Power Steering Pump Pressure

I’ve got a Chevy LT1 in my 1991 XJ40. All is well but for the fact that I’m on my 3rd steering rack. So - I’m convinced that the Chevy power steering pump is producing too much pressure for my Jaguar steering rack. Does anyone know what the power steering pump pressure to the rack is supposed to be for a 1991 XJ6 Jaguar? I’m thinking I just need to restrict the Chevy pump’s pressure down to match the factor rack’s expected input.

Can’t speak to that application. My 83 is LT1 powered and uses the pump in conjunction with the Jag rack.
So far, no issues. I have vague recollections that the Lt1 pump and my rack are pressure compatible. But that an earlier GM pump might not be. And, your car probably has a different rack. Sounds as you are on to something.

I have two suggestions:

  1. Contact Andrew Weinberg at Jaguar-Specialties.

Good guy and ahs made or consulted in almost all versions of conversions. Yours is most likely familiar to him.

  1. I enjoy the work of the various mechanics on You Tube. One of my favorites is “Iron Thumper”. A fellow and his mate in the UK!! They repowered an ancient Soviet army truck. A ZIL. with a 12 valve Cummins diesel. Included were the aventures of the power steering. that included an adjustable pressure regulator. . It had a guage to exhibit the PSI and enable an adjustment. he did too much and the box blew an oil ring!!! Might think long that line…
    but how much??? Somewhere on line might indicate the workig psI for the XJ40 rack.


Thank You Carl! I spoke with Andrew, and viola - he had the answer to all of my questions and issues. He saved me a lot of time and dead-end diagnoses. Short answer - I’ve got the wrong pump on my engine.

I have similar worries about my PS pump set-up (5L Ford).
I do not know what type pump I have on the car, but it is not standard of course (“lump”), and was installed for convenience and not yet tested (car is STILL inop, awaiting numerous other hookups).

So, I’m wondering, is there a universal in-line external pressure regulator that could be installed regardless of pump make, along with a pressure gauge, such that I could back this down at a very low setting, and then gradually increase/adjust “to fit”.
Does such a thing exist?

Aye, see my prior post as to You tube’s iron thumper…

Yah, IronThumper has quite a few YouTube posts – at least 21 “Awesome” episodes of at least 30 minutes each. Very interesting, and I learned more about pipe organs than I ever wanted to know… BUT, they are quite an interesting crew!

Found one of their posts entitled " Project Drift - Electric Power Steering and Cooler Install" (at https://www.youtube.com/watch?v=YhjIRCISjNs ), but I don’t see where an adjustable pressure valve is mentioned.
Do you have the specific link for the P-control on IronThump/Zil b/c frankly, I don’t want to watch hours and hours of guys dicking around with something of minimal interest, ya know what I mean?

Yes, I do. but organs did interest me at one time. The organist at our church not only played stupendously, but also serviced, repaired and installed them.

As to thumper and his mate. A search of the posts on his channel . But, that might involve a message to them as to the source of the device. and, it is in the UK, and I don’t knw where you are, that might lead no where.

If in the USA, a Google search might find a source for a hydraulic pressure regulator.


Sure enough… plenty of PS pressure adjustment valves available – e.g., Heidts PS-101 Adjustable Power Steering Valve (no affiliation).
I imagine I could also just use a disc/drum brake proportioning valve, right?

Perhaps. But,. the bias is unknown and probably differs, car to car.

As you said earlier. Simplist, get the right pump. Rebuilds are not expensive. When I did my car,I found the threads were stripped in the one that came with my engine package. I could have gotten a used one from the source. I chose a rebuild… It wasn’t as hard as I expected to make the swap. .


I wound up buying a kit from Summit that reduced both the pump flow and maximum relief pressure.