Hydroboost conversion using Astro Van HB unit.

[Blazer406]

I just started my conversion tonight. I took my still working (but who knows how much longer) PM unit. I had already purchased a junkyard HB unit off an Astro Van..... mid 90's model......I guess I've got about $40 in the HB unit.

Came back and read TinMan's thread where he converted his car to refresh my memory on what is next.....

Looks like tomorrow night I will continue ahead. I'll try and take some pictures along the way and post them in this thread if others want to do this....

I'm going to try and use a parts house hose/s to keep it cheap.... my goal is under $100.

More to come....

 

[BIG HEAD CHRIS]

so the astro van unit is a useable piece then?

 

[Blazer406]

so the astro van unit is a useable piece then?

Yes it is..... however... I am having second thoughts because of the modifications you must do.

The stock GM PM bracket can be re-used but you must cut the studs off, heat up and hammer the big hole out flat, then build up the hole a small amount with weld closing up the diameter a little.... then grind the hole out to fit the HB unit.

Mods to the HB unit itself (the part I'm not too happy about)... is you must cut the stock rod that connects to the brake pedal.... cut the one off the PM unit.... and weld it on the HB unit at the correct overall length. Her is why I don't like that mod.... if I were to have a AstroVan HB failure.... and I went and got a re-man'd unit from the parts store... I would have to cut and weld the rod again... and the "core" unit I would return wouldn't have the whole rod attached...

So... I am on the fence...

 

[novaderrik]

for the "core" problem- just get another one to have around to use as a complete core.

 

[Blazer406]

for the "core" problem- just get another one to have around to use as a complete core.

Will do....

Decided to proceed ahead with the AstroVan unit.... looked into using the 85GN unit... and the national warehouse that advanced pulls from had 2..... only 2 in the country..... no thank you sir.... I want something that I can go get another in a hurry if I have to and be easy to locate.... I figure there was one ore two mor AstroVan's made than 84-85 GN's.....

More to come.

 

[buttonfly]

Will do....

Decided to proceed ahead with the AstroVan unit.... looked into using the 85GN unit... and the national warehouse that advanced pulls from had 2..... only 2 in the country..... no thank you sir.... I want something that I can go get another in a hurry if I have to and be easy to locate.... I figure there was one ore two mor AstroVan's made than 84-85 GN's.....

More to come.

Hey Blazer its funny I am doing the same thing right now. I am using the same hydro unit. Now I was thinking of making a plate to position to the back of the hydro and use the remaining studs. It may or may not work, just my first thought. I hadn't pulled my PM unit yet, because I really wanted to get my hoses back first. I just didn't want to go so far that I couldn't easily turn back in about 20 min's. I don't know what you thought of everybody pulling the intercooler and pump. Hell I dropped the belt, pulled the tensioner, and I pulled the lines so I could get a good look at the ends of the lines. PM me I wouldn't mind talking to you abit more. J

 

[Blazer406]

Leaving now to go to Napa and see if their heater core looks like it might fit.... probably going to work on the car tonight later... after I get back from parts run and supper.

As far as looking at everything.... my engine is out now on the stand.... waiting to be installed.... thought this would be a good time to do the conversion when I could stand inside the engine compartment to get to everything....... so I am doing the HB conversion and R&R on the heater core prior to the new engine being installed.

I am planning on buying stock 85GN hoses. The HB to Gearbox should work fine... the PS pump to HB I am hoping I can tweak to make work. Worst case... I have to use the bottom of my stock line (discard the rest)... and the top of the new line... and do a ferrule (sp?) type splice on the old hardline. I'm fairly certain that will work....

More to come...

 

[Blazer406]

....snip..... Now I was thinking of making a plate to position to the back of the hydro and use the remaining studs.

