Cpp tubular rear suspension #6372trs-k

[PLYONS11]

Hey guys,

Been while since I have been on. I was working on finishing my basement over the winter but I'm just about ready to get back in the garage. Ill be in South Africa later this month, but plan on having a pile of parts waiting for me when I return. I have had a lot of time to think over the winter and decided that I am going to start with a rear end swap and coil spring conversion. I have mentioned this in a couple other posts but was not sure where I was going to start.

I have decided to use CPP's tubular rear end kit. For now I am going to keep the coil springs that come with the kit, but I will likely use Ride Tec bags in the future when I convert the front end. I have also all but given up on trying to find exactly what I want in a junk yard rear end. I am going to drop the coin and buy a Moser 12 bolt already set up for a 63 C10.

Has anyone out there used this kit from CPP? I get some conflicting info when I call them. Based on my research the 3/4t and 1/2t frame is the same, but one guy at CPP told me it was different and though this kit would work I would need to do some fabrication. I realize that converting to a coil spring I will need to buy/make a shock mount cross member and a track bar/panhard bar mount. Is there anything I am not thinking of? Is the frame the same? I have a 63 3/4 ton long bed GMC with leaf springs. The kit I am looking at ( http://www.classicperform.com/NewPro...ionPackage.htm ) comes with trailing arms, c-notch, trailing arm cross member, coils, shocks, and shock relocate kit. I will also be buying the tubular shock cross member, carrier bearing bracket for the 2 piece drive shaft, and a new carrier bearing. That will be paired to a moser 12 bolt that will come with stock perch mounts and such.

[Clyde65]

I would talk to John Porter and Porterbuilt. Better quality and HUGE difference on customer service\satisfaction.

http://pbfab.com/shop/amfinder/?find...-c10-1965-1434

[The Rocknrod]

And a $1,000.00 dollar difference too.

[PLYONS11]

Originally Posted by Clyde65

I would talk to John Porter and Porterbuilt. Better quality and HUGE difference on customer service\satisfaction.

http://pbfab.com/shop/amfinder/?find...-c10-1965-1434

Originally Posted by The Rocknrod

And a $1,000.00 dollar difference too.

I have looked at Porterbuilt before and considered it, but as The Rocknrod stated it is significantly more coin. I don't doubt quality and service are better. I have seen his products used in many applications and talked about all over this form.

The fact is I just don't want to dip that deep into my pockets. I have looked at a lot of products and feel that the CPP kit is a good balance of price, quality, adjustable to my changing taste/want for airbags in the future, and all in one bolt on ease.

The only fact that really concerns me about this, or any other product is that the application really only states that it is for a C10. I am fairly good at working on cars/trucks and have a good basic knowledge, but I am still learning a lot about these old trucks. If this had not been a project I wanted to do for the fact that it was my late grandfathers truck I would have started with a SB C10. Unfortunately my truck is a 3/4ton LB GMC and there is just a lot of conflicting info out there.

All I'm really looking for is what, if any differences there are in the frame of the short bed / long bed and 1/2t vs 3/4t. If they are the same I am confident that I can work out the other issues in time. I am also looking for any advise/knowledge from someone who has used this exact product in the past.

That said, Thank you for the input!

[Captainfab]

There really isn't any major differences between a C10 frame and a C20 frame and suspension. The issue with your truck is that GMC's came with leaf springs, not trailing arms and coils. It has nothing to do with C10 versus C20. The kit you are looking at does appear to come with everything you need to convert to trailing arms and coils. I just do not know for sure if the holes are already in the frame or if you will have to drill those once you locate the pieces. I am thinking the holes are not there.....it's been a while since I have been under a '63+ GMC.

[PLYONS11]

Originally Posted by Captainfab

There really isn't any major differences between a C10 frame and a C20 frame and suspension. The issue with your truck is that GMC's came with leaf springs, not trailing arms and coils. It has nothing to do with C10 versus C20. The kit you are looking at does appear to come with everything you need to convert to trailing arms and coils. I just do not know for sure if the holes are already in the frame or if you will have to drill those once you locate the pieces. I am thinking the holes are not there.....it's been a while since I have been under a '63+ GMC.

