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#1 |
Registered User
Join Date: Mar 2013
Location: Ephrata WA
Posts: 140
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Uhh...Anyone else running hydroboost???
Ive got a 79 k10 swb that came factory with hydroboost brakes (came w/ 5.7 olds diesel) and the brake booster needs replaced...But im having a little trouble finding the correct one. Niether Napa or Orielly's had the part listed under my truck, so i came up with a part number for a '79 and had one ordered. However, it wont work. As you see in the picture, the new one came without the piston spring and baffle and spring retainer, so i pulled it out and tried to re install it on the new unit, but there was a substantial bore size difference between the two. Like 3/8 of an inch. Makes no sense. How many different units are there? Anyway...I have a different one on the way, no clue if it will work, i just found one that had a different part number. So we'll see. I'll try to get more pics up. Any help is appreciated
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1976...no...79...Chevy....wait...GMC shortbed 4x4. 5 inch lift on 35s, 355, sm465, daily driver. One day I'll figure out the story in that one. 1957 Chevy long stepper...not sure what I'm doing with that one yet. Awaiting funds I suppose. Last edited by Tdubbyount; 03-29-2013 at 01:29 AM. Reason: added stuff |
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#3 |
Registered User
Join Date: Mar 2013
Location: Ephrata WA
Posts: 140
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Re: Uhh...Anyone else running hydroboost???
Same PN as the one i already bought. The other one came in today and its wrong too.
__________________
1976...no...79...Chevy....wait...GMC shortbed 4x4. 5 inch lift on 35s, 355, sm465, daily driver. One day I'll figure out the story in that one. 1957 Chevy long stepper...not sure what I'm doing with that one yet. Awaiting funds I suppose. |
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#4 |
Registered User
Join Date: May 2009
Location: Pinehurst, Idaho
Posts: 311
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Re: Uhh...Anyone else running hydroboost???
The only difference I knew of was when they switched from flare fittings to o ring fittings sometime around 80'. Maybe there is a difference in bore size from 1/2 to 1 ton. Are the ones your getting to small or to big.
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#5 |
Registered User
Join Date: Mar 2013
Location: Ephrata WA
Posts: 140
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Re: Uhh...Anyone else running hydroboost???
The ones im getting are too big. All of the fittings are the same and it bolts right up on the firewall side, but the rod assembly for the master cylinder is too small for the new one.
__________________
1976...no...79...Chevy....wait...GMC shortbed 4x4. 5 inch lift on 35s, 355, sm465, daily driver. One day I'll figure out the story in that one. 1957 Chevy long stepper...not sure what I'm doing with that one yet. Awaiting funds I suppose. Last edited by Tdubbyount; 03-29-2013 at 12:31 PM. |
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#6 |
Registered User
Join Date: Mar 2013
Location: Ephrata WA
Posts: 140
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Re: Uhh...Anyone else running hydroboost???
Screw it. I'm converting to vacuum.
Posted via Mobile Device
__________________
1976...no...79...Chevy....wait...GMC shortbed 4x4. 5 inch lift on 35s, 355, sm465, daily driver. One day I'll figure out the story in that one. 1957 Chevy long stepper...not sure what I'm doing with that one yet. Awaiting funds I suppose. |
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#7 |
I know the pieces fit
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
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Re: Uhh...Anyone else running hydroboost???
I'd dig a little deeper to figure it out. The hydraboost works better plus you'll have to create a vacuum source to swap.
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#8 | |
Registered User
Join Date: Mar 2013
Location: Ephrata WA
Posts: 140
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Re: Uhh...Anyone else running hydroboost???
Quote:
Posted via Mobile Device
__________________
1976...no...79...Chevy....wait...GMC shortbed 4x4. 5 inch lift on 35s, 355, sm465, daily driver. One day I'll figure out the story in that one. 1957 Chevy long stepper...not sure what I'm doing with that one yet. Awaiting funds I suppose. |
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#9 |
Junior Member
Join Date: Dec 2006
Location: Southeast Missouri
Posts: 2,436
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Re: Uhh...Anyone else running hydroboost???
