ray42

Just recently got a 1998 Z-28, to replace a stolen 1994 Trans Am. This "new to me" Z28 is very good in most ways, but it takes respectable effort to steer, not at all normal. Even manual steering would be easier, at highway speeds. The power steering pump started leaking, then the pump's main seal blew out. A new power steering pump was installed. Then the high-pressure hydraulic hose blew out, and that got replaced. It all works now, but I still have the original problem; the effort needed at the steering wheel is high, even at highway speeds. We put the car up on a wheel-alignment rack, and "unpinned" the front wheel pivot plates.. The mechanic, under the lift, was able to turn the front wheels left and right by hand, so I believe the front suspension is all good, but maybe I have a steering rack with a hydraulic problem. I have never heard of such a problem (no leaks but very stiff steering). Before I plow big bucks into a new (or rebuilt) hydraulic steering rack, is there anything else I should check?. I'm hoping that somebody here has an idea. Thanks.

Injuneer

Wish I could get specific, but not a problem I have run into. In the meantime, I would suggest that you download the 1998 factory service manual and look at Volume 2 of 3. The first section is "STEERING" and there are diagnostic guides. For example, on page 2-13 there is a chart for "The steering is hard".

Free download courtesy of GaryDoug:

http://www.mediafire.com/?40mfgeoe4ctti

ray42

Fred,

Yeah, me neither. Well, there's not much else there to replace, except the rack itself. I think a good (used) rack would probably cost me less than replacing the valving in there. It just seems odd that the steering is stiff to both sides. That would usually say "bad hose" to me, except I just got a new hose in there. Thought I should ask, anyway.

Gotta say, you and this forum are a great resource for knowledge for the average Z28 owner. I see lots of good stuff here. Thanks.

DrewHMS97SS

I just replaced my rack with a re-manufactured rack from O'Reilly auto parts about a year ago and think I paid $180. It's not the steepest cost, but having to get an aliment on top of that is a bit annoying.

Injuneer

From the manual, seems like testing the system pressure is important. Who knows how good the rebuilt pump is?

DrewHMS97SS

Good point. I think it would be rare to have zero change in difficulty going from a known bad pump to a rebuilt, but it's entirely possible. You're right though, this is exactly the type of situation where full testing prevents throwing money at parts.

ray42

There was a slight improvement between the old pump (which actually worked until the PS pump main seal blew out) and the new pump. The new pump promptly blew out the old high-pressure hose, so I believe the new pump's output pressure is now sufficient. I do not have a way to measure that pressure, though.

My Z28 came with the standard power steering from the factory, not the high performance option. Chevy no longer produces a new steering rack for my 1998 Z28.

The steering rack was next to be replaced. The old steering rack input shaft could not be rotated by hand, once out of the car. The new rack input shaft was much easier to turn by hand, before installation.

Final result, so far: Steering effort is greatly reduced now, but still somewhat heavier than I expect from new (rebuilt) components.

Advice is certainly welcome, here.
.

DrewHMS97SS

That is definitely an issue. With nothing connected to the rack, you should definitely be able to turn it by hand.

After everything was replaced, did you bleed the new rack? If I remember correctly, with the car running, you need to turn the wheels hard over back and forth about 25 times. You will need to monitor the fluid in the reservoir as you do this. If you have help, watch the reservoir for bubbles and continue the process until no bubbles are present.

ray42

Drew,

Done and done. Thanks, man.

No more bubbles, and no leaks. It's really not terrible (as it was) but my full-sized 4x4 Blazer is still easier to steer, even when stopped.

DrewHMS97SS

Easy is relative. If you can one handed without struggle turn the wheels over at a stop, I would say it's doing it's job. These cars take a ton of effort to turn a power rack when the pump is not working. Not all cars are the same, so comparing doesn't really work. Which tires are wider? What is the PSI in the tires, and what is the tread pattern? More tread contact with the ground, wider tires, or lower PSI in the tires can all impact the resistance on the wheel. The gearing in the racks could also be different.

ray42

Drew,

The big 1991 Blazer (1500 Silverado) has much wider tires and more weight on those front tires, at the same PSI. My Z28 steering unit now is definitely doing work, but maybe not as easy as it should be, for the driver. I am also comparing to memories of my (stolen) 1994 Trans Am steering effort. What I have now is somewhat heavy steering in the Z28, but it is not terrible. I'd still be looking for a problem, but I don't know what else there could be wrong.
.

DrewHMS97SS

The ratios could still be different between the racks. What kind of PS fluid did you use? I run Redline in mine.