Disc Brake Upgrade Reference Thread

[64RC20]

The first thread I found on this subject was from Hilandr451, for his totally awesome project on his '66 C20:

http://www.67-72chevytrucks.com/vboa...d.php?t=357610

He upgraded to power steering, which I decided to forgo, based on the expected cost (and I'm scared to death to cut my steering shaft!). I would reconsider this if power steering proves easier and cheaper. But in an effort to find a way to save my original steering, and figure out all the "gotcha's" concerning a C20 disc swap as opposed to a C10, I read through all 21 pages of this current thread looking for every reference to a C20. The list below includes every such post I found:
.
36-39, 48-50, 55-56, 89-90, 155-160!!!, 165-171, 189!, 216-(217!)-219, 293, 336-337, 378, 384-385, 515!-516!, 519!-520!

[64RC20]

Hmmm...the "Quote message in reply?" check box is not working for me. So please bear with me....

In post 216, user 65ChevyC20 asked this:

My question is should I do the complete crossmember swap or should I swap the various pieces over to the crossmember on my 65. Which would be easier is what I am asking.

And Captainfab, you replied:

Well from a easier perspective, just switching the ball joints, spindles, rotors, calipers, etc. would be the easiest. The '79 lower control arms will not bolt up to your '65's crossmember, since there are no saddles there..

There was no mention of the tie rods, so I guess I'd better ask about them. I'll have my old ones and the new ones from the donor truck so hopefully I'm covered. So, will tie rods, or anything else, be a problem with this "easiest" option? And this option lets me keep my stock manual steering box, right?

From a durability/parts availability perspective, swapping in all of the donor truck's suspension (with or without the crossmember) would definitely be wise, too. But then I think I would have to locate the donor truck's idler arm on the frame and drill new holes for it, right? (I think I could handle that). And then I'm still up against a new 73-79 (to avoid metric) steering box. Can I get it in without cutting my steering shaft? Maybe with your adapter?

[Captainfab]

With one of my booster brackets you can use a readily available booster and master from a wrecking yard, and have it mounted correctly and safely for a bit less than $300.

Originally Posted by 64RC20

No, if I can accomplish this disc upgrade, I'll definitely want a booster/MC and proportining valve. And with my Social Security budget, I'm open to suggestions on those parts...I found a combo package at Classic Parts but it's over $300 and though it looks nice, I'm hoping to find a less expensive alternative!

My previous engine spun a cam bearing and died (a used 350...lasted 29 years, God bless it) right after I invested $1200 on nice new wheels and tires, so I wanted to protect that $1200 investment. Got lucky on another used 350 from PicknPull ($150 out the door, plus another $100 or so in timing chain, gaskets, etc.). Got lucky there...perfect compression and it runs like a Swiss watch! But now my brakes are wanting attention. So now I'm trying to get them done, including splitting front from rear, as cheaply and safely as possible. When I found this forum, I realized disc brakes were doable.

(If my next posts looks weird, it's because I'm gonna try to use the "quote message in reply" function. That's another learning curve where I'm still looking way up!)

[Captainfab]

I can not verify that the disc brake lower ball joints will press into the '63-'66 C20 lower control arms. Until someone verifies that, I continue to recommend just changing the entire front suspension, crossmember and all.

Yes you will have to drill new holes for the later model idler arm. When converting to power steering you must shorten the original steering column shaft. There's no way around it.

Originally Posted by 64RC20

Hmmm...the "Quote message in reply?" check box is not working for me. So please bear with me....

In post 216, user 65ChevyC20 asked this:

And Captainfab, you replied:

There was no mention of the tie rods, so I guess I'd better ask about them. I'll have my old ones and the new ones from the donor truck so hopefully I'm covered. So, will tie rods, or anything else, be a problem with this "easiest" option? And this option lets me keep my stock manual steering box, right?

