Disc Brake Upgrade Reference Thread

[Captainfab]

There are no rivets attaching the front crossmembers. They are all bolts. If your engine is currently out, this can be a quick and easy way to upgrade to front disc brakes if the donor suspension is in good runable condition. If the suspension, steering and brakes need parts replaced, then just changine the control arms and outward parts, may be the better option. The complete crossmember can be changed with the engine in place, but it is not an easy task.

On changing the axles from 6 lug to 5 lug, yes there is one hole that overlaps the other, and ata minimum that hole needs to be plugged. I believe there is another pair of holes that is close as well. If I were changing from 6 x 5.5 to 5 x 5, I would just plug all 6 holes and be done with it. If you have to pay someone to do this for you, be sure to compare the cost of that work with the cost of new conversion axles. Also be sure to closely inspect the axle/wheel bearing surface of the axles prior to investing money in the wheel bolt pattern change. If you do decide to change the bolt pattern yourself, be honest about your skill level to perform a critical job such as this.

Originally Posted by Darkrider

Ok....Just revisiting this from the perspective of possibly going the route of 5 lug...I know where there is a C10 Burb that i could prob get the parts from that if im not mistaken is just a roller. So to convert my truck to 5 lug front i have two options correct?

drill out the rivets of both front suspensions and swap in the entire front assembly from the Burb

or remove the Control arms and spindles from the burb and bolt them to my existing crossmember

As for converting the rear to 5 lug how reliable is having the original rear axles redrilled? If im not mistaken only one of the 5 holes needs to be drilled through part of an existing hole from the 6 lug correct?

[slick copper]

Hey CapFab! Interested in some disc brakes! HMU!

[Darkrider]

Ok this isnt Disk brake related but power brake related. When i was digging into the parts from my truck that were sitting in the bed from when my buddy disassembled it i found out that the truck in fact did have power drum brakes. Now i have a couple questions on this.

Drum brake and Disk Brake MCs directly interchange correct? (this is if i stay gas)
Or reverse situation say i wanted to retrofit a Hydraboost system with the Diesel engine i have and want to stay with drums for the moment. will my Drum MC bolt up to the Hydraboost unit and which pushrod would i use if so? the one from between the drum m/c and the vac booster or the one from between the hydraboost unit and the disk m/c that originally was attached to it?

[Captainfab]

The drum/drum masters and the disc/drum masters interchange in that they will physically bolt up in place of the other. Most of the drum/drum masters have the deep bore in the back of the piston. There are some that have the shallow bore.

If you bolt a drum/drum master onto a hydroboost unit, you will have to be sure you use the correct intermediate pushrod. I have not attempted this, so I do not know if the pushrod interchanges with the vacuum boosters or not.

[Rat66]

OK so I have read through all the posts and have found a few that kinda answered a some of my questions but not exactly the same scenario as me. Hopefully I can get some clarification.

I have a 66 C20 Long bed with a sbc/4spd/eaton (456). I am looking at doing a C10 suspension swap. I have a guy locally that has a rolling chassis including the complete power brakes and power steering setup from a 72 C10. I know the rear is a bolt in swap but I am a little confused on the front still. What parts do I need off the donor to make this swap? Can I keep my cross member or do I have to swap it out? Will I have to swap out the control arms or just swap out ball joints? I understand what to do if I was doing a 1/2 ton to 1/2 ton swap but not the 3/4 to 1/2.

Thanks

[Captainfab]

Because your truck is a C20, you will have to switch the entire crossmember. The '63-'66 C20's use a flat lower control arm shaft, that bolts flat to the crossmember. The C10's from '63 and up, use a round lower control arm shaft, which sit in saddles that are riveted to the crossmember. Your C20 crossmember does not have those saddles to accomodate the C10 lower control arm shafts. Yes you could weld some saddles to your C20 crossmember, but you would have to be very precise in doing so, as they have to be in an exact location. IMO it would just be easier to change the entire crossmember.

[Rat66]

Great! Thanks for clearing that up.

[Captainfab]

Something I always recommend when keeping the original front suspension crossmember and changing the control arms, is upgrading to the '73 and up lower control arm shaft U-bolts. One reason is I have had 2 of the original LCA U-bolts break on me. I have been very lucky in that it was only 1 at a time. If both on the same control arm were to break at the same time, the lower control arm will hit the pavement, and all sorts of chaos will occur if it happens while driving.

