69 SWB Drop and Disc Conv Questions - The 1947 - Present Chevrolet & GMC Truck Message Board Network

jholley · 07-30-2008, 10:09 AM

I just got this truck and I'm getting ready to drop the front and rear and convert the front brakes to discs. I have two questions for y'all before I start ordering parts.

1. How far can I lower it before I have to consider c-notching the frame? I was considering a 2 1/2, 4 or a 3 1/2, 6 inch drop.

2. Will the wheels that are currently on it still fit after the disc brake conversion? They are six lug rallys with center caps that say 4x4. I don't know if the 4x4 cap means they are 4x4 wheels or if its just a different cap. The truck is not a 4x4.

Ok, I lied, Three questions...

3. The truck currently has power brakes. Will the master cylinder and booster thats on it work with the disc brakes?

There will be many more, I'm sure, over the course of this project. Thanks in advance for any help.

RunninLo · 07-30-2008, 10:24 AM

1) 4" will put you pretty close to the frame but you should be ok. use an aftermarket "button" style snubber.

2) wheels should fit fine.

3) you will need to add some type of proportioning valve either stock or aftermarket because the discs require a lower line pressure to operate.

Josh

jholley · 07-30-2008, 03:17 PM

Thanks for the info!

Do you know if these wheels were 4x4 specific or are they just different center caps?

Rooster's 67 · 08-07-2008, 12:59 AM

the rims on your truck were factory rally rim on the 73-87 4x4 trucks hence the 6 bolt pattern, 2wd were the 5 bolt pattern. and as far as the disk conversion there is a post of using??88 up?? 3/4 ton components that have the same 6 bolt pattern as our trucks

Longstep70 · 08-18-2008, 05:25 PM

Not wanting to hijack but my wheels look pretty much the same and i wonder if they are the same. i want to do the disc conversion but I'd like to keep the rims and i want to know how I can find out for sure if they will clear discs. Is there a way to be sure?

-Andy

jimmydean · 08-18-2008, 06:02 PM

I had those same wheels on my '69 and they were great.

Sitting on bags:

<edit> mine cleared the McGaughy's 5 lug brake kit. If they are off the 4x4, they will clear.

Longstep70 · 08-18-2008, 07:07 PM

Great diagram. Thanks jd.
I'll have a look when i get home later.

-A

Riveted1 · 08-18-2008, 07:59 PM

A lot of ppl on this board swear up and down that u can get away w/a 6" rear drop w/out going to a C-notch. Others say you can't. I don't have any personal experience w/that. But, I tend to believe u can as long as you aren't driving 80 down a pothole-riddled dirt road.

I will add that when going to a 6" drop, a shock relocator kit would definitely help keep the axle off of the frame, along w/shorter bump stops as mentioned before. Many would recommend an adjustable panhard bar too, to keep the rearend centered w/that much of a drop.

jholley · 08-18-2008, 09:02 PM

Thanks for all the tips guys. Good Stuff, I love this place!

07-30-2008, 10:09 AM	#1
jholley Registered User Join Date: Jul 2008 Location: TX Posts: 737	69 SWB Drop and Disc Conv Questions I just got this truck and I'm getting ready to drop the front and rear and convert the front brakes to discs. I have two questions for y'all before I start ordering parts. 1. How far can I lower it before I have to consider c-notching the frame? I was considering a 2 1/2, 4 or a 3 1/2, 6 inch drop. 2. Will the wheels that are currently on it still fit after the disc brake conversion? They are six lug rallys with center caps that say 4x4. I don't know if the 4x4 cap means they are 4x4 wheels or if its just a different cap. The truck is not a 4x4. Ok, I lied, Three questions... 3. The truck currently has power brakes. Will the master cylinder and booster thats on it work with the disc brakes? There will be many more, I'm sure, over the course of this project. Thanks in advance for any help. Attached Images

