C30 disk brake swap questions

[enonz65c30]

Hey y'all,

New member here. I have been doing alot of reading here on the forum and lurking around. I'm collecting parts to start working on my 1965 chevy c30. I want to upgrade the breaks and steering with the newer 73-86 parts and I have located a possible donor vehicle.

The donor I located is a 1986 chevy g30 box van. I was wondering if the front crossmember in the g30 will work on my 65. From what I have found the upper and lower control arms are the same for the same vintage c30 trucks. The only problem I for see is that the owner of the g30 uses it for storage and wants to keep the motor and transmission.

Now the other question I have is can I pull the front crossmember with the motor and transmission in place? This truck is in a field and I am not allowed the use of a cutting torch. But the owner is willing to sell me the front and rear out of the g30 wheels and all. When I get home I will try and upload some pics of the c30. Thanks for any help or advice in advance

[blazer-k5]

If you cut that cross member out with a grinder or sawsall you will be there for hours. Depending on where the exact engine mounts are on them things the engine could fall on you while your doing it. If you use those standalone metal chop saws your going to be laying on your back and you still have a big chance of setting something on fire.

Course since I'm not there I really have no idea. I suggest finding a frame at a junk yard.

Oh...hey man whats up be sure to post a pic of your truck. Everybody likes photos.

[enonz65c30]

It looks like the front crossmember bolts in with the 14 bolts just like the trucks. If the motor was not there it would be pretty easy

[enonz65c30]

here are the pics of my little project. This was a pic after I pulled it out of the weeds and getting ready to go into the shop. work on this will be slow sence this is the busy time of year at work.

[BMERDOC]

Hey! I know you!!

[enonz65c30]

Originally Posted by BMERDOC

Hey! I know you!!

well Nick here she is you know you want to help me pull that G30 frontend

[jtrichard]

Looks like you have a 66 not a 65

[BMERDOC]

Originally Posted by enonz65c30

well Nick here she is you know you want to help me pull that G30 frontend

Oh yeah. Laying in a field in the middle of Winter pulling a front crossmember from hub-to-hob sounds like a hoot! I'm not sure about the van stuff but I'm gonna go with the fact that it'll fit. The bad part is that if it IS the same you aren't going to get that front end out with the motor still in it. You may be able to make some kind of rig to hang the engine from but its not worth it. If the guy wants to keep the motor and trans have him pull them out first. It'll make the removal SOOO much easier. Let someone else on here confirm that the crossmember is a bolt-in swap before continuing.

[Captainfab]

If it is a typical G series van that is a unibody design, the crossmember is different than for a C series truck. If it has a typical frame as a C series truck does, then the crossmember should be the same. The good news is that I do believe the control arms are the same as the C series as well as the spindles and calipers. However I do know that on the G20 vans, the lower control arm shaft is a wierd looking piece with an outter sleeve with rubber in between. The G30's may be different.

The steering box from a G series van will not work in your '66 C30. Even if you change the pitman arm, the sector shaft turns the opposite of the input shaft.

[enonz65c30]

Captinfab,

I figure worse case if the front crossmember is different. I was going to Atleast get the upper and lower control arms, hubs, calipers, steering linkage(leave the steering box) and sway bars. Then I would also not have to worry about the motor if I went that route. I have a lead on a c20 as well that I might steal the crossmember from. I also found a P30 in a junk yard with no motor or trans and missing the spindles. Would a p30 crossmember fit? It has frame rails like a c30 not unibody

[enonz65c30]

Originally Posted by jtrichard

Looks like you have a 66 not a 65

What would make it a 66 vs a 65?

[Captainfab]

Yes a P30 front suspension and crossmember will bolt right into your truck. As far as I know the C/P20 crossmember and control arms are the same as C/P30 crossmember and control arms.

Originally Posted by enonz65c30

Captinfab,

I figure worse case if the front crossmember is different. I was going to Atleast get the upper and lower control arms, hubs, calipers, steering linkage(leave the steering box) and sway bars. Then I would also not have to worry about the motor if I went that route. I have a lead on a c20 as well that I might steal the crossmember from. I also found a P30 in a junk yard with no motor or trans and missing the spindles. Would a p30 crossmember fit? It has frame rails like a c30 not unibody

[tincan1966]

Why all the fuss to switch crossmembers? Just R & R the control arms. I switched out my '69 C30 from drum to disc and never touched the cross member. I used all 1976 C 30 JB-8 brakes.

one thing I see a lot of with guys switching the entire crossmember out is that they seldom rebuild the "donor" so just changing out worn parts for more worn parts.
If you're going to tear it down and install new ball joints, etc, no need for the extra work of switching the X member.
Just my two cents worth.

Too bad no one close needs a completely NEW disc brake C-30 FE My truck got totaled about 500 miles after rebuild. Everything including the control arms are brand new.

