Hydroboost question

[Custom 68]

I am thinking about finally getting around to installing a hydroboost on my truck. I have the "boost" part and need a master cylinder. Some reading I found lead me to one off a 99 Tahoe which is where I think my parts came from. They have a diesel or the police package with the hydroboost.
The bore on this cylinder is 1.25 inches diameter instead of the 1.125 as I believe is standard.
I wanted to get to the new style master cylinder with the aluminum body and plastic reservoir as mine seem to always end up leaking and looking ugly. I currently have Wilwood D52 calipers on the front with stock drums on the back. Do you think this master cylinder is a good option? I thought the larger diameter would be better than the smaller diameter since I will have more boost. I know there are options for 7/8 1 and 1 1/8 bore.
If not this cylinder what would you suggest?
Also which on these cylinders is the front system and which is the rear brake system?

[BR3W CITY]

Take a look at my build and my "hydroboost rebuild " threads. I have a very similar setup, the only difference being that the M/C and booster came from an AstroVan.

I have an 06 hydroboost pump, 96ish van hydro unit, d52's, and a 71 steering rack. Install was pretty easy, and although mines not perfect it works pretty well. Only things I can ad, are that the unit puts out PLENTY of boost to lockup anything, I wouldn't worry about having too little pressure. They also overboost the steering a little bit.

[Custom 68]

ok back to the top as I need some help.
I got the master cylinder and the front and rear ports seem to be swapped. currently I have the large hard line on the rear port of my old master cylinder. I thought I had done my research and got a newer modern master cylinder for a 99 tahoe police package and had the hydroboost. It looks like these are swaped from what I need. What master cylinder can I use that is the newer aluminum and plastic? I will keep searching but was hoping for a quick answer I have this apart and wanted to go to a show this weekend and thought I could make it now I have hit a snag...
thanks
Dave

[dwcsr]

Look at Raybestos MC390542 its a hydra-boost for 4 wheel disc.
Material Type: Aluminum
Number of Outlets: 2
Primary Outlet Size: 1/2"x20
Secondary Outlet Size: 1/2"x20
Bore: 1.45"

[BR3W CITY]

Originally Posted by Custom 68

ok back to the top as I need some help.
I got the master cylinder and the front and rear ports seem to be swapped. currently I have the large hard line on the rear port of my old master cylinder. I thought I had done my research and got a newer modern master cylinder for a 99 tahoe police package and had the hydroboost. It looks like these are swaped from what I need. What master cylinder can I use that is the newer aluminum and plastic? I will keep searching but was hoping for a quick answer I have this apart and wanted to go to a show this weekend and thought I could make it now I have hit a snag...
thanks
Dave

I had to rebend some brake lines anyway, swapping the locations didn't seem like an issue.

[Custom 68]

Thanks Dave, I have disks in the front and drums in the rear so that one is probably out.

Brew, I will look thru your pics but if you have one handy could you post it for me?
I knew I had to bend my lines some but I have very short ones, I will go by my parts store and see if they have some longer ones as what I have now wont work.

[Custom 68]

I found your pictures, here is what I am dealing with.

[Custom 68]

Brew
Crisis diverted... lol Ok I used your advice and was able to bend some new lines. I now have the brake hardlines in place I got the wrong adapter fitting for my power steering pump I had a male fitting and assumed it was like the female on my bench. I will grab one today and hope to have things buttoned up tonight. When you only have a couple hours in the evenings it goes slower than hoped. No biggie it is about wrapped up I hope.
Unless I have made a gross mistake I will have hydroboost by tomorrow. It looks better than what I had I can atleast say that. Thanks again and I will keep you all posted.
Dave

[BR3W CITY]

I hadn't checked the thread in a few days, glad its coming together; I didn't have a prop valve where yours is, so I had longer stretches to manhandle around to get what I needed.

[Custom 68]

thanks with your input I thought outside the box and grabbed some longer tube and bent some to fit... anyway I was over complicating things and ended up with a quick change and it looks great.
I had a couple other unforeseen things I had to deal with. the fitting on my power steering pump was a funny male fitting rather than the female I had planed for. I was able to swap it out but it took some to get to as usual. We thrashed on it till midnight on Friday so we could drive a couple hundred miles the next morning for a show. It was alright and we finished bleeding them and jumped in and made it. Nothing like the maiden voyage to drive out of state.
I will post some pics. It turned out slick.

