brake question

[86chevybanshee]

when i go to order brake parts they always ask me what system i have, its eather jb6/jd6 or jb7/jd7, whats the difference and how do u tell what i have, its for an 86 3/4 with the semi floater and 10 bolt

 

[pauly383]

Which parts are you replacing ? I just looked for pads and shoes on Autozones site and got same part numbers for either system of brakes. Actually most of the parts are the same . I haven't worked in an auto parts store for years , maybe call or check yourself both ways and compare part numbers /forums/images/graemlins/k5.gif

 

[84_Chevy_K10]

The rear brakes are different, one of the systems uses 13 x 2.5 shoes, the smaller ones are 11" like the 1/2 tons.

Front pads are 52s or 154s, your choice of. The bigger rear brakes will come with the 154 front pads. I believe both will fit either way though, the 154s are just slightly thicker.

Those numbers are pretty much the same wherever you go, D52, MKD52, GMD52, BMD52, or similar.

 

[ugly_blazer]

What about master cylinders? My 79 K20 has 2 different part numbers for the master cylinder but they both look the same, except for a different color "marking paint" on them. Any idea what the difference is between the two mc's? More volume?

 

[diesel4me]

I've benn going through the same BS trying to get a power brake booster for my 79 C10,the JB3,JB7,ect refers to the size of the rear shoes and front pads,as Tim just stated. My truck doesnt have the "options" sticker on it anymore,so I guess I'll have to pull a back tire off and measure the shoes.I know they are either 11x2 or 11-5/32x2/34,but I cant tell for sure with the tire and rim on! /forums/images/graemlins/angryfire.gif
According to the Hollander book at the boneyard,only 79 and 80 are the same,and they have different boosters for bendix master cylinders vs delco-moraine master cylinders,making my search for a booster a real arsepain.I think the two master cylinders have different bolt patterns and internal differences,but I'm not absolutely sure exactly if the bore sizes are different,I think the bolt pattern is smaller on the bendix master.
I'm wondering if I could find out from the chevy dealer by running my trucks VIN # would tell me what brake system was installed in my truck-- /forums/images/graemlins/confused.gif.
Has anyone swapped a booster from a newer truck into a 79 vintage? /forums/images/graemlins/1zhelp.gif--there are lots of 82-87 trucks with good boosters in the salvage yard,only one 79,but its so rusted I dont want to waste my time with it--Can anyone help? /forums/images/graemlins/1zhelp.gif /forums/images/graemlins/ears.gif