Cummins 4BT & Diesel Conversions Forums banner

1 - 10 of 10 Posts

·
Registered
Joined
·
1,366 Posts
Discussion Starter · #1 ·
Hello,
I have the hydroboost setup from my Frito Lay P30 van and I'm going to install it in my project truck. Is this booster used elsewhere (and thus is available new or rebuilt), or if it ever needs replacing, am I going to be stuck with something unfixable or unreplaceable?
Thanks,
Mikel
 

·
Registered
Joined
·
225 Posts
Yes, these units were available on some GM 1 ton and heavier trucks so you can replace them if needed though I understand they are not cheap. Buddy of mine that is a GM nut say we can convert to corvette master cylinder for 4 wheel disk brakes at a later date.
Carl

1979 F-250 crew cab 4 x 4
4 bta with modified H1C
Cold air intake
ZF S-42 5 speed
Borg Warner 1356 x-case
Dana 60 rear
Dana 44 front
3.55 gears
255/85R16 tires (33.5x10.5)
Hydroboost steering and brakes
Custom 40 gal. fuel tank
Much more later
 

·
Registered
Joined
·
126 Posts
I recently got a Hydra-Boost out of a 1-ton Cab/Chassis- and kits are available. I plan to use the (iirc) 79-82 Corvette MC with 1-1/8 bore to accomodate the added volume of my larger disc calipers...
 

·
Premium Member
Joined
·
1,660 Posts
Some guys have done the work to get them to bolt into regular trucks.., which works but takes time.... My own method is go the junkyard and buy a complete hydroboost from a M series Chevy Van (Astro, Safari), about 20% of them had hydroboost.. It is the same booster with different mounting points, massive master.. With this setup my 6K Land Cruiser stopped better than my 4W disk European car... :) Then it's also an easier swap assuming it does fail somewhere, more common part at a regular parts store...
 

·
Registered
Joined
·
10 Posts
Out of curiosity why is a bigger mc needed? Also my booster doesn't seem to add much assist. Is it possible that it needs bled or something? PS works fine.
 

·
Registered
Joined
·
808 Posts
I use a Bendix 11584 ( NAPA 39017) MC with my hydroboost. This MC has a bore of 1.3125". I found on my installs that a 1.125 bore was not enough for a good reserve on the pedal. With full pedal push, the pedal would be almost to the floor. The larger MC solved that problem. by pushing more fluid on brake application.

Paul
 

·
Registered
Joined
·
1,366 Posts
Discussion Starter · #8 ·
I also have a brand new, never used, hydroboost booster from a M1008 truck. It doesn't have a pushrod. Can the pushrod be switched from the Frito Lay unit I have, to this one?
Thanks,
Mikel
 

·
Registered
Joined
·
500 Posts
Anyone got a P/N on that 78-82 corvette MC that works with the hydroboost? I'm running 4 wheel discs, so I need one - PM or post me if you've got a good #!
 

·
Registered
Joined
·
126 Posts
NAPA sells new and reman:

http://www.napaonline.com/masterpag...39052&Description=Brake+Master+Cylinder+-+New

Reman is like 28 bucks but I prefer new in this dept. On my streetrods I built 4WDiscs using calipers with fairly large fluid volume. For my planned FJ55 I presently plan to use Monte Carlo on all corners, (emergency brake is at transfer case output in stock form).

Everyone on this forum probably already knows this but I feel for safety it is important to mention:

  • Whatever MC gets used, be sure it is a dual circuit (mostly an issue in early-60's cars).
  • Be certain the MC is Disc/Disc since Disc/Drum will have residual valves and 4WDisc should have none to avoid dragging.
  • A Proportioning valve is highly recommended mounted in line someplace in the rear brake line circuit, it just gives that much more control over stopping power :smokin: (great for burnouts amongst rodders!)
Dang, I kinda wished I knew about the M-series Chev Vans, then I would not have to mess with getting the HydraBoost rod dialed-in, but that is not too hard to fab. Mounting to the firewall is the challenge if you have 'the FJ rib' in the way...

I also wanted to mention the rod connection to the brake pedal lever. The rod that came with my particular HBoost is super-long (1977 Chev 1-ton) so I plan to cut and thread the rod, and screw on a clevis/jam nut. With this rod being adjustable it becomes much easier to dial-in custom disc brake systems.

If the stroke seems too long using HydraBoost even after adjustment, then lowering the hole in the pedal arm will increase stroke, thus reducing mechanical advantage (more "pedal resistance"). HBoost will supply ample pressure so I am sure effort will not be too hard.

Thought "stating the obvious" would be necessary here, my apologies if this seems like a ramble... ...I'll edit this away if it irritates.

Best Regards,
George

P.S. my brakes and steering will be powered by the same source, I need to learn what fluid(s) will be the best "all arounder" (maybe a new thread?):idea: Ain't this great?!!
 
1 - 10 of 10 Posts
Top