From a durability/parts availability perspective, swapping in all of the donor truck's suspension (with or without the crossmember) would definitely be wise, too. But then I think I would have to locate the donor truck's idler arm on the frame and drill new holes for it, right? (I think I could handle that). And then I'm still up against a new 73-79 (to avoid metric) steering box. Can I get it in without cutting my steering shaft? Maybe with your adapter?

[Thommyknocker]

Hi guys,
One thing I didn't find while I was researching the crossmember swap was a good picture of the hole modifications needed.

This is the template I made to transfer the hole pattern.
We are putting a 71 crossmember under my son's 61 C10

I hope these pictures help someone else.
TJ

[68ihscout]

I was reading through this whole thread ,unless i missed it i couldnt find any info on 1970 c20 8lug disk conversion ,i found a donor 73/87 crossmember and all should bolt right up ,i have power assist drums now ,do i need a new booster and brake lines ?? Thanks in advance (or ahould i ask what all do i need )
Posted via Mobile Device

[Captainfab]

Yes a '73-'87 C20 front suspension crossmember will bolt up just like a '73-'87 C10 crossmember will. In fact on the '67-'72 C20/30's, you do not have to change the entire crossmember like you do on the '63-'66 C20/30's. You can change just the spindles. I believe the '73-'87 lower balljoints should press into the '67-'72 lower control arms. Yes you will need to change the master cylinder and add a proportioning valve. I do not know of a disc/drum master cylinder that has the deep bore in the back of the piston, so you will likely need to change the booster also.

Originally Posted by 68ihscout

I was reading through this whole thread ,unless i missed it i couldnt find any info on 1970 c20 8lug disk conversion ,i found a donor 73/87 crossmember and all should bolt right up ,i have power assist drums now ,do i need a new booster and brake lines ?? Thanks in advance (or ahould i ask what all do i need )
Posted via Mobile Device

[68ihscout]

Originally Posted by Captainfab

Yes a '73-'87 C20 front suspension crossmember will bolt up just like a '73-'87 C10 crossmember will. In fact on the '67-'72 C20/30's, you do not have to change the entire crossmember like you do on the '63-'66 C20/30's. You can change just the spindles. I believe the '73-'87 lower balljoints should press into the '67-'72 lower control arms. Yes you will need to change the master cylinder and add a proportioning valve. I do not know of a disc/drum master cylinder that has the deep bore in the back of the piston, so you will likely need to change the booster also.

Thank you Captain for that great info , any recomendations on what booster to use ,or does 73/87 work?
Posted via Mobile Device

[Captainfab]

Many people insist on using the '73-'87 boosters, but you have to drill holes to mount it and it is not exactly mounted correctly. My booster brackets use all available factory attachment pints and securely attaches the booster/master to the pedal bracket as GM designed. There are many, many, many compatible boosters. In addition to those mentioned in the for sale thread, every booster bracket comes with a list of compatible boosters including a few part numbers.

Originally Posted by 68ihscout

Thank you Captain for that great info , any recomendations on what booster to use ,or does 73/87 work?
Posted via Mobile Device

[66_C20]

So I’ve read thru all sorts of threads in the FAQ section regarding a disc brake conversion and I’m still trying to clarify what exactly I need to accomplish this. I have a 1966 C20 and would actually like to keep it an 8 lug and not really worried about lowering the truck much. I figured these compromises would make the swap fairly easy with sourcing new parts for say a 1976 C20 and just swapping them out. I’d much rather do a parts swap than a full blown crossmember swap. It seems as though Rock Auto has upper and lower control arms for both sides with ball joints, inner and outer tie rod ends as well as the tie rod end adjusting sleeve. Figured I would just buy these components new and be good to go but would that even work and if so, what else would I need? Any help/insight would be greatly appreciated and I apologize if it’s a stupid question.

I also saw where CaptainFab mentioned the possibility of pressing the newer style ball joints into 63-66 control arms which I would imagine would make this conversion much easier. I could be the guinea pig on this to confirm whether it’s possible or not and report back with the results.

[Clyde65]

Roll the cross member out and roll the disc brake one in, 14 bolts, 4 you will need to drill.

