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Old 01-07-2021, 11:03 AM   #1
chappys4life
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Join Date: Oct 2008
Location: Austin, TX
Posts: 72
1978 k5, 3/4 ton caliper swap parts help

Working on a 1978 k5 i picked up recently and needs all the basic maintenance done. I was going to replace the calipers, rotors, and rubber lines. It has power disc brakes and a new master cylinder is on the way. I found the 3/4 ton upgrade and it seems worthwhile since i need to change the parts anyway but confused on what I need to buy.
What I found is
1985 Chevrolet C20 (3/4 Ton), 2wd, 5.7 engine
Front Calipers for Heavy Duty brake system, 13" rear drums
These require the 10mm banjo bolt and hose use 1985 C10 with the heavy duty brakes.

So I am looking on napa now and want to verify im getting the right parts
- napa total eclipse 3 5/32" piston calipers CAL SE4674 & CAL SE4673
- napa pads CAL SE4674 (should i use ebc ultimax 2's? cannot find the right part)
- napa brake lines UP 38065 & UP 38066
- 2 banjo bolts for calipers

Does this sound right? I already have the rotors for the stock 78
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Old 01-07-2021, 03:10 PM   #2
kwmech
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Re: 1978 k5, 3/4 ton caliper swap parts help

You're not going to gain anything noticeable by swapping to a 3/4 caliper. In fact you may lose a little with the bigger piston
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Old 01-07-2021, 03:36 PM   #3
chappys4life
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Re: 1978 k5, 3/4 ton caliper swap parts help

Quote:
Originally Posted by kwmech View Post
You're not going to gain anything noticeable by swapping to a 3/4 caliper. In fact you may lose a little with the bigger piston
What makes you say that? Seems super popular. I am ok not just asking why you say that.

The only upside i saw was I could get them today at napa where my stock k5 calipers had to be ordered.
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Old 01-07-2021, 06:29 PM   #4
kwmech
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Re: 1978 k5, 3/4 ton caliper swap parts help

Are you actually putting the 3/4 ton 14 bolt with the 13'' drums under the K5? and converting the front to 8 lug rotors? and additionally putting the 3/4 master cylinder on the existing booster
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Old 02-09-2021, 03:48 PM   #5
buffydores
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Re: 1978 k5, 3/4 ton caliper swap parts help

More piston area = more clamping force. Made a big difference on my K5 with 35s. The guys at Offroad Design have been preaching this for year. It works.

Chappy: Go to RockAuto.com. Easier to see the part numbers I mention in the original post:

http://67-72chevytrucks.com/vboard/s...d.php?t=777221
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