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Power Steering and Brakes


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Guest
Anonymous Poster
n8brophy@hotmail.com

Feb 24, 2007, 11:19 AM

Post #1 of 3 (1693 views)
Power Steering and Brakes Sign In

So last night i was delivering this trailer in my Chevrolet Express 15 passenger van. When i get to the place and go to park the trailer my power steering stops working. and it takes a whole lot more effort to make the brakes work... almost like the vacuum line in the brakes broke...
the fluids are all fine... but im stumped. why would both go at the same time?


steve01832
Veteran
steve01832 profile image

Feb 24, 2007, 7:16 PM

Post #2 of 3 (1682 views)
Re: Power Steering and Brakes Sign In

If you have the 4.3 liter engine the brake assist comes off of the power steering. If you look behind the master cylinder you won't see the traditional round brake booster. It is one of GM's "better" designs. You should first check the power steering belt tension. If it's ok, then the pump may have failed.

Steve


DanD
Veteran / Moderator
DanD profile image

Feb 25, 2007, 6:02 PM

Post #3 of 3 (1673 views)
Re: Power Steering and Brakes Sign In

Oh Yea. I can just about picture what has happened to the system.
Like Steve said the power brakes on these vans use what is called hydra boost that the power brake assist comes from the power steering pump.
Why; because there’s a chance that under heavy load the engine will not make enough vacuum to run the vacuum power brake system if it were used.
These vans also have variable rate steering: EVO (electronic variable orifice) is its official name. Meaning that at lower speeds the steering can be turned with one finger for ease of parking lot manoeuvres: once above a certain speed the power steering assist is lowered making the steering wheel harder to move; giving better road feel.
With all this going on the poor power steering pump is working its arse off because it’s a positive displacement pump; in other words the pump, pumps as hard as it can all the time.
With EVO they restrict the fluid flow to the steering gear which makes the pump’s internal pressures soar and the effort to turn the pump go through the roof.
The end result is the pump’s driveshaft breaks because of all this effort to turn it.
The first one I came across you couldn’t see a physical problem with the pump, the pulley or belt; everything looked normal and in place.
What happen’s is the pump’s driveshaft breaks inside; behind the seal and the thing doesn’t produce any pressure.
Take the belt off and you’ll likely be able to pull the pulley and a portion of the pump’s driveshaft right out the end of the pump.
Dan.

Just rereading this; damn I’m long winded LOL but I didn’t know how else to explain what has likely happened.

Canadian "EH"






(This post was edited by DanD on Feb 25, 2007, 6:05 PM)






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