Hydroboost

[Tin Man]

I just finished up a hydroboost conversion last night. It is incredible. I held 15 psi on the footbrake with no effort. I bought the car with a failing PM so I cannot compare to a properly working PM. I converted to vacuum and it was ok. I rebuilt the motor with a 215/220 cam and I was only pulling 10-12" of vacuum. I could build 0 boost on the line. The HB conversion was pretty simple. The only fabrication was to the firewall bracket. I used the PM bracket as it has the correct angle to keep the unit from hitting the hood. I will post the details with part numbers and the fab needed, etc.

The unit came from a 1995 Chevy Astro van. I paid $46 for the HB/Master cylinder and $190 for all the fittings/lines, etc. There are companies that sell a ready to bolt on kit for between $650-$800. I am on a budget.

Zac

 

[SVORay]

Nice


So where is Hays county Texas anyways

 

[Tin Man]

HB continued

A lot of off-roaders have been doing the conversion. HB units are used on a lot of new vehicles today. Most 2500 series and up GM trucks have it, Avalanches, Escalades, and the Ford Mustangs get them. Supposedly, the heavier the vehicle the better the system is at stopping them. The color of the accumulator (nitrogen reserve) correspondes with the weight of the vehicles. I researched that the Ford is the weakest of the systems. I do know that the GM hydroboost have a nut that allows you to remove the bracket. New GM units run about $350 from the dealer. There are bargains to be found.

Safety wise, the units use an accumulator or nitrogen reserve that allows you to have brakes in the event of failure. From my research, you get about 3 pumps of the brake. The first being at about 77% braking efficiency (still better than vacuum) and it lessons from there.

 

[yullose]

So what did you use for hydraulic pressure ?

Did you Tee into the factory TR PS pump pressure line ?

 

[Tin Man]

HB continued

Bracket fab: The buick firewall angles upward. The GM HB units have a flat bracket. I am pretty certain that this angle would place your MC into the hood. I used the PM bracket as the angle slopes down to put the unit level. The fab needed was to heat the center section and hammer it flat. There is a slight raised lip around the hole. You will need to remove or cut out the 2 studs that the PM used to mount to (you don't need them to mount the HB). This will allow you to get a hammer in to flatten the lip. Once that is done, if you try to put the bracket on the HB unit you will see that the bracket has too much play on the unit. I welded arounded the hole building it out until it would not fit on the HB. From there I used a grinder until it fit perfectly. This allows the retaining nut to fit perfectly flat and have entire surface area to rest up against. I am told there is a specific socket/wrench to fit this retaining nut ($150). You have limited space as there are 4 studs to mount to the firewall in the way. I used a pipe wrench to get it snug. I also cut some grooves in the nut to allow me to get a screwdriver in to hammer it tighter. I used a liberal amount of locktite.

You can now test fit the unit. I found out that the HB is not compatible with the vacuum brake peddle. It does line up with the PM peddle. Swapping peddles is not fun. Search this site for details on how to do this. As far as fabrication, the arm that attaches to the brake peddle is too long. I measured that I needed to shorten it by exactly 1 1/4". Your results may vary. The rod on my unit is crimped into place, so i cut the length out while on the unit and rewelded it.

That is all the fabrication needed. It is a pretty simple do-it-yourself project if you have the tools. I would not imagine it would cost too much to have someone do this for you.

 

[Gbodyolds]

sounds like a neat little project, did you consider finding a Hydroboost setup off a G body rather than fabricating ? or is there something less desireable about the G body Hydroboost setups ?

 

[Tin Man]

Fittings

My cars (1987 GN) power steering fittings are all o-ring fittings. I purchased my fittings from Summit. There are 2 pressure lines running from the HB unit.

To connect the HB passenger side fitting I used a male 18mm x 1.5 o-ring to -6AN adapter, attached a -6AN hose end with 90 degree angle to -6AN PS braided teflon hose. I cut the hose to the appropriate length and attached this line to the PS pump. I cheated a little here. Instead of going directly to the pump itself (16mm x 1.5 0-ring) you can attach to the end of the factory hard line. It is a male o-ring fitting. I used a 16mm "female" to -6AN adapter, attached to a -6AN hose end with 45 degree angle, to the -6AN hose. That takes care of this line.

The other HB pressure line (driver side) used a male 16mm x 1.5 o-ring to -6AN adapter, attached a -6AN hose end with 90 degree angle to -6AN PS braided teflon hose. Cut to the appropriate length and attach to the PS gear box. The fitting on this end (into gear box) is a male 18mm x 1.5 o-ring to -6AN adapter, -6AN hose end with 90 degree angle to the -6AN braided PS hose. You are now done with the pressure lines.

Return hose. This is a rubber hose that is hard to find locally. I have heard that heater hose will work, but I just ordered from Summit. Get the appropriate length of 3/8" inch hose and attach one end to the HB unit with a clamp. Route the other end near the PS reservoir. I researched and used a brass 3/8" tee fitting. You can get them on the net, but I got mine from a local hardware store. You can get these in the plumbing supply area. The orientation is supposedly important. The HB return line should go to the post that intersects into the tee (not the straight through path). For the other two posts on the tee, you are going to tee into the return line that runs from the reservoir to the gear.

That is pretty much all there is too it. There is bleeding procedure for the power steering as well as the master cylinder. I can post all specific part numbers if people want them as well as pictures. Remember these are brakes and it is important that they work correctly. Do not undertake this if you are unsure of your abilities. I hope this is of help to someone.

