Brake help! auto parts people just dont know anything about old stuff. JB1 JB3???? 1in 1 1/4

[Nasty-LSX]

So the 86 Im working on has been sitting since 2017. I got it running and driving and the right front
caliper locked up on the rotor. Vids and updates coming soon. my friend has brand new front rotors and
brake pads he just gave me because he went to 1 1/4 in rotors. I measured mine and I have 1 1/4 inch rotors LOL.

The auto parts (everywhere I call) ask a bunch of crazy info I dont even know. So Since my truck is equipped with
1 1/4 inch rotors I guess (HD) does anyone know the part #'s for left and right calipers and rotors? THANKS.

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[Keith Seymore]

Need to know a little more:

C10?

Do you know the GVW rating?

I wouldn't mind knowing what that little paper sticker on the brake master cylinder says, too.

 

[Nasty-LSX]

C10 1500 2WD long bed. Used to have a 305 with a TH350 trans.

I'll see if there is a tag on the MC tomorrow. Not sure on GVW. Thanks
I looked at the SPID and there was nothing on the brakes.

 

[Keith Seymore]

Well - in the absence of further detail - let's take a look at the chart.

These are the charts that the brake engineer developed and referred to in order to release parts for production and service.

Your two most probable choices are JB3 or JB5. The vast majority of trucks were built with JB5 so I would start there. If your rotors are in fact 1.25" then that would confirm JB5.

Your master cylinder looks like a "ZF" from here, which doesn't help us distinguish between JB3 or JB5.

Calipers were 18010201 and 18010202; rotors were 6274216.

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[Keith Seymore]

The SPID might not show anything because your order package might have included power brakes as standard.

Even so - at most it will show J50 or J55, which are "merchandised options". That is - the customer says "I want power brakes" and so the dealer selects J50 or J55.

The engineering release charts then select the specific "non merchandised options" like JB3 or JB5 or JB7 or whatever, based on model type and GVW rating. ("B" is vacuum assist; "D" is hydroboost - Diesel, in this vehicle range).

It's like springs; the customer (normally) would not select which spring they want. They would tell the dealer what kind of truck they want and the engineering release charts determine the right spring for the job.

K