Author Topic: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster  (Read 3864 times)

Offline ThunderLizard

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1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« on: January 10, 2016, 09:43:50 AM »
Truck: 1985 c30 Big Dually w/dump bed, 350 w/manual 4-speed, affectionately named ďUrsulaĒ. 

The Winter Projects continue on my truck.  Iíve had a leaky brake hydro booster for a while and I finally decided to try to replace it.  I ordered the parts and dove in, but Iím having a problem.  It is very challenging to get under the dash to the top of the brake pedal, where the hydro booster rod attaches to the brake pedal.  Iím 41 years old and weigh 270 lbs.  In other words Iím too old and fat to get a good look or grip this far under the dash.

I canít get the pin out, the pin that holds the hydro booster rod to the brake pedal.  Everything I read in preparation said that this was easy.  You just remove the cotter pin and then remove the retaining pin.  My truck seems to be an exception to this.  Iíll get into more detail below.

I got on my back and was able to see the cotter pin (YES!) and was able to hook it and pull it out.  The whole time thinking ďhow the heck will I get that back in when this job is done?Ē.  (Iíll cross that bridge when I get to it.)  Hereís the thing about the cotter pin though: it wasnít on the end.  It was in the middle of the stack of brake pedal, rod, spacers, washers, and some mystery pull arm with a spring hooked to it.  I would expect the stack to have the cotter pin on the end. 

One side (referred to henceforth as ďside AĒ, is the right/passenger side) has a head of the pinÖ at least what I thought was the head.  When I look and feel the other side, ďside BĒ, it feels like it is wider and flatter than the other side.  Maybe side B is the head and I need to push the pin that way?

Iíve taken a bunch of pictures to try to help explain my issue. 

So here are my real questions:
  • Which way does this pin go or is there some other clip or retaining device that Iím missing?
  • What is the ďmystery partĒ that is within this stack?  Something for trailer brakes or something?  It is not the brake light switch: that was easily identified and right where I thought it would be.
  • Are there some tricks to this that I donít know about?  It doesnít seem like it should be this difficult?  Should I take the dash apart?  Drop the steering column?  Take the brake pedal completely off/out?
I know that there are many very smart people, and probably some professional mechanics on here.  Iím really hoping someone can give me some advice that can make getting this Hydro Booster replaced a little easier. 

Offline zieg85

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #1 on: January 10, 2016, 11:16:12 AM »
I wish I could help you.  I even had the instrument cluster and complete dash when I was pulling the juice clutch/hydro brake pedal set for a project out of a 1987 GMC 1 ton.  I am sure there is an exploded view somewhere but I have yet to find it.  As much as I hate automatic trucks I don't think I have the dexterity to make the swap on mine without torching it out of frustration.
1985 C30 Custom Deluxe Ext. cab 5.7L TH400 3.21 
1985 C20 Scottsdale 7.4L 4 speed 3.21
1986 C10 under construction
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Offline bd

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #2 on: January 10, 2016, 01:07:46 PM »


Post a supplemental pic that pans toward the right from the one above for verification of the following:  from memory, the "pin" is welded to the pedal arm on "Side B."  The booster pushrod, thrust washers and retaining clip (or cotter pin) are caged between the pedal arm and the bracket that bolts to the pedal arm in the image.  IIRC, the 'bracket' is just a pedal return stop - the requested image is to ensure it is not more complicated than that with additional springs involved.  If I am correct, the bolt and nut at the top of the image simply needs to be removed so the bracket can be separated from the pedal arm. 

The "What the heck?" is a stout return spring that should remain undisturbed as you slide the pushrod off the pin once the bracket is out of the way.  Be sure to grease the pin, thrust washers and pushrod, before you slide the rod back into position and install a new cotter pin.  Then reattach and tighten the return stop bracket.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Terryr85

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #3 on: January 10, 2016, 05:06:11 PM »
Loosen that nut, the tab over the rod can now be moved and you can take the hyrdoboost rod off the brake pedal
73 K20 RC/LB, D60, 14bolt, 5.3l, NV4500

Offline ThunderLizard

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #4 on: January 10, 2016, 06:16:26 PM »
bd - great to hear from you.  Please see the picture attached.  To the right is the brake light switch, and not much else. Everything you described sounds correct: welded side B, etc.   I'm pretty sure now that the "what the heck?" is a return spring.  I'm also fairly certain that loosening that nut will work.  Hopefully it will be warmer tomorrow and I can pretzel my way back under there.  I'm encouraged by this information!

Terry85 - Yes, I think I see it now. I'll let you guys know how it ends up.
Thanks again!!!

Offline bd

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #5 on: January 10, 2016, 09:38:33 PM »
After it's all back together, you may need to adjust the brake switch.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline ThunderLizard

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #6 on: January 12, 2016, 07:59:30 AM »
*facepalm*

OK, so this was one of those moments where I find myself kicking myself.  Getting the rod off the brake pedal is MUCH easier than I was trying to make it.  Taking off the bolt/nut that holds the brake light switch actuator arm allowed me to move it out of the way and easily remove the rod without disturbing the retaining spring.  By the way, this nut is 15mm, just like most of the nuts and bolts for this project.  I discovered that I have one 9/16Ē wrench that is stretched out enough to fit onto a 15mm nut.  You can imagine my confusion as I chased down that anomaly.
 
