70 c30 front disc swap help?

[70c30]

Got a 70 c 30 and wanted to swap front disc brakes from drums. As Well as power brakes. I have 8 lug 2wd. Is it true that I can use the newer gen brakes and swap em in? From what I see I need, from a 73 and up, rotors bearings ball joints calipars spindles..and rubber brake lines and expect custom steel lines? And as far as power brakes I need a booster master and brake pedal and perp valve? Now what all years can I get the booster and brake pedal from? do I need to cut the firewall to fit?
I did some research and some of it was confusing and advertising kits. Just would like someone that has done this to verify that I'm gonna buy the right stuff. Thank you
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[airdale94]

You will also need the lower control arms. They went to metric fittings sometime in the late 70's: ps pump and gear box, brake hose fittings at caliper. The drum hoses will screw into the SAE calipers. That's what I'm using on mine. What I did was get a whole front stub from a junk yard. They cut the frame and you get everything. Get a 71-72 booster and master cylinder and it will bolt right up. Shouldn't need pedals but make sure you get the push rod.

[70c30]

Mine has an un needed clutch pedal but I read that the lca are the same or something about the bushings? I wanna do it as cheap a s possible and i will be pulling yard parts so its gonna be fun. Now mine has power steering and I havent read anything about the gear box itself or ps pump on any site?
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[lolife99]

Originally Posted by 70c30

Got a 70 c 30 and wanted to swap front disc brakes from drums. As Well as power brakes. I have 8 lug 2wd. Is it true that I can use the newer gen brakes and swap em in? From what I see I need, from a 73 and up, rotors bearings ball joints calipars spindles..and rubber brake lines and expect custom steel lines? And as far as power brakes I need a booster master and brake pedal and perp valve? Now what all years can I get the booster and brake pedal from? do I need to cut the firewall to fit?
I did some research and some of it was confusing and advertising kits. Just would like someone that has done this to verify that I'm gonna buy the right stuff. Thank you
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Grab all the parts you can get from the 73.
You can swap everything from the a-arms out to your 70, (maybe the easiest solution),... OR,... just use the spindles out, but this will require you to install 73-87 C30 balljoints in your original 70 a-arms.
You will also need all of the 73 steering linkage, since the 73 tie rods are larger than your original 70 tie rods.

Please post up some pics of your 70 c30!

[terry b]

If 71 parts will work i will cut the frame at the fire wall and sell you the whole setup. Check the parts posts for amount.

[airdale94]

Upper control arms same but need new ball joints. Lower control arms are different.

[lolife99]

Originally Posted by airdale94

Upper control arms same but need new ball joints. Lower control arms are different.

What is different?

The arm should be the same with the exception of the balljoint.
1/2-ton a-arms are different.
They have a smaller ball joint hole.

73-87 C20/C30 lower a-arms would be the same as 67-72 C20/C30 a-arms.

73-87 a-arms are rubber bushed instead of steel bushed like the 67-72 arms.
But the 1-ton 73-87 a-arms should also have steel bushings.

[71swb4x4]

I went to hydroboost when I did the swap on my 67 C30, I love it. My swap isn't that detailed in the photos but the swap starts on the fourth page: http://67-72chevytrucks.com/vboard/s...d.php?t=327476

[70c30]

Okay this is what worries me. Multiple opinions. I can't go into this swap.with maybes. Not trying to be an A$$ but I don't have the place or $ to come upon a snag . Who has done this on their c30 ?
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[lolife99]

Originally Posted by 70c30

Okay this is what worries me. Multiple opinions. I can't go into this swap.with maybes. Not trying to be an A$$ but I don't have the place or $ to come upon a snag . Who has done this on their c30 ?
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How much money do you have?

The last time I rebuilt a front end, (just the suspension pieces),... my parts bill from my local parts store was around $600.
(a-arm cross shaft kits are expensive)
Used parts from a junkyard are wore out.
(unless you find a recently rebuilt front end on a wrecked truck)
These are 25-40 year old parts.
Everything that you buy used, will need to be inspected.

Additional cost will be required if you don't have the ability to change a-arm bushings or press in the lower ball joints.
Switching to front disc brakes will also requre a new M/C.
(I would neve use a used one),
A disc brake prop valve, brake pads, calipers and either new rotors or paying to turn down a used set, brake hoses,... along with bending up and flaring a few small steel brake lines.