[BR3W CITY]

How does it feel? Mine took (and is still being fiddled with) a while to get the bias correct. I have un-cooled drums in back, under the M/T's, so the risk of heating and lockup is there. These put out soo much pressure you gotta be careful the first few trips out.

How's your steering? Are you getting any of the lightness in the front end?

Oh, last, are you getting any "bog" from the pump loading up the engine?

[Custom 68]

First off my pedal seems to "engage" the brakes lower than it did before this swap. I dont know if I said that right or not but I have a bit more pedal travel than I did. I was in a rush to finish so I could drive it to a show and have some fun so I am going to bleed them again I dont know it that may be part of the cause. However it is very predictable. I swapped master cylinders to one on a 1996 Tahoe with hydroboost It seemed to be the right choice. I had read something about take up or something? But all seems to be working good on that end like I said I think bleeding may bring my pedal up before engagement some.
I also have drum brakes rear, I like you am still adjusting some. I have a gravel drive way and the rears lock up quicker than the fronts still this is at a crawl speed, on dry pavement I have not jammed them on super hard but they do seem great.
I have not noticed any difference in my steering It does not seem like it is lighter and no jerking as I can tell yet.
I have not felt any "bog" from the steering as of yet either. I am still in the early stages.

I used AN -6 fittings and PTFE stainless braided lines with a 3/8 rubber line with a Tee fitting right before it all dumps back into my pump.
I will re-bleed and keep you posted. So far so good.
Thanks
Dave

[BR3W CITY]

cool cool. Thinking about it, since your turbo 5.3 is probably using a less agressive cam AND a manual trans...it might explain why you don't get the bogging. My low-lsa cam and heavy auto trans means less-than-ideal conditions on sudden decel and load up.

Be careful with the brakes. Mine felt good at 20-40 on dry land, but one near miss on the freeway had me rethink that. Rear end goes away really easy under lockup, I need to either put discs out back, or redo the bias again.

My pedal also feels "lower" than it did on the manual discs. I've got a linelock also, and chase my bleed all over.

[Custom 68]

my cam is a Lingenfelter GT2-5 it is a 222 222 with a .566 lift on 112 it is less than ideal with the turbo I am sure but it is what I was running before the turbo addition. Yes I am sure with my Manual transmission it also helps. I have a bias valve for my rear brakes that is adjustable you can see it in the picture above just below my disk/drum prop valve I can just loosen or tighten it up. I "loosened" it just a bit more this morning to keep the rear from locking. I will keep turning it.
Thanks for the advice I will get a few pictures up and keep working with it and bleed them some more. I am going to drive this as much as I can... We head on the 3000 mile power tour in a couple weeks. So far it is working good and helped clean up that corner under my hood.

[allons]

Originally Posted by BR3W CITY

cool cool. Thinking about it, since your turbo 5.3 is probably using a less agressive cam AND a manual trans...it might explain why you don't get the bogging. My low-lsa cam and heavy auto trans means less-than-ideal conditions on sudden decel and load up.

Be careful with the brakes. Mine felt good at 20-40 on dry land, but one near miss on the freeway had me rethink that. Rear end goes away really easy under lockup, I need to either put discs out back, or redo the bias again.

My pedal also feels "lower" than it did on the manual discs. I've got a linelock also, and chase my bleed all over.

Since you've been through the 'hydro boost' learning curve, I could use some wisdom on my build. Mine is a ground up resto-mod with a 350 RamJet, Tremec 5 speed, Moser Posi 3.42 and 4 wheel discs. The only thing that I've really done different is I've put an electric hydraulic pump from a Mercedes to drive the hydroboost, and get it off the engine. What do you think?

[Custom 68]

I had the pump for my power steering already and didn't know how much more the brake system would take. I am sure your electric pump will help all that anyway.
The only thing I would suggest is to get a master cylinder off something that came with hydroboost. The cylinder bore is larger and will keep the brakes from feeling touchy. At least that is what I did and think. You could probably go with one off a new tahoe police package, they had hydroboost. I would get one that the truck it came from had disk disk configuration.
I went with a 1999 Tahoe police package master cylinder, it had disk drum configuration.

