Anybody know...

[Pinchecharlie]

What size 73-87 brake caliper piston are? Know what size the same year rear drum cylinders are? I asked willwood some questions and they said the need this info and Google isn't cooperating . And what pedal ratio do we have in 65? Thanks for any help.

[Keith Seymore]

Long answer: There are four or five different brake systems released during that era, depending on model, brake assist type (vacuum vs hydraulic), brake RPO and/or GVW rating.

Need a bit more detail of what you are starting with before answering the question (ie C10? K20? or whatever)

http://67-72chevytrucks.com/vboard/s...d.php?t=510519

K

[Keith Seymore]

Short(er) answer after reviewing the '87 charts:

2.94 inch piston diameter for JB1, JB3, JB5 and JB6

3.14 inch for JB7

3.38 for JB8.

Wheel cylinders:

1.062 inch diameter for JB1 and JB3

.9375 for JB5

1.00 for JB6

1.062 for JB7 and JB8 SRW

1.188 for JB8 dual rear wheel

I can't answer the pedal ratio question. I only have the charts back to 1969 model year.

K

[Pinchecharlie]

thank you. should have been specific!
84 c10 2 whel drive front calipers
65 c10 two wheel drive rear drum cylinders

think the ratio is 8.6 to 1 (from others posting)

[VictoriaHardware]

Originally Posted by Pinchecharlie

And what pedal ratio do we have in 65

Pedal pivot to footpad distance divided by pivot to pushrod distance= 14.75/2.5 = 5.9

[Pinchecharlie]

Thanks I appreciate it!