Hydroboost on a 58 -59 3100

[dwcsr]

I decided to use a hydro-boost brake system after seeing one of the other posters here put one on a later model. I researched the parts and found a 2001 Chevy Silverado 1500 w/4 wheel disc had hydro-boot. This setup is from the 2001 Silverado with four wheel disc so if you are going to do this conversion with rear drums you need to get the master for rear drums.

The booster unit is an A1-Cardone # 52-7359 this comes with a diagram to connect the hoses correctly.
Brake Master Cylinder is Raybestos # MC390542 it’s new and comes complete with reservoir and cap Don’t get the MC390541 its for a vacuum booster. Don’t ask me the difference I didn’t see it but Raybestos says the 542 is the one.

You will need to get the push rod, pushrod spring and the spring retainer that goes between the master and the booster it does not come with a rebuilt unit. I did get a complete unit from a junk yard with master for $75.00.
The other items are Hose kit for the P/S lines going to the booster unit and P/S unit. Pump to booster hose you can use if you don't want the expense of AN type fittings and lines is an Edelman 92082 and some Russell P/S fittings -6 AN x M16x1.5 O ring fitting for the pressure out side of the booster to the rack. The M18x1.5 was for the pressure in side of the booster.

I ended up using some Aeroquip AN -6 to metric adapters M18x1.5 and 2 M16x1.5 with O rings which were made of steel rather than aluminum the Aeroquip fittings also had a taper on the end to help keep the O ring in place which the Russell ones didn't. This may not be a problem for some but the O ring on the Russell kept getting stuck in the bore or falling out completely when I was test fitting all this. The advantage to the Russell was half the cost of Aeroquip. I also use -6 AN fittings and hose to plumb the pressure side of the install.

We also need a Heidt’s adjustable P/S valve PS-114 so we can have full pressure to the booster but reduced pressure to the rack. The 86 TBird rack uses 600-800 psi. If we run full 1500 - 2000 psi from the GM pump to the Ford rack it will eventually blow out the seals and leak it would also be very touchy at higher speeds. So we put the Valve in the lines to reroute some of the pressure back to the return side of the pump.

Brake proportioning valve for 4 wheel discs or an adjustable. I used a Wilwood adjustable valve with an LBS (Lock Resistant Brake) valve from Larsen Racing it helps keep the fat tires on the back from locking up and spinning you around on wet or damp pavement. Metric nuts M10x1.5 to bolt on the master cylinder and some fender washers to bolt it to the firewall with.
You will need some lengths of brake line. I used copper/nickel line that is DOT approved and very easy to work with, you honestly can’t screw up a flare with this stuff unless you forget to put the nut on first. It flares very well, it bends nicely and you can give it a polish to a golden color. www.fedhillusa.com is the US supplier. It is a little more expensive but the advantages make up for it the cost

At the same time I’m doing the booster I am also fabing a brake pedal because I’m to cheap to buy the one at classic performance so I will include the How-to on that as well.

Here is the boost unit and as you can see the mounting plate is heavy enough to use without modifying it.

[dwcsr]

The output pushrod, retainer and spring is for some reason not available thru GM, in fact if you go looking for it they will undoubtedly tell you that either Gm has not used Hydroboost since the early nineties or that they never put it in a 1500 pickup. They may even ask for a vin # because they can’t do anything without a vin #. Call the junk yards and say “you gata hydraboost for a 2000 silveraada” they say “yup” you say “ow much” they say “75” you say “yank it I’ll be over”. Now that’s a transaction, nobody wasted time and we both got what we wanted. I got the spring retainer, spring and rod out of the junk booster. I’m sending the old booster back for a $50 core charge so I really paid $25 for a used master and the rod and spring.

The spring and rod are an important part in the system; the spring puts tension on the booster piston so it releases the pressure on the rod and doesn’t stay engaged to the master and drag the brakes when you let off the brakes. The disc on the inner end keeps the rod centered in the booster rear cup and the retainer of course keeps the spring in but also centers the rod to line up with the master cylinder indent. If the rod were to drop out on either end it could cause your brakes to apply and not release in a panic stop of just plain fail. So if your fabing these pieces remember these dimensions are for a 2001 Silverado 1500 with 4 wheel disc brakes, the Hydroboost and master cylinder are for the same truck.
I have no idea if the rod and spring is the same for any other year or model truck.

Rod diameter 0.34” with a length of 3.16” it appears to be as hard as a grade 8 bolt.
The rear spring disc is .970” diameter with a thickness of .040” and placed .25” from the inner end and it is made of plastic.
The spring is 4” long and .945 diameter. The wire thickness is .073. It feels like a 20 – 25
Lbs. spring tension.

