jbaum02

I'm in the process of an engine swap on my 2005 1/2 ton 4wd. The pull out engine I bought came from an escalade and included all the accessoroies and the ps pump had the extra port for the Hydroboost return so I figured I'd do the conversion along with the engine swap.

I picked up the Hydroboost, lines, and brake pedal from a local junkyard. I tried the install tonight, but ran into some trouble. The install thread I was following is here https://www.performancetrucks.net/fo...w-pics-441147/

It seems like most people are using their existing master cylinder. The Hydroboost I got doesn't bolt up to my master cylinder. The bolts are too narrow, and the part of the master cylinder that fits into the booster is too long.




Hydroboost bolt spacing compared to my vacuum booster bolt spacing.



This is the end of the master cylinder that came attached to the Hydroboost.



This is my existing master cylinder end.



This is the inside of the Hydroboost where the master cylinder fits inside.

I suppose I could use the master cylinder that came with the Hydroboost, but I'd rather not drain the brake fluid and chance having to make a trip to the dealer to bleed the ABS.

Are there different Hydroboost units that fit the different master cylinders?

LPCWS6

The hydro boost you got is from a older truck than yours. I'm not sure on the exact years but I think 99-02 used the narrower master cylinder and 03-06 used the wider ones. Your options are change the master cylinder, get a newer hydro boost, or say f_ck it and put it back the way it was.

jbaum02

Ok, thanks for the help.

I didn't make it to any of the local junkyards to see if they had anything else before the weekend. I did stop by an Autozone and they let me look at a reman they had in stock. There computer said it would fit my truck. The bore for the master cylinder was deeper, but the bolts were still the narrow spacing. So apparently there are several different configurations. I've got a little time to keep looking while I'm working on the engine swap since the truck isn't running anyway.

jbaum02

Still not having any luck finding a Hydroboost unit that matches the 4" spacing on my master cylinder.

Has anyone that's done the conversation had the wider master cylinder and knows the part number for the Hydroboost that matches it?

If I switch master cylinders can I just bench bleed it and swap them without worrying about messing up the abs module and needing to take the truck to the dealer to have the abs bleed? I'm still trying to shy away from this as the master cylinder I got from the junkyard is pretty nasty inside the reservoir. It's got a lot of black residue in it. How should I try to clean this out?