J

I used the astro van plate... and cut it down....drilled two holes in it that matched the l/o of the stock PM studs....so it fits onto the existing PM mounting bracket. I then had to use a 2" electrical knockout to punch the old PM bracket hole out to 2" so the big @ss nut can clear. Then attache the Astro HB unit to the modified Astro Van plate... and tighten the nut back up and put the snap ring back on.....

This will enable me to remove the HB unit by unhooking the rod to the brake pedal.... and then the two studs in the engine compartment. Otherwise.... if I had done it like on Tin Man's thread... you would have to remove the 4 nuts (that is such a joy to get to) inside the car.... just to remove the HB. After spending about 20 minutes on my head removing the nuts.... I said there had to be a better way.....

I did cut the old astro van HB rod off... leaving myself room to cut and weld the PM rod on it.... In hindsight.. I wish I would have cut it off and threaded it... and done something different other than cut and weld the rod that is going to actuate the brakes at 130 mph...We'll see how this holds up.... I am wishing I had a threaded sleeve.. and some jam nuts... and both male pieces would be threaded...that would be the way to do it...

IMHO... in an ideal situation... you would somehow adapt the stock AstroVan HB rod to yhe GN brake pedal.... so if the HB went out... you just drop a parts house one in... no mods necessary.

Well... making progress.... should finish up with the HB this afternoon except the hoses... then I am dropping the engine in.....

 

[buttonfly]

I used the astro van plate... and cut it down....drilled two holes in it that matched the l/o of the stock PM studs....so it fits onto the existing PM mounting bracket. I then had to use a 2" electrical knockout to punch the old PM bracket hole out to 2" so the big @ss nut can clear. Then attache the Astro HB unit to the modified Astro Van plate... and tighten the nut back up and put the snap ring back on.....

This will enable me to remove the HB unit by unhooking the rod to the brake pedal.... and then the two studs in the engine compartment. Otherwise.... if I had done it like on Tin Man's thread... you would have to remove the 4 nuts (that is such a joy to get to) inside the car.... just to remove the HB. After spending about 20 minutes on my head removing the nuts.... I said there had to be a better way.....

I did cut the old astro van HB rod off... leaving myself room to cut and weld the PM rod on it.... In hindsight.. I wish I would have cut it off and threaded it... and done something different other than cut and weld the rod that is going to actuate the brakes at 130 mph...We'll see how this holds up.... I am wishing I had a threaded sleeve.. and some jam nuts... and both male pieces would be threaded...that would be the way to do it...

IMHO... in an ideal situation... you would somehow adapt the stock AstroVan HB rod to yhe GN brake pedal.... so if the HB went out... you just drop a parts house one in... no mods necessary.

Well... making progress.... should finish up with the HB this afternoon except the hoses... then I am dropping the engine in.....

Thanks Blazer! I like how you did that. I am curious to see how the lines work. I have mine at napa right now. They are supposed to be making them for me. They said they were waiting on a couple of the fittings. If the stock 84-85 lines work what a nice solution. Great work, I appreciate all the info. J

 

[Blazer406]

Thanks Blazer! I like how you did that. I am curious to see how the lines work. I have mine at napa right now. They are supposed to be making them for me. They said they were waiting on a couple of the fittings. If the stock 84-85 lines work what a nice solution. Great work, I appreciate all the info. J

I am planning on using the stock 85 GN (NAPA replacement) HB to steering box hose.... and planning on using the 85GN (NAPA replacement) PS pump to HB line... in conjunction with the first part of the stock 87 PS pump to gearbox line.... I figure somewhere before the stock line (after it leaves the pump)... before it goes to the flexable line... I will cut it.... then use a compression union splice... and cut the factory 85 line near the end that hooks to the pump... and splice the two there...

Maybe this will work?

The return line should be a piece of cake.. just a brass barbed tee and some return hose and hose clamps...... ought to work just fine....

I am curious to see if the Astro van master cylinder will work... that puppy is long.... might hit the PS reservoir... not sure yet....

I'm trying to do the conversion for under $100....as I am on a tight budget....

