early C4 steering rack ID
 

I have 4 Z51 steering racks. 1 from an 84 and 3 from 86. 3 out of the 4 have all aluminum housings, and 1 rack has a cast steel section for the pinion shaft and the fluid line connections. Is this an aftermarket rack of some sort or were there more than 1 manufacturer of oem steering racks? I need to know if this steel housing rack is any good and worth spending the money on to have rebuilt.

The early rack & pinion gears were all aluminum. They also had an issue with spool valve seal leakage causing lack of assist cold " morning sickness". Spool valve bore could wear. Aftermarket rebuilders were installing SS sleeves in spool bore. The metal housing unit would be repairable depending on condition after disassembly. IDK where the best to send them.

But is the steel unit an OEM or an aftermarket?

The cast iron housing is an OEM unit built for the 88-96 model years. If you got it off of an earlier model year, then the original was replaced at some point with the later model rack.

Thanks,
Junior
Turn One

Were there any markings or identifiers identifying a Z51 rack from a non Z51 rack other than the turns lock to lock?

From the factory, the racks had a broadcast code on the dust cover opposite the input shaft. However, those covers are not rack specific and can be interchanged from rack to rack without issue. Counting the turns lock to lock would be your best bet to know for sure what you have.

Thanks,
Junior
Turn One

Put a pair of locking pliers on the input, turn and count the revolutions from lock to lock.

You will need to look it over, aftermarket (new) would not have GM markings. GM did redesign racks, the "Top Hat " with iron spool valve housing in mid eighties.

The 2 letter code on the dust cap, AK on 84 rack and WT on 86 rack are Z51 codes. Don't rely on that 100% because the caps can be interchanged.

I had read somplace earlier that later model racks were a different length. This rack measures same as aluminum 86 rack.

We have a C2 restomod with SRIII aftermarket chassis, C6 suspension, C4 rack. 18x9 front w/ 275's. Plenty of fender clearance to gain more. Turning radius is terrible. Handles in normal street driving but parking, driveway maneuverability, etc. very bad. 3-point turns. Any suggestions for swap out or rack modifications given our setup?