[Captainfab]

It's not that easy on the '63-'66 C20/30's. The '63-'66's use a flat LCA shaft, so there is no saddle to locate a later model LCA shaft. I have not had the time to verify whether or not a disc brake lower ball joint will press into a '63-'66 LCA. If they will, that definitely would simplify the conversion.

Originally Posted by tincan1966

Why all the fuss to switch crossmembers? Just R & R the control arms. I switched out my '69 C30 from drum to disc and never touched the cross member. I used all 1976 C 30 JB-8 brakes.

one thing I see a lot of with guys switching the entire crossmember out is that they seldom rebuild the "donor" so just changing out worn parts for more worn parts.
If you're going to tear it down and install new ball joints, etc, no need for the extra work of switching the X member.
Just my two cents worth.

Too bad no one close needs a completely NEW disc brake C-30 FE My truck got totaled about 500 miles after rebuild. Everything including the control arms are brand new.

[Tx Firefighter]

Originally Posted by Captainfab

It's not that easy on the '63-'66 C20/30's. The '63-'66's use a flat LCA shaft, so there is no saddle to locate a later model LCA shaft. I have not had the time to verify whether or not a disc brake lower ball joint will press into a '63-'66 LCA. If they will, that definitely would simplify the conversion.

My later model dually has the bolt on lower control arms. No u bolts. Curious if the bolt pattern is the same as early trucks.

[tincan1966]

Originally Posted by Captainfab

It's not that easy on the '63-'66 C20/30's. The '63-'66's use a flat LCA shaft, so there is no saddle to locate a later model LCA shaft. I have not had the time to verify whether or not a disc brake lower ball joint will press into a '63-'66 LCA. If they will, that definitely would simplify the conversion.

I did not know that. Thanks for the info! I've only converted the one C-30 and it was a '69

[Captainfab]

Your '88 R30 has flat LCA shafts? I have never seen that on anything but '63-'66 C20 and 30's. But then I don't recall having been under a R30 either.

Originally Posted by Tx Firefighter

My later model dually has the bolt on lower control arms. No u bolts. Curious if the bolt pattern is the same as early trucks.

[Tx Firefighter]

Originally Posted by Captainfab

Your '88 R30 has flat LCA shafts? I have never seen that on anything but '63-'66 C20 and 30's. But then I don't recall having been under a R30 either.

Yes, big square cast shafts with ears that bolt to the crossmember where u bolts would be on most trucks.

[Captainfab]

Interesting........I'll have to see if I can find some time to crawl under my '66 C20 and get some measurements.

Here is a pic of a '63-'66 C20 lower control arm.

Originally Posted by Tx Firefighter

Yes, big square cast shafts with ears that bolt to the crossmember where u bolts would be on most trucks.

[Alan's Classic]

So from reading this thread if I wanted to convert a 68 C30 from drum to disc I need to look for 1971-19?? C/P 20/30 donor. What is the year range?

[Tx Firefighter]

Originally Posted by Alan's Classic

So from reading this thread if I wanted to convert a 68 C30 from drum to disc I need to look for 1971-19?? C/P 20/30 donor. What is the year range?

Through the end of the square body style. Mostly, 87 was the last year, but there were exceptions of square bodies that went all the way through 91. For instance, I have an 88 model square body truck which is a cab and chassis configuration (never came with a bed). My truck would be a viable donor in this case.

Basically, any square body dually.

[Alan's Classic]

I just located a 76 C20 burb. He said he would cut the rails off at the firewall for $225. I assume that I just add my top hats to the rotors for the reverse wheels.

[Tx Firefighter]

My dually uses dually rotors, not adapters bolted on. It's all one giant casting.

[Alan's Classic]

Originally Posted by Tx Firefighter

My dually uses dually rotors, not adapters bolted on. It's all one giant casting.

TY Kevin I've never worked on a front end of a C30. I've done plenty of C10 swaps. The only thing I can't wrap my head around is the rotors. The C20 Burb (donor) is not a dually rotor of coarse but my 68 C30 is a dually. So if I buy 76 Dually rotors all will work correct? Are the spindles the same for a C20 non dually and a C30 dually?

Will the brake hose location where it attachs to the frame be different? I will have to relocate?

[Tx Firefighter]

I just went out to the shop and took a picture of my dually rotors.



Now, I know they look foreign to what you're used to, but the guts, ie the bearings, threaded nut, cotter pin, etc are located down in a recessed well in the center. While the rotor is deep, the spindle itself is way down inside the center bore.

Also, I know for a fact, the center dust cap is the same between 3/4 and 1 tons. I had to order one Friday for my own truck and spent a lot of time looking.

I have heard that the spindles are the same. I know the semi wheel dually crowd often swap rotors around to get different track widths.

If it were me, I'd open two tabs on my browser and catalog the inner bearing, outer bearing, grease seal, upper ball joint, lower ball joint, and outer tie rod ends between 3/4 and 1 tons. I use OReilly Auto Parts website for such projects. It would seem that if all the above parts were the same part number between the 3/4 and 1 ton, the spindle would be the same. No guarantees doing it that way, but it would sure seem very likely.