 

[Blazer406]

Well.... got her bolted up.......ran into a snag.... the factory AstroBoost master cylinder is too long. It interferes with the PS reservoir cap.....I don't like it.... might look to see if I can find a shorter aluminum master cylinder... I really don't want one of those cast iron pieces that are in some of the conversion pictures..... I'll see what I can find....

 

[zpd307]

can you post up some pics of the reworking you did on the the astro van firwall bracket.

 

[novaderrik]

any aluminum master cylinder from a 78 and newer rwd car should work.
like, say, one for a Monte SS.

 

[buttonfly]

Well.... got her bolted up.......ran into a snag.... the factory AstroBoost master cylinder is too long. It interferes with the PS reservoir cap.....I don't like it.... might look to see if I can find a shorter aluminum master cylinder... I really don't want one of those cast iron pieces that are in some of the conversion pictures..... I'll see what I can find....

I grabbed an aluminum m/c off a rwd car thinking about running into the same thing. Have you tried the lines yet?? I am really anxious to see if that worked.

I like the idea of using the metal portion of our existing line, and splicing there. I have napa trying to locate the end that bolts up to the metal line. I was trying to take that route. If that doesn't work then I might try a splice there. What are you doing fro the pressure line from the HB to the gear box?? You are right the return line is a piece of cake.

 

[Blazer406]

Update... pics....

I snapped these with my phone this morning...on the way out the door to work....

You can see the plate the HB is fastened to... and that fits over the factory studs....

Also notice the M/C is too long....I really want to leave the PS reservoir in it's original location...

Going to try and see if that Suburban M/C is any shorter.... 1-2" would be nice....

 

[Blazer406]

any aluminum master cylinder from a 78 and newer rwd car should work.
like, say, one for a Monte SS.

I think the key is trying to get one with the correct size fittings so you don't need any adaptors... and also a 1.125" bore... or real close... I might would try one slightly smaller bore than that... but definately not bigger.... too big.... and you will go from no brakes to 4 wheels locked up in 1" of brake pedal travel...

 

[Blazer406]

I grabbed an aluminum m/c off a rwd car thinking about running into the same thing. Have you tried the lines yet?? I am really anxious to see if that worked.

I have not messed with the lines yet.... I only have the 85 PS pump to HB line... the one I am sure I will have to marry with the stock 87 line to get it to work.... have the compression union I need to splice it as well... I won't be able to do that until I drop the engine in and get the PS pump in it's final resting place...

The other line... the HB to gearbox... ought to drop right in.... NAPA found one.. and it should be in on Tuesday after 2 PM....

 

[buttonfly]

I have not messed with the lines yet.... I only have the 85 PS pump to HB line... the one I am sure I will have to marry with the stock 87 line to get it to work.... have the compression union I need to splice it as well... I won't be able to do that until I drop the engine in and get the PS pump in it's final resting place...

The other line... the HB to gearbox... ought to drop right in.... NAPA found one.. and it should be in on Tuesday after 2 PM....

Heck I might try the same thing. It is going to be nice all week and all I am lacking from driving the damn thing is these brakes! Usually comes in handy. I might try the stock 85 line hb to gear box. If that drops in that would be nice!!

 

[Blazer406]

After looking at the inside part tightening the nuts on the inside of the passenger compartment... I have decided the best thing to do.... albeit probably not too easy.....is to weld a small piece of flat bar the same thickness as the brake pedal.... onto the back side of it behind the existing pin that the HB rod attaches to.... there appears to be enough room.....and install a new larger diameter pin.... the right distance back .... so you don't have to modify the HB in any way..... will make it easier the next time if you need to replace it...just pull it and bolt the new one in.... The downside to this is that it would require removal of the stock PM brake pedal to make the modifications.......

I might still do that now... as I don't like the cutting and welding to the HB rod.....

I have another junkyard hb setup I might get.....

 

[TurboBob]

can the PS reservoir be moved?

B