InstallAs mentioned, this is my second time running power steering and I’d already done the braising step to convert to a Vette pump when I first swapped my car. The output fitting of the F-body pump (upon which the Turn One pump is made) is different so I needed to procure an F-body power steering line. I bought that line from a local parts store. Here’s where I started component wise.
Factory fitment F-body hose on top, former PS hose on the bottom, Vette output fitting braised to the mating hose fitting on the left.
Here’s what is left of the F-body hose, now braised to the high pressure fitting end needed.
I pulled the exterior fitting shell of my hose since this hose was going to be a slightly different length and I wanted to show how these fitting go together anyways. (Note, all of the normal high pressure fittings I’m aware of are steel. Standard –AN aluminum fitting like you might use for an oil cooler are not appropriate as you’d like the devices to be rated well above the working pressures: ~1600 psi is the upper limit of most GM pumps we care about.)
The threads on the exterior part of my fitting (those threads which engage the OD of the hose) were left hand threaded aka opposite from normal tightening direction so you may want to check for that.
You first screw the exterior fitting onto the outside of the hose. This takes some gusto because the high pressure hose is a stiff mother with steel braids that don’t really want to be compressed into a smallish hole. Once it’s on, you then screw in the internal fitting piece. There’s a second set of thread in the tip of the exterior fitting which will pull this down into position. The hose will be wedged into the taper between exterior and interior sections of fitting.
Before you actually install the fittings you need to verify length of the line via a test fitment on the car. Here was my assembly for trial:
Hardware was only hand tightened at this point, but this was enough to prove that this bolts up nice, aims the hose in a generally happy direction. As mentioned a 90 deg AN -6 fitting would be a good starting point as well.
You want to verify this yourself on your car as fitting selection and engine mounting kit used both mater. Power steering works great with both Ronin Speedworks and Samberg mounts.
Moving on…
Now it’s time to cut hoses to length. When cutting any kind of braided hose, I wrap the outside in electrical tape to keep it from fraying and use a cut off wheel (the kind made for cutting metal) on an angle grinder. You’ll want to cut right through the middle of the tape so you leave some tape on both sides. Take your time to keep it neat and square and be careful because the hose may want to snag and pull. Use of a vice and two hands on the grinder is recommended. Note this type of cut will result in rubber dust getting inside the hose, but we’re going to flush before final install so it’s ok.
Now that hoses cut to length you can install the fittings. The below shot is just about fully installed (Note they tell me a 1/16” gap between housing and wrench hex on the core is about right).
The internal fitting will be damn hard to turn at this point. There’s a lot of friction going on. You can see the braising at this end as well. Before you take the fitting all the way tight you need to do one more fit check. This time, we need to check the “clocking” of the ends. The high pressure hose is so stiff that it’s unforgiving in twist. You need to hit the right angle and hit it right on so the banjo can lay flat against the quill housing.
This is a good time to talk about variations in Mazda racks. In the above shot, you’ll notice that my Mazda rack has two holes at the quill housing. This was the standard 17:1 ratio steering rack which is also the more common of power steering racks available for FC RX7s. However, see the suspicious looking blank at the bottom of the quill? That was for a variation of FC which used a three hole rack, came with speed sensitive steering and had additional valving to hook up a third hydraulic interface to the rack. There was a dedicated controller to run that. GM doesn’t have any of those options, so if you do have a three hole you need to plug that front most hole with a bolt and thread tape to have this function.
That said, the assist for the 15:1 ratio was intended to be disabled at speed; that’s how the speed sensitive part worked. Since we can’t, you end up with a car that can be twitchy at speed. I’ve never run it that way, but I’ve heard very strong opinions from folks who have, Charlie Shatzen of Mazcare being one such voice of experience. To paraphrase Charlie… on the off chance you have a “three hole rack” (which is what the 15:1s are usually referred to as), do yourself a favor and sell it. You really want the 17:1 ratio.
Since we’re talking about racks and details thereof, if you removed or need to replace the hardlines which run from the steering shaft quill to each the two inputs on the rack itself, they’re oriented as follows.
FC
FD is the same idea
None of the three pics above are mine, but the 17:1 rack I bought had its hardlines cut during junkyard removal by the gent I bought it from, so figured this info might be helpful. In both FC or FD the port on the rack closer to middle of rack connects to the port closer to the splined steering column input at the quill.
Note, if the hardlines on your rack are reversed it’ll set up a crazy feedback loop where your steering wheel jumps side to side.