[Captainfab]

You can NOT just swap the control arms on a '63-'66 C20 as can be done on the C10's. The C20 suspension crossmember does not have any saddles to accommodate the '73+ round LCA shafts. The '63-'66 C20 LCA shafts are flat. I do not know if on the C20's you can just change the outer tierods to accommodate the disc brake spindles. Additionally I do not know of anyone that makes the special aluminum tierod adapters as they do for the C10's. You may end up changing the entire steering linkage, which is what I always recommend doing on the C10's.

I replied to your PM from earlier today. With help from member Aotte1, I have determined that in order to install the K6129 lower ball joints into the '63-'66 lower control arms, the holes will need to be enlarged .010-.012". The K6129 lower ball joint fits '73-'92 C20/2500 and '71-'91 C30/3500's.

Originally Posted by 66_C20

So I’ve read thru all sorts of threads in the FAQ section regarding a disc brake conversion and I’m still trying to clarify what exactly I need to accomplish this. I have a 1966 C20 and would actually like to keep it an 8 lug and not really worried about lowering the truck much. I figured these compromises would make the swap fairly easy with sourcing new parts for say a 1976 C20 and just swapping them out. I’d much rather do a parts swap than a full blown crossmember swap. It seems as though Rock Auto has upper and lower control arms for both sides with ball joints, inner and outer tie rod ends as well as the tie rod end adjusting sleeve. Figured I would just buy these components new and be good to go but would that even work and if so, what else would I need? Any help/insight would be greatly appreciated and I apologize if it’s a stupid question.

I also saw where CaptainFab mentioned the possibility of pressing the newer style ball joints into 63-66 control arms which I would imagine would make this conversion much easier. I could be the guinea pig on this to confirm whether it’s possible or not and report back with the results.

[66_C20]

Originally Posted by Clyde65

Roll the cross member out and roll the disc brake one in, 14 bolts, 4 you will need to drill.

You make it sound so easy but I think we can all agree it’s never quite that easy. At least with the cross member swap, there shouldn’t be any issues with what tie rod ends to use where or any of that.

Originally Posted by Captainfab

You can NOT just swap the control arms on a '63-'66 C20 as can be done on the C10's. The C20 suspension crossmember does not have any saddles to accommodate the '73+ round LCA shafts. The '63-'66 C20 LCA shafts are flat. I do not know if on the C20's you can just change the outer tierods to accommodate the disc brake spindles. Additionally I do not know of anyone that makes the special aluminum tierod adapters as they do for the C10's. You may end up changing the entire steering linkage, which is what I always recommend doing on the C10's.

I replied to your PM from earlier today. With help from member Aotte1, I have determined that in order to install the K6129 lower ball joints into the '63-'66 lower control arms, the holes will need to be enlarged .010-.012". The K6129 lower ball joint fits '73-'92 C20/2500 and '71-'91 C30/3500's.

So it sounds like the only option for us C20 guys is to do a full crossmember swap from the 73-87 trucks? If so then that’s fine, at least I know for sure what has to be done to accomplish this. Looks like I’ll be doing some junkyard shopping.

[Chevy Fleetside]

Originally Posted by 66_C20

You make it sound so easy but I think we can all agree it’s never quite that easy. At least with the cross member swap, there shouldn’t be any issues with what tie rod ends to use where or any of that.



So it sounds like the only option for us C20 guys is to do a full crossmember swap from the 73-87 trucks? If so then that’s fine, at least I know for sure what has to be done to accomplish this. Looks like I’ll be doing some junkyard shopping.

http://www.67-72chevytrucks.com/vboa...d.php?t=357610 This might help a bit. I was personally involved with this one.

[Clyde65]

[QUOTE=66_C20;8381327]You make it sound so easy but I think we can all agree it’s never quite that easy. At least with the cross member swap, there shouldn’t be any issues with what tie rod ends to use where or any of that.


