940 power steering question

[Aidan]

Hi folks, like most Volvo's I've driven, the steering on mine is somewhat heavy compared to typical US or Japanese steering, (its about right compared to other Volvo's) I'd like to get it a bit lighter. Basically its a case of increasing the fluid pressure, has anyone done this or know how to do it, I'm asuming its possible to alter something such as a pressure relief valve spring in the pump or rack??? I've had a search through the FAQ's etc but haven't found anything on this so any info would be much appreciated, thanks,
Aidan.
BTW, its a '95 940 SE wagon with an LT6 2.4TDic auto RHD

[v8volvo]

Likely a relief valve in the rack that you could fool with. There may be something with an orifice that you could enlarge, etc. However, like your other question about modifying the autobox's lockup speed, this would be a pretty radical, unusual thing to try, something that few or no people have attempted in the past to my knowledge and a lot of work and R+D for a pretty small change in how the car works... Might be better advised to learn to love your smooth, heavy Volvo steering. ;-) I agree it is sometimes a little more work than other cars for driving around town, but once you get on the open highway there is no finer steering wheel to be behind than that of a 700 or 900 series Volvo...

[Aidan]

Ordinarily I wouldn't bother but due to where I live and the type of roads I drive on it would be a very worthwhile task. I live in a very mountainous area and you can rarely drive more than a hundred yards without having to turn the wheel hard over, after 30 or 40 miles of that you do get a bit tired of it. I remember on some of the early 80's European Fords it was simply a matter of removing the check valve cover on the rack and take out a shim or two from under the check valve to make the steering lighter.

[v8volvo]

Could be the case. I have a Greenbook about re-habbing the steering racks on these, next time I am over where the manuals are I will take a look and see if it seems like something along those lines is possible.

[nick]

Aidan, my steering is stiffer than other vehicles I've driven too. I'm interested to find out a fix for it.

[Aidan]

Could be the case. I have a Greenbook about re-habbing the steering racks on these, next time I am over where the manuals are I will take a look and see if it seems like something along those lines is possible.

Thank you, that would be greatly appreciated.

[Aidan]

Aidan, my steering is stiffer than other vehicles I've driven too. I'm interested to find out a fix for it.

there is definately a way to do it, it's just a matter of finding out how. Centuries back when I did my apprenticeship at a UK Ford dealer, they used 1 rack across the model range with differing lenght arms depending on the model. When fitting new one's you would remove a certain number of shims to increase the power asist if fitting it to the bigger cars. Other manufacture's have different methods of setting the assist pressure so it can be done, just need the neccesary info.

[casioqv]

I'm not sure if it's possible, but the limited assist level was definitely an intentional design choice from Volvo to improve steering feel/feedback to the driver. Usually cars with significantly more assist have a totally different (worm and roller gear) steering system design as opposed to Volvos rack and pinion system.

[Aidan]

I'm not sure if it's possible, but the limited assist level was definitely an intentional design choice from Volvo to improve steering feel/feedback to the driver. Usually cars with significantly more assist have a totally different (worm and roller gear) steering system design as opposed to Volvos rack and pinion system.

I'm not looking to go ultra light, just enough to take the sting out of it would be fine, say a 10/15 per cent increase in assist. Irrespective of what system is in use, it has a means of regulating the assist pressure, such as valve's, springs, shims and the like, even just an orifice of pre determined size. It's just a matter of if you can get to it and alter the setting.

[nick]

Aidan, have you discovered a solution?

[Aidan]

No, not yet Nick, been trawling thru the internet trying to find the info but just getting bogged down in endless lists of companies supplying recon racks. Found plenty of sites offering free repair manuals but when you click the link all you get is a load of advertising crap. I'll keep trying and if I get anything I'll stick it here. If anyone has the info I would really appreciate it, thanks.

[nick]

I found two brief articles that I will probably try to implement soon (with pictures):

Saginaw Style Pump Mod (http://westtexasoffroad.homestead.com/powersteering.html)

Article by Jim Weed (No Pictures) (http://www.off-road.com/trucks-4x4/tech/boosting-your-power-steering-pump-19296.html)

If I find the setup is similar to the "Saginaw" article, then I will try to shim the spring similar to the "Jim Weed" article.

[Aidan]

Thats the type of article I'm looking for Nick, I'm not sure about cars sold in the states but from what I've been reading, apparently there are 4 different racks that were fitted to the 940's sold in Europe so I need to identify what one I have and then see what I can turn up. If I find anything usefull I'll let you know.