Zac

 

[Tin Man]

SVORay, Hays County is south of Travis County (Austin). I am not in a city but between Kyle and Driftwood.

yullose, did the rest of my posts answer your questions? I did not want to cram it all in one post.

Gbodyolds, the new designs are supposedly much superior and the rebuilt units are hit or miss.

These new units are capable of putting out 1500-2000 psi. Twice that of vacuum systems.

I will be racing at Noble for the Buick vs Ford race this month for anyone wanting to check it out.

 

[Brer Rabbit]

So what was the total cost?

My buddy and I are going to do this conversion also so I was wondering what the dent on the wallet was the way u did it?

 

[Tin Man]

Brer Rabbit, I am into it for about $250. I saved a lot from getting the used 1995 Astro unit. I have seen brand new in the box GM units sell for about $200. So for a new unit at $250, roughly $200 for the hoses/fittings, and if you bought a new master cylinder $50, you could have a new system for around $500. DIY would save you a little money over say Hydratechs system, but the Hydratech may be worth saving the headache of ordering parts, fabricating brackets, etc.

Going used for $250 over $800 was a no-brainer for me.

Zac

 

[SVORay]

SVORay, Hays County is south of Travis County (Austin). I am not in a city but between Kyle and Driftwood.

Thats my last name is why I asked...thought it was funny. If I'm every in the Austin area, I'll have to check it out.

 

[Tin Man]

Ray, the County seat is San Marcos. Home of Texas State University (formerly Southwest Texas State University).

I was in West recently for the Czechfest.

Zac

 

[Gbodyolds]

can you post some pics ? I'm wondering if the lines from a Hydratech kit might allow a little more of a plug and play setup. you mentioned that you used a modified part off the powermaster but what is someone to do when they are converting from a standard vacuum brake setup

 

[Ormand]

Summit has them for the GNs/Turbo Regals. They are $550 complete, or you can spend more and get powder coated or chrome. That includes the master cylinder, and the hoses, and the mounting hardware. Pretty good pictures in the Summit web catalog.

 

[Ormand]

There's a thread on one of the corvette forums about using hydroboost, or hydraboost. One guy in Canada had bought a used unit off a truck for $50 (canadian) and installed it on his 'vette. It's compact, so the 'vette guys like it if they using big blocks and/or tall valve covers. The $550 for brand new, from Summit, or $50, plus hoses, for parts from a salvage yard? Would be nice if somebody would write up the "how to". Tin Man?

 

[Tin Man]

I discovered how much boost you can hold on the footbrake with the hydro system. Answer: more than the stock tranny can take. LOL I was in the driveway at about 18 lbs and climbing, the car was rock steady and boom. The tranny has no forward or reverse gears. I dropped the pan and there are no big pieces of metal. I had spline wear on the input shaft when I reinstalled the motor not too long ago so this may be the case. Going to drop the tranny this weekend and see.

 

[mhogan6]

trans

I discovered how much boost you can hold on the footbrake with the hydro system. Answer: more than the stock tranny can take. LOL I was in the driveway at about 18 lbs and climbing, the car was rock steady and boom. The tranny has no forward or reverse gears. I dropped the pan and there are no big pieces of metal. I had spline wear on the input shaft when I reinstalled the motor not too long ago so this may be the case. Going to drop the tranny this weekend and see.

No forward/reverse. Sounds like the stator support splines are gone.
Hope you can get it fixed for Noble. Our man Keith can fix it,but prolly not that soon. I got a loaner trans(10 sec.) if that'll help. PM me for cell ph#.
Mike.

 

[Tin Man]

PM sent Mike.

 

[POWERBRAKEBOB]

Hydroboost Conversions

Hi Guys. Power Brake Bob Here. A Year Ago, I Was Talking About The Hydroboost Conversion And How Well It Worked, But I Was Shouted Down Pretty Hard By The Vacuum Booster Proponents. We Have Been In The Power Brake Business For 56 Years, And Have Rebuilt Many Powermasters, And Also Did The Vacuum Conversions. We Had Nothing But Complaints, And Lost Friends When They Were Not Satisfied With The Vacuum Booster. We Are The Only Company Authorized By Bosch, (the Successor To Bendix) To Sell New Hydroboosts Outside Of The O.e.'s. I Proposed The New Hydroboost Units 3years Ago Here, And Then Gave Up With All The Bickering. We Have The Correct Brackets, A New Hydroboost Unit, And Prefer Stainless Hoses, But Others Can Be Used. Besides The Performance Of The Hydroboost, It Also Uses The Same Pedal Ratio As The Powermaster, Saving That Changeover. Master Cyls Are Easily Replaceable, Ands New Units Last 200,000 Miles. If You Want Bigger Brakes, Or 4 Disc, The H/b Easily Handles It. With Your Foot On The Brake, Bringing Up The Rpm Also Speeds Up The Pump, Locking The Hydroboost On Harder, The Manifold Pressure Keeps Going Up, And Even The Stall Speed Of The Converter Can Be Surpassed. All Of This Makes The Car Leap Off The Line. One Guy Called, And Said He Was In The Points Standing At The Drag Races, But Lost Out, As The Car Creeped Three Times And He Redlighted Away His Position We Do Have Reman Units For Those Guys On A Budget.

 

[POWERBRAKEBOB]

Hydroboost Conversions

I Saw The Comment On The Availability Of Hydroboosts From Summit. We Supply Them.