Which brake lines go into which port on the Brake Pressure Modulator? on 2002 GMC Yukon XL 1500

I replaced my front brake lines but don't know which brake line to screw back into which port on the Brake Pressure Modulator in the middle of the undercarriage?

by in Verona, KY on November 13, 2010
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2 answers 8 comments
ANSWER by , November 13, 2010
clean it i think it has LR, RF,LF,RFmarked on box
COMMENT by , November 14, 2010
There are no markings on the box, unfortunately. There are five ports total, the top right of which runs to the back (I did not disconnect this one). The other four all go to the front. Two route directly to each front caliper (left and right), and two route to the brake master cylinder. I wish it were that simple--thanks for your reply anyway!
ANSWER by , November 13, 2010
I looked in the manual and did not see any brake line schematic. So, this is an old trick that I learned from working at Dealerships. Go find a similar vehicle crawl under and draw a picture, it sounds primitive, but it has saved my but a zillion times. So, in your case go to a used car lot, there has to be a few Yukon/Suburbans for sale that are the same body style as yours, it is one of the most popular vehicles ever made.
COMMENT by , November 14, 2010
I appreciate your reply, but I did that on Friday, before I emailed RepairPal yesterday. The problem is, I cannot see over the frame to tell which of the four brake lines goes to which port. Any other support you can give would be terrific...I went to the manuals also and saw the schematics, but they did not include the BPMV in the diagram. I also saw the BPMV by itself, but no markings and no brake lines included in those schematics.
COMMENT by , November 17, 2010
As you face the BPMV you have the 5 holes top 3 to outputs(brakes) and bottom 2 inputs(master) Upper Left supplies Left Front brake Upper Middle supplies Right Front brake Upper Right supplies Rear brake only one that turns and goes directly to rear. Lower Left supplies Master Cylinder Secondary/Front Input Lower Right supplies Master Cylinder Primary/Front Input
COMMENT by , November 17, 2010
My gosh--you have no idea how many 'experts' on various sites this question has stumped! You, my friend, have saved the day in a very big way...and you've apparently done so anonymously! If you don't mind my asking, how did you figure this out? Does this apply to a certain year-range of GM vehicles? Amazed, impressed, and *very thankful*, Dave (dstrasin)
COMMENT by , November 17, 2010
I know for sure a 2000 yukon xl 1500 4x4 for sure, I am sure there is a good range they used it on. I had mine sitting for about a year and when I went to drive it the break lines started leaking, I would change one then the next failed. So I decided to change them all which was much easier than just changing the one. So 2 days of following and cutting small sections at a time and a notepad I finally got it.
COMMENT by , November 19, 2010
Thanks for sharing your experience--I'm very appreciative. My family will be back on the road this weekend thanks to you! One question about the master cylinder: I have one big fluid reservoir versus two separate reservoirs, so it's not obvious brake line port is primary and secondary--do you happen to know which is which?
COMMENT by , January 24, 2011
I've had the same problem. Couldn't remember what line goes where. Thanks so much. Mr. Anonymous!!
COMMENT by , June 22, 2011
Thank you..I lost track when i was trying to follow the lines to where they went...after lines breaking then leaking all over the place i lost track where they went...thanx for the info...much appriciated!