07-30-2008, 10:24 AM	#2
RunninLo 3DrDwn--the 'burb not the band Join Date: Jan 2007 Location: missoula, mt Posts: 598	Re: 69 SWB Drop and Disc Conv Questions 1) 4" will put you pretty close to the frame but you should be ok. use an aftermarket "button" style snubber. 2) wheels should fit fine. 3) you will need to add some type of proportioning valve either stock or aftermarket because the discs require a lower line pressure to operate. Josh __________________ Slo and Lo that is the tempo. '72 burb build page here: http://67-72chevytrucks.com/vboard/s...d.php?t=259256 '89 GMC Dually crew build page coming soon. 88 4x4 crew DD duallys past/present pics here: http://67-72chevytrucks.com/vboard/s...46#post4001246 89 1 ton Dually rear flip kit install here: http://67-72chevytrucks.com/vboard/s...d.php?t=354327

07-30-2008, 03:17 PM	#3
jholley Registered User Join Date: Jul 2008 Location: TX Posts: 737	Re: 69 SWB Drop and Disc Conv Questions Thanks for the info! Do you know if these wheels were 4x4 specific or are they just different center caps?

08-07-2008, 12:59 AM	#4
Rooster's 67 Registered User Join Date: Sep 2003 Location: DFW Posts: 765	Re: 69 SWB Drop and Disc Conv Questions the rims on your truck were factory rally rim on the 73-87 4x4 trucks hence the 6 bolt pattern, 2wd were the 5 bolt pattern. and as far as the disk conversion there is a post of using??88 up?? 3/4 ton components that have the same 6 bolt pattern as our trucks __________________ The problem with America is stupidity. I'm not saying there should be a capital punishment for stupidity, but why don't we just take the safety labels off of everything and let the problem solve itself?

08-18-2008, 05:25 PM	#5
Longstep70 Junior Member Join Date: Jan 2005 Location: San Jose , Ca Posts: 235	Re: 69 SWB Drop and Disc Conv Questions Not wanting to hijack but my wheels look pretty much the same and i wonder if they are the same. i want to do the disc conversion but I'd like to keep the rims and i want to know how I can find out for sure if they will clear discs. Is there a way to be sure? -Andy

08-18-2008, 06:02 PM	#6
jimmydean Registered User Join Date: May 2005 Location: Beaverton, OR Posts: 3,728	Re: 69 SWB Drop and Disc Conv Questions I had those same wheels on my '69 and they were great. Sitting on bags: <edit> mine cleared the McGaughy's 5 lug brake kit. If they are off the 4x4, they will clear. __________________ New Project: 1966 LWB C20 Plans: 1/2 ton conversion Dropmember front Dropmember rear Corvette discs Restored raised bed http://67-72chevytrucks.com/vboard/s....php?p=4295210 Last edited by jimmydean; 08-18-2008 at 06:06 PM.

08-18-2008, 07:07 PM	#7
Longstep70 Junior Member Join Date: Jan 2005 Location: San Jose , Ca Posts: 235	Re: 69 SWB Drop and Disc Conv Questions Great diagram. Thanks jd. I'll have a look when i get home later. -A

08-18-2008, 07:59 PM	#8
Riveted1 Tasty Cakes! Join Date: Apr 2003 Location: Gilbert, AZ Posts: 2,112	Re: 69 SWB Drop and Disc Conv Questions A lot of ppl on this board swear up and down that u can get away w/a 6" rear drop w/out going to a C-notch. Others say you can't. I don't have any personal experience w/that. But, I tend to believe u can as long as you aren't driving 80 down a pothole-riddled dirt road. I will add that when going to a 6" drop, a shock relocator kit would definitely help keep the axle off of the frame, along w/shorter bump stops as mentioned before. Many would recommend an adjustable panhard bar too, to keep the rearend centered w/that much of a drop. __________________ I'm a little and a lot Ground beef: A cow with no legs. ---------------- '66 Chevy SWB "Penny" '67 Chevy Big Window SWB- aka "Pearl" '72 Burb- "Betty" "It's not a hearse dammit" '99 Chevy Ext. cab Silverado Last edited by Riveted1; 08-18-2008 at 08:02 PM.

08-18-2008, 09:02 PM	#9
jholley Registered User Join Date: Jul 2008 Location: TX Posts: 737	Re: 69 SWB Drop and Disc Conv Questions Thanks for all the tips guys. Good Stuff, I love this place! __________________ ------------------------------------------------- Jim Garage fillers... 85 Chevy C10 Silverado LWB 07 Nissan Altima 2006 Mini Cooper S



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