This post will hopefully help anyone who needs to replace a hydro boost on a 2nd generation truck (Mine is a 1999 2wd). I've detailed the removal & installation as well as I could. The unit i used is a remanufactured unit from A-1 Cardone that I picked up at Oreilleys for just under 175. 00. The part number is 52-7354. Go ahead and pick up an extra quart of power steering fluid as well as some gojo wipes while you're there. There are some parts that have to be re-used on the new unit and that will be shown as well. They are the pushrod/spring assembly for the master cylinder, and the flange that mounts to the front of the hydroboost as well as the seal.
Here's a photo right before starting the work. The hard line on the right side was leaking as well as inside the truck where the brake pedal linkage comes out of the unit. I had some leakage on the firewall.
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Remove the two 9/16" bolts holding the master cylinder to the hydroboost. There are actually four bolts and the one Im removing here is not necessary at this point.
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Break the master cylinder loose from the hydroboost. Notice the black plate at the front of the mounting surface of the master cylinder. Its a bracket that holds the hydraulic lines. It will come into play later.
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Break the top line loose with an 18 mm wrench.
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Break the side line loose as well.
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There's not a lot of room to use a full length wrench in here. I ended up taking my 19mm flar nut crows foot wrench used on the injector lines to finish taking the nut out once I broke it loose with the 18mm wrench. I ONLY USED IT BY HAND so as not to damage the threads. Just a little tip here:
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Remove the rubber line. Pull the clamp back and pull hard. This one had 260k miles on it. It was a bit hard to remove but it came off with some manipulation.
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Pull the lines back out of the way. The bracket will move back as well. Notice the o-rings on the end of the hard lines. The new hydroboost comes with new o-rings for those lines. As I sit and write this, I realize that I didn't replace them. I think the guy at Oreilleys laid them out on the counter and didnt put them back in the box when we put it back inside the box...
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Here's a photo right before starting the work. The hard line on the right side was leaking as well as inside the truck where the brake pedal linkage comes out of the unit. I had some leakage on the firewall.

Remove the two 9/16" bolts holding the master cylinder to the hydroboost. There are actually four bolts and the one Im removing here is not necessary at this point.

Break the master cylinder loose from the hydroboost. Notice the black plate at the front of the mounting surface of the master cylinder. Its a bracket that holds the hydraulic lines. It will come into play later.

Break the top line loose with an 18 mm wrench.

Break the side line loose as well.

There's not a lot of room to use a full length wrench in here. I ended up taking my 19mm flar nut crows foot wrench used on the injector lines to finish taking the nut out once I broke it loose with the 18mm wrench. I ONLY USED IT BY HAND so as not to damage the threads. Just a little tip here:

Remove the rubber line. Pull the clamp back and pull hard. This one had 260k miles on it. It was a bit hard to remove but it came off with some manipulation.

Pull the lines back out of the way. The bracket will move back as well. Notice the o-rings on the end of the hard lines. The new hydroboost comes with new o-rings for those lines. As I sit and write this, I realize that I didn't replace them. I think the guy at Oreilleys laid them out on the counter and didnt put them back in the box when we put it back inside the box...