[Aidan]

Nick, I just found this article, sounds like what we're both looking for,,,

http://www.swedishbricks.net/700900FAQ/Steering1.html#Rack%20Identification

scroll down to "stiff power steering" near the bottom of the page

[Aidan]

Got it Nick, this is what we want,,,,

http://westtexasoffroad.homestead.com/powersteering.html

I'm going to try this at the week end on my old 740 first and see what the results are, if it works out ok then I'll do the same to the 940. I'll let you know how it turns out.

[nick]

Great! I'm excited to hear how it turns out for you. That looks like the same article I posted above (Post #12).

I don't think I have time to try it in my 760 this weekend, I'll probably have to wait until next week. I don't think I'm going to to drill anything, instead I'll just shim the spring to increase to the bypass pressure.

[Aidan]

Right, my 740 has a totally different pump so that blew that idea out, anyway, I decided to go ahead on the 940 and see what happens. I'll give a full run through of the procedure for anyone else wanting to try this. Before attempting this, make sure your pump and rack seals are good, if there is any sign of leaks it would be a good idea to get them done now as increasing the pump pressure could very well blow the seals out.

Ok, first place a clean container under the pump, clean the pump and run a wire brush around the fittings to remove any crap and muck. The fittings are very tight so use a spanner (or wrench as you yanks like to call them) to hold the high pressure fitting as you undo the feed line fitting otherwise the whole lot will turn and you wont be able to remove the feed line from the fitting
212

Once the feed pipe is removed, remove the high pressure fitting then use a magnet to draw out the pressure piston and then a pair of long nose pliers to remove the piston spring. This is what you'll have
213

and this is the part that you'll be working on, the pressure relief piston
214

the article that I gave a link to says to hold the piston in a vice,,, DONT, you'll fuck it up, instead use a pair of vice grips to hold it like this so that you dont damage the machined surfaces
215

also be aware that in the end of the retaining cap there is a very fine gauze filter so dont go poking around at it
216

remove the retaining cap, be very carefull as the cap is VERY tight so make sure you've got a good grip of everything. When the cap is loose undo it with your fingers and be prepared for it to fly off as there is quite a bit of spring pressure behind it.

[Aidan]

This is what you have inside the pressure piston. I had to borrow this pic as my camera decided to play silly buggers at this stage
217

Some pumps will have 1 or 2 shims as shown, other's wont, my one didn't. If you do have shims then remove one at a time and refit the whole lot to the pump and see how it is, if it gives you what you want, great, if not then you need to shim the spring that controls the pump pressure. basically what you do is get a couple of shims or washers and put them into the piston body then refit the spring, stud, ball bearing and cap. I used a couple of 6mm spring washers as they were a smaller diameter than the piston body, so that I could remove them easily if need be and also they wont restrict the fluid flow.
218

I used 2 pair of pliers to remove the "spring" from the washers so that they sit flat, the height of the 2 washers was just under 3mm.
219

The linked article says to grind off part of the stud to prevent it blocking fluid flow but I found that even with the spring fully compressed, the stud is still shorter than the spring so there is no way it can block off the fluid flow so I left the stud as it was.
220

Now fit everything back together, be carefull as there is now a lot more spring pressure on the retaining cap and it can be a bit of a pig to get it back in.
Refit everything to the pump, top up the fluid, start the engine and let it run to bleed any air out and to make sure you have no leaks.
Ok, time for a test run. Well, there was a slight increase in power assist but nowhere near as much as I was expecting, or hoping for,,, however, what I did find was the steering was a lot smoother, and no longer suffers from "kick back" when driving round a bend on a rough surface so it was much nicer to drive and the self centering action was a lot better than before so definately some improvement, but I still wanted it lighter so I thouyght I'd have a go at stretching the main spring that the piston rests against in the pump, although I didn't hold out much hope for any improvement to be honest. The spring in my pump was just under 2 inches long so I stretched it to 2 and a half inches, fitted it back in the pump and went for a drive,,,
221

Whoa, thats more like it now, a noticable improvement in the lightness of the steering, I can one finger it now quite comfortably under normal driving, and, there's no loss of road feel at all. So all in all, not too bad a result for 30 minutes work.

[nick]

Wow! Thanks for the write up Aidan. Now I'm even more excited about trying this on my 760!

[nick]

I just found this video for a Saginaw type pump like my 760: Here (http://www.youtube.com/watch?v=G0e7MlIPZt4). Skip to about 1:30 for the good info. At 2:00 the guy pulls out the pressure regulator.

[Aidan]

hahaha, what a doughnut, I love the way he just grabs a hammer and belts shit out of the housing and stuff goes flying everywhere, a real proffesional,,,