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  #11  
Old 05-03-2010, 02:17 AM
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496BBC 496BBC is offline
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Well I found out that I have a 2.5 gpm and 900psi valve in my pump.

Now the question is were can I find the correct fitting for my needs?

Can I just go by the junk yard and take one apart and rob the fittings form it. The question will be what type of vehicle to look for and what parts will I need to get?

Can I drill the fitting in the pump I have? What will this do for the pressure. Sounds like the pressure and flow are set with different parts in the pump.

Looks like I'm looking for 1200psi with 3 plus gpm flow.

Any help out there is much appreciated.

Neal
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  #12  
Old 05-03-2010, 12:20 PM
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Originally Posted by 496BBC View Post
Well I found out that I have a 2.5 gpm and 900psi valve in my pump.

Now the question is were can I find the correct fitting for my needs?

Can I just go by the junk yard and take one apart and rob the fittings form it. The question will be what type of vehicle to look for and what parts will I need to get?

Can I drill the fitting in the pump I have? What will this do for the pressure. Sounds like the pressure and flow are set with different parts in the pump.

Looks like I'm looking for 1200psi with 3 plus gpm flow.

Any help out there is much appreciated.

Neal
I thought I commented that in MY case I felt the stock pump valving for a shark was fine for the rack, works well, I would at least try it seeing what you think....

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  #13  
Old 05-03-2010, 11:38 PM
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496BBC 496BBC is offline
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I don't have the stock valving for the vette.

GM used a higher flow and relief pressure, this pump is set up for a Ford rack using lower flow and pressure, somethings Zoops didn't tell me when I ordered this setup. They do offer a pump with GM stock flow and pressure settings now and are checking if they have the parts to upgrade my pump.

Reading on the KRC site and talking with their tech dept a higher flow as GM used would more than likely resolve my issue "pump catch" per the KRC site.

From the KRC site;

Larger flow valves are required when using steering quickeners or 3.4 inch per revolution or faster rack-and-pinions. If you run on smaller tracks, a larger flow valve can give you more assist through the tight corners. Cars with wide tires and a lot of positive caster may also require more fluid flow. If you drive into the corner and feel as though the steering has a slight catch to it, commonly called "pump catch", a larger flow valve may be required.

When I apply the brakes and turn the wheel I can feel a slight catch.

Pump relief pressure may not need to be adjusted, KRC tech suggested increasing the flow and see what happens.

The only issue is they don't think the GM type II has an adjustable flow fitting and indicated that their fitting won't work with this pump.

I've had this setup on the car for a couple years now and while this issue is not a major issue its something I want to resolve and get the feel I'm looking for.

Neal

Last edited by 496BBC; 05-04-2010 at 09:46 AM..
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  #14  
Old 05-04-2010, 02:34 AM
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Something doesn't sound right. A Hydroboost unit works like a vacuum booster. There is a small nitrogen filled canister that accumulates fluid from the pump when the brakes are not being used (just like a vacuum booster gets it's vacuum "charge" when the brakes are not being used). So there is no demand from the pump when your brakes are depressed, in fact, the supply port is shut off IIRC. This is why a properly functioning Hydroboost will supply assist for 1 or 2 applications of the brake with the engine (pump) off.
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  #15  
Old 05-04-2010, 11:16 AM
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Originally Posted by BBShark View Post
Something doesn't sound right. A Hydroboost unit works like a vacuum booster. There is a small nitrogen filled canister that accumulates fluid from the pump when the brakes are not being used (just like a vacuum booster gets it's vacuum "charge" when the brakes are not being used). So there is no demand from the pump when your brakes are depressed, in fact, the supply port is shut off IIRC. This is why a properly functioning Hydroboost will supply assist for 1 or 2 applications of the brake with the engine (pump) off.
No it don't....I don't understand your question/statement, I suppose....

if you look at the diagram of my '72/early shark vac booster, you find a spring between the input and output shafts...it's a tough little bastard like a valve spring on steroids....but it's a spring, after all.....

the HB has nothing like that, the shafts are solid from input to output, there is a valve that hung up on me due to whatever/rust/storage on a unit I put in a camper/motor home last week, and it's fixed now, solid as a rock...

the feel of a HB is totally confident over any vac booster I have ever driven...

IMO...vacuum sux...no other way to describe it....

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  #16  
Old 05-04-2010, 10:21 PM
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Shark,

if I rmember correctly you can get the HB without the reserve.

Neal
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  #17  
Old 05-05-2010, 01:19 AM
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All the hydraboosts have an accumulator, most have the external gas filled cylinder but some have an internal one inside the piston and some are spring loaded and not gas.

When you apply the brakes the pump fluid is used by the HB first and the steering gets the residual.

The proper way to plumb the return lines is to have 2 separate ports into the resevoir, some kits that used pressure lines and jic fittings with a tee didn't always work in all situations. The rather tiny holes in some of those fittings can actually work like an oriface and restrict flow.

If you are using a tee in the returns, that would be a good place to start.
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  #18  
Old 05-05-2010, 12:20 PM
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I have a T in both installs, and yes, I used 1/4" ID fittings to keep flow up...the hose is 3/8.....

I did note that the HB on the vette had a normal looking pin on center to hit the m/cyl piston....never took that one apart....

but the one on the M/Home is different, that pin and surround came off the old vacuum booster, modified the length to fit the install, works fine, the piston looked hollow with a 1" hole in the center, sorta strange, but when looking them up from various applications, what I got for the vette chanced to be just what it would be for in applications at the parts house...similar weight vehicle, the one I got for the camper I got lucky again, and got what looks like for a large truck....dumb luck, I never knew any differences....

look at the options on that from O'Reilly AP.....
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