We just picked up a '75 C-30 and it has hydro boost brakes.
__________________
'67 Chevy C-20 short stepper - build complete, 454/SM-465. '75 C-30 Single Cab DRW-350 small block/NP-435. '77 GMC-6500 Dump Truck, 427 Tall Deck. '92 GMC K-3500 Duallie, 454/4L80E. |
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#10 |
Registered User
Join Date: Mar 2013
Location: Ephrata WA
Posts: 140
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Re: Uhh...Anyone else running hydroboost???
Swapped everything over today. Still have no pedal. Darn. Did a complete flush of the brake fluid and power bled all four corners. Very little improvement. Booster and master cylinder work fine. Last thing I can think of is calipers?
It also pulls hard to the right under braking. New problem that just came up today. Posted via Mobile Device
__________________
1976...no...79...Chevy....wait...GMC shortbed 4x4. 5 inch lift on 35s, 355, sm465, daily driver. One day I'll figure out the story in that one. 1957 Chevy long stepper...not sure what I'm doing with that one yet. Awaiting funds I suppose. |
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#11 |
I know the pieces fit
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
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Re: Uhh...Anyone else running hydroboost???
This is really hard to diagnose with that many changes going on at once. Unfortunately China is making it worse for us, lots of master cylinders are bad out of the box.
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#12 |
Registered User
Join Date: Mar 2013
Location: Ephrata WA
Posts: 140
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Re: Uhh...Anyone else running hydroboost???
We disconnected the brake lines from the master, plugged the holes and tried it and the pedal was very firm while running. That rules out a bad cylinder or booster. Power bled everything. Still no pedal. I'm absolutely sure there's no air in the lines. We have good pressure at all four corners so the proportioning valves are fine. I'm thinking calipers. Wheel cylinders aren't leaking either.
Posted via Mobile Device
__________________
1976...no...79...Chevy....wait...GMC shortbed 4x4. 5 inch lift on 35s, 355, sm465, daily driver. One day I'll figure out the story in that one. 1957 Chevy long stepper...not sure what I'm doing with that one yet. Awaiting funds I suppose. |
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#13 |
I know the pieces fit
Join Date: Nov 2007
Location: MONTGOMERY, AL
Posts: 5,523
|
Re: Uhh...Anyone else running hydroboost???
Pulling hard right makes the left front brake line suspect.
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#14 |
Registered User
Join Date: Mar 2013
Location: Ephrata WA
Posts: 140
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Re: Uhh...Anyone else running hydroboost???
I recently put on skyjacker stainless brake lines, and there's good pressure on either side.
Posted via Mobile Device
__________________
1976...no...79...Chevy....wait...GMC shortbed 4x4. 5 inch lift on 35s, 355, sm465, daily driver. One day I'll figure out the story in that one. 1957 Chevy long stepper...not sure what I'm doing with that one yet. Awaiting funds I suppose. |
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#15 |
Registered User
Join Date: May 2009
Location: Pinehurst, Idaho
Posts: 311
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Re: Uhh...Anyone else running hydroboost???
If the whole system was open like that, you're probably better off just letting it gravity bleed for a while. Having air in the lines could make it pull like that.
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#16 |
Registered User
Join Date: Jul 2009
Location: washington
Posts: 4,178
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Re: Uhh...Anyone else running hydroboost???
Rebuild kit http://www.piratejack.net/index.php?...emart&Itemid=6
Posted via Mobile Device
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377 sbc thumpr cam autogear m23 muncie 3:73 Detroit trutrac 3''spintech prostreet mufflers xpipe 1 3/4 headers build thread !http://67-72chevytrucks.com/vboard/s...d.php?t=577217 Iroc gauge threadhttp://67-72chevytrucks.com/vboard/s...d.php?t=554511 |
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