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Discussion Starter · #1 ·
Been lurking and soaking up info for a while now, thank y’all very much! New problem I can’t find any previous posts about though…

1995 AWD Astro Tiger GT, new redhead steering box, all new hoses, new cooler, and now new pump. Bleed all the ways, so not much air if any.

When I first installed the pump, I put a PS filter on the return line after the steering gearbox. Bleed fine, but immediately on first start of the engine, the top blew off the filter and made a huge mess. I figured it was just a defective filter, so replaced that section of hose with new again. Bleed as normal again, and all seemed good. Finished buttoning everything up, and made it less than 100 ft out of the garage before the return line to pump blew off, made a huge mess, and immediately emptied the system completely. WTF!

Any ideas? Bad pump? Did I do something wrong? How does the return line have that much pressure?


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92 stro base
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I think you have your hoses mixed up.
Start with the reservoir, it is unpressurized. The hose going from the reservoir to the pump is also unpressurized. The line going from the pump to the rack and pinion is pressurized. The line returning from the r&p to the reservoir is not.
If you are getting pressure in any of the lines other than from the pump to the r&p, the filter itself is causing the pressure build up.
I'm not aware of any cooler for the steering fluid.
 

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Discussion Starter · #5 ·
Kind of hard to mix up the hoses. No Astro has rack and pinion. No filter in the system now.

Hoses are:
-Pump to hydro boost
-hydro boost to steering gearbox
-gearbox to cooler
-cooler to pump reservoir (blown off)

If ya wanna get technical, there are two more hoses-
-external reservoir to pump reservoir
-hydro boost to external reservoir

Problem is why is there so much pressure in return line?


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Discussion Starter · #8 ·
Thanks for the suggestions.

I haven’t been able to find a smoking gun besides a less than perfect hose clamp on the return hose. I’ve reattached it with 2 high quality hose clamps….so fingers crossed!

I do find it amazing the entire steering and brakes is dependent on one little hose clamp on the power steering return hose. I guess that is GM par for the course! LOL


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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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In all my decades, never once had an issue with this on ANY vehicle... including numerous Astros.
 
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2003 Safari
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I'm not familiar with this hydra-boost but I'm sure I will be eventually. Ford had similar systems in some mid-60's cars which were good while they worked but were and are almost universally hated the moment anything goes wrong, which isn't uncommon, and the wrong is often something weird like this.

I was literally astonished to find these vans have such a system when clearly the usual discrete systems are hugely better. GM should have "just said no".
 

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I'm not familiar with this hydra-boost but I'm sure I will be eventually. Ford had similar systems in some mid-60's cars which were good while they worked but were and are almost universally hated the moment anything goes wrong, which isn't uncommon, and the wrong is often something weird like this.

I was literally astonished to find these vans have such a system when clearly the usual discrete systems are hugely better. GM should have "just said no".
Let me educate you. These vans are heavy. They have a relatively small engine. In a lot of driving conditions, they do not create enough vacuum for consistent safe braking. That is why they have a hydroboost system, it is better and stronger. It is also a safety factor. That is why they are,and have been , used on even light duty trucks,for many years,3/4 ton and up, and lots of diesels. I think a Astro hydroboost is even a drop in replacement for some Fords.
Now if you really don't like it, there is a company that makes a standard vacuum booster system for them, but if you have big tires/awd/4wd or a hot rod engine, you won't like it, and will be forced to buy the optional vacuum pump, so you still have acceptable brakes.
 

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2003 Safari
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My E350 is 5800lbs empty, more than an Astro with a full load. It has a 5.8 with a vacuum booster and stops well with a ~2200lb load. Lots of meduim-weight trucks have vacuum boosters and no vacuum pump. So weight-wise, these don't need a hydroboost at all. I may not know Astros in particular but I'm no mechanical newbie having made a living in past times working on everything from motorcycles to 18-wheelers. On the lack of engine vacuum, every vacuum-boosted diesel uses a vacuum pump and there's plenty of those on the roads, so I don't see that as a good reason either.

Just a difference in how we see things I think :cool: Where it works I prefer simplicity and discrete systems which usually give you fewer chances of a single-point failure causing larger or more widespread problems. My Safari has a hydroboost and so be it. I'll learn the thing whether I like it or not because it's there and it works, and because I don't intend to do any mods or upgrades other than for weight-carrying reasons since I'll normally have a full load on board.

In time everything which normally wears will get replaced or rebuilt on my Safari if I keep it around long enough- I just like my 'keeper' vehicles that way.
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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Just a difference in how we see things..
Apparently a difference in how manufacturers see things too. Hydroboost (of some sort) has been introduced as an improvement in many vehicles, and for good reasons such as Bob mentioned too.

My rear drum brakes are capable of fully engaging 100% (and full lock up) on hard stops.. but NO ONE is going to dispute that 4-wheel disc brakes are an overall improvement. You won't find too many switching back either.

My carburetor can be tuned to make relatively similar top-end horsepower as any fuel injection system, but no one is going to dispute that fuel-injection is an improvement as well.

No doubt vacuum assist brakes are more than capable of stopping any size vehicle... and under normal conditions they typically work fine. But there ARE reasons this system was improved upon.

My vacuum-assist 92 has terrible braking at idle and low speeds (to the point of being dangerous), but it also has poor vacuum a low-rpms due to performance cam-overlap. I know how to muscle it if need be, and is fine otherwise. This however, is an exception to the rule and this discussion.

Don't get me wrong... I love "old-school" and usually prefer it for it's simplicity and reliability. But I also understand technology improves over time. They didn't switch to it because it was cheaper. Hydroboost is capable, better control, overall reliable, and here to stay.
 

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2003 Safari
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When you lose brake effectivness, steering becomes your lifeline. When you lose steering effectiveness brakes become your lifeline. I see little wisdom in a more complex system where it's failure can affect both. And no, my 91 E150 is much older with a vacuum booster and a discrete PS pump. Loss of one system does not affect the other.

I'm not a luddite against new technology. I just see realistically and recognize when it's not living up to it's claims. My 94 Buick had over 300 wires involved to make it work, my 52 Ford pickup maybe 20. The Buick was awesome once I got all the bugs worked out and I wish I still had it, but a split PS hose spraying onto an exhaust manifold put it to a fiery death :( I'd hoped that my Safari would be cut from the same cloth but it seems it isn't. No big deal as long as it can be made reliable and will haul me and my tools around. If it turns out otherwise it will go away and something better will replace it.
 

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2003 Safari AWD
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My wife tested my work on the power steering return line/filter/cooler during the start of the blizzard, at night. I used a non-barbed fitting and it popped off. She did great! Called me, told me she lost power steering and brakes and said she was bringing it home! 👱‍♀️

What an f'n mess too.
 

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Discussion Starter · #19 ·
Well….OP here. Found some nice rolled edge high quality hose clamps and re-worked the blown off return hose. All went well for almost a mile, then the return hose blew off the cooler line! Much smoke ensued as the open line was pretty much aimed at the exhaust and radiator fan (shroud off for test drive) giant mess again, and a slow careful drive home with no power steering or power brakes.

At least it blew off on the way to the car wash rather than after!!

I'm thinking the filter I installed the first time around wasn’t actually bad, it was just the weakest link. 2nd time the return hose blew off the pump, and now 3rd time blew off the cooler tube. Such a huge mess

Next I think remove and replace the just replaced pump. Can’t really be anything else at this point….hopefully
 
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