Hydroboost Questions

[icanfixall]

I just bought the boosters for my changeover to the hydroboost system. I got a good deal on a 1999 booster and a great deal on a 2005 booster for 99 cents.... Anyway what are your thoughts about master cylinder bore size? I have a new 1 1/4 inch bore master cylinder and it fits the mounting end of the booster fine. No opening up the holes. I know some here feel if we installed a 1 1/4 or 1 5/16 inch master the brake peddle would be harder to press down and we would get less braking pressure to the original vacuum system. I don't feel thats true but anyway what will happen if I use my original 1 1/8 or a 1 1/16 bore master cylinder? Easier brake peddle effort and feel? My thoughts it would feel like air brakes. By that I mean when you apply air brakes all your doing is opening an air valve so more air reaches the system. It not like hydraulic brakes that require more foot effort on the brake peddle. I'm interested in your thoughts but be able to back up what you think. I just need more information for knowledge. Thanks....

 

[Exekiel69]

I can't comment for the others but I used the one I had in the truck and it works just fine.

 

[typ4]

I filed the holes out and used the original to the truck, I did the math on the hydraulics and the bigger one would not work well with a tow rig , to much pedal pressure to do the work. I also had to move the push rod point up a little to keep the hydro shaft in line throughout the travel.
my 2 c

 

[Exekiel69]

I filed the holes out and used the original to the truck, I did the math on the hydraulics and the bigger one would not work well with a tow rig , to much pedal pressure to do the work. I also had to move the push rod point up a little to keep the hydro shaft in line throughout the travel.
my 2 c

I didn't do that (not a surprise ), please explain some more with a pic if possible.

 

[Mr_Roboto]

Here's my thought, take it for what it's worth.

With hydroboost you could probably increase the MC size considerably and be able to stop with little pedal effort. UNTIL you lose a power steering belt and you have no assist.

In my line of work I see the "what ifs" become reality every day.

 

[icanfixall]

The psssibility of loosing a serpentine belt or V-belt is always possible. I have lost the belts before and yes its very hard to get any braking power. I feel like I'm going to pull the steering wheel off the colume. But continued foot pressure will create some braking. Its just really slow in coming. The hydroboost system was designed for the 1 1/4 and 1 5/16 inch master cylinders so all things equal it will work using them. I just wanted to see what the thoughts on using a smaller bore master cylinder. I value others comments and lots of times I learn something I hadn't thought too much about.

 

[jauguston]

Icanfixall,

That hydroboost was designed to operate a "complete" brake system that included a 1 1/4" bore master cylinder. The wheel cylinders and caliper pistons are sized accordingly.

You would be wise to not try and overengineer the swap and change only the booster and keep the rest of the system as it was designed.

Jim

 

[Exekiel69]

If You loose a belt You'll know and the hydrobooster has a reservoir there to power the brakes a few times even after is looses the power steering pump.