Brake issues 2Ton Viking 59

[Softpatch]

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.http://67-72chevytrucks.com/vboard/s...d.php?t=770501
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Reading this thread and doing more home work will open more question with no answer need some guidance
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I suffer from pedal bleed down
when I let off the pedal the fluid violently return back to master
Residual valve .?
is this not built into the master cylinder.?

My system is stock (one resivor) and the bore is 1.1/4
could I use a 1. bore just know it would take more pedal.?
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I have been fighting this for many years
don't know where im going with my truck
what i do not want to do is change the originalatly of the truck
the original brakes might have to be sacificed for over all driveability
would pitch the Hydrovac and 1.1/4 bore signal master cylinder for a 7" vacuum booster double master Like this
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any feed back to get my dad's truck back on the road would be much apreciated Thanks ...SP
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Hydrovac and 1.1/4 bore master cylinder
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[mr48chev]

You normally do get some rapid fluid return on that setup but the residual/check valve in the master cylinder may have failed.

I'm thinking that those little master cylinders intended for smaller pickups aren't going to have the volume that you need for your drum brake setup. You have to move a lot of fluid to have those large wheel cylinders push the shoes out tight to the drum.

If you go dual you have to have a master cylinder with enough volume to work the brakes.

[Softpatch]

thanks for the reply
Is there much diffrents from the 1" to the 1" 1/4.?

[1project2many]

Hydrovac systems don't behave as most people expect. There are rules to using one and if you don't follow them you get strange results. On the flip side, I've spent plenty of time fighting bad Hydrovacs over the years and I really believe most rebuilders can't do the job correctly.

When the HV system is working properly the pressure form the master cylinder only signals the HV how much to apply the brakes. Switching to a smaller master would make the HV apply more brake with less pedal but you could run into trouble if the HV fails and you need to use the master to apply the brakes directly. You could try a later unit from a C50/C60. They seemed to be a bit more reliable than those old Bendix units.

I know you've made some posts. Do you have to pump the pedal each time to get pressure? If so what happens to boost when you pump the pedal several times?

[farmall]

1955 Chevrolet Truck Shop Manual 2nd Series


http://chevy.oldcarmanualproject.com...uck2/index.htm

[Softpatch]

thanks for the reply..
The truck would lock up the front brakes only while driving
I bleed the brakes without the motor running.
First bleed hyrdovac then the brakes,
Closes first then work my way around the truck......
....All new parts hydrovac, master ,lines ,hoses, wheel cylinders, brake shoes,
the Pedal does return to stop without interference from floor...

My vision is to UX the hydrovac and go with a Vacuum boost set up with two seperate system one for the front drums and one for the back drums
again this is not a show truck just more of a weekend cruiser i do have a shed to keep it out of the weather.
I like the feel of the truck but at my age...
I'm thinking i have to deal with two major component the brakes and the steering and believe if I upgrade these it will not denounce the truck originality
......Sp
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[Softpatch]

I posted this in the general section because this is were i troll mostly....
not much to post Due to Family issues.... haven't had much to do with my truck.
Now i feel it the last chance and the time is right to bond once more with my truck just need some guidence.

I may have been luled into a sense of security.
Because I paid $600 to have the Hydroboost rebuilt and
$300 for a new not rebuilt master.
I now see the same master on amazon is $80
still at $80 this antiquated system is not were i want to be driving this truck down the road.!

So I believe an upgrade to move this truck from "Yard art" to a driver
the C50 I have seen in the junk yard have disc in the front not drum to drum.

now i could just sorse a late model C50/60 and reuse the drivetrain....
but then the "feel" will be gone and nolonger be the truck i drove 40 yrs ago in Highschool..!

It's hard to explain and it's a fine line from what it was and trying to keep it
that way.

I could buy a nicer truck but it's not this truck...
I just need it to be able to drive it around without changing the characture....
............................Sorry if i sound like a broken record
I just dont want to change to much with this truck but want to drive it without to much angst....

It had 3 switches just to start this truck...
and I try to keep them like I remember (Fuel on Ignition on Start)
has a side marker on the dash for L,O, pressure....Sp
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[tmoble]

cool truck.

so it locks up the fronts after a little driving?? that's pretty much always caused by the piston in the M/C not returning all the way. see if there's any free play in the rod from the bottom of the pedal to the piston in the M/C. At least in the lighter weight trucks there's an eccentric bolt where the rod meets the lever, it can be adjusted to get a little free play.

Make sure nothing is limiting the travel of the whole pedal arm as it returns.

[tmoble]

What is UX? throw away? I wouldn't do that just yet.

[Softpatch]

interesting ...thank you
for the idea
I just did little more digging
My master is the 1.1/8 bore
the master in a 1969 L88 corvette is 1.1/8 bore

....and i know were there is an extra master for a L88/L71
in my garage from my 69 corvette( L/71)

.I have some options But going to look at that adjustment nut first
thank again.......... will keep you posted
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