Finally finished the disc install

[ERASER5]

I am finally all done with the disc brake install on the 70 GMC. My parts are standard off the self stuff except for the 6 lug McGaughy rotors, the 10# residual valve from Master Power Brakes and the stupid banjo bolts. I may post some pictures later, but there will not be any thing fancy.

I used the 73-87 donor method with a Disc/Disc or Disc.Drum MC and 7" dual diaphram booster. I can now for the first time lock all four wheels up!

I had a few bumps in the road, but I learned a lot of small details. For instance, in 1979, GM changed from a 7/16-20 banjo caliper bolt to a 10mm banjo caliper bolt. I just happened to pick "1978" as the reference year for all of my brake parts. None of the box stores carry or even list a 7/16-20 banjo bolt. Only the 10mm for about $3.00. I had to special order my bolts on line for $10ea plus shipping. Another delay.

The firewall MC boot/grommet for manual brakes will not work for the power brake setup. Had to order it and wait.

My Power Booster/MC came with no instructions, so I had to look at my 72 (lucky me) and take some measurements. To get the final fitting, I had to cut 3/8" off of the booster "input" rod to get it short enough and on the MC side, I had to trim the bolt face that hit the MC so as to let the MC retract all the way.

My e-bay MC did not work on the rear section. I pulled the snap ring out and removed the rear piston and found chunks of junk in it! The piston was not able to refill. So I cleaned, cleaned, wiped and re-wiped, then re-assembled the MC. Fixed that.

I used the later model brake lines, putting the proportioning valve at the front crossmember. I will not be doing that again. What a pain to install the lines and then bleed! I also learned about the valve locking the rear brakes out (brake light comes on all the time) and how to re-center the valve using the bleed screws.

Oh, and due to my MC, I needed to install a 10# residual valve in the rear brake line.

The truck has shiny new painted front suspension, steering, and disc brakes and fresh alignment.! So now I am happy! Or grumpy, or dopey or one of those guys.

[70c10]

Congrats on the new safety feature!

[70cst]

Good investment in your truck. Safety comes first then the rest can take shape safely.

[MikeB]

Good job! It's ALWAYS a learning experience.

I did my 69 pickup 14 years ago when there were virtually no kits available. Used spindles from a 86 pickup, but later found out it was a light duty model with smaller rotors, bearings, and calipers. Made several trips to the parts store before they finally sold me the correct parts. I plan to update everything to larger 71-72 parts someday, but I've been saying that for 10 years!

[ChevLoRay]

I love being able to press on the Whoa! pedal and have it stop in a straight line, without any unexpected lockups.

My components all came from Early Classic Enterprises, and I don't recall any of the issues that you encountered. Not to dis what you bought, just to say that my install was without any undue hitches. But, my truck had power brakes from the factory, and that may/may not have been a factor in the process.

[MikeB]

Originally Posted by ChevLoRay

My components all came from Early Classic Enterprises, and I don't recall any of the issues that you encountered.

When it comes to brakes and suspension, those guys are the best. What I really like about them is every one of their phone sales guys seems to have hands-on experience. At least that's the way it used to be there.

I bought some springs, shock relocation brackets, and adjustable track bar from them in the late 90s when there were very few Internet retailers selling truck parts. I plan to use their spindles when I re-do my front brakes.

[ERASER5]

The rotors were about $80 apiece. No bearings. Standard 73-87 HD bearings. That is a lot of jack, but not nearly as much as changing the rear to 5 lug.

Most of my problems hinged on two things. First, I bought the booster/MC off of e-bay before I really had my plan together. I should have gone junk yard hopping instead. The bracket and linkage was the thing I needed most. I found 3 sets AFTER I bought the e-bay stuff. Second, I was stupid and did not record the actual year of the donor truck.

As for cost, I have about $935.76 ( I kept all my receipts) in it and I just re-couped about $80 at the scrap yard. That got me rotors, calipers, pads, caliper bolts, banjo bolts, hoses, bearings, ball joints, tie rod ends, adjusters, spindles, backing plates, proportioning valve, 10# residual valve, springs, A-arms with rubber bushings, lots of brake cleaner, prep- all, towels, rags and of course, shiny paint.

I am not really disagreeing about EEC, but I just do not have that kind of cash flow at the moment. To get power disc brakes from EEC the price is $1148 plus shipping and tax. From GMC Pauls, the price is $920 plus shipping and tax. The rest of the suspension will remain old unless you drop a lot more cash. So I got more, for less, and I learned a lot. If I had gone minimum, it would have been less than half the price.

[michael bustamante]

if you dont mind sharing, what did you cough up for the 6 lug rotors and did they come with the bearings?