Has anyone 'shimmed' their power steering pump?

[Dino]

I found this article and would like to try this. 

http://www.moparaction.com/tech/beep/PUMP_IT_DOWN-re-v1.4.pdf

Has anyone done this mod?

I don't have access to the car right now so what does a 69 Charger normally have, a Saginaw or a Federal pump?

I still plan on installing a firm feel stage 3 pump but this mod doesn't cost much so I thought it may be worth a try.

[1BAD68]

Interesting. I never heard of this but it makes sense.
I shimmed the relief valve in my John Deere front end loader which resulted in huge increase in how much weight it could lift.
This may be worth a try.

[PA Dodger]

I thought it was a great idea. I never liked the feel of the factory steering. I planned on doing this mod on my cars. But, then I talked to the folks at Steer and Gear about this mod when I saw them at the Nats last summer. They said " It was one of the most moronic ideas he's heard. The hydraulic system is designed to run within a specific pressure range and that lowering the pressure would be like lowering your car's voltage to make it run better."
I'm not a hydraulics expert so I can't argue with his logic.  I like R. Ehrenberger's tech articles, but I know some have turned out to be BS. So, I'll wait to see what the experts say.

I shimmed the relief valve in my John Deere front end loader which resulted in huge increase in how much weight it could lift.

Hopefully you don't find out the hard way what the safety factor of the lift cylinders is.

[Ghoste]

I think there is some bad blood between E'burg and Steer and Gear.

[BrianShaughnessy]

I think there is some bad blood between E'burg and Steer and Gear.

Maybe.......     Seeing as how I had to yank the SnG box out of the Savoy and replace it with a Firm Feel 

Otherwise,  Yes I did shim.   I used some brass washer from the hardware store that I ground down to fit.   Already have FF stage 2 box.   I didn't like the lack of assist in parking lot situations.    But I guess my pump was already on the way out cause it really died shortly thereafter.   Actually it was pretty dead by Carlisle.
So I got a new pump from autozone ( the correct oval version ) and just left the valving alone.   Rick likes yanking the wheel around...   me not so much. 

It's personal preference.   If you don't like the so called over assist... then try it.  It's easily reversible.   I'm not afraid to say I will never convert any car to manual steering either. 

Oh yeah... the pix in thar article.    I almost heaved getting thrown around in the back seat that day... no rear belts.     Trying to take a decent pic on a curvy azz road with only a rock wall barrier between a 100 foot cliff over the hudson river in a car driven by a nutso       It was near West Point on rt 218.

[PA Dodger]

I think there is some bad blood between E'burg and Steer and Gear.

This is exactly why I tend to take the " wait and see" approach. I couldn't argue S&G's reasoning but I don't expect to be led down the path just because someone is in a pissing contest.

Dino,
Here is good reference material on the subject. Sorry, it doesn't have what pumps were used on what year cars but it does mention the shims to reduce pressure. Apparently this trick can be done on the Federal pumps too but you have to take it apart to access the valve.
http://www.bigblockdart.com/techpages/pspumps.shtml

[Rolling_Thunder]

Yep - I have done it several times. I also have done it on the newer GM pumps. I first learned about it when I was working on some guy's 1967 Mustang he was taking out to Willow Springs - he was doing last minute stuff at his house and he asked me to do it and explained what it does...     good times.   

[chargerbr549]

I shimmed up my power steering pump on my 69 Charger and it worked great, I didn't even have to take the pump off the engine just unbolt the hipressure hose and take a wrench or a crows foot and unbolt the fitting to get at the spool valve, I had several saginaw pumps laying around so I robbed the shims out of those pumps and then experimented with different thicknesses until I found the amount of "feel" that I wanted, great and cheap upgrade.

Kevin

[Nacho-RT74]

I never have done it, But already did know about that. I like how feels mine at this moment

[Bigtree]

E-Burg's the man! Just do it!

[Dino]

Alright looks like this may be a worthwhile mod.  I don't think a firm feel pump is in the budget this year so maybe this will ease the waiting a bit.  The only time I fell that the steering is too loose is when I pass someone and go from 45 to 70 pretty fast while going around cars.  Sometimes it feels like the steering wheel is not connected to anything and at those times it gets a bit dicey.  Cruising or going straight on the highway I don't really care that it's so loose.

Thanks all!

[Tilar]

Interesting. I never heard of this but it makes sense.
I shimmed the relief valve in my John Deere front end loader which resulted in huge increase in how much weight it could lift.
This may be worth a try.

I've worked on heavy equipment and hydraulic systems all my life and you really need to excercise a lot of caution in doing something like this. A power steering system runs roughly 850 to 1000 pounds of pressure, where the system on your John Deere can run anywhere from 2000 pounds to as much as 5000 pounds and more depending on how big a unit you have. You go jacking that up to 3000 or 6000 lbs respectively and you can go above the rating of the framework of your loader or the working pressure of the hoses or pump that run the loader which can result in a serious injury or worse. Each .010 thick shim can raise the pressure as much as 50 pounds on a low pressure like a power steering system and 150 pounds or more per shim on a higher pressure system like the JD or any other equipment system.  

I've had people bring their equipment in to me after doing this with their hydraulic pump split open like a coconut.

These old power steering pumps can benefit from it because after 40 years they are generally weak, but you still need to be careful.  A small pinhole in a hydraulic/power steering hose can force hydraulic/power steering oil under the skin which can cause some really painful issues.

[resq302]

What I got out of the article was that if you shimmed the valve, it would drop the pressure not increase it.  This would cause it to act more like manual steering and not increase the pressure.

[BrianShaughnessy]

What I got out of the article was that if you shimmed the valve, it would drop the pressure not increase it.  This would cause it to act more like manual steering and not increase the pressure.

Correctamundo...    lower the pressure to reduce the over-assist that some people don't like.

[resq302]

Ok, thats what I thought but got confused when Tilar said that with each .10 thick shim, it raise the pressure by 50 lbs.

[Tilar]

I was referring to hydraulic systems and their reliefs, specifically 1BAD68 where he said he boosted his system on a John Deere tractor.  I've never messed with the shims on power steering units and just assumed they were like a small hydraulic system... Sorry for the confusion.

[1BAD68]

I completely agree that messing with hydraulic pressures can be asking for trouble. But in my case (I have a little loader), I put a gauge on and the factory pressure showed around 775psi and the loader could lift about 250lbs.
After shimming, the pressure showed 1250psi and could then lift 600lbs. The hoses are rated for 3000psi so I feel OK about it.
But your right about possibly blowing hoses and damaging equipment.

[Kern Dog]

I have the Stage 3 steering chuck in the Charger along with the Fast Ratio idler and pitman. The car feels like slightly assisted manual steering. Absolutely perfect, but pricey. The steering box rebuild was over $300 plus shipping and the fast ratio arms were over $200. These shims could be a cheap upgrade for guys that have chucks in good condition.
The consensus that I have read elsewhere is that a total of .100 to .125 of shims still allows a boost pressure adequate enough to steer at low speeds. I have a couple A body project cars here that will certainly get this trick.