Thanks again for the knowledge Captain. I was kinda thinking the same thing about the bolt holes, but had nothing to test my theory. I can handle drilling some holes. Based on the one picture they supply it looks like the holes will need to be drilled for the c notch and then the spring perch bolts to the c notch. Other than that it appears that I will need to drill holes for the new shock cross member and the trac bar.

im going to go ahead and order this kit tomorrow. While we are on this subject does anyone have any advice on the easiest way to remove the bed? I would like to remove it in one piece. I can't really get a good idea of what I need to do as there is a fair amount of crud covering everything up.

Captain, off the subject but I am in need of one of your power booster brackets with the clutch master. Could you please PM me what you need from me and how I pay you? Thanks!
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[Captainfab]

If all the bed to frame bolts are there, there will be 8 total. There will be 2 at the ends of the frame, and 3 each side forward of the differential. They will be in the form of carriage bolts thru an eccentric flat washer in the wood down to the frame at the rear and brackets up front.

I will send you a PM.

[PLYONS11]

Well, I ordered the rear end kit today from CPP. It should be here in a few weeks. I also had to order the tubular shock crossmember as my truck is a leaf spring currently and doesn't have any provisions to mount the shocks in the manner required for this kit. I also picked up a carrier bearing and bracket for the 2 piece drive shaft. I'll be starting this project May 20th. I'll make sure to take plenty of pictures and update the post in case anyone else is debating on whether or not to use this setup.

It was recommended by CPP to buy the 4" drop kit because it comes with the heavy duty c notch and heavier springs for added support for the long bed.

I have mixed opinions of the service and knowledge I've gotten by different reps at CPP, but today I spoke with a gentleman named Mario who was very helpful and seemed to know his stuff.

Next I just need to find a rear end. I was going to bite the bullet and buy a new one from Moser, but I just can't justify spending that kind of money. I have been having some trouble finding a 69-72 12 bolt near by but today I actually found 2. I'm waiting for a call back from the junk yards, but I'm hopeful that I will have one soon

[Captainfab]

Don't limit yourself to just '69-'72

The truck 12 bolt was used from '63-'82. The '63 to early '70 12 bolts are 62" wide and all 6 lug. The late '70-'82 12 bolts are 63.5" wide and all 5 lug in the C10's. The '71-'72 are of course setup for trailing arms. The '73-'82 12 bolt will work but the leaf spring perches and shock mounts will need to be cut off and trailing arm mounts welded on at the correct pinion angle. Then a panhard bar mount will need to be either welded onto the passenger side axle tube or an aftermarket panhard bar and mounts used. I do make trailing arm mounts for the 12 bolt.

[KALAHEO]

I just went through building my 12 Bolt. I used Moser axles, Eaton posi, Yukon gears & all new bearins Ect... I also upgraded to 31 spline on the axle. Unfortunately I'm still limited by the C clip axles. If I were to do it again I would use the 12 bolt rear end but have the torino style bearing ends installed on the axle housing that way eliminating the C clips. You can then run the big 33 spline axles, much stronger. Currie can do this conversion for a nominal fee . This would've been a lot stronger axle than what I ended up with for the same money.

[PLYONS11]

Originally Posted by KALAHEO

I just went through building my 12 Bolt. I used Moser axles, Eaton posi, Yukon gears & all new bearins Ect... I also upgraded to 31 spline on the axle. Unfortunately I'm still limited by the C clip axles. If I were to do it again I would use the 12 bolt rear end but have the torino style bearing ends installed on the axle housing that way eliminating the C clips. You can then run the big 33 spline axles, much stronger. Currie can do this conversion for a nominal fee . This would've been a lot stronger axle than what I ended up with for the same money.

This same reason is exactly why I seriously considered buying a whole rear end from Moser. Id rather have 33 spline and no c clips. These bearing you a referring to, are they a part that one could install themselves or does it require machining and welding?

When you say Currie can do this for a nominal fee, what are we talking? Have you looked into it? I would imagine that would require me to ship the rear end to them?