GM upped the size of the LCA shaft U-bolts once in around 1971, and then again in 1973. I always go with the larger '73 and up pieces. If there was not a need for the increase in diameter, I doubt they would have done so. In case some of you don't quite understand what I'm talking about, and also for those of you that do, here is a visual comparison of an early U-bolt next to a '73+ U-bolt



This pic was oriignally posted by RockTonka in his Suburban build thread

[ChiefRocka]

Originally Posted by Rat66

OK so I have read through all the posts and have found a few that kinda answered a some of my questions but not exactly the same scenario as me. Hopefully I can get some clarification.

I have a 66 C20 Long bed with a sbc/4spd/eaton (456). I am looking at doing a C10 suspension swap. I have a guy locally that has a rolling chassis including the complete power brakes and power steering setup from a 72 C10. I know the rear is a bolt in swap but I am a little confused on the front still. What parts do I need off the donor to make this swap? Can I keep my cross member or do I have to swap it out? Will I have to swap out the control arms or just swap out ball joints? I understand what to do if I was doing a 1/2 ton to 1/2 ton swap but not the 3/4 to 1/2.

Thanks

Being that he has a 3/4 ton, he could just leave his current a-arms, and run 88-98 1/2 ton bj's and brakes.
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[Captainfab]

Good point Chief. I sometimes forget that the '88-'98 spindle, rotor and calipers can be used for the 5x5 wheel bolt pattern as well as the 6x5.5 wheel bolt pattern. This is quite easy to do on the C20's

Originally Posted by ChiefRocka

Being that he has a 3/4 ton, he could just leave his current a-arms, and run 88-98 1/2 ton bj's and brakes.
Posted via Mobile Device

[66 GMC 351E]

Originally Posted by ChiefRocka

Being that he has a 3/4 ton, he could just leave his current a-arms, and run 88-98 1/2 ton bj's and brakes.
Posted via Mobile Device

Wait. What? I have a '66 3/4 ton GMC and I'm about to make this upgrade. I pulled the entire crossmember from an '81 Chevy 3/4 ton and was planning to use just the spindles, rotors and calipers from the donor and leave my existing crossmember and control arms. Can't I do this by just swapping out the ball joints? And what about the tie rods. Can I use the stock inner and outers?

[Captainfab]

We were talking about converting a C20 to a C10.

In keeping with a C20, you should be able to just change the ball joints and add the spindles and such. As for the tie rods, I always recommend changing the entire steering linkage to the pieces that came on the disc brake donor. This way there is no special adapter sleeve, and no guessing on which tie rods you need later when they need replaced. You will just have to drill 2 new holes to mount the later style idler arm.

Originally Posted by 66 GMC 351E

Wait. What? I have a '66 3/4 ton GMC and I'm about to make this upgrade. I pulled the entire crossmember from an '81 Chevy 3/4 ton and was planning to use just the spindles, rotors and calipers from the donor and leave my existing crossmember and control arms. Can't I do this by just swapping out the ball joints? And what about the tie rods. Can I use the stock inner and outers?

[joesscamaro]

I've looked through a lot of threads on this topic and don't think I've read an answer to a question that came to mind today. I'm trying to swap over to disc brakes on the front of my '65, so I went to an auto parts store to get some ball joints for an '85 Chevy. I remember reading on here, that the spindles are different for 1" and 1 1/4" rotors. I plan on running some steelies when I can find them...but my question is...does it matter if the ball joints are for a 305 ci truck? Aren't the 1 1/4" rotors offered only on the 350 trucks? Does this make a difference when ordering ball joints? I plan on ordering spindles for the 1 1/4" rotors. Thanks!

[Captainfab]

I don't know if the light duty trucks always came with a 305, and the standard duty with the 350 or not. It sounds logical though. The engine size should not be the determing factor on ball joints though. Either the rotor thickness or the 'light duty' option should be mentioned.

