disc brake conversion for a 70 1/2 ton 4X4 - The 1947 - Present Chevrolet & GMC Truck Message Board Network

**Ricks1971** · 10-12-2011, 09:03 PM

Just want to get some input on a disc brake conversion for a 70 1/2 ton 4X4 truck. A friend has the parts off a 1975 1/2 chevy 4X4 and my question with these rotors and hubs work on the 1970 iI want to convert? thanks Rick

coops714x4 · 10-14-2011, 11:59 PM

Rick it all depends on what they are... "crossbreeding" usually don't work now if they are the same then its possible. it would be easier to just put the whole front axle in and match the gears. Coop

**Ricks1971** · 10-15-2011, 09:13 AM

I was thinking of doing that but is there a list of gear ratios out there if I pull the covers off the rear ends and front ends? thanks Rick

coops714x4 · 10-15-2011, 09:59 AM

I don't know about a list. there is a number stamped on the right side of the "pumpkin" it can be coded to tell you what gear ratio you have, or you can count the teeth on the ring gear then divide that by the number of teeth on the pinion. there is no need to pull the cover on the rear end the ratios on both will be the same. If you change front ends make SURE you get the pinion angle right. Coop

**Ricks1971** · 10-16-2011, 10:10 AM

I wonder if someone would post a pic of the exact location where this number is on the pumkin?

onebadbowtie · 10-16-2011, 10:26 PM

you will also need a different master cylinder and booster

coops714x4 · 10-16-2011, 11:36 PM

Quote:

Originally Posted by onebadbowtie

you will also need a different master cylinder and booster

This is new to me, why does he need to change is booster and master cylinder??? is it because disc require more psi ????

10-12-2011, 09:03 PM	#1
Ricks1971 Senior Member Join Date: Mar 2006 Location: Clarkrange Tennessee Posts: 1,771	disc brake conversion for a 70 1/2 ton 4X4 Just want to get some input on a disc brake conversion for a 70 1/2 ton 4X4 truck. A friend has the parts off a 1975 1/2 chevy 4X4 and my question with these rotors and hubs work on the 1970 iI want to convert? thanks Rick

10-14-2011, 11:59 PM	#2
coops714x4 Registered User Join Date: Mar 2011 Location: Cement Oklahoma Posts: 916	Re: disc brake conversion for a 70 1/2 ton 4X4 Rick it all depends on what they are... "crossbreeding" usually don't work now if they are the same then its possible. it would be easier to just put the whole front axle in and match the gears. Coop __________________ 1971 K20, Coop's beast (project) 1972 C30 wrecker, "Big Ernest" (SOLD) 1975 K5 Blazer (wife's toy) she got it in the divorce 2014 Street Glide Special 1983 K20 Big Block, auto (work horse)

10-15-2011, 09:13 AM	#3
Ricks1971 Senior Member Join Date: Mar 2006 Location: Clarkrange Tennessee Posts: 1,771	Re: disc brake conversion for a 70 1/2 ton 4X4 I was thinking of doing that but is there a list of gear ratios out there if I pull the covers off the rear ends and front ends? thanks Rick

10-15-2011, 09:59 AM	#4
coops714x4 Registered User Join Date: Mar 2011 Location: Cement Oklahoma Posts: 916	Re: disc brake conversion for a 70 1/2 ton 4X4 I don't know about a list. there is a number stamped on the right side of the "pumpkin" it can be coded to tell you what gear ratio you have, or you can count the teeth on the ring gear then divide that by the number of teeth on the pinion. there is no need to pull the cover on the rear end the ratios on both will be the same. If you change front ends make SURE you get the pinion angle right. Coop __________________ 1971 K20, Coop's beast (project) 1972 C30 wrecker, "Big Ernest" (SOLD) 1975 K5 Blazer (wife's toy) she got it in the divorce 2014 Street Glide Special 1983 K20 Big Block, auto (work horse)

10-16-2011, 10:10 AM	#5
Ricks1971 Senior Member Join Date: Mar 2006 Location: Clarkrange Tennessee Posts: 1,771	Re: disc brake conversion for a 70 1/2 ton 4X4 I wonder if someone would post a pic of the exact location where this number is on the pumkin?

10-16-2011, 10:26 PM	#6
onebadbowtie Registered User Join Date: Feb 2010 Location: Parsons, KS Posts: 357	Re: disc brake conversion for a 70 1/2 ton 4X4 you will also need a different master cylinder and booster __________________ James 94' Chevy K1500 Extended Cab 4x4 5.7 72' Chevy LWB K10, 350, SM465, NP205 Project "Daily Driver"



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