[Custom 68]

It does sound like you have a nice rig in progress.
Also I just went to Speedway motors and bought their adapters to go from the pump, booster, steering fittings to a -6 AN fitting, then I got the correct hose and fittings to go in the end, I cut my hoses to length and fit it all together it is much better than chasing around factory hoses plus I had metric fittings on my hydroboost and with these that problem was solved.
Good luck
Dave

[allons]

Originally Posted by Custom 68

It does sound like you have a nice rig in progress.
Also I just went to Speedway motors and bought their adapters to go from the pump, booster, steering fittings to a -6 AN fitting, then I got the correct hose and fittings to go in the end, I cut my hoses to length and fit it all together it is much better than chasing around factory hoses plus I had metric fittings on my hydroboost and with these that problem was solved.
Good luck
Dave

Thanks for the hose tip. The Mercedes pump is metric for sure, but I don't know what the fittings are on the hydroboost. I was thinking about 'custom' hoses that I can have cut-to-length that I can get the fittings crimped on and routed the way I want them. Thanks, Jim

[BR3W CITY]

Originally Posted by allons

Thanks for the hose tip. The Mercedes pump is metric for sure, but I don't know what the fittings are on the hydroboost. I was thinking about 'custom' hoses that I can have cut-to-length that I can get the fittings crimped on and routed the way I want them. Thanks, Jim

The setup sounds fine, if you can keep an eye on 1 important factor; how much amperage does the pump draw?

If its got a reasonable draw, then by all means it sounds pretty good, provided you can get ample return to it, so it doesn't foam etc. The hydrobooster build SERIOUS heat, and I would want to make sure any part I was using was capable of taking said heat. You may want to consider a p/s cooler if its a concern.

Other than that, the idea is pretty interested. If I were building a drag car again, I'd consider switching to a manual rack and just running the e-pump for brakes.

now i'm thinking.....

[allons]

Originally Posted by BR3W CITY

The setup sounds fine, if you can keep an eye on 1 important factor; how much amperage does the pump draw?

If its got a reasonable draw, then by all means it sounds pretty good, provided you can get ample return to it, so it doesn't foam etc. The hydrobooster build SERIOUS heat, and I would want to make sure any part I was using was capable of taking said heat. You may want to consider a p/s cooler if its a concern.

Other than that, the idea is pretty interested. If I were building a drag car again, I'd consider switching to a manual rack and just running the e-pump for brakes.

now i'm thinking.....

The pump runs on a 12V supply and has wire gage and safeties like you would for electric cooling fans. Power does seem to be an issue, but I'd like to know about the heat issue. Mercedes used to run its PS and PB off this pump but they have recently upgraded to electric steering.

Can you tell me more about the heat issue? Thanks, Jim

[Custom 68]

I have heard they can get hot too not sure what is all happening inside the boost part but I am going to add a small power steering cooler this weekend. Cheap insurance.

[allons]

Originally Posted by Custom 68

I have heard they can get hot too not sure what is all happening inside the boost part but I am going to add a small power steering cooler this weekend. Cheap insurance.

I know that when something gets compressed or pressurized it generates heat, so I guess my question is 'how much heat', and 'is it manageable'?

What kind of heat exchanger are you going to use? I'm thinking of using a passive heat-to-air exchanger and putting it in the airstream, maybe along a frame rail. What are your thoughts?

[BR3W CITY]

I'm not running a cooler at the moment, but considering it.

The lines coming out of the booster unit can get hot enough to not want to touch (but not hot enough to really burn). I would say maybe *105-115? Like when your a little hungover and turn the shower on, then get in without adjusting the temperature.....weird analogy, but hopefully you get the point.

This heat is not generated at all times, it primarily occurs when you have it "loaded", meaning the unit is working to move fluid, and not just sitting allowing fluid to pass through. I don't think at any time it gets hot enough to risk boiling or compromising the fluid, unless there was an additional mechanical problem in the braking system.

[allons]

Originally Posted by BR3W CITY

I'm not running a cooler at the moment, but considering it.

The lines coming out of the booster unit can get hot enough to not want to touch (but not hot enough to really burn). I would say maybe *105-115? Like when your a little hungover and turn the shower on, then get in without adjusting the temperature.....weird analogy, but hopefully you get the point.

This heat is not generated at all times, it primarily occurs when you have it "loaded", meaning the unit is working to move fluid, and not just sitting allowing fluid to pass through. I don't think at any time it gets hot enough to risk boiling or compromising the fluid, unless there was an additional mechanical problem in the braking system.

That makes sense! Work generates heat also. LOL

Anyway, I think that to be on the safe side, I'm gonna put in a passive, pass through heat exchanger. This is good stuff, it's nice to share ideas.