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Another Hydroboost thread (to add to all of the the others)
Nothing really new or earth shaking here, just a reference for someone later on, maybe. (cross posted from the other place)

72, BB Astrovan unit, stock (newer-metric) cast master cylinder

Ordered a reman Delco unit for a 94-95 astro/safari van (couldn't find a scrapped one in any of the local wreckers)




Cut the pedal end off


Threaded the remaining shaft 3/8-24 (fine)


Installed the original pedal clevis with a jam-nut


Pulled out the studs from the mounting plate


Remove snap ring and large locking nut




Installed the studs from inside the firewall (yes, never have to get at those stupid nuts again !!!)
Used a larger nut and then the correct (metric) nut to set the stud splines


Test fit the mounting plate in it's new orientation (flipped the hydroboost to have the lines underneath)


Now since I didn't have a scrap one to start with, the rod that goes between the hydroboost and the master cylinder is not included in the re-manufactured units. You're supposed to re-use your original

Tallon Hydraulics sells a universal replacement kit that includes their version of the spring and retainer


The large washer is held in with the internal c-clip.


The shaft is machined to fit the application (.010-.020 gap)
(image)

Couple of coats of paint and some clear


Had to make up something different to cover the accumulator (I'm part crow, gotta have shiny stuff)










Reinstall the hydroboost to the mounting plate (don't forget to tighten the nut and install that c-clip cough cough cough, don't ask)

Adjust the brake pedal clevis.
There are various ideas on this as for adjusting the pedal lower than normal since you will not have the pedal travel that the vacuum used to give.
I set mine about a 1/4 down from the stop at this time.
The system needs to have some play for when the hydraulics heat up, if the pedal can't lift (already against the stop) the system will push the other way and put the brakes on.



Tighten the jamb nut and install the clevis pin



Old master was leaking a little between the MC and the booster so I ordered a replacement. MC is empty, time to work on the plumbing

I ran all the hoses using 3/8 rubber to get the routing and lengths and then made up the braided lines.
For now, I'm just using a Tee fitting into the return line and rubber hose.

Cut 3-1/4" inch off the original return line from the steering valve and installed the Tee fitting.


Then removed another 1" from rest of the stock line to make up for the body of the Tee fitting

Following instructions I found from Jim Shea, I installed the Tee fitting with the steering going straight through and the hydroboost coming in at the 90 deg.
Some people have had some issues with this creating back-pressure on the hydroboost, others have been fine. Even then, it seems to only be a problem when hard-braking and steering at the same time.
I'll leave it this way until I see a problem



The fittings I used are all from Tallon. Great service but honestly the fittings all needed some deburring on the threads and ends to get them to fit nicely.
Russell 648080 Tallon THI 4990- 18X1.5 o-ring to 6AN (HB unit High Pressure in)
Russell 648060 Tallon THI 4991- 16X1.5 o-ring to 6AN (HB unit High Pressure out)
Tallon THI 8203- 5/16-24 o-ring to 6AN (HB unit low pressure return)

Russell 697100 Tallon THI 8201- 7/16-24 thread to 6AN (1/4" inverted flare, steering valve pressure in)
Russell 640380 Tallon THI 4996- 5/8-18 inverted flare to 6AN (PS pump high pressure out)

Tallon THI 6601- 3/8 x 3/8 x 3/8 Tee fitting (low pressure return)


Russell 620421 Tallon THI1389- AQP 90deg 6AN to 3/8 reusable hose ends, four of them
Tallon THI????- 90 deg 6AN to 3/8 barb fitting (can't find the PN right now) for the HB return line

Aeroquip FCC0606 6 feet of -06 teflon braided line

I ran the lines from the bottom up, routed them under the edge of the upper control arm (it's all the way down now so there is room)

When running the braided hose to the control valve, route the slack beside the existing rubber hose (the one the Tee was installed into) and make sure you check with the wheels turned both left/right to make sure it's not binding or running into anything.

Needed to make some hose separators (yeah you can buy these but since I can and I can get the 2 small hoses along with the 3rd larger one in the same loom...))






Tucked all the lines over by the inner fender and kept the two braided lines in front of the brake manifold and the return behind it











Where the two lines run to the steering control valve, I put on some spiral hose protector (fancy expensive name for nylon spiral wire loom) on the rubber hose to protect it from the braided line. I also put a few inches of this where the two braided lines run over the frame/under the control arm to protect them from each other and the frame


(I've got to replace that zip-tie with a metal one at some point)



This is what's left over from a 6' length of Aeroquip hose


I suspect down the road (figuratively and literally) I'll look into a different pump can with remote reservoir but for now this should work just fine. If I do, I'll likely change the return line to braided just because :thumbs:

Anyway, another checkmark off the list
M
 

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Looks clean. I really like the accumulator cover. :cheers:

If you do go with a remote mount reservoir, perhaps you could find one with provisions for 2 returns. Or a place to add a second return. Or a larger diameter return so your return hose size can go up after the 2 tee together.
 

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Discussion Starter #3
Looks clean. I really like the accumulator cover. :cheers:

If you do go with a remote mount reservoir, perhaps you could find one with provisions for 2 returns. Or a place to add a second return. Or a larger diameter return so your return hose size can go up after the 2 tee together.
Thanks

Several of the pumps I've looked up are the same physical size as the stock pump so I can swap my pump into the new body. At least one (can't remember which one, glad I wrote it down, now where is my note....) was also used in a hydroboost equipped van and has two return ports already on it.
Someone (grumpy?) also did a whole bit on returning to a remote reservoir (foaming etc) but hopefully I won't get in that deep
M
 

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Great job. We do things very similarly. I made a polished aluminum cover for the accumulator on mine too, and I always use that Cast Coat Iron paint for my engines and Hydroboosters. :smack
 

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Thanks for the post, I will have to tackle this job at some point. My engine has the pump setup for hydroboost and I bought a polished remote reservoir for it. I really like how neat all the lines are ran, great job man. :thumbsup:


:cheers:
Mark
 

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I can't see any pictures. Is it just my computer or are they missing?
I have planed to do this for a long time in DIY style, think finished kits are too expensive for me shipped to Norway.
So I have to figure this out. Should I make another thread about this?
 

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Discussion Starter #7
Yeah it's one that photobucket destroyed when they wanted $$$ after tones of forums already used their images


It's posted full over on the other forum.
Just google


corvette mooser another hydroboost and it'll take you there.


Let me know if I can help otherwise
M
 
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