With some extensions, and contortion, I was able to fairly easily remove the 2 under-dash retaining nuts.  Then I did a brief dance of joy for being done under the dash for a few minutes, straightened my back, and removed the four under-the-hood retaining nuts.  Pulled the old hydrobooster and marveled at the mess on the underside.  I knew this thing was leaking, but it has been leaking a lot of a long time.  So I pulled the plunger, spring, and star-shaped retainer from the front end and was able to remove the mounting plate from the back side. 

The mounting plate retaining nut was a little tricky since it is very large (no wrench big enough) and recessed (no pipe wrench).  I tried a few things, but after just a few minutes tried a blunt-nosed punch and a small hammer.  I was able to tap-tap-tap counter-clockwise and it came loose pretty easy.  Then I grabbed it with a large channel lock and got it off: not all that hard!  The mounting plate was caked in grime.  I hit it with degreaser and a heavy duty scraper and it cleaned up pretty nice.  I re-installed these items onto the new hydrobooster without incident.  Cleaned up the firewall area, and bolted that bad boy back into place. 

And that is where I had to stop for the night.  My sons got home off the bus and I needed to help with dinner and homework.  Iím hoping to finish this job this afternoon after work.  It is back under the dash, reattach master cylinder, reattach lines, a bleed the system.  This job is almost whipped.
The first 2 pictures below are of the old booster.  The others are of the new one.

Thanks again to all of you.  I wouldnít be able to fix and learn and succeed with this truck if it wasnít for this board.  I donít think I can fully express my gratitude for you all or the help you offer. 

Offline ThunderLizard

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #7 on: January 13, 2016, 07:49:10 AM »
So, a little hiccup last night as I went to finish this install.  I went to "slide" the hydrobooster rod end onto the brake pedal, and it wouldn't fit.  It was too tight, and with the angle of the rod I was unable to get it to cooperate.  I couldn't tap it with a hammer, or really persuade it in any way, since it is in no-hands land (so far up under the dash that not even the smallest hands can reach  :) ).   So, I drove into town, to the new giant Menards that just opened around Christmas.  There I bought a hardened steel stepped drill bit ($42!), a round metal file, and some power steering fluid.  The first picture below is the rod end before modification.  The second picture is after I reshaped this hole so that it would slide onto the brake pedal.  I beveled the inside lip and cleaned up the burrs on the inner hole.  This worked like a charm.  Slathered on some fresh grease and dang if that sucker didn't slide right on.  After that it was a cake walk.   Bled the system.  Got some foam in the power steering pump, so I'm going to bleed it again today.  Still squeals like a stuck pig, but I think that is my new belts. 

Next episode in the Ursula Sagas: "Gas Gauge, Part II"

Thanks again to all y'all!


Offline bd

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #8 on: January 13, 2016, 10:19:48 AM »



This might make adjusting the PS pump belts a little easier.
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline ThunderLizard

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #9 on: January 14, 2016, 08:32:13 AM »
 ;D ;D ;D
I could not be more please with the result of this project!
I went ahead and bled the system 2 more times.  The squealing is gone!  Before this, Ursula would squeal and scream anytime you turned the wheel or pressed the brakes.  I didn't mind too much, since I thought it was funny to see the looks I would get.  Ursula is quite boisterous.  8)
But now, she is a dream to drive: no squealing, no squawking, no popping backfires when shifting.  And the steering and brakes are like a brand new truck.
What a pain to get under the dash for this project, but it was so worth it!  I'm going to drive it into town today just to make sure everything is working tip-top.
Thanks again everyone!

Offline bd

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #10 on: January 14, 2016, 10:06:55 AM »
You are most welcome!  A job well done with satisfying results is always a welcome event and joy!
Rich
It's difficult to know just how much you don't know until you know it.
In other words... if people learn by making mistakes, by now I should know just about everything!!!
87 R10 Silverado Fleetside 355 MPFI 700R4 3.42 Locker (aka Rusty, aka Mater)

Offline Rattler12

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Re: 1985 c30 350 V8 "Ursula", sub-project: Hydrobooster
« Reply #11 on: January 14, 2016, 10:57:28 AM »
Those rods came with 2 different sized holes in them.......one is 9/16 with power brakes and the other is 5/8 for manual brakes. My pedal on the 83 with manual took the 5/8 and the original rod mistakenly went to the dump with the original master cylinder. I changed over to power and didn't have a rod. Went to a local salvage yard and got a one.........with a 9/16 inch hole. I went though 3 5/8 bits trying to drill out the hole in the rod.......nary a scratch. Those things are harder than Chinese arithmetic. Finally cut off and drilled out the 5/8 shaft from the brake pedal and welded in a 9/16 rod cut and drilled to fit.........    ;D
83 C-10 shorty 454, 5spd, 3:73 posi