Hydroboost with 40MM master cylinder pressure checks

Did a brake pressure check. Bob Stone hydroboost kit with 40 MM master. This was after 2,500 miles. 1,350+ psi front and rear, Calipers are 80MM front 80MM mid, and 66MM Kelsey Hayes rear with park brake. This is with about 1,400 psi available from the steering pump. Mounts are Lambke style mid and Branscombe rear. Manny reaction arm system. Rear pressure improved after it got some miles on. Bob Stones hydroboost kit came from http://www.appliedgmc.com/

                                   

 

Graph shows what the pressure was with a P30 and modified 40MM JF9 master cylinder. 

 

          Master cylinder booster combinations and theoretical pressure

Force available from vacuum booster panic stop 1,473 lbs

Force available from hydroboost 1.56” piston diameter and 1,350 psi steering pressure 2,579 lbs

                                                                                     Bob Stone

                                          Vacuum  Booster              Hydroboost

                                                                                  

1.25” master cylinder          1,198 psi                          2,098 psi

34 mm master cylinder        1,048 psi                          1,835 psi

37 mm master cylinder           852 psi                          1,549 psi

40 mm master cylinder           761 psi                          1,332 psi

The hydroboost force does not include additional force that can be applied by the pedal

Vacuum boost force does include additional force that can be applied by the pedal

Later on we got a 1,650 psi steering pump and even more brake pressure

Iceland and a little nyc

                                     Reykjavík Summit house.
              https://en.wikipedia.org/wiki/Reykjav%C3%ADk_Summit

                                     Geothermal steam venting

                                     Harpa Concert Hall, Reykjavík

                      Hydroponic tomato greenhouse with geothermal heating

                                        World trade center memorial

34MM P30 master cut away

             notice the poppet valves are tilted open

Arduino relay board test

Arduino relay board test. The darn  thing was doing unexpected stuff testing for a dishwasher controller. Testing the relays  confirms I have a software error and the relays do work. Think the TONE function is conflicting with the pins I was using.

JF9 40 mm master install

Hydroboost with 40 mm master cylinder

       Counter bore hydroboost so 40mm master nose fits in.

Spacer plate is .312" and along with the counter bore in the hydroboost lets the nose fit in so the master's flange mates up.

snow blade back drag mod

Some of the truck mounted snow blades have been modified to clean both directions. Decided to mod our tractor blade the same by adding an additional hinged blade. I can back drag away from garage doors then  push  with out getting off the tractor to swivel the blade.

40 mm master cylinder reservoir swap

Should clear the hatch just barely. If it fits it stops?

40 mm master mods hydroboost adapter and changing stops

40 MM internals on top P30 below for size comparison.

Fabricated two piece spring retainer to allow more stroke on primary

   Recessed stop for more primary stroke, far as it could go without spring bind.

                               Before modification

                          Two piece retainer installed, original below.

                                       Two piece on the rod

            Primary spring not binding when on the stop.
   I wanted a 3.2 to 1 ratio but that would require new pistons. 3 to 1 worked OK.

 The bottom of the bore is not flat. Spacer makes up the difference that was put on the primary side.

               grooves go to the bottom to let any air out

Hydroboost being installed has an output stroke of 1.708"

 This is the 40mm master shown and it fits:

2001

Chevrolet

C3500HD

Base Cab & Chassis 4-Door

8.1L 496Cu. In. V8 GAS OHV Naturally Aspirated

Doorman M630028
 http://www.dormanproducts.com/itemdetail.aspx?ProductID=6760&SEName=m630028

Ours came from Rock Auto and I see them on Ebay too.

Reaction arm and new brakes

Hydroboost gets a bore job

Opening up a hydroboost output end to accept a 40MM master cylinder. Going to use this in combination with a spacer. Not bored full depth so the spider that holds the output rod will still be usable.

Studs are left hand thread where they go in the boss.

GMC brake booster output stroke measurements

 Original motorhome booster, a "metric" replacement and Hydroboost. These are output rod strokes.

I used these straps and a rod to hold the input rods all the way in.