I imagine that someday I will bite the bullet and buy a Moser unit, but for now I just don't have the cash. I am only considering Moser over others because they are right here in IN and shipping would be fairly cheap, or I could go pick it up. Their 12 bolt come standard with the bearing ends. The c clip version is "special order". For now I am going to get the suspension and brakes worked out and continue to drive the truck with the stock 305 and Muncie 4 speed. In the future when I do the BBC swap and 5 speed I will need to look into beefing up the rear end.

[PLYONS11]

Originally Posted by Captainfab

Don't limit yourself to just '69-'72

The truck 12 bolt was used from '63-'82. The '63 to early '70 12 bolts are 62" wide and all 6 lug. The late '70-'82 12 bolts are 63.5" wide and all 5 lug in the C10's. The '71-'72 are of course setup for trailing arms. The '73-'82 12 bolt will work but the leaf spring perches and shock mounts will need to be cut off and trailing arm mounts welded on at the correct pinion angle. Then a panhard bar mount will need to be either welded onto the passenger side axle tube or an aftermarket panhard bar and mounts used. I do make trailing arm mounts for the 12 bolt.

I think we discussed this on another post in the past. I am trying to find these years for ease of use. I don't have the ability or tools to fabricate anything. I am trying to avoid welding. I also would like to find a 71-72 because it is as close to the stock width of the current D60 (65"). My goal is to get an axel that will bolt directly to the CPP rear end. The CPP rear end has a mount for the panhard bar already built into it. All I will need to do is find a way to mount it to the frame rail. CPP told me that they have a bracket that comes with the panhard bar that will work in some applications. If not they also sell a frame adapter bracket (CP55C), but it is not listed on their webpage. I opted to hold off on this until I know if the one supplied will work.

when we discussed this last it was my understanding that any 69-72 coil spring set up would bolt on with the only difference being the width (69-70 being 62" and 71-72 being 63.5") Is this correct, or did I misunderstand?

The one I am waiting to hear back on is a '72 12 bolt from a C10. When I spoke with the guy yesterday he told me it was a drum brake setup and he thought it was 6 bolt. The bolt pattern does not concern me because I will likely change axels and internals anyway. I'm leaning towards using your d52 bracket and finding some D52 calipers with the parking brakes. This is probably for another time and another post, but I'm not really sure how to get the parking brakes to work. Currently my parking brake is a floor lever that attaches to a band and drum around the output shaft of the trans. For the time being this will work, but once I get to the engine and trans swap its obviously going to need to be changed. My thought is that I can use the Pbrake lines from the D52 calipers and somehow attach them to the floor mounted lever in the truck?

[Captainfab]

The whole differential width thing is spelled out in my previous post. When deciding on a differential width, you need to consider what tires and wheels you will be running. The 3/4 tons have wider differentials than a 1/2 ton. You are changing your 3/4 ton to a 1/2 ton, so the 3/4 ton differential width is irrelevant. All '71-'72 C10's were 5 lug. Only '71-'72 K10's were 6 lug.

For your e-brake, it will be much simpler to just convert to a C10 style e-brake assembly. That way you just use factory style components and nothing has to be custom made.

Originally Posted by PLYONS11

I think we discussed this on another post in the past. I am trying to find these years for ease of use. I don't have the ability or tools to fabricate anything. I am trying to avoid welding. I also would like to find a 71-72 because it is as close to the stock width of the current D60 (65"). My goal is to get an axel that will bolt directly to the CPP rear end. The CPP rear end has a mount for the panhard bar already built into it. All I will need to do is find a way to mount it to the frame rail. CPP told me that they have a bracket that comes with the panhard bar that will work in some applications. If not they also sell a frame adapter bracket (CP55C), but it is not listed on their webpage. I opted to hold off on this until I know if the one supplied will work.

when we discussed this last it was my understanding that any 69-72 coil spring set up would bolt on with the only difference being the width (69-70 being 62" and 71-72 being 63.5") Is this correct, or did I misunderstand?

