you swap the rear axle you will need to make sure you get the front axle from the truck as well, or do an 8-lug conversion on ur current one.
 
You will need to move your spring perches if the axle is coming out of a 1-ton. As far as the brakes, I just bled mine after the swap and it was good. Oh yeah, the brakes on your one ton are 13" while the 3/4 tons drums are a little smaller.
 
questions again

:bow: thanks guys!! now i will buy it for shore this 14 bold ff,i already have an SM465+NP 205 fixed yoke combo lying here ,so this with the 14 bold ff should be a good combo isn,t it:confused: . i,m on 38.5x14.5x15 Super Swampers and now have 4.88 diffs. this combo makes about 2500/2600 rpm/min at 60 miles an hour(383 stroker) is this okay or to much?it uses 34 liters of Petrol in 100 kilometers is this normal?:confused:
 
The 14 BOLT ff axle will need to have the spring pads and the shock mounts relocated if it comes out of the 1 ton truck. Make sure you do a gear swap in the front axle to match the rear axle if you're keeping your original front axle and do an 8 lug conversion unless you like carrying 2 spares.
 
koldsimer said:
Oh yeah, the brakes on your one ton are 13" while the 3/4 tons drums are a little smaller.

not entirely accurate,,,i got my 3/4 ton 14bff from a chassis/cab truck, came with 3.73 gears, and had the 13" brakes...

Also another issue i had, was going with the larger brake setup, it was easier to lock up the rears. I wrote this off as essentially having more brake shoe surface than previously with the small shoes on the 10bolt.

Even now with the disk setup i have, i didn't change the prop vale, and i go through rear pads in about 3-4 months...
 
RPM's aren't too much, but they are higher than they have to be. No easy way to change that though, unless you went with the 4.56 gears. (or change tires, or different trans, or overdrive unit, etc)

As to "mileage", if I've got my math right, that's something like 6.9 Miles Per Gallon, which is terrible. Have you changed your speedometer so that it is accurate? Changing gear ratios, transfer case, or tire size all throws the speedometer off, if you haven't fixed that, then the fuel consumption figures are all wrong.
 
Even now with the disk setup i have, i didn't change the prop vale, and i go through rear pads in about 3-4 months...

Wow, i did not change my master cylinder when i swapped in my 14 bolt and even went the rear disc conversion as well and 4 years later i'm on the same brake pads.
 
dyeager 535
My truck originally came with the 29 inch tires,3.73 diffs and now has 4.88 diffs but bigger tires(38.5inch) but if you calculate this back its the same as original in final ,my speedo is okay and the ignition timing( 10 degr for BDP on first cilinder) too. it has a 650 holley double pumper(4777-1) on it, Edelbrock rpm intake, rebuild parttime NP 203(MM replacement shaft-kit), MM supreme hubs on the frontaxle so its only the back thats in action on th road. what can be the problem then with the fuel consumption?:confused:
 
something about fuel mileage??? just my .02, my "used to be stock" 89 Burb had 31/10.5 15", with 10 bolts and 3.42 gears, running the TBI 350/700r4/241, it went from about 15-18 mpg on the highway, to about 12-14 with the 4" lift, 35"tires and 14bff with 4.10 gears. I just recently found out also that my speedo is pretty close to being right on.

I believe just the lift and bigger tires are what's killing me anyways. :crazy:

something about rolling mass or something or the other:doah:
 
:bow: I think it,s the 8 inch lift ,2inch bodylift,the roofrack with the 4 hella 3000 on it, i also have a costum build 250 kg puchbar with a Warn x.p 9.5 on it, this in combination with the bigger tires,sparetire-carrier also 80 kg,s , could be the fuel problem i think, do you guys drive on LPG? instead of normal petrol(1 liter Petrol costs here 1 1/5 dollar!!!) while LPG costs 60 dollarcents a liter!!!! my trucks foto is on holley.com in the truckssection (the orange 75 k5):bow:

Patrick.
 
Not too many on CK5 run LPG, especially guys that are still driving their trucks on the highway. There are some trucks that are hauled to the trail on trailers that run LPG.

I have looked into it, but the biggest issue I have is where to put the tank. With a full body K5 there are not too many options. You can get a special tank that is safe to use in a passenger compartment, vapor seal tanks I believe they are called. It is still going to take a lot away from the cargo area.

The other consideration is range. I figure I would really have to plan out the fuel stops on a long trip. Plus I would want some decent range which would mean a bigger tank taking up more space.

A website called gotpropane.com makes great kits using all new parts. They are not cheap, but high quality.

In my state I could get 50% of the cost of the kit as a tax write off.

If I could figure out the problem with the tank, I would do propane.
 
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