Hydro Boost conversion questions

[WHITEOUT]

So my brakes started acting up over the weekend, with pedal dropping to floor on hard braking. My mechanic told me my Master Cylinder (MC) is bad, so I need a new MC.
I ended up picking up a Hydro Boost setup. Came with Hydro boost, MC, pedal and all lines out of a 2002 HD 2500. Unfortunately he sold the motor with the power steering (PS) pump. I wasn't going to convert to Hydro Boost, but since this deal came up, just seemed easier to go the conversion route since so many like it. Hopefully is right decision to convert. anyways....

I have a few questions in regards to how and if stuff will work.

Will it be ok to use HD 2500 MC & Hydro Booster without using PS Pump off same vehicle? Can I use my stock PS pump with this setup?

Will it cause any issues? i.e. low pressure? over heating? enough fluid? ect....anything.???

Difference in MC between Tahoe vacuum boost MC vs MC hydro boost? I know each mount the same, but is bore/piston size, fluid rate, or pressure different?

Reason I am concerned or questioning, is most writeups I have read the installers are using the Hydro Booster no problems, but keeping there stock MC and stock PS Pump. Just want to make sure I will not run into issues later on? Install seems simple enough, but hopefully I should be ok using this new MC since my stocker is going bad.

Just want to make sure I am ok using the HD 2500 Hydro Booster & Master Cylinder with my stock Power Steering Pump?

Thanks guys, and any info you can give me in regards to this is greatly appreciated.

 

[yukonese]

From all the conversion threads I read, this set should just fit well. However, I'll consider a new or rebuilt MC. The seal in a MC breaks eventually (like yours). Since the 2500 MC is already 10 years old, how many more years it can last? I would do it now and pay once, rather than do it one year later and pay twice.

Don't forget the stainless steel brake lines.

 

[WHITEOUT]

appreciate the response bro. Ya, I will probably be getting a new MC tomorrow and be converting over to Hydroboost Sunday. I already have SS lines so this Hydroboost setup should really help.
As for Power steering pump, think your right, and it shouldn't be an issue. From what I have read also, main difference is not having low pressure return line, which I may just modify my reservoir and add on a a fitting. Or go simple by T'n into return line. Idk yet

I do have another question, hopefully someone who has done the Hydroboost conversion will answer!! PLEASE!! PLEASE!! !! PLEASE!!!

How much travel n force does your pedal take now compared to before? What MC are you using with it?

Why I ask is. Since I will be getting a new MC, I am trying to decide what master cylinder to go with. The stock 34mm( vacuums MC) or the HD's 37mm(HydroBoost MC)? From info I'm gathering, the 34mm should give more pedal travel, but less force to stop. The 37mm should give less pedal travel, but take more force to stop. Hopefully that makes sense to everyone. but since bore sizes are different, more or less fluid is going to flow thru the lines different, which affect pedal travel n stopping force. Just from research I've done on Web n talking with brake guys.
So not quite sure which one I want. Either way I know it is gonna be night n day difference from vacuum boost, what I have now. But just wanted peoples input on what they went with, and how it feels and how much pedal travel and force needed to stop?

thanks guys again, and hopefully someone will respond by tomorrow

 

[podwarrior63086]

http://www.gmfullsize.com/forum/showthread.php?t=156800&highlight=hydroboost

 

[WHITEOUT]

thanks bro, but have read that one a hundred times. very good info for anyone looking into doing hydro boost conversion. thanks

Probably gonna go with the 37mm MC. on my way to get one and start installing it all today.

 

[01Konvict]

I swapped mine and kept the stock MC. I didn't want to bleed a new one and get it all working. I just swapped the booster and put a T in the return line. Kept stock PS pump with no issues so far. Pedal travel reduced about halfway of vacuum. Overall an excellent swap and is easy to do at your house.

 

[yukonese]

I'm curious how much stronger the 37mm MC can do? It seems the stock MC (34mm) can do a decent job. But if the stock has to go, 37mm is an option. Besides SS brake lines, the ABS originally for 34mm can take the pressure from 37mm?

If the pedal travel reduces half way with hydroboost, 37mm MC will reduce the travel even more? 10%?

Which stainless steel brake lines are the most popular?

 

[yukonese]

37mm MC

Reviewed how hydraulic systems work:

If we just swap the 34mm MC with a 37mm MC, nothing else, the pressure will drop 18.4%, with the same pedal force. Because

P = F/A

P: pressure
F: force
A: area

That means we need to increase the booster power.

I think that explains why Wade cut the brake pedal travel by half after converted to the hydroboost. The bigger MC is used to relax the pressure, so that the pedal travel can be same as the vacuum one.

Any experts here?

 

[yukonese]

After reading a couple of articles, I can confidently say, if everything else is the same, 34mm MC needs less pedal force, but longer stroke; 37mm MC need greater pedal force, but shorter stroke. If 34mm MC stroke is not a problem after the conversion, I'll stay with it.