A 71-72 M/C and prop valve are your easiet swap.
73-87 parts can be used here,... but will require making a brake pedal push rod with the correct length.
Nothing about this swap is cheap,... when you are talking about brakes and your safety along with others.

[powerdriver 1958]

Lots of info in lolife99's link

http://67-72chevytrucks.com/vboard/s...68&postcount=4

[SS Tim]

Originally Posted by 70c30

Got a 70 c 30 and wanted to swap front disc brakes from drums. As Well as power brakes...I wanna do it as cheap as possible... I don't have the place or $ to come upon a snag...

I can really understand wanting to have power disc brakes but some of your key words concern me. Are you planning on rebuilding or resealing the "new" used parts? Have you inspected and tested the brakes you currently have? Not having a place or money is a bad way to start a project as important as brakes much less a conversion. Rebuilding the existing brakes as required and adding a booster might be more cost effective and keep you up and running.

[terry b]

1971 M/C and prop valve no problem.

[RichardJ]

I used '76 C30 disc brake setup for my '67 C20.

To straighten out one item mentioned, no GM truck used a brake proportioning valve. They used a combination valve in all disc brake applications. The Combination Valve does contain a proportion valve in combination with other valves. The later '70s truck placed the combination valve under the radiator on the small crossmember instead of the ugly one hanging off the MC.
Disc brake rubber lines go through the frame in front of the axle instead of behind the axle like the drum brake lines. Mine already had a hole there that just needed drilled larger.
Drum brakes have the brake line on the back side of the suspension crossmember that connects the driver side with the pass side. Disc brake lines are all routed forward to the combo valve.

Both disc and drum brakes have an inline fitting, aft of the firewall and inside the frame rail. If you take all the brake lines from that inline fitting forward, it becomes a simple matter of bolting the new stuff in your truck.

I had crossmember and complete suspension from the C30. It unbolts very simply. I picked and chose parts from both and don't remember exactly. The C30 had a 454 so I kept the small 6cyl front coil springs. The C30 had a bigger sway bar so I used that.
The '67 crossmember had forged steel bracket (ears) that bolt to frame and upper A-arm so I kept that. The '76 only had a pressed steel bracket, but compensated by placing a stiffener plate inside the frame rail. I added that piece to my '67 frame rail.


I did replace the steel bushings and I think two of the ball joints, but only because they were shot. I don't make it a habit of replacing things that aren't bad, just because.
NAPA had blue poly bushings in stock for the sway bar, because the old were oil swelled. Everything else was junk-yard fresh.

[lolife99]

Great info.
Thanks.

Unless you have the complete list of parts you mentioned from the donor truck,... there is no need to move to "combination valve" to the front frame rail or use all the associated brake lines.
The crossmember swap isn't necessary either.
If the engine is out,... some consider swapping the entire crossmember as an easy swap.
My opinion, I consider it unneccessary,... especially if the engine is still in place.

I think what you call a "combination valve",... I call a proportioning valve.
The pre-71 drum brake trucks have what I call a "distribution block".
Performance Online calls them both.
http://www.performanceonline.com/GM-...e-Brass-17010/

My opinion,... again,... if the part is 40 years old, and I have the entire front end blown apart,... I replace everything, that is a wear item.

[70c30]

Alright lots of posts. Money not a lot. Um hookup at a local yard yes. I know what to look for and wouldnt buy worn out junk. A place to do it yes I have that but a place to let it sit torn apart after hitting a snag no. I plan on getting a booster and master as it is. Again if its junk I wouldn't buy it. Will 73 and up boosters work on my 70? Also need the pedal would that work too? I can drill n cut to make fit sure. But finding a used one for a 70 is just as finding a used one from a 73. Old and used. Now plumbing n custom lines I can do but i dont want to get into welding brakes n all that. And yes I can press balljoints . My brakes as it is.. hmm Well when I got it there was no pedal at all. Repaired the font line and bled it.to get a pedal for temp moving. If I Was to redo the brakes i would fo with all 4 wheel cylinders and all spring kits and all new shoes. And going over the lines but for some reason I dont trust my m/c. It looks stock flaking rust and the firewalls.rusted around it bad. I want power brakes regardless. I plan on using it for a d d when I can.
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[70c30]

And as I'm interpreting from that write up I need 73 n up spindles ball joints calipars rotors bearings and outer tie rods. As well as brake lines?
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[N2TRUX]

It appears to me that your questions have been answered, just not the answers you want to hear. We understand that money is an issue, but safety is our concern. Our staff seasoned members avoid recommending replacing safety related items with old used parts for a good reason. The liability that goes with that is just not worth the risk.

