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GM Tech (Cam)
GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29395
Experience:  GM Grand Master Technician 2007. 14 years experience.
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I am replacing the hard brake lines on my 99 Silverado. 4wd. ext.

Customer Question

I am replacing the hard brake lines on my 99 Silverado. 4wd., 5.3l. All the lines rusted out at the frame rail and ABS box. Can some one give me a diagram of the 5 Lines which go into the ABS box. I know one...that goes to the rear. The other 4 just twisted too much to follow up the frame rail and broke apart. Now all the lines are out of the truck and I have nothing to look at!

Also, do you have to drop the gas tank to replace the rear hard line from ABS to Flex line?

Please help!
Submitted: 7 years ago.
Category: Chevy
Expert:  Tim's Auto Repair replied 7 years ago.


this may help..this is all i have,i hope this will work for you


please ACCEPT my answer so I can get credit for my work.i don't receive commission unless you do ..I'm not always going to be giving you good news,so please don't let this stand in the way of you accepting my does not cost you more money.we will still be able to communicate.. Bonuses and positive feedback are appreciated!if you are not satisfied with my answer,please do not leave bad feed back,i will gladly opt out and let another expert handle the question.PLEASE ASK IF YOU NEED MORE HELP

Hydraulic Control Assembly - Antilock Brakes
Fluid Diagrams

Customer: replied 7 years ago.

Not what I needed.... I know how to plumb the entire brake system which you laid out in your schematic. What I don't know is the 5 In/Out lines on the ABS Module, located on the frame rail under the Driver Seat. Your image layout does not even have an ABS module in line.


Sorry, please opt out and let another person answer.

Expert:  GM Tech (Cam) replied 7 years ago.

Welcome. I cannot find a diagram, but below is a very specific description of where each port goes. Please let me know if this is what you are looking for.

Also, Removing the gas tank does make it easier, but What I have done is sent the bulk line in from the back bending it into shape as I went, but I had the truck on the hoist.

the 5 brake lines from the brake pressure modulator valve (BPMV) when looking at the brake pipe port face of the BPMV, the ports are assigned as follows:

Upper Left--Left Front Output

-to left front caliper

Upper Middle--Right Front Output

-To right front caliper

Upper Right--Rear Output

- to rear axle


Lower Left--Master Cylinder Secondary/Front Input

-the front most fitting on the master cylinder


Lower Right--Master Cylinder Primary/Front Input
-Rear most fitting on the master cylinder.

GM Tech (Cam), Chevy Technician
Category: Chevy
Satisfied Customers: 29395
Experience: GM Grand Master Technician 2007. 14 years experience.
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