Originally Posted by joesscamaro

I've looked through a lot of threads on this topic and don't think I've read an answer to a question that came to mind today. I'm trying to swap over to disc brakes on the front of my '65, so I went to an auto parts store to get some ball joints for an '85 Chevy. I remember reading on here, that the spindles are different for 1" and 1 1/4" rotors. I plan on running some steelies when I can find them...but my question is...does it matter if the ball joints are for a 305 ci truck? Aren't the 1 1/4" rotors offered only on the 350 trucks? Does this make a difference when ordering ball joints? I plan on ordering spindles for the 1 1/4" rotors. Thanks!

[ljackson]

I have completed this swap using parts from an '81. The truck turns tighter to the left than right. What can I do to correct this?

[Captainfab]

I am assuming that you also converted to power steering? If so, a front end alignment should get your turning radius balanced again.

Originally Posted by ljackson

I have completed this swap using parts from an '81. The truck turns tighter to the left than right. What can I do to correct this?

[ljackson]

Originally Posted by Captainfab

I am assuming that you also converted to power steering? If so, a front end alignment should get your turning radius balanced again.

Yes I did. I guess we (myself or the alignment shop) will have to center the pitman arm by changing the tierod lengths. I set them to the original '81 lengths when I installed new ends. This makes the piman a little to the right of center.

Thanks

[1966C30]

I attempted to do a crossmember swap on my 66 c30 and the frame widths are not the same between these. the c30 chassis is 3/8 of an inch wider than the later 73-87 crossmember. I am however going to drill out the holes to mount the newer a-arms and spindles onto the crossmember. The only question i do have is what would it take to install the inner tie rod ends of the newer 73-87 into the drag link of the 66.

[Captainfab]

There is no difference in the frame widths from '63 thru '87 in the C series and thru '91 in the R series.

It is not uncommon for the frame rails to spring apart a little once you unbolt the original crossmember. All you need to do is squeeze them back together a little, and bolt in your new suspension.

How do you plan on locating the lower control arms without saddles on your original crossmember? Unless you have something different than I have seen in 35 years of working on these trucks.

To use the '73-'87 tierods with your original draglink you will need to purchase the aftermarket aluminum tie rod adapters. I believe the original outters become your inner tierods. I'm not sure as I have never bought them. I just change the entire steering linkage to the '73 -'87 components.

You might want to check out Henry's thread. He is in the process of upgrading his '64 C30.

http://www.67-72chevytrucks.com/vboa...=531513&page=4

Originally Posted by 1966C30

I attempted to do a crossmember swap on my 66 c30 and the frame widths are not the same between these. the c30 chassis is 3/8 of an inch wider than the later 73-87 crossmember. I am however going to drill out the holes to mount the newer a-arms and spindles onto the crossmember. The only question i do have is what would it take to install the inner tie rod ends of the newer 73-87 into the drag link of the 66.

[1966C30]

I have new saddles and was just going to weld them onto the older crossmember. but if that newer one will bolt on then i'll just use it. I also made the mistake of not buying the crossmember with my control arms and spindles and the studs to mount my control arms are smaller on the new one but the old studs fit it perfectly any idea on that?

Originally Posted by Captainfab

There is no difference in the frame widths from '63 thru '87 in the C series and thru '91 in the R series.

It is not uncommon for the frame rails to spring apart a little once you unbolt the original crossmember. All you need to do is squeeze them back together a little, and bolt in your new suspension.

How do you plan on locating the lower control arms without saddles on your original crossmember? Unless you have something different than I have seen in 35 years of working on these trucks.

To use the '73-'87 tierods with your original draglink you will need to purchase the aftermarket aluminum tie rod adapters. I believe the original outters become your inner tierods. I'm not sure as I have never bought them. I just change the entire steering linkage to the '73 -'87 components.

You might want to check out Henry's thread. He is in the process of upgrading his '64 C30.

http://www.67-72chevytrucks.com/vboa...=531513&page=4

[Captainfab]

If you were to weld new saddles onto your original crossmember, they have to be absolutely perfectly located. Otherwise you will have all sorts of alignment issues

Just what studs are you referring to? The ones for the upper control arms?

Originally Posted by 1966C30

I have new saddles and was just going to weld them onto the older crossmember. but if that newer one will bolt on then i'll just use it. I also made the mistake of not buying the crossmember with my control arms and spindles and the studs to mount my control arms are smaller on the new one but the old studs fit it perfectly any idea on that?