stephenwt

I apologize if this topic is addressed on another thread, but I didn't find one so I thought I would ask. I just purchased a 78 silver anniversary edition with a cammed 5.3 LM7 from an 02 Silverado 1500 and T-5 transmission. Because of the lack of vacuum I want to install a hydroboost hydraulic brake booster off the power steering pump. I thought this would also be a good time to replace the original cast iron master cylinder. I can purchase a new hydroboost specific for the 78 for approximately $450, or as is mentioned on several threads I can get a used one for approximately $25. For some reason, the most common source of these are Chevy Astro vans, but their push rods attach to the brake pedal differently and require a quite bit of modification to work. Are there other GM hydroboost models that use a clevis pin similar to those on C3s? And is there any reason to use a master cylinder other than the one that goes with whatever hydroboost unit I use? Thank you for the assistance.

ratflinger

Mine came off of a 3/4 ton truck and did not need to perform any mods to the unit. I am also using the master cylinder from the car. (79). But the Wilwood ones look so cool.

stephenwt

That certainly sounds good. Did the truck unit have a similar type of cletis pin to attach to the brake pedal? Where did you get your hoses?

ratflinger

Hoses can be custom made down at the hydraulics shop (they service large trucks, Cat gear, farmers, etc). It's been a while but either I used the clevis pin from the Vette or the hydro, thinking I used the one off the Vette, but in either case it was a no mod situation. One thing I wished I had done was to reverse the studs so that the nuts were in the engine compartment, making the booster easy to remove. Not exactly sure how that's done since the studs are press-in, but I know it's been done before.

v2racing

Mine came out of an Astro van. I just cut off the Astro clevis and cut threads in the remaining shaft. I threaded my original Vette clevis back on with a lock nut and it worked perfectly.

Mike

MN80Vette

I chose a Hydratech hydroboost and chromed aluminum master cylinder for my '80. You can spend a LOT less, but I liked the quality.
Hydratech chromed aluminum master cylinder

stephenwt

Has anyone added a separate power steering reservoir or is it not necessary? Is there isn't one, do you run the return lines back to the pump?

MN80Vette

I think using a T to run 2 return lines into one is pretty common. That has worked for me for years.

v2racing

I got new later pump for a truck with hydroboost. It has 2 return inlets on the reservoir. It doesn't fit the mounting bracket exactly, but not much of a problem to modify.

Mike