[dwcsr]

I lined up the mounting point between the brackets on the dash support and started to drill the bolt holes in the firewall and then used a cutter for the center hole. I used the fender washers and nuts to secure it to the firewall. You need to have it close to center of the dash support and far enough away from the engine.

[dwcsr]

The Dash support bracket needs to have some way of hanging the pedal. So I cut out 2 side panels so the pedal has a mount point.
I tacked in the plates and drilled a hole for the pedal pivot. I temporarily used a piece of copper tube to hang the pedal. You may have to fab a pedal or you could get luck an just used one that is close to the dimensions you need.. Because I have a recessed firewall I had to make some bends to mine and decided to fab one complete.
The pedal is from a 77 and it gives me a rough idea of where the new pedal has to go and what bends I need to put into it. We also need to put in some bracing because as its just to flimsy for the stresses of a brake pedal.

[dwcsr]

I ordered some steel from onlinemetals.com the list is below.
1018 - FLAT BAR COLD FINISH 3/8" x 1-3/4" CF FLAT
4130 - ALLOY TUBE ROUND 3/4" OD x .1875" WALL
BRASS TUBE - ROUND SEAMLESS 7/8" OD x .065" Wall
A36 - HOT ROLL SHEET / PLATE 0.1875" A36 Hot Roll Plate
A513 - TYPE 5 STEEL TUBE DOM 1.25" x 0.188" Wall DOM

The following is the pivot and swing arm being made?
I drilled out the outershaft to accept the brass bushing and drilled out the brass bushing to accept the center rod then tapped the rod so it will bolt in the dash support.

[dwcsr]

More of the pivot fitting the center rod tapping the rod for 7/16 course.

[dwcsr]

The outer shaft welded and hung for mockup. Where it’s close to the dash support I needed to put a bend. The Hydroboost only has a 3” throw so I don’t need to worry about bottoming out against the firewall and running out of brake pedal.

[dwcsr]

I will have more later on connecting up the plumbing for the hydroboost to the GM P/S pump and a TBird rack. It appears that I may have to move the booster over to the left about an inch.

[Jebb1978]

You are Awsome man!

[dwcsr]

Thanks,

I have some pics of the brake line tubing I used. I made a bracket to mount the adjustable proportioning valve onto the booster. I cut it out and bent it on my new sheet metal brake. The $200 brake from Harbor works well for the money.

Next on the list to do is to make a drop down arm on the pivot to connect the booster push rod. I'm going to leave the lower end of the pedal arm the way it is until I get it into the other cab with some type of seat.

[dwcsr]

I installed the Pump to booster line. it was for a 2001 silverado and fit perfectly. I had to tweak the pump end a bit but not very much at all. This is what the fitting end looks like. Its called "standard O-ring Flare". The heidt's pressure valve as I said before is to reduce pressure going to the rack by bypassing some pressure back to the return line.

[dwcsr]

While I'm waiting on the rest of the P/S fittings and hose to arrive I braced the dash support and it as done as it get before i insatll it. It just needs to be wire brushed, smoothed out and painted. I put some bends in the back brace to make it more ridged and the right side brace is very close the the pedal arm so I may have to give the pedal arm a bend. We'll see how it fits in the new cab. Once in the new cab I will weld on the arm for the booster rod. One note of interest is that after the back bracing is welded in you either have to remove the booster or the light switch and choke cable to be able to swing it into place.

[Jebb1978]

Thanks for the pics, I am going to use that line for sure. I have had nothing but bad luck with bending these in the past. They have always functioned but have a little kink to them. Yours look awsome.

Can I ask why the loops in the brake lines? I bent new lines for one of my old cars and didn't do it. Had no issues with braking but the factory lines I replaced were looped. I figured it was to use up the extra line but now that I know you custom cut yours I am thinking there is more to it????

[dwcsr]

I was always told that it helped absorbe vibrations so the line would not crack, but I don't really know if thats true. The lines have been that way on most cars and trucks I've owned so I just do it. It may be there when they are first built the truck so they have a little flexability on the assembly line.

The loops in mine were made by wrapping it around a 2.25" pipe. Try that with regular brake line.

[Jebb1978]

I agree with the theory that if they do it from the factory then there must be a good reason for it. I will do them that way when I bend my new ones just to make sure.

Thanks!

[dwcsr]

One thing to remmeber is that this copper nickle line will work harden, so try to get the bends the frist time around.