The one I am waiting to hear back on is a '72 12 bolt from a C10. When I spoke with the guy yesterday he told me it was a drum brake setup and he thought it was 6 bolt. The bolt pattern does not concern me because I will likely change axels and internals anyway. I'm leaning towards using your d52 bracket and finding some D52 calipers with the parking brakes. This is probably for another time and another post, but I'm not really sure how to get the parking brakes to work. Currently my parking brake is a floor lever that attaches to a band and drum around the output shaft of the trans. For the time being this will work, but once I get to the engine and trans swap its obviously going to need to be changed. My thought is that I can use the Pbrake lines from the D52 calipers and somehow attach them to the floor mounted lever in the truck?

[PLYONS11]

The conversion is complete. CPPs totally tubular rear end was a breeze to install. For anyone looking to do this conversion on a long bed 3/4 ton with a 2 piece drive shaft I would recommend considering this package.

I found a 71' 12bolt at a local junk yard. It was in fairly good shape, but does have a lot of gunk in the axel tubes. Need some recommendations on how to best clean it out. I'd like to have it dipped, but I can't seem to find a shop locally that will do it.

All in all the conversion took around 24 hrs with 2 people. The hardest parts of the job were removing the bed and cutting out all the old rivets from the cross member and leaf spring perches. Because my truck is not currently mobile and is tucked tightly into my garage we had to take the bed over the frame rails and could not back it off. This took some doing with only 2 people. Not going to try that again!

Once all the old bits were removed we cleaned up the frame with POR15 metal prep put 3 coats of POR15 on it and 2 coats of duplicolor chasis paint. Very pleased with the results considering that it was not media blasted. From there everything was pretty much a bolt on application. We did have to drill the frame for the new shock tower cross member as there were no provisions for this originally on the GMC frame. I chose not to install the c notch at this time as I only did a 4" drop. At full compression the axel tubes just barely contact the frame rails. I will need to add bump stops in the future however. If I had decided to also use the 1" drop blocks I think I would have had no choice but to install the c notch. Had we not bed in a time crunch I would have probably went ahead and installed them, but I was a bit concerned with cutting the frame! Obviously there is no turning back once the frame is cut.

The only real issue I have run ito thus far is with the 2 piece axel and the pan hard bar. The drive shaft from the 3/4 ton has a larger dia spline that will not fit into the carrier bearing supplied in this kit. This kit comes with the light duty carrier. The kit does not have provisions for mounting the HD bearing as it mouns differently. I'm going to have to do some research on this to figure out the best option. I considered finding a shaft from a 1/2 ton, but I'm not sure that it's going to mount up the same to my trans. The other issue is that I don't have a bracket to mount the pan hard bar to the frame. I think CPP sells one, but I haven't had the chance to call and ask them yet.

Any suggestions on the issues I have encountered are welcome as well as any questions from those looking to do the same conversion.

[KALAHEO]

Would require cutting off old ends and welding on big bearing ends. Should be done in a jig. Currie gets a few hundred for this I believe. I like Moser products, If your close by it might be the way to go. Shipping has gotten ridiculous.

[lsjrl07]

Do you have that part number for that silver crossmember? I am needing that same one for my swap.

[PLYONS11]

Originally Posted by lsjrl07

Do you have that part number for that silver crossmember? I am needing that same one for my swap.

I just moved from Indiana to Alabama and all my invoices and documents are still packed up. I'll try to locate them ASAP. I'll also take a look on CPPs webpage. I think the part is there, but if I remember correctly it's really hard to find. If I remember correctly you can also download their actual catalog and there was a picture of it.

[PLYONS11]

Originally Posted by lsjrl07

Do you have that part number for that silver crossmember? I am needing that same one for my swap.

Found it.........the crossmember pn is 6372RTSC-s for silver or -b for black. The xmember is 129.00 You will also need the shock relo brackets pn 6373srk. The brackets are 59.00. These are just the brackets that bolt to the xmember where the shocks bolt to. I would also recomend getting a pair of shock studs pn 140357. They are 8.00 a pair

Let me know if you need anything else. The guys at CPP are very helpful, if you don't mind holding for a bit! I would recommend calling them for the order. It's much easier than using the website IMO.