GMT 400 Hydroboost swap

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mars2878

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I always though the 3500s got the Hydroboost standard as well, or maybe it was the 3500HDs. Pretty sure all the 6.5s got one (I got the HB for my swap from a 2000 2500 with a 6.5 IIRC)


I had a 99 c3500 cclb 5.7L, it had hydroboost. But was A/C delete.
 

deadbeat

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I'm having some trouble getting mine all right. Should my pedal stay solid after the truck is turned off for a while? Trying to figure out if I have a small leak or something, mine will go to the floor after sitting, and when I start the truck it comes back up like it should. I put a new MC on it.
 

Jesse_Wenting

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I'm having some trouble getting mine all right. Should my pedal stay solid after the truck is turned off for a while? Trying to figure out if I have a small leak or something, mine will go to the floor after sitting, and when I start the truck it comes back up like it should. I put a new MC on it.
Yeah that sh*t isn't normal dude, pedal should stay solid at all times. You're right that it sounds like you have a leak, but if you do you shouldn't get good pedal feel with the engine running either. Does this happen as soon as you turn off the engine?
 

deadbeat

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Ok, I popped the hood and see a drop of fluid on the larger brake line coming out of the master cylinder that feeds the rear brakes, let me reflare it and see if it clears it up.
 

deadbeat

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i have the tech 2 and motive bleeder, truck had the wrong master cylinder on it, it had one for one with rear discs. I put the correct master cylinder on, and I can see one of my lines is seeping there. I'll fix it and see if the leak stops, otherwise I need to check if the new master cylinder is leaking out the back, it is wet there and I just cleaned it all with de greaser.
 

deadbeat

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I fixed the leak, used the tech 2 to bleed abs, and bled again. I put this master cylinder on it, but my pedal is still not solid after turning it off. As soon as I turn it off, I can put the pedal to the floor, not sure if the new master cylinder is bad or if I still have some air trapped somewhere. Pedal is pretty good, goes down a little further before getting stiff, not as good as it was with the wrong master cylinder, lol. I'm gonna drive it a few thousand miles next week and then bleed it again.

 
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