[70c30]

I wouldn't put just crap on my truck I plan on buying what I can new. Not everything. I wouldnt build a deathtrap Im a little smarter than that thank you though . I'm looking for a set list of what i need for the swap from someone that has done it.
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[lolife99]

Originally Posted by 70c30

I wouldn't put just crap on my truck I plan on buying what I can new. Not everything. I wouldnt build a deathtrap Im a little smarter than that thank you though . I'm looking for a set list of what i need for the swap from someone that has done it.

71-72 C20/C30 Parts List:
1) Spindle
2) Dust Shield
3) Rotor
4) Caliper
5) Rubber brake hose
6) Upper Ball joint
7) Lower Ball joint
8) Steering Center Link
9) Inner Tie Rod
10) Outer Tie Rod
11) Tie Rod sleeve

* Swap ball joints or use complete 71-72 C20/C30 a-arms
* Use disc brake M/C from a 71-72 truck. BOLT ON SWAP
* Use Brake Booser from a 71-72 truck. BOLT ON SWAP
* Use Prop/Combination Valve from a 71-72 truck.
* Bend new steel brake lines from the M/C to the frame.
* Connect 71-72 rubber brake hoses to the original 63-70 steel line location.
(may require the use of 1 inverted flare adapter)
* If you are using a donor truck,... get the power steering box also.
* Replace the idler arm and pitman arm if your original parts are worn.

[lolife99]

73-87 C20/C30 Parts List:
1) Spindle
2) Dust Shield
3) Rotor
4) Caliper
5) Rubber brake hose
6) Upper Ball joint
7) Lower Ball joint
8) Steering Center Link
9) Inner Tie Rod
10) Outer Tie Rod
11) Tie Rod sleeve

* Swap ball joints or use complete 73-87 C20/C30 a-arms
* Use disc brake M/C from a 73-87 truck.
* Use Brake Booser from a 73-87 truck.
This will require drilling a couple new holes in the firewall.
May also require redrilling the 70 brake pedal push rod hole.
May require making a longer or shorter brake pedal push rod depending on which brake booster you use.

* Use Prop/Combination Valve from a 73-87 truck.
* Bend new steel brake lines from the M/C to the frame.
* Recommend using a 71-72 rubber brake hoses to connect to the original 63-70 steel line location.
(may require the use of 1 inverted flare adapter)
* If you are using a donor truck,... get the power steering box also.
* Replace the idler arm and pitman arm if your original parts are worn.

[70c30]

Thank you thats what I needed as soon as the truck is half ass decent ill post pics n progress
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[ColumbianIndian]

If you check the bottom of this page you can see what I did

http://67-72chevytrucks.com/vboard/s...57#post6122657

1985 - 2500 Spindles (junk yard)
1972 - 2500 Top and bottom ball joints (auto zone)
1972 - 2500 inner outer tie rod and sleeves (auto zone)
1972 - 2500 caliper pads, brake hoses, rotors, inner and outer bearings(auto zone)
1972 - 2500 booster master cylinder (auto zone)
1972 - 2500 proportioning valve and mounting bracket (Inline tube)
1972 - 2500 front stainless brake lines (inline tube)
1972 - 2500 longhorn front to rear line (inline tube)
1970 - 3500 dually rear axle line (inline tube)
1970 - 3500 shocks (auto zone)

I have the pictures of the bottom Booster/line pictures to come

[Don Quixote]

Years ago I had to swap out the chassis for my '72 and scored a '69 camper special (it's a 1 ton frame with some rear extenders). To make a long story short, I kept the front end from the donor chassis which had drum brakes and changed the valve and master to match. I am actually quite satisfied with my new setup. I have typical issues like the truck's desire to go zinging off into the weeds on occasion but a problem I don't have anymore is warping the rotors whenever I pull my moving trailer. Yes it stops a little slower even with the 7in booster but I am in the habit of downshifting and I just leave a little extra space and try harder not to go postal whenever someone cuts me off.