Hydroboost using new parts question

[Tbruz]

Pretty much decided to go with all new parts(versus rebuilt or boneyard pull) for a Hydorboost upgrade on my 1997 2 door Tahoe.

I understand from my reading of posts that the rebuilt HB units do not have a spring/plunger/star washer assembly inside the bore that goes between the Master Cylinder and the HB unit. Recommendation is to remove these essential parts from your old HB unit and reinstall in your rebuilt one.

Does any one know if new AcDelco units p/n 178-578 or 178-579 come with these essential parts or do I need to hit a boneyard to score these parts?

Would love to hear form somone who has used all new parts versus a donor truck for any pitfalls or issues to watch for.

I can post up all of the PNs I think are needed if anyone is interested.
Thanks
Tbruz

 

[SunlitComet]

the new ones are usually equipped with them already. the two concerns you have are you will need a cooler that is not made anymore so an alternative will be needed. tube and fin design 2 row say 12-16 long. and you can not mount a nbs mc to the obs boosters with out machine and loosing the retention ability of the pushrod parts.

 

[Tbruz]

Thanks Sunlit.
I got the PS cooler and mounting bracket already from GM, Pn's 26041420 and 15655032 for around $90.
Cardone PS filter for $20
All new hoses, 36365490,36365460,36368460 from RockAuto around $80

Picked up a new OBS Master Cylinder AcDelco 18M-712 from Ebay for $50
That MC works with both AcDelco HB units 178-578 and 178-579.

The spendy item is the HB unit at around $400. I'm being very cautious about pulling the trigger on either 178-587 or 178-579 until I know EXACTLY which one I need.
Would you happen
to know differences between those two HB units?
Tbruz

 

[SunlitComet]

there are internal differences i would need to know the power steering pump you bought or the brake classification your are using or the model, frame size and engine you are basing your parts purchase from in order to ensure you pick the correct one.

 

[Tbruz]

Sunlit,
PS is AcDelco 15909826.
Appreciate your help and your continual sharing of your knowledge.
Tbruz

 

[SunlitComet]

178-578

 

[wtbtahoe]

I know that this is an old post, but does anybody have an updated parts list? Most of these have changed and some of the superseding part #'s aren't available. Thinking of doing this to my '99 OBS Tahoe two door two wheel drive truck.

 

[Tbruz]

Go to RockAuto.com and look up the items for a 1997 diesel Tahoe. Those had HB brakes from the factory. If I recall correctly the biggest issue I had back then was locating the correct brake pedal.
8 years later and I still daily drive and love the 2 door. The HB upgrade has performed flawlessly.
Tbruz

 

[wtbtahoe]

Hi Tony,

I don't know if you remember, but you helped me with my factory driving lights switch and harness a few years back.

I went on RockAuto and there are two different HB units- with either a blue or gold accumulator- which appear to have different mounting configurations. Does one have the correct offset for the vacuum booster pedal setup? And did you go with a reman unit or step up to the new AC Delco? Thanks again for your help.

 

[Tbruz]

Back when I did this I went all new parts. I suspect that "new" is not an option today. My unit has the gold accumulator and fit without any additional alignment plates or issues. I think that the HB brake pedal itself is going to be the tough find- everything else, HB unit, master cylinder, PS cooler, PS pump and the lines themselves are wear items that someone should be remanufacturing.
Tbruz