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Thursday, December 10, 2020

GMC Motorhome brake booster comparison OEM vacuum, Hydroboost and Hydromax

 

Top to bottom Hydromax, Hydroboost with 40mm master, and OEM Vacuum booster

OEM vacuum booster


Hydroboost with 40 mm master cylinder


Hydromax with 2" master cylinder

http://1999southwind.com/DOWNLOAD/Bosch%20HydroMax%20Booster%20Manual.pdf

Hydromax manual link

Brake pressure from Hydromax


2" Hydromax master with reservoir removed. Built like a "P30" master

Booster poppet valves


Hydromax master at assembled length. Volume ratio between sections 1 to 1


Hydromax rod does come out and a few styles are available or make what you want. New grommets are available.

Hydromax is different than Hydroboost in that the hydraulic flow path can have no restriction on the outlet, not a power beyond deal. Need a separate engine driven pump on the GMC or some kind of dual section pump. Relatively huge volume from the large master should satisfy all disk brakes with big pressure. Backup electric pump on primary flow failure.




Thursday, June 18, 2020

Kiln control retrofit



Original control was two switches with high low off for each element. No temperature control at all. It required close watching.
  New control kit has two SSR's a type K thermocouple and a ramp and step control. From Amazon https://www.amazon.com/gp/product/B07YN5YLS6/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1

Mostly installed, I put the SSR's low to keep them out of the heat and made a heat shield for the controller.
Thermocouple installed in the upper peep hole. Controller pulses SSR's to control heat input.

Thursday, February 27, 2020

EDM test with Dave and Roy

We build and test a low budget EDM for burning out broken taps, bolts and making holes in hard metals. Stepper motor control is an Arduino UNO set up for gap current control. This was steel
Test with aluminum. Hex hole burned with EDM. 35 -45 volts electrode positive
Redesign with a linear actuator for ram

Saturday, January 11, 2020

Copper chill weld repair

Our storage box for a Sioux seat grinder kit was missing the tab one one side to latch the top down. I didn't notice until I'd already painted the box. My plan was to use a copper chill to mask off what I didn't want wire feed weld to stick on and then the tab could be ground to fit. I used flattened copper tube for the chill.







Tuesday, December 17, 2019

Manganese Steel Safe repair

I got this safe in the mid 80's and didn't get around to fixing the locks until 2019. It had been in a fire with the door open. We got it looking good and used it for fire proof record storage and that was good enough until now. It was made by the Manganese Steel Safe company in the 1920's by the serial numbers on the time lock movements. The metal is steel with around 14% manganese in it. It is non magnetic and tough to machine. High speed steel won't touch it and modern carbide is a slow process. Originally it was ground to fit. This turned out to be an issue trying to fit modern threaded stem dials on it.
Here it is when I picked it up. Took two of their forklifts to lift it.
It weighs 4,400 lbs by the scale at my work. Front axle 2,710 lbs rear 6,480 lbs
To unload it was hooked to my ash tree and I drove out from under it. My neighbor got a huge kick out that process. Then I dragged it into the garage and stood it up.
Here it is refinished but without the locks working. It was short one dial and the other was fubar. I looked for years for reasonably priced dials that fit on a square shank like the spindles on the locks had. I gave up
The door rotates to open kind of like an artillery breech. The are two bolts that keep the door from rotating when it is locked.
Lock plate with two combination locks covers removed and a three movement time lock. Either combination lock will open it and any time movement. Redundancy on these. Combo locks are indirect drive so drilling the spindles to get it open wouldn't do any good. Spindles are tapered and also made of Manganese steel. Pounding on tapered spindle would only make it tighter. These Yale time lock movements became kind of a standard. New movements are available in mechanical and electronic versions and would fit right in this case.
Back of lock plate pin on lever actuates dog clutch that operates bolt mechanism. Time locks inhibit the combo locks until they time out.
Dog clutch, spindles on inside of door
Combination lock spindles had a external square shank that the original dial fit on. We were missing one dial and the other was fubar. My plan was to adapt available modern dials with a 5/16x 40 threaded stem. To do this we drilled the original spindles partway with a 1/2" carbide spade bit and pressed in a piece of mild steel that could be drilled and tapped.
We got Sargent and Greenleaf dials which fit the original dial rings. Notice the spindle taper.
Checking for runout. The locks have a little adjustment for alignment and they turned out fine.
 These are four wheel locks with 100 million possible combinations based on a 100 division dial. The lever is gravity operated so no spring to give out.
I made a lever out of a crank by bending with heat and welding in an extension.
Locks fixed with new dials. Operation is locks set the dog clutch to operate the bolts by turning the crank then the lever rotates the door to open.
Covers not on the combo locks in this picture. The covers can only be removed and installed by another combination setting.

Saturday, February 10, 2018

Powermaster booster pump repair

Replace vanes, rotor and cam ring. This pump would run but made no pressure
pump parts come out the end after ring is removed
         Drilled a hole to get at an end of the wire ring
        wear plates, cam ring, and outlet only fit one way as they are keyed or pinned
       Vanes had worn enough that one got out and no pumping happened.
          going back together

Sometimes the wire snap ring can be reused, We used a snap ring on this one with some machine work

Monday, October 2, 2017

Powermasterbrake boosters

Messing around with powermaster brake boosters try to get them to function

This valve was pitted by rust and caused the pump to cycle periodically