1960 8 lug disc brakes

[fourhundredorbust]

I think I already know the answer but in searching I cannot fully confirm it...is there a way to:

1) put disc brakes on my 1960 8 lug truck
2) put a dual master cylinder on same truck (manual transmission)

I would really like disc brakes but short of that I'd like a dual system but with the clutch and brake reservoir being the same piece I'm not finding anything.
Am I missing something?

Thanks!
Jeremy

[James]

Here is what I did.
https://6066gmcclub.com/album.php?albumid=323

However I have a mechanical clutch.

[fourhundredorbust]

Looks great. I can probably figure out a way around the hydraulic clutch but the parts I'm not sure about are all the parts! What did you use for the discs and calipers, spindles, etc. Did they bolt on etc? Thanks!

[James]

First off it took me about 2 years of web research for the following info. No one need to go through this much work. I did it for part availability and safety, new drum brake parts are hard to find.

I used the front spindles and brake calipers from a 81-82 1500 GMC pickup. With this I had to reamed the holes (for a different taper) for the ball joints and rod end. Then I used the rotor from a 81-82 2500 GMC pickup. The studs on the rotor is larger the're 9/16" instead of 1/2".

Minimum rim dia. is 16" four all four wheels. If you have manual steering make sure you have at least 1" offset on the rim, this with keep the steering as easy as possible. You want to keep the tire pivot point (upper and lower ball joints and the center of the tire) in the center of the tire. Also be sure to follow the manual for wheel alignment. The caster should be ZERO or 1/8° positive, this is with an empty bed (unloaded). Set the camber and toe to match the maintenance manual spec.

For the rear axle I went to:
http://tsmmfg.com/Rear%20Disc/2629.html
I updated the rear studs to match the front. The rotor they provided has two set of holes. One for the 1/2" studs that they had to drilled. And 9/16" studs that the factory drilled. To keep all four rims the same you will have to remove the rear hubs to have the 9/16" stud installed.

Full floater axle side note: The bearings in the hubs gets lubricated with the oil from the rear axle and not wheel bearing grease. When you assemble the rear hubs onto the axle coat everything with rear axle lube. Once you have finished the rear brakes and had filled the axle with oil. With the rear tires on the ground raise one wheel as high as you can go to allow the hub to fill with axle oil for about a half an hour. Then raise the other wheel. Then reservice the rear axle oil.

All of the brake lines I fabricated. The kits that I found out there are cheap. No one thought on anchoring the lines to prevent rub. It would just float around from master cylinder to the rear axle. I basically modify what the factory had for the single master cylinder for my dual master cylinder installation. I do have pictures if needed.

[fourhundredorbust]

Great info, thank you James! A couple things unclear to me:

When you say you reamed the holes do you mean you reamed out the ball joint tapered holes on the "new" spindles to fit the "old" ball joints?

If so, why not just put a new rod end on instead of reaming the steering arm hole too? Was it to keep everything spindle out "new" and everything ball joint in "old"?

Also, in searching I found the "new" spindle taper is 2:12 but I cannot find what the old taper is. Do you recall what taper the old ball joints are so I can buy the correct reamer?

All this being said, my truck is a 1960 1500 with the torsion bar front end...do you forsee any issues with that since it is different from your truck or do you think the "new" spindles will still work?

Great info on the rear end too, thank you. That sounds like the easy part!

[James]

My truck drum brakes spindle had 1-1/2" per foot taper, also known as a 7° tapered.

The 2" per foot reamer, also known as a 10° tapered, new ball joints.

Reamers: https://www.speedwaymotors.com/Searc...l+Joint+Reamer

My Upper Ball Joints: Raybesto P/N: 500-1062B
My Lower Ball Joints GMC: Raybesto P/N: 505-1008
I don't remember whether it was the upper or the lower ball joint taper hole that I had to do (I want to say it was the upper one). Tie rod end is stock.

Tie rod end boot: Energy Suspension P/N: 9-13119G

[James]

Last night I realized that I forgot to tell you a couple of issue I had with the spindles. I do not know if this will be an issue for you, however I try to keep you inform in case it is.

1. The top of the spindle is beefier. With the truck on jack stand and the suspension hanging I could not turn the wheel. The spindle was rubbing on the upper control arm. I bought a pneumatic file from Harbor Freight and filed the upper control arm for clearance.

2. The turn stop is different on the 81-82 GMC. When turning the wheel out to the control arm stop, the spindle stop is shaped like a chisel, I fear it would pierce the lower control stop. With it in this position I use a sharpie to scribe a line parallel with the lower control arm stop (to removing the chisel point). Use a cut off wheel to trim the spindle stop. When I did check my wheel travel I did get 44° of travel from straight ahead, Spec. is 44°, I luck out.

If you are installing a power brake booster you will need to drill a new hole in the brake pedal lever, 1" lower (center to center) than the one for manual brake. Can be done with the lever still in the truck.

[fourhundredorbust]

James, thank you very much for all the info. This sounds very doable for me once I figure out a way around the co-joined brake/clutch master cylinder in my truck.

[Funky61]

I used this guys bracket when I went to a dual brake MC system and kept my manual transmission.

https://67-72chevytrucks.com/vboard/...ght=CaptainFab

[fourhundredorbust]

Awesome lead! Thank you! That will make it much easier. I think that is the route I will go.