The post above is where I got my answer from, I followed that when I did my dad’s 3/4 ton. It really is that easy if you have the room! I would also agree with the link where they say clean while your there! You will be glad you did!

Good luck!

[66_C20]

Originally Posted by Chevy Fleetside

http://www.67-72chevytrucks.com/vboa...d.php?t=357610 This might help a bit. I was personally involved with this one.

That does help a bit, thank you for that

[quote=Clyde65;8381404]

Originally Posted by 66_C20

You make it sound so easy but I think we can all agree it’s never quite that easy. At least with the cross member swap, there shouldn’t be any issues with what tie rod ends to use where or any of that.


The post above is where I got my answer from, I followed that when I did my dad’s 3/4 ton. It really is that easy if you have the room! I would also agree with the link where they say clean while your there! You will be glad you did!

Good luck!

Yeah I do intend on cleaning everything as well as replacing bushing and everything too before actually swapping it over. Just got to find a good donor.

[Chevy Fleetside]

Check Craigslist. You might be able to pick up a whole truck for a few bucks. Sell the rest off for parts. That is if you have the room for that. I did that with two trucks and scraped what I didn't sell or use.

[66_C20]

Originally Posted by Chevy Fleetside

Check Craigslist. You might be able to pick up a whole truck for a few bucks. Sell the rest off for parts. That is if you have the room for that. I did that with two trucks and scraped what I didn't sell or use.

Yeah that’s what I’ve been going back and forth with lately, whether to snag the full crossmember assembly from a junkyard or buying a truck off craigslist, snagging the crossmember assembly off of it and then scrapping the rest. I just don’t want to end up upside down money wise and I’m not quite sure what a fair price of the crossmember assembly would be versus what I could get for a scrapped square body.

[Chevy Fleetside]

Originally Posted by 66_C20

Yeah that’s what I’ve been going back and forth with lately, whether to snag the full crossmember assembly from a junkyard or buying a truck off craigslist, snagging the crossmember assembly off of it and then scrapping the rest. I just don’t want to end up upside down money wise and I’m not quite sure what a fair price of the crossmember assembly would be versus what I could get for a scrapped square body.

I think up to $200 is a fair price but also you will probably want to rebuild it.

[66_C20]

Originally Posted by Chevy Fleetside

I think up to $200 is a fair price but also you will probably want to rebuild it.

I would absolutely rebuild it with all new bushing and whatnot before swapping it over. I found this, it’s about an hour and a half away from me, guy says it’s a 73-87 but doesn’t know the exact year and wants $250 for it.

[Chevy Fleetside]

If you go for it offer him $150 because of all the rust. He might come back with $200 but bring the whole $250. Just mention how the bushings are all cracked and need to be replaced.

[Captainfab]

Years ago I used to sell C10 front suspensions for $150. I can't sell a C20 suspension around here. I just end up taking them to the scrap yard.

Since it does have the steering box, entire steering linkage, sway bar and engine mounts, which are all usable on your truck, $250 isn't a bad deal. I would still try and get it for less. Also take into consideration whether the seller is willing to load it for you.

The C20's have the steel control arm bushings, not rubber as the C10's do. They do still wear though.

[66_C20]

Got him to take $200 for it. Just need to figure out how to load it and if it’ll fit in the back of my 2 door wrangler. Doing a little research, it looks like that generation of truck has a front track width of 65.8”. Which it means it just barely will fit with some finagling. I guess we’ll see.

[Chevy Fleetside]

[HSRACER]

Originally Posted by Captainfab

Many people insist on using the '73-'87 boosters, but you have to drill holes to mount it and it is not exactly mounted correctly. My booster brackets use all available factory attachment pints and securely attaches the booster/master to the pedal bracket as GM designed. There are many, many, many compatible boosters. In addition to those mentioned in the for sale thread, every booster bracket comes with a list of compatible boosters including a few part numbers.

I bought one from you for my 64 and never used it. Looking at your thread it looks like it won’t work on the 67 I have now, is that correct?