[dwcsr]

Just some notes I researched while waiting on parts.

The rear brake line port on master cylinders are not the same through a maker or style, some will have different size thread and some have the same size threads. Some have rear port to the rear brakes and some have front port to the rear brakes. I must have searched 400 sites before I saw a pattern.

The easiest way to tell visually is the size of the bowls. Larger one goes to the front Disc and in the event of same size bowls the rear brake port will have a residual valve in it and a larger brake line if it’s a Disc/Drum system. The master cylinder ports on most late model cylinders have a built-in residual valve in the drum side. Early drum/drum have one in each port. It needs to be removed on a Disc/Disc system. Disc/Disc corvette master cylinder is rear port to rear brakes. It seems that falls true for all disc/disc systems but I can't say for sure.

On the Disc/drum system there needs to be a residual pressure on the wheel cylinder pistons so they don’t return completely as you let off the pedal and sucking the pistons back into the wheel cylinder bores away from the shoe push rods. This would make for a low or slow responding brake application because it has to push the wheel cylinders piston out to contact the push rods and then engage the drum and then build line pressure to engage the discs. The residual valve keeps the wheel cylinder pistons extended and in contact with the push rods to the point that 10 psi of back pressure is needed to retract them and they will not be sucked back in when letting off the brakes as the fluid moves backward into the line.

Disc/Disc does not have this problem because the resistance of the big o-ring against the caliper piston is greater than the vacuum created by letting off the pedal. The disc out of round actually pushes the piston back in. there is one exception with GM low drag calipers which retract further than normal. They were early 80's cars and possibly trucks.


In the first pic you see restrictor plate in the rear port; the residual valve would look much like this. In the port hole in pic 2 you see nothing.

[dwcsr]

I plumbed the Hydroboost today. The pressure circuit goes from the pump to the Hydroboost unit from there is splits to full pressure to the Heidt's pressure bypass and to a return line that also goes to the bypass valve. It comes out of the pressure side of the valve to the rack and the return comes out of the bypass to the pump return. The rack return also goes to the pump return. I put a gage into the rack side of the bypass so I can dial down the pressure to the right PSI. This gage can also be used to test brake pressure when they are applied. It came with several adapters for brake cylinders and disc's and is a 3500 PSI gage.
Once the fenders are on I'll trim up the line lengths as anchor them properly.

[dwcsr]

I needed some line separators for the PS hoses and the prices for the ones I wanted were $12- $15 each. I needed 4 and it seemed like a lot for what they are. I had some aluminum stock and this is the result. $2.00 in metal and 3 hrs time. I drilled the sizes I needed, cross drilled and tapped a 10-32 hole for a stainless steel screw to hold the halves together. Then cut each off the stock, then cut them down the center. I used a mill file to shape them and sand paper to smooth the out. Once they are polished on the buffer they will look just like the ones I wanted. If you make these just remember to drill a larger hole in the top half so the screw will slide in and screw into the bottom.

[Kabwe]

dwcsr,

My buddie just put a hydroboost on his 56 Bel air and man that thing stops on a dime now. He is just trying to make me spend more money on my 55 210, because I am going to do this upgrade. I could not believe the difference.

[dwcsr]

When they first came out they could be scary as hell. When I moved to Houston from CT we had a Ryder truck with the hydroboost on it. we found out coming down the back side of the Black mountains in TN when the belt slips you could either steer it or stop it but not both at the same time. My then 19 yr old son was driving and came of onto an exit to fast we damn near rolled the 24ft truck with car attached.

Jump ahead 8 years and they have really go it working well. I have it in my one ton van and it stops great for the size. It almost doubles the line pressure to the wheels. Its std on most all sierra from 99 up w/ 4 wheel disc.
Its great for those low vacuum long duration cams.

I just got a Dodge P/S cooler and BMW remote fluid canister to replace that big alumnum one I have. once its done I'll post the final pics with the vendors for the fittings and odd stuff with the numbers and costs I have.

[dwcsr]

I changed the fitting on the return line from the booster unit from the straight up nipple to an -6 AN fitting. Part numbers and pics are as follows.

For those who didn't know JIC fittings is the equivalent to -AN fittings. 37 degree flare. A BOSS fitting is one that has an O ring boss with a nut that tightens the fitting I used it on the return from the unit to the reservoir. It is pic #4 below which is a BOSS on one end and JIC on the other.

If I didn't mention it before -AN fittings are measured in 1/16 increments. -6 AN is 6/16" and -4 AN is 4/16" and a -20 AN is 20/16" or 1-1/4”. Most -AN is measure by ID, -8 AN is 1/2" hose. Teflon hose seems to be measured by OD so a -6 AN, SS covered, Teflon lined hose is actually 5/16" ID hose and a 3/8" OD so remember to get hose ends for Teflon if your using Teflon lined SS covered P/S hoses.

One important tip is to not tighten up the hose fitting to working pressure spec until you are sure that the length and position are correct. The ferrules can't be reused and are not cheap or easy to get from Jegs or Summit. Hoseandfitting.com has them @ $2.75 each. So just snug it enough to hold the line while you work with it. After your sure it s right tighten it up. The ferrule is cone shaped and holds the braid between it and the nut and when it’s tight it crushes onto the Teflon hose locking everything together that’s what allows the 2500 PSI working pressure and 9,000 PSI burst. You don't want a hose end blowing of on the highway because you tried to reuse a ferrule.


From Hoseandfitting.com

Male JIC x Male BOSS 90 Degree adaptor
6801-04-02-FG - $4.80 this is the adaptor that screws into the return line threads in the booster unit. It needs to be drilled out to the size of the stock straight nipple. I suggest you buy 2 the drill is most likely to break and you will have to dig it out if you can. It’s a forged fitting so use a good bit.

Female JIC x Male JIC adaptor
2406-04-06 $2.45 this adaptor make the above fitting into a -6 AN fitting so you can run the -6 hose and fittings back to your reservoir.

Parker-Hannifin
090-6B Brass ferrule $2.70 each. these are for the reusable Teflon 90 series fittings -6 AN
20090-6 -6 AN Nut for the -6 line. $4.87 Steel.
06-SS $2.55 /ft This is -6 AN 5/16 ID 3/8 OD Teflon lined stainless covered hose. This hose is a bargain same as Jegs and Summit at 1/3 the cost.

Russell performance
620411 Endura hose end 45 degree -6 hose for Teflon
648060 -6 to M16 x 1.5 w/O ring. This is the adapter that goes into the pressure side near the return on the booster
648080 -6 to M18 x 1.5 w/ O ring. This goes on the pressure side coming from the pump on the right side of the unit

Aeroquip - for Teflon hose - steel fittings
FCM2608 -6 AN to metric for the P/S pump on metric pumps it has a better o ring retainer that the Russell and is steel not aluminum
FCM1122 -6 AN 90 degree steel swivel.
FCM1103 -6 AN straight steel swivel.
FCM2521 -6 AN to 3/8 pipe, steel
FCM2517 -6 AN to 1/4" pipe, steel


The pics are of the fittings and a before and after changed the fittings on the booster unit

[dwcsr]

For those who have PM'd me on making the rod for a different year master. When the rod is seated and the correct length, the master mounting flange will not be flush with the Booster unit flange when not bolted on. The master will sit against the rod, when not bolted in place, and leave a gap of approximately 0.065" which will close up when you tighten the nuts. This should take a lot of the guess work out of measuring the parts and trying to see if it’s the right length. Polish up the ends of the new rod so it doesn't gall the rod cups on each end.

You do need to have all the original parts, except the rod, so it seats properly into the unit and the retainer centers the front of the rod correctly. If you can't get the plastic disc off the rear of the old rod or it breaks. You need to tack weld a washer of the same dimensions in its place on the new rod. You still need the spring and retainer. The retainer when laid on a flat surface looks either like a spider or an upside down spider. It has all the legs bent in the same direction. To remove it from the unit gently grab a leg with some needle nose pliers on one side and hold it, Then push inward on the opposite side, then with a little twist pull the retainer out with the pliers. It installs by just pushing it into place in the bore groove with the bent legs pointing outward toward the master cylinder.

Pic below is of my boost unit with a used matching master of the same year and model. It shows the gap.

the gap.

[Kabwe]

dwcsr,

My buddy just installed the hydroboost kit on his 56 bel air and you want to talk about stoping power this is the way to go. I will be installing one on my 55 Chevy210 soon. I don't think I will on the truck because I do not want anything mounted on the firewall. If I can figure out a way to mount it on the frame I would love to put hydroboost in that also.

Good luck

[dwcsr]

It will mount just like a frame mount master and vacuum booster same parts as the firewall mount just longer lines and of course the frame mount and pedal. You would need to make a bracket/plate for the booster unit to attach to the frame mount but that’s the easy part.

Cal 58 GMC has that mount setup with a vacuum booster below, just put the hydroboost unit there